[go: up one dir, main page]

WO2018146579A1 - Élément de conversion photoélectrique, dispositif d'imagerie, dispositif électronique et procédé de production d'un élément de conversion photoélectrique - Google Patents

Élément de conversion photoélectrique, dispositif d'imagerie, dispositif électronique et procédé de production d'un élément de conversion photoélectrique Download PDF

Info

Publication number
WO2018146579A1
WO2018146579A1 PCT/IB2018/050578 IB2018050578W WO2018146579A1 WO 2018146579 A1 WO2018146579 A1 WO 2018146579A1 IB 2018050578 W IB2018050578 W IB 2018050578W WO 2018146579 A1 WO2018146579 A1 WO 2018146579A1
Authority
WO
WIPO (PCT)
Prior art keywords
layer
selenium
photoelectric conversion
sample
electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/IB2018/050578
Other languages
English (en)
Japanese (ja)
Inventor
山内諒
川田琢也
太田将志
堅石李甫
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Semiconductor Energy Laboratory Co Ltd
Original Assignee
Semiconductor Energy Laboratory Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Semiconductor Energy Laboratory Co Ltd filed Critical Semiconductor Energy Laboratory Co Ltd
Priority to JP2018566658A priority Critical patent/JPWO2018146579A1/ja
Publication of WO2018146579A1 publication Critical patent/WO2018146579A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/20—Deposition of semiconductor materials on a substrate, e.g. epitaxial growth solid phase epitaxy
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F30/00—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors
    • H10F30/20—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors
    • H10F30/21—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors the devices being sensitive to infrared, visible or ultraviolet radiation
    • H10F30/22—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors the devices being sensitive to infrared, visible or ultraviolet radiation the devices having only one potential barrier, e.g. photodiodes
    • H10F30/225—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors the devices being sensitive to infrared, visible or ultraviolet radiation the devices having only one potential barrier, e.g. photodiodes the potential barrier working in avalanche mode, e.g. avalanche photodiodes
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F39/00—Integrated devices, or assemblies of multiple devices, comprising at least one element covered by group H10F30/00, e.g. radiation detectors comprising photodiode arrays
    • H10F39/10—Integrated devices
    • H10F39/12—Image sensors

Definitions

  • One embodiment of the present invention relates to a photoelectric conversion element, an imaging device, and an electronic device.
  • one embodiment of the present invention is not limited to the above technical field.
  • the technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method.
  • one embodiment of the present invention relates to a process, a machine, a manufacture, or a composition (composition of matter). Therefore, the technical field of one embodiment of the present invention disclosed in this specification more specifically includes a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a memory device, an imaging device, An operation method or a manufacturing method thereof can be given as an example.
  • a semiconductor device refers to any device that can function by utilizing semiconductor characteristics.
  • a transistor and a semiconductor circuit are one embodiment of a semiconductor device.
  • a memory device, a display device, an imaging device, and an electronic device may include a semiconductor device.
  • CMOS complementary metal oxide semiconductor
  • the area of the pixel When the area of the pixel is reduced, the area of the light receiving portion of the photoelectric conversion element included in the pixel must be reduced. When the area of the light receiving portion of the photoelectric conversion element is reduced, the sensitivity to light is reduced, so that imaging under low illuminance may be difficult.
  • Patent Document 2 As a method for forming a photoelectric conversion layer using crystalline selenium, a method of crystallizing amorphous selenium after forming amorphous selenium on a substrate and forming a film such as an electrode thereon is considered.
  • amorphous selenium is crystallized by heat treatment, a film peeling region may occur, and there is a problem that uniform and high-quality crystalline selenium cannot be obtained.
  • Patent Document 2 it has been proposed to select an appropriate heating method and temperature
  • Non-patent Document 3 a method for forming a photoelectric conversion layer using crystalline selenium.
  • Patent Document 3 discloses an imaging device in which a transistor including an oxide semiconductor and having extremely low off-state current is used for a pixel circuit.
  • the conventional image sensor In order to increase the resolution of an image sensor, it is necessary to reduce the area per pixel. Since the reduction of the pixel area is accompanied by the reduction of the light receiving area of the photoelectric conversion element, the photosensitivity is lowered. In particular, in imaging under low illuminance, the S / N ratio of imaging data may be significantly reduced. That is, the conventional image sensor has a problem that the resolution and sensitivity are in a trade-off relationship.
  • One solution to the above problem is to use a photoelectric conversion element using an avalanche multiplication effect with high photosensitivity.
  • crystalline selenium when used for a photoelectric conversion layer, when amorphous selenium is crystallized by heat treatment, a film peeling region may occur due to aggregation of selenium accompanying crystallization. If a film peeling region exists, it may cause variation in characteristics of the photoelectric conversion layer. Further, in an imaging device having a high resolution, since the area per pixel is small and the area occupied by the photoelectric conversion element is small, the influence of variations caused by one photoelectric conversion element becomes larger. That is, this causes variations in the photoelectric conversion elements of the respective pixels, resulting in a problem that the imaging performance of the imaging apparatus is lowered.
  • an object of one embodiment of the present invention is to provide a photoelectric conversion element with high photosensitivity. Another object is to provide a photoelectric conversion element having uniform crystal selenium with few film peeling regions. Another object is to provide an imaging device with little variation in characteristics. Another object is to provide a method for manufacturing a photoelectric conversion element having uniform crystalline selenium with few film peeling regions. Another object is to provide a method for manufacturing an imaging device with little variation in characteristics. Another object is to provide an imaging device that can easily perform imaging under low illuminance. Another object is to provide an imaging device with low power consumption. Another object is to provide an imaging device with high resolution. Another object is to provide a highly reliable imaging device. Another object is to provide a novel imaging device. Another object is to provide a novel method for manufacturing an imaging device. Another object is to provide a novel semiconductor device or the like.
  • One embodiment of the present invention includes a first electrode, a second electrode, and a photoelectric conversion layer provided between the first electrode and the second electrode.
  • the photoelectric conversion layer contains selenium and the element X.
  • the element X is a photoelectric conversion element that is one or more selected from silver, bismuth, indium, tin, or tellurium.
  • the ratio of the number of atoms of the element X to the number of atoms of selenium (X / Se) is 0.0010 to 0.70.
  • the element X is more preferably one or more of silver and bismuth.
  • One embodiment of the present invention includes a first electrode, a second electrode, and a photoelectric conversion layer provided between the first electrode and the second electrode.
  • the photoelectric conversion layer includes crystalline selenium.
  • a photoelectric conversion element having a stack of a layer and an amorphous selenium layer.
  • One embodiment of the present invention includes a first electrode, a second electrode, a hole injection blocking layer, and a photoelectric conversion layer, and the hole injection blocking layer includes the second electrode and the photoelectric conversion layer.
  • the photoelectric conversion layer is provided between the first electrode and the hole injection blocking layer, and the hole injection blocking layer and the photoelectric conversion layer have a region in contact with each other;
  • the electrode has translucency, the hole injection blocking layer has an oxide containing indium and gallium, and the photoelectric conversion layer has a stack of a crystalline selenium layer and an amorphous selenium layer. It is an element.
  • the amorphous selenium layer preferably has a region in contact with the hole injection blocking layer.
  • the crystalline selenium layer is preferably thinner than the amorphous selenium layer.
  • the thickness tn of the hole injection blocking layer is preferably 5 nm or more and 20 nm or less.
  • an alloy layer of silver and selenium is preferably provided between the photoelectric conversion layer and the first electrode.
  • a crystalline selenium layer is preferably provided between the silver and selenium alloy layer and the first electrode.
  • One embodiment of the present invention is an imaging device including, in a pixel, the above-described photoelectric conversion element and a transistor including a metal oxide in a semiconductor layer.
  • the metal oxide preferably includes In, Zn, and M (M is Al, Ti, Ga, Sn, Y, Zr, La, Ce, Nd, or Hf).
  • One embodiment of the present invention is an electronic device including the above-described imaging device and a display device.
  • One embodiment of the present invention includes a step of providing a base layer containing the element X over the first electrode, a step of heating the base layer to provide a layer containing selenium on the base layer, and a layer containing selenium And a step of providing a second electrode, wherein the element X is one or more selected from silver, bismuth, indium, tin or tellurium.
  • the first electrode is heated to provide a layer containing selenium and the element X over the first electrode, and the second electrode is provided over the layer containing selenium and the element X
  • the heating temperature is preferably 50 ° C. or higher and 90 ° C. or lower.
  • One embodiment of the present invention includes a step of providing a base layer containing the element X over the first electrode, a step of providing a layer containing selenium on the base layer, and a step of performing a first heat treatment on the layer containing selenium. And a step of performing a second heat treatment at a temperature higher than the first heat treatment to form a layer having crystalline selenium, and a step of providing a second electrode on the layer having crystalline selenium, X is a method for producing a photoelectric conversion element that is at least one selected from silver, bismuth, indium, tin, or tellurium.
  • One embodiment of the present invention includes a step of providing a layer containing selenium over the first electrode, a step of providing a base layer containing the element X over the layer containing selenium, and a first heat treatment for the layer containing selenium.
  • the element X is a method for producing a photoelectric conversion element that is one or more selected from silver, bismuth, indium, tin, or tellurium.
  • the first heat treatment is preferably 50 ° C. or more and 90 ° C. or less
  • the second heat treatment is preferably higher than the temperature of the first heat treatment and 70 ° C. or more and 220 ° C. or less. .
  • the element X is more preferably one or more of silver and bismuth.
  • a photoelectric conversion element with high photosensitivity can be provided.
  • a photoelectric conversion element having uniform crystal selenium with few film peeling regions can be provided.
  • an imaging device with little characteristic variation can be provided.
  • a method for manufacturing an imaging device with little variation in characteristics can be provided.
  • an imaging device that can easily perform imaging under low illuminance can be provided.
  • an imaging device with low power consumption can be provided.
  • an imaging device with high resolution can be provided.
  • a highly reliable imaging device can be provided.
  • a novel imaging device can be provided.
  • a novel imaging device manufacturing method can be provided.
  • a novel semiconductor device or the like can be provided.
  • one embodiment of the present invention is not limited to these effects.
  • one embodiment of the present invention may have effects other than these effects depending on circumstances or circumstances.
  • one embodiment of the present invention may not have these effects depending on circumstances or circumstances.
  • Sectional drawing explaining the structure of a photoelectric conversion element Sectional drawing explaining the manufacturing method of a photoelectric conversion element. Sectional drawing explaining the manufacturing method of a photoelectric conversion element. Sectional drawing explaining the manufacturing method of a photoelectric conversion element. Sectional drawing explaining the manufacturing method of a photoelectric conversion element. Sectional drawing explaining the manufacturing method of a photoelectric conversion element. Sectional drawing explaining the manufacturing method of a photoelectric conversion element. Sectional drawing explaining the manufacturing method of a photoelectric conversion element. Sectional drawing explaining the manufacturing method of a photoelectric conversion element. The figure which shows the structure of a photoelectric conversion element. The figure which shows the structure of a photoelectric conversion element. Sectional STEM image of the selenium layer. The figure which shows the electrical property of a photoelectric conversion element. 3A and 3B illustrate a band structure of a photoelectric conversion element. The figure which shows the electrical property of a photoelectric conversion element.
  • FIG. 1 is a diagram illustrating a configuration of an imaging device.
  • the block diagram of an imaging device Sectional drawing which shows the structure of an imaging device. Sectional drawing which shows the structure of an imaging device. Sectional drawing which shows the structure of an imaging device.
  • 10A and 10B each illustrate an electronic device. Sectional drawing explaining the sample of Example 1 and Example 2.
  • FIG. 1 is a diagram illustrating a configuration of an imaging device.
  • the block diagram of an imaging device Sectional drawing which shows the structure of an imaging device.
  • Sectional drawing which shows the structure of an imaging device.
  • 10A and 10B each illustrate an electronic device. Sectional drawing explaining the sample of Example 1 and Example 2.
  • FIG. 2 is a planar SEM image according to Example 1.
  • FIG. 2 is a planar SEM image according to Example 1.
  • FIG. 2 is a planar SEM image according to Example 1.
  • FIG. 2 is a planar SEM image according to Example 1.
  • FIG. 2 is a planar SEM image according to Example 1.
  • FIG. 2 is a planar SEM image according to Example 1.
  • FIG. 2 is a planar SEM image according to Example 1.
  • FIG. 2 is a planar SEM image according to Example 1.
  • FIG. 2 is a planar SEM image according to Example 1.
  • FIG. 2 is a planar SEM image according to Example 2.
  • FIG. Sectional drawing explaining the sample of Example 3. FIG. The XRD spectrum which concerns on Example 3.
  • FIG. 4 is a planar SEM image according to Example 3.
  • FIG. 4 is a cross-sectional STEM image according to Example 3.
  • FIG. 4 is a cross-sectional STEM image according to Example 3.
  • FIG. 4 is a cross-sectional STEM image according to Example 3.
  • FIG. 4 is a cross-sectional STEM image according to Example 3.
  • FIG. 4 is a cross-sectional STEM image according to Example 3.
  • FIG. 4 is a cross-sectional STEM image according to Example 3.
  • FIG. 4 is a cross-sectional STEM image according to Example 3.
  • FIG. 4 is a cross-sectional STEM image according to Example 3.
  • FIG. 4 is a cross-sectional STEM image according to Example 3.
  • FIG. 4 is a cross-sectional STEM image according to Example 3.
  • FIG. 4 is a cross-sectional STEM image according to Example
  • FIG. 4 is a cross-sectional STEM image according to Example 3.
  • FIG. 4 is a cross-sectional STEM image according to Example 3.
  • FIG. 4 is a cross-sectional STEM image according to Example 3.
  • FIG. 4 is a cross-sectional STEM image according to Example 3.
  • FIG. 4 is a cross-sectional STEM image according to Example 3.
  • FIG. 4 is a cross-sectional STEM image according to Example 3.
  • FIG. FIG. 6 is a diagram illustrating Ag / Se according to a third embodiment.
  • film and “layer” can be interchanged with each other depending on the case or circumstances.
  • conductive layer may be changed to the term “conductive film”.
  • insulating film may be changed to the term “insulating layer” in some cases.
  • FIG. 10 A schematic view of a cross-sectional structure of the photoelectric conversion element 10 according to one embodiment of the present invention is illustrated in FIG.
  • the photoelectric conversion element 10 includes a first electrode 411, a photoelectric conversion layer 413 on the first electrode 411, and a second electrode 415 on the photoelectric conversion layer 413.
  • the photoelectric conversion element 10 may include a hole injection blocking layer 417 between the photoelectric conversion layer 413 and the second electrode 415 as illustrated in FIG. Good.
  • the photoelectric conversion element 10 according to one embodiment of the present invention may include an electron injection blocking layer 419 between the photoelectric conversion layer 413 and the first electrode 411 as illustrated in FIG. .
  • the photoelectric conversion element 10 according to one embodiment of the present invention may include a hole injection blocking layer 417 and an electron injection blocking layer 419 as illustrated in FIG.
  • the photoelectric conversion element 10 may be formed on a substrate, or may be formed on a driving transistor formed on the substrate or formed on the substrate.
  • a selenium-based material can be used for the photoelectric conversion layer 413.
  • a photoelectric conversion element using a selenium material has a high internal quantum efficiency with respect to visible light.
  • photoelectric conversion efficiency can be increased by amplifying carriers generated by incident light using a charge amplification effect due to an avalanche phenomenon.
  • a photodiode using avalanche amplification may be referred to as an avalanche photodiode (APD: Avalanche Photodiode).
  • APD Avalanche Photodiode
  • the selenium-based material has a high light absorption coefficient, it has production advantages such that the photoelectric conversion layer can be formed as a thin film.
  • a thin film of a selenium-based material can be formed using a vacuum evaporation method, a sputtering method, or the like. Note that in this specification and the like, the photoelectric conversion layer may be referred to as a p-type semiconductor layer.
  • Crystal selenium is preferably used for the photoelectric conversion layer 413.
  • Selenium can be classified into single crystal selenium, polycrystalline selenium, microcrystalline selenium, amorphous selenium (amorphous selenium) and the like according to its crystallinity.
  • crystalline selenium refers to crystalline selenium, for example, single crystal selenium, polycrystalline selenium, and microcrystalline selenium.
  • selenium in which crystalline selenium and amorphous selenium are mixed may be used. Note that in this specification and the like, having crystallinity may be referred to as crystalline.
  • crystalline selenium Compared to silicon and amorphous selenium, crystalline selenium has a high absorption coefficient over the entire wavelength range of visible light, so that the film thickness can be reduced. By reducing the film thickness, a high electric field can be applied. Crystalline selenium undergoes avalanche amplification at a low voltage and has high photosensitivity. Therefore, a photoelectric conversion element having crystalline selenium in the photoelectric conversion layer 413 has high sensitivity and is suitable for imaging in a low-light environment. Further, it is preferable because it can operate at a low voltage.
  • XRD X-ray diffraction
  • ED electron diffraction
  • TEM transmission electron microscope
  • STEM Scanning Transmission Electron Microscopy
  • the photoelectric conversion layer 413 which is one embodiment of the present invention includes selenium and the element X.
  • the element X is one or more selected from silver, bismuth, indium, tin, and tellurium.
  • the photoelectric conversion layer 413 preferably has a region where the ratio of the atomic concentration of element X to the atomic concentration of selenium (X / Se) is 0.0010 or more and 0.70 or less. Further, the photoelectric conversion layer 413 preferably has a region where X / Se is 0.0030 or more and 0.50 or less. Further, the photoelectric conversion layer 413 preferably has a region where X / Se is 0.0050 or more and 0.30 or less.
  • the photoelectric conversion layer 413 having uniform crystal selenium with few film peeling regions can be manufactured.
  • an imaging device with little variation in characteristics can be manufactured.
  • energy dispersive X-ray analysis EDX: Energy Dispersive X-ray Spectroscopy
  • SIMS secondary ion mass spectrometry
  • TOF-SIMS Flight Time-type secondary ion mass spectrometry
  • XPS Xray Photoelectron Spectroscopy
  • AES Auger Electron Spectroscopy
  • ELS Electron Energy-Loss Spectroscopy
  • ratio of atomic concentration and “ratio of number of atoms” are synonymous, and “ratio of atomic concentration” can be replaced with “ratio of number of atoms”. That is, the value of X / Se is the ratio of the atomic concentration of element X to the atomic concentration of selenium, and can also be said to be the ratio of the number of atoms of element X to the number of atoms of selenium.
  • the first electrode 411 will be described.
  • gold, titanium nitride, molybdenum, tungsten, aluminum, titanium, or the like can be used for the first electrode 411. Further, for example, a stack in which aluminum is sandwiched between titanium can be used.
  • the first electrode 411 can be formed by a sputtering method or a plasma CVD method. Note that the first electrode 411 may be formed over a substrate, may be formed over the substrate, or may be formed over a driving transistor formed over the substrate.
  • the first electrode 411 illustrated in FIGS. 1A to 1D has flatness to prevent a short circuit with the second electrode 415 due to poor coverage of the photoelectric conversion layer 413 or the like. High is preferred. High flatness of the first electrode 411 also contributes to improvement of flatness of the upper surface of the photoelectric conversion layer 413.
  • an indium tin oxide film containing 1 to 20 wt% of silicon oxide can be given.
  • the flatness is confirmed by observation with an atomic force microscope (AFM: Atomic Force Microscope), a scanning electron microscope (SEM: Scanning Electron Microscope), or the like.
  • AFM Atomic Force Microscope
  • SEM Scanning Electron Microscope
  • the indium tin oxide film is crystallized at a relatively low temperature even if it is amorphous at the time of film formation, so that surface roughness due to crystal grain growth is likely to occur.
  • the indium tin oxide film containing silicon does not show crystallinity in X-ray diffraction (XRD) analysis even when heat treatment is performed at a temperature higher than 400 ° C. That is, the indium tin oxide film containing silicon maintains an amorphous state even when heat treatment is performed at a relatively high temperature. Therefore, the surface roughness of the indium tin oxide film containing silicon hardly occurs.
  • the second electrode 415 includes, for example, indium-tin oxide (ITO), indium-tin oxide containing silicon, indium oxide containing zinc, zinc oxide, zinc oxide containing gallium, zinc oxide containing aluminum, and tin oxide. Further, tin oxide containing fluorine, tin oxide containing antimony, graphene, or the like can be used, but indium-tin oxide and indium-tin oxide containing silicon are particularly preferable.
  • the second electrode 415 is not limited to a single layer, and may be a stack of different films. Note that the indium-tin oxide includes In, Sn, and O.
  • the second electrode 415 preferably has high light transmittance in order to allow light to reach the photoelectric conversion layer 413.
  • an imaging device with high definition can be provided by increasing the light transmittance of the second electrode 415.
  • the second electrode 415 can be formed over the photoelectric conversion layer 413 by a sputtering method or a plasma CVD method.
  • the photoelectric conversion element 10 is further provided with a hole injection blocking layer between the photoelectric conversion layer 413 and the second electrode 415. 417 may be included.
  • the hole injection blocking layer 417 has a function of suppressing injection of holes from the second electrode 415 to the photoelectric conversion layer 413.
  • the hole injection blocking layer 417 has a function of suppressing charge injection into the photoelectric conversion layer 413 and may be called a charge injection blocking layer.
  • a photoelectric conversion element using a selenium-based material for a photoelectric conversion layer has a problem of a low S / N ratio because of a large dark current when an electric field is applied.
  • one of the causes of dark current is that charge injection from the electrode to the photoelectric conversion layer could not be suppressed. Therefore, in order to suppress charge injection into the photoelectric conversion layer, a hole injection blocking layer made of gallium oxide may be provided between the photoelectric conversion layer and the electrode.
  • the hole injection blocking layer may be referred to as an n-type semiconductor layer.
  • the photoelectric conversion element 10 can also be referred to as a pn junction photodiode.
  • the layer needs to have a certain thickness or more.
  • the film thickness is preferably 5 nm to 1 ⁇ m, and more preferably 10 nm to 500 nm.
  • a material whose thickness can be controlled more easily than gallium oxide can be used for the hole-injection blocking layer 417.
  • an oxide material can be used for the hole-injection blocking layer 417.
  • the oxide material used for the hole-injection blocking layer 417 include indium oxide, tin oxide, zinc oxide, In—Zn oxide, Sn—Zn oxide, Al—Zn oxide, Zn—Mg oxide, Sn— Mg oxide, In—Mg oxide, In—Ga oxide, In—Ga—Zn oxide, In—Al—Zn oxide, In—Sn—Zn oxide, Sn—Ga—Zn oxide, Al— Ga-Zn oxide, Sn-Al-Zn oxide, In-Hf-Zn oxide, In-La-Zn oxide, In-Ce-Zn oxide, In-Pr-Zn oxide, In-Nd- Zn oxide, In-Sm-Zn oxide, In-Eu-Zn oxide, In-Gd-Zn oxide, In-Tb-Zn oxide, In-Dy-Zn oxide, In-Ho-Zn oxide ,
  • an In—Ga—Zn oxide means an oxide containing In, Ga, and Zn. Moreover, metal elements other than In, Ga, and Zn may be contained.
  • a film formed using an In—Ga—Zn oxide is also referred to as an IGZO film.
  • an In—Ga—Zn oxide is particularly useful.
  • the In—Ga—Zn oxide is preferably a crystalline oxide.
  • As the crystalline oxide an oxide having a nanocrystalline structure, an oxide having a CAAC (C-Axis Aligned Crystalline) structure, or the like can be given.
  • the hole injection blocking layer 417 formed over the photoelectric conversion layer 413 is also likely to be a crystalline oxide.
  • a structure in which crystalline selenium is used for the photoelectric conversion layer 413 and an In—Ga—Zn oxide having a CAAC structure is used for the hole-injection blocking layer 417 is preferable. With this structure, since both the photoelectric conversion layer 413 and the hole injection blocking layer 417 have a crystallinity, the adhesion between the photoelectric conversion layer 413 and the hole injection blocking layer 417 can be improved.
  • the hole injection blocking layer 417 and the second electrode 415 preferably each include the same metal element. Specifically, a structure in which an In—Ga—Zn oxide is used for the hole-injection blocking layer 417 and an In—Sn—Si oxide is used for the second electrode 415 is preferable.
  • the hole injection blocking layer 417 and the second electrode 415 each include the same metal element (In), adhesion between the hole injection blocking layer 417 and the second electrode 415 can be improved.
  • the hole injection blocking layer 417 can be typically formed by a sputtering method or a plasma CVD method.
  • the photoelectric conversion element 10 As illustrated in FIGS. 1C and 1D, the photoelectric conversion element 10 according to one embodiment of the present invention is further provided between the first electrode 411 and the photoelectric conversion layer 413 and further has an electron injection blocking layer 419. You may have.
  • the electron injection blocking layer 419 has a function of suppressing injection of electrons from the first electrode 411 to the photoelectric conversion layer 413.
  • the electron injection blocking layer 419 may be called a charge injection blocking layer because it has a function of suppressing charge injection into the photoelectric conversion layer 413.
  • the electron injection blocking layer may be provided with nickel oxide or antimony sulfide.
  • the photoelectric conversion element 10 may include a hole injection blocking layer 417 and an electron injection blocking layer 419 as illustrated in FIG.
  • FIGS. 2A to 2D are cross-sectional views illustrating a method for manufacturing the photoelectric conversion element 10.
  • the first electrode 411 is formed over the layer 441 (FIG. 2A). Note that in FIG. 2A, the formation layer of the first electrode 411 is illustrated as a layer 441 for convenience.
  • the layer 441 may be a substrate, or may be a layer including a driving transistor formed over the substrate or formed over the substrate.
  • the base layer 443 includes one or more selected from the element X.
  • the element X the elements described above can be used.
  • the base layer 443 may be a single layer or a stacked layer.
  • the element X included in the base layer 443 has a large diffusion coefficient in selenium and preferably forms a compound with selenium.
  • a compound having selenium and the element X is referred to as a selenium compound.
  • the selenium compound preferably has crystallinity.
  • Table 1 shows a crystal space group, a crystal system, and a lattice constant in a selenium and a selenium compound.
  • the values shown in Table 1 are quoted from an inorganic crystal structure database (ICSD: Inorganic Crystal Structure Database).
  • SSD Inorganic Crystal Structure Database
  • the degree of mismatch of the lattice constant between single crystal selenium and the selenium compound is small. Further, it is more preferable that the crystal structures of the selenium compound and the single crystal selenium are the same, but the crystal structures may be different as long as the degree of lattice mismatch is small.
  • the photoelectric conversion layer 413 of one embodiment of the present invention may include the selenium compound illustrated in Table 1.
  • the selenium compound included in the photoelectric conversion layer 413 of one embodiment of the present invention is not limited thereto, and may include compounds other than the selenium compounds illustrated in Table 1.
  • the base layer 443 preferably has high wettability with respect to selenium.
  • the selenium compound preferably has high wettability with respect to selenium.
  • a material containing silver is preferably used for the base layer 443.
  • Silver has a high diffusion rate in selenium.
  • compounds of selenium and silver (Ag 2 Se) has a high wettability.
  • the base layer 443 is preferably formed using a material having bismuth.
  • the thickness of the base layer 443 is preferably 0.20 nm or more and 140 nm or less. Furthermore, 0.60 nm or more and 100 nm or less is preferable. Furthermore, 1.0 nm or more and 60 nm or less are preferable.
  • the underlayer 443 is formed by sputtering, vapor deposition, pulsed laser deposition (PLD: Pulsed Laser Deposition), plasma enhanced chemical vapor deposition (PECVD), thermal CVD (Chemical Vapor Deposition), or thermal CVD (Chemical Vapor Deposition).
  • PLD Pulsed Laser Deposition
  • PECVD plasma enhanced chemical vapor deposition
  • thermal CVD Thermal Vapor Deposition
  • thermal CVD Thermal Vapor Deposition
  • MOCVD Metal Organic Chemical Vapor Deposition
  • FIG. 2B illustrates an example in which the shape of the base layer 443 is not processed
  • the present invention is not limited to this.
  • the base layer 443 may have an island shape. Further, a stripe shape, a mesh shape, a shape having an opening, or the like may be used.
  • the base layer 443 can be partially formed over the first electrode 411 using a metal mask.
  • the base layer 443 formed over the first electrode 411 may be processed into a predetermined shape by dry etching or wet etching.
  • the amount of the element X included in the base layer 443 may be adjusted with respect to the amount of selenium included in the selenium layer.
  • the base layer 443 can be provided in a desired region.
  • the base layer 443 is heated, and selenium is formed in the heated state.
  • the base layer 443 can be heated by placing the layer 441 on a heated stage.
  • the substrate temperature during the selenium film formation is preferably a temperature at which the layer 441 is 50 ° C. or higher and 90 ° C. or lower.
  • the element X included in the base layer 443 diffuses into the selenium layer during the selenium film formation. Further, the diffused element X and selenium react to form a selenium compound having selenium and the element X.
  • the selenium compound has a small degree of mismatch in lattice constant with single crystal selenium, crystal selenium is formed using the selenium compound as a crystal nucleus. That is, uniform selenium having high flatness can be formed while forming selenium.
  • the photoelectric conversion layer 413 including crystalline selenium is formed over the first electrode 411 (FIG. 2C). Note that the photoelectric conversion layer 413 may partially be amorphous selenium.
  • film formation with a substrate heated may be referred to as heat film formation.
  • forming a film without heating the substrate may be referred to as room temperature (RT) film formation.
  • a method for producing crystalline selenium As a method for producing crystalline selenium, a method of forming a film of amorphous selenium and performing a heat treatment is known. However, as amorphous selenium is crystallized by heat treatment, selenium may aggregate to generate a region where selenium does not exist. In this specification and the like, a region where selenium does not exist is called a film peeling region. When the film peeling region occurs in the photoelectric conversion layer, characteristic variation occurs between the photoelectric conversion elements, which may cause a decrease in imaging performance of the imaging device.
  • the photoelectric conversion layer 413 is preferably uniform crystalline selenium with less film peeling region, high flatness, and uniformity.
  • the photoelectric conversion layer 413 which is one embodiment of the present invention has uniform crystalline selenium because crystalline selenium is formed when the selenium film is formed.
  • the selenium compound is formed, adhesion between the base layer 443 and crystalline selenium is increased, aggregation of crystalline selenium and generation of a film peeling region are suppressed, and crystalline selenium having high flatness can be obtained. That is, the photoelectric conversion layer 413 having uniform crystal selenium with few film peeling regions and high flatness can be obtained.
  • an imaging device with little variation in characteristics can be manufactured.
  • FIG. 2C illustrates an example in which the base layer 443 cannot be clearly confirmed after the photoelectric conversion layer 413 is formed, and the photoelectric conversion layer 413 is formed over the first electrode 411; however, the present invention is not limited thereto.
  • the base layer 443a may be thinner than the base layer 443, and the photoelectric conversion layer 413 may be formed over the base layer 443a.
  • the base layer 443a may have a thickness that is similar to that when the base layer 443 is formed, or may be thicker than that when the base layer 443 is formed. As illustrated in FIG.
  • the base layer 443 may be an island-shaped base layer 443b, and the photoelectric conversion layer 413 may be formed over the first electrode 411 and the base layer 443b. Further, the boundary between the base layer 443a and the base layer 443b may not be clear from the photoelectric conversion layer 413.
  • the base layer 443a and the base layer 443b may include selenium in addition to the components included in the base layer 443. Note that in this specification and the like, the base layer 443a and the base layer 443b may be referred to as buffer layers.
  • the selenium layer can be formed by sputtering, evaporation, pulsed laser deposition (PLD), plasma enhanced chemical vapor deposition (PECVD), thermal CVD, ALD, vacuum evaporation, or the like.
  • PLD pulsed laser deposition
  • PECVD plasma enhanced chemical vapor deposition
  • thermal CVD ALD
  • vacuum evaporation or the like.
  • An example of the thermal CVD method is the MOCVD method.
  • the orientation of the substrate shown in FIG. When the evaporation method is used for forming the selenium layer, the orientation of the substrate shown in FIG.
  • the substrate is sandwiched between the substrate holder and the vapor deposition mask, the metal vapor deposition mask is attracted by a permanent magnet installed on the substrate holder, and the substrate is fixed, and below the exposed underlayer 443.
  • Vapor deposition is performed with the vapor deposition source located.
  • the pressure during vapor deposition is preferably 1.0 ⁇ 10 ⁇ 3 Pa or less. Furthermore, 1.0 ⁇ 10 ⁇ 4 Pa or less is preferable. Furthermore, about 1.0 ⁇ 10 ⁇ 5 Pa is preferable.
  • the base layer 443 After forming the base layer 443, it is preferable to deposit selenium without leaving any time. Further, after the formation of the base layer 443, selenium is preferably formed without exposing the surface of the base layer 443 to the air atmosphere. Furthermore, it is preferable to form a selenium film continuously in a vacuum after forming the base layer 443 in a vacuum. By continuously forming selenium after forming the base layer 443, it is possible to suppress the deposition of impurities such as atmospheric components on the surface of the base layer 443, and the photoelectric conversion layer 413 with few impurities can be formed. Further, generation of a film peeling region in the photoelectric conversion layer 413 can be suppressed. In addition, the photoelectric conversion layer 413 with high crystallinity can be formed.
  • continuous film formation or continuous formation means that the processing substrate is not exposed to the air atmosphere between the underlayer film formation and the selenium layer film formation and is always placed in a vacuum, nitrogen, or a rare gas atmosphere. Sometimes called membrane.
  • the exposure to the air atmosphere after the formation of the base layer and the subsequent formation of the selenium layer may be referred to as discontinuous film formation or discontinuous film formation.
  • a multi-chamber type sputtering apparatus having a plurality of film formation chambers and a plurality of targets and continuously forming a plurality of types of film types in a vacuum
  • a multi-chamber evaporation apparatus that has a plurality of evaporation sources and continuously forms a plurality of types of film types in a vacuum
  • Heat treatment may be performed after the photoelectric conversion layer 413 is formed. By performing the heat treatment, the crystallinity of crystalline selenium included in the photoelectric conversion layer 413 may be further increased. Note that heat treatment may not be performed after the photoelectric conversion layer 413 is formed.
  • the second electrode 415 is formed over the photoelectric conversion layer 413.
  • the photoelectric conversion element 10 according to one embodiment of the present invention can be manufactured (FIG. 2D).
  • heat treatment may be performed after the second electrode 415 is formed.
  • the crystallinity of crystalline selenium included in the photoelectric conversion layer 413 may be further increased. Note that heat treatment may not be performed after the second electrode 415 is formed.
  • FIGS. 4A to 4C are cross-sectional views illustrating a method for manufacturing the photoelectric conversion element 10.
  • the first electrode 411 is formed over the layer 441 (FIG. 4A).
  • the first electrode 411 is heated, and selenium is formed in a heated state.
  • a co-evaporation method can be used. Note that the co-evaporation method is a method in which a plurality of different substances are vaporized by simultaneously evaporating from different evaporation sources.
  • the first vapor deposition source a material having one or more elements X can be used.
  • the first vapor deposition source for example, silver, bismuth, indium, indium oxide, tin, tin oxide, tellurium, or the like can be used.
  • a mixture of a plurality of materials may be used as the first vapor deposition source.
  • a material having bismuth as the first evaporation source.
  • the second evaporation source a material having selenium can be used.
  • the first electrode 411 By placing the layer 441 on the heated stage, the first electrode 411 can be heated.
  • the substrate temperature during the selenium film formation is preferably a temperature at which the layer 441 is 50 ° C. or higher and 90 ° C. or lower.
  • the element X included in the first vapor deposition source and the selenium included in the second vapor deposition source react to form a selenium compound including selenium and the element X. Since the selenium compound has a small degree of mismatch in lattice constant with single crystal selenium, crystal selenium is formed using the selenium compound as a crystal nucleus. That is, crystalline selenium can be formed while forming selenium.
  • the photoelectric conversion layer 413 including crystalline selenium is formed over the first electrode 411 (FIG. 4B). Note that the photoelectric conversion layer 413 may partially be amorphous selenium.
  • a co-sputtering method can also be used for forming selenium.
  • the co-sputtering method is a method in which a plurality of different substances are simultaneously formed from different targets by sputtering.
  • a material having one or more elements X can be used.
  • the first target for example, silver, bismuth, indium, indium oxide, tin, tin oxide, tellurium, In—Sn oxide (ITO), In—Sn—Si oxide (ITSO), or the like can be used.
  • a material containing selenium can be used.
  • Heat treatment may be performed after the photoelectric conversion layer 413 is formed. By performing the heat treatment, the crystallinity of crystalline selenium included in the photoelectric conversion layer 413 may be further increased. Note that heat treatment is not necessarily performed after the photoelectric conversion layer 413 is formed.
  • the second electrode 415 is formed over the photoelectric conversion layer 413.
  • the photoelectric conversion element 10 according to one embodiment of the present invention can be manufactured (FIG. 4C).
  • heat treatment may be performed after the second electrode 415 is formed.
  • the crystallinity of crystalline selenium included in the photoelectric conversion layer 413 may be further increased. Note that heat treatment is not necessarily performed after the second electrode 415 is formed.
  • FIGS. 5A to 5E are cross-sectional views illustrating a method for manufacturing the photoelectric conversion element 10.
  • the first electrode 411 is formed over the layer 441 (FIG. 5A).
  • a base layer 443 is formed over the first electrode 411 (FIG. 5B). Description of the base layer 443 is omitted because the above description can be referred to.
  • the substrate temperature at the time of forming the selenium film is preferably a temperature at which the layer 441 is at least room temperature and less than 50 ° C. By setting the above temperature range, it is possible to suppress the occurrence of a film peeling region in the selenium layer 445. Note that the selenium layer 445 is amorphous, but may be partially crystalline.
  • the selenium layer can be formed by sputtering, evaporation, pulsed laser deposition (PLD), plasma enhanced chemical vapor deposition (PECVD), thermal CVD, ALD, vacuum evaporation, or the like.
  • PLD pulsed laser deposition
  • PECVD plasma enhanced chemical vapor deposition
  • thermal CVD ALD
  • vacuum evaporation or the like.
  • An example of the thermal CVD method is the MOCVD method.
  • the selenium layer 445 is formed without any time after the formation of the base layer 443. Further, after the base layer 443 is formed, the selenium layer 445 is preferably formed without exposing the surface of the base layer 443 to the air atmosphere. Furthermore, it is preferable to form the selenium layer 445 continuously in a vacuum after the base layer 443 is formed in a vacuum.
  • the base layer 443 and the selenium layer 445 in succession, it is possible to suppress impurities such as atmospheric components from adhering to the surface of the base layer 443, and the photoelectric conversion layer 413 with few impurities can be formed. Further, generation of a film peeling region in the photoelectric conversion layer 413 can be suppressed. In addition, the photoelectric conversion layer 413 with high crystallinity can be formed.
  • the base layer 443 may be processed into an island shape. Further, a stripe shape, a mesh shape, a shape having an opening, or the like may be used. Then, as illustrated in FIG. 6B, a selenium layer 445 may be formed over the island-shaped base layer 443 and the first electrode 411. By forming the base layer 443 into an island shape, the amount of the element X included in the base layer 443 with respect to the amount of selenium included in the selenium layer 445 may be adjusted. Further, the base layer 443 can be provided in a desired region.
  • the second heat treatment is performed at a temperature higher than that of the first heat treatment.
  • the temperature of the first heat treatment is preferably 50 ° C. or higher and 90 ° C. or lower. Furthermore, 60 degreeC or more and 80 degrees C or less are preferable.
  • the temperature of the second heat treatment is preferably 70 ° C. or higher and 220 ° C. or lower. Furthermore, 90 degreeC or more and 210 degrees C or less are preferable. Furthermore, 110 degreeC or more and 200 degrees C or less are preferable.
  • the first heat treatment is preferably performed at a temperature at which the element X included in the base layer 443 diffuses into the selenium layer 445 and a selenium compound including selenium and the element X is formed.
  • the second heat treatment is preferably higher than the temperature of the first heat treatment and a temperature at which the selenium layer crystallizes.
  • the temperature within the above range, crystalline selenium is formed using the selenium compound as a crystal nucleus. Therefore, generation of a film peeling region in the photoelectric conversion layer 413 can be suppressed.
  • the photoelectric conversion layer 413 with high crystallinity can be formed.
  • the second heat treatment may be performed continuously after the first heat treatment, or the first heat treatment and the second heat treatment may not be performed continuously.
  • an electric furnace, a laser annealing apparatus, a lamp annealing apparatus, or the like can be used.
  • An apparatus for heating an object to be processed by heat conduction or heat radiation from a heating element such as a resistance heating element may be used.
  • a hot plate may also be used.
  • a rapid heating (RTA: Rapid Thermal Anneal) apparatus can be used.
  • RTA apparatus include a GRTA (Gas Rapid Thermal Anneal) apparatus, a lamp rapid heating (LRTA) apparatus, and the like.
  • the GRTA apparatus is an apparatus that performs heat treatment using a high-temperature gas.
  • the LRTA apparatus is an apparatus that heats an object to be processed by radiation of light (electromagnetic waves) emitted from a lamp such as a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high pressure sodium lamp, or a high pressure mercury lamp.
  • a lamp such as a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high pressure sodium lamp, or a high pressure mercury lamp.
  • a rare gas such as argon, air, nitrogen, oxygen, dry air, or the like can be used.
  • a mixed atmosphere of a rare gas and oxygen, or a mixed atmosphere of a rare gas and nitrogen can be used.
  • FIG. 5D illustrates an example in which the base layer 443 cannot be clearly confirmed after the photoelectric conversion layer 413 is formed, and the photoelectric conversion layer 413 is formed over the first electrode 411; however, the present invention is not limited thereto.
  • the base layer 443a may be thinner than the base layer 443, and the photoelectric conversion layer 413 may be formed over the base layer 443a.
  • the base layer 443a may have a thickness that is similar to that when the base layer 443 is formed, or may be thicker than that when the base layer 443 is formed. As illustrated in FIG.
  • the base layer 443 may be an island-shaped base layer 443b, and the photoelectric conversion layer 413 may be formed over the first electrode 411 and the base layer 443b. Further, the boundary between the base layer 443a and the base layer 443b may not be clear from the photoelectric conversion layer 413.
  • the base layer 443a and the base layer 443b may include selenium in addition to the components included in the base layer 443.
  • the second electrode 415 is formed over the photoelectric conversion layer 413.
  • the photoelectric conversion element 10 according to one embodiment of the present invention can be manufactured (FIG. 5E).
  • FIGS. 7A to 7E are cross-sectional views illustrating a method for manufacturing the photoelectric conversion element 10.
  • the first electrode 411 is formed over the layer 441 (FIG. 7A).
  • the substrate temperature at the time of forming the selenium film is preferably a temperature at which the layer 441 is equal to or higher than room temperature and lower than 50 ° C.
  • the selenium layer 445 with few film peeling regions is formed over the first electrode 411 (FIG. 7B). Note that the selenium layer 445 is amorphous, but may be partially crystalline.
  • the selenium layer can be formed by sputtering, evaporation, pulsed laser deposition (PLD), plasma enhanced chemical vapor deposition (PECVD), thermal CVD, ALD, vacuum evaporation, or the like.
  • PLD pulsed laser deposition
  • PECVD plasma enhanced chemical vapor deposition
  • thermal CVD ALD
  • vacuum evaporation or the like.
  • An example of the thermal CVD method is the MOCVD method.
  • a base layer 443 is formed over the selenium layer 445 (FIG. 7C). Description of the base layer 443 is omitted because the above description can be referred to.
  • the base layer 443 is preferably formed without leaving any time. Further, after the selenium layer 445 is formed, the base layer 443 is preferably formed without exposing the surface of the selenium layer 445 to the air atmosphere. Further, it is preferable that after the selenium layer 445 is formed in a vacuum, the base layer 443 is continuously formed in a vacuum.
  • FIG. 7C illustrates an example in which the shape of the base layer 443 is not processed
  • the base layer 443 may be processed into an island shape. Further, a stripe shape, a mesh shape, a shape having an opening, or the like may be used. By forming the base layer 443 into an island shape, the amount of the element X included in the base layer 443 with respect to the amount of selenium included in the selenium layer 445 may be adjusted. Further, the base layer 443 can be provided in a desired region.
  • FIG. 7D illustrates an example in which the base layer 443 cannot be clearly confirmed after the photoelectric conversion layer 413 is formed, and the photoelectric conversion layer 413 is formed over the first electrode 411; however, the present invention is not limited thereto.
  • the base layer may be thinner than the formation of the base layer 443, and the photoelectric conversion layer 413 may be formed under the base layer.
  • the base layer may have the same thickness as that when the base layer 443 is formed, or may be thicker than that when the base layer 443 is formed.
  • the underlayer may have an island shape. Further, the boundary between the base layer and the photoelectric conversion layer 413 may not be clear.
  • the base layer may include selenium in addition to the components included in the base layer 443.
  • the second electrode 415 is formed over the photoelectric conversion layer 413.
  • the photoelectric conversion element 10 according to one embodiment of the present invention can be manufactured (FIG. 7E).
  • Embodiment 2 In this embodiment, a photoelectric conversion element having a structure different from that of Embodiment 1 is described with reference to drawings.
  • One embodiment of the present invention is a photoelectric conversion element using selenium in a photoelectric conversion layer, and can perform imaging using an avalanche multiplication effect at a relatively low voltage. Further, by using crystalline selenium and amorphous selenium for the photoelectric conversion layer, photosensitivity can be improved in almost the entire visible light region. Furthermore, by using an oxide having a suitable film thickness and a wide band gap as the n-type semiconductor layer for forming the pn junction, dark current can be reduced and photocurrent can be increased.
  • the photosensitivity can be increased as compared with the conventional photoelectric conversion element using silicon for the photoelectric conversion layer, and imaging under low illuminance can be facilitated.
  • a high-resolution imaging device can be realized.
  • FIG. 8 is a perspective view illustrating a structure of a photoelectric conversion element of one embodiment of the present invention.
  • the photoelectric conversion element 10 includes a photoelectric conversion layer 11, a hole injection blocking layer 12, a buffer layer 13, a first electrode 15, and a second electrode 14.
  • the photoelectric conversion element 10 is a pn junction photodiode, and the second electrode 14 side is a light receiving surface.
  • a selenium-based material can be used for the photoelectric conversion layer 11.
  • light (Light) incident on the photoelectric conversion element 10 is indicated by an arrow.
  • the photoelectric conversion layer 11 is preferably a stacked layer of a crystalline selenium layer 11a and an amorphous selenium layer 11b.
  • FIG. 8 illustrates an example in which the crystalline selenium layer 11a and the amorphous selenium layer 11b have substantially the same film thickness. However, as illustrated in FIG. The thick amorphous selenium layer 11b may be formed thin.
  • the structure and manufacturing method of the photoelectric conversion layer 413 described in Embodiment 1 can be used.
  • the crystalline selenium layer can be formed by solid layer growth using an amorphous selenium layer as a starting film. At this time, unevenness may occur on the surface of the layer due to grain growth. In addition, segregation of impurities easily occurs on the layer surface and the crystal grain boundary.
  • the surface of the layer is a region that becomes a pn junction surface, and the presence of a shape factor such as irregularities and impurities may cause deterioration of interface characteristics.
  • the pn junction plane in order to make the pn junction plane as flat as possible, it is preferable to form another p-type semiconductor layer on the crystalline selenium layer. Further, by forming the p-type semiconductor layer, the impurity concentration in the region serving as the pn junction surface and in the vicinity thereof can be reduced.
  • the p-type semiconductor layer amorphous selenium having physical properties close to those of crystalline selenium is used in one embodiment of the present invention.
  • FIG. 10A shows an indium-gallium oxide (IGO) corresponding to the hole injection blocking layer 12 and an indium corresponding to the second electrode 14 on the solid phase grown crystal selenium layer (c-Se). It is a cross-sectional STEM image of the laminated body which provided the tin oxide (ITO). It can be seen that unevenness is generated at the interface between the crystalline selenium layer (c-Se) and the indium-gallium oxide (IGO).
  • IGO indium-gallium oxide
  • FIG. 10B illustrates a laminate in which an amorphous selenium layer (a-Se), indium-gallium oxide (IGO), and indium-tin oxide (ITO) are provided over a crystalline selenium layer (c-Se). It is a cross-sectional STEM image of.
  • the photoelectric conversion layer 11 is preferably a stacked layer of a crystalline selenium layer 11a and an amorphous selenium layer 11b. Moreover, the application voltage for making the avalanche multiplication effect appear can be reduced by including the crystalline selenium layer 11 a in the photoelectric conversion layer 11.
  • Amorphous selenium is a material that is easily crystallized at a relatively low temperature, and the amorphous selenium layer 11b may crystallize in a later manufacturing process. Therefore, impurities that suppress crystallization may be added to the amorphous selenium layer 11b. Examples of the impurities include arsenic, antimony, silicon, and titanium. In addition, under an appropriate concentration, crystallization can be suppressed even with a group 16 element such as sulfur.
  • the concentration of the impurity is 0.1 at% to 10 at%, preferably 0.1 at% to 5 at%, more preferably 0.1 at% to 1 at%.
  • FIG. 11 shows a device A using a single layer of an amorphous selenium layer (a-Se) as a photoelectric conversion layer, and a stacked layer of a crystalline selenium layer (c-Se) and an amorphous selenium layer (a-Se). It is a figure which compares the wavelength dependence of the electric current amplification factor ( Iphoto / Idark ) of the element B which it was.
  • the size of the light receiving surfaces of the elements A and B is 2 mm ⁇ 2 mm, and the voltage (reverse bias: V R ) applied between the electrodes is ⁇ 15V.
  • the current gain on the long wavelength side can be improved with respect to the element A.
  • the element B is the current amplification factor is lower than the element A, which is the dark current (I dark) is larger better elements B.
  • the photocurrent (I photo ) is larger in the element B than in the element A.
  • the increase in the dark current of the element B is considered to be caused by an increase in the impurity concentration in the photoelectric conversion layer during the crystal growth process.
  • the thickness of the photoelectric converting layer 11 may be relatively reduced.
  • the thickness of the photoelectric converting layer 11 may be relatively thick, when performing an imaging operation with higher sensitivity irrespective of a voltage.
  • the photoexcited carriers outside the depletion layer formed by the pn junction and the applied voltage are almost deactivated, so that the depletion layer is efficiently applied to almost the entire photoelectric conversion layer. It is preferable to select the film thickness so as to spread.
  • the thickness of the photoelectric conversion layer 11 is preferably about 500 nm.
  • the film thicknesses of the crystalline selenium layer 11a and the amorphous selenium layer 11b can also be determined depending on the application. For example, when priority is given to the sensitivity on the long wavelength side, the crystal selenium layer 11a may be made relatively thick. Further, when priority is given to imaging under low illuminance, the film thickness of the amorphous selenium layer 11b that can reduce the dark current may be relatively increased.
  • the buffer layer 13 is a region where a metal and / or an alloy of metal and selenium is formed.
  • a metal for example, silver, indium, tin, tellurium, bismuth, or the like can be used. In this embodiment, an example in which silver is used as the metal will be described.
  • a crystalline selenium layer can be obtained by solid phase growth of an amorphous selenium layer, but it has poor adhesion to the base, and agglomerates during crystal growth and a film peeling region occurs in the layer. There is. Therefore, in order to prevent them, it is preferable that a material for forming an alloy with selenium is provided between the base and the amorphous selenium layer for solid phase growth.
  • a crystalline selenium layer is formed by providing a thin silver layer over the first electrode 15 which is a base, and providing an amorphous selenium layer over the thin layer, followed by heat treatment at a maximum of about 110 ° C. Form.
  • the thickness of the thin layer can be set to, for example, 1 nm to 2 nm.
  • Silver and selenium form an alloy in the initial stage of the heat treatment, and then crystalline selenium grows on the alloy. Therefore, the problem of adhesion and aggregation can be solved, and the occurrence of a film peeling region can be suppressed. Note that all thin silver layers may be alloyed.
  • the thickness of the crystalline selenium layer 11a is 50 nm to 100 nm
  • the thickness of the amorphous selenium layer 11b is 400 nm. It is preferable that the thickness is about 450 nm.
  • the amorphous selenium layer 11b is provided after the crystalline selenium layer 11a is formed.
  • the crystalline selenium layer 11b is selected as shown in FIG.
  • the crystalline selenium layer 11c can also be formed directly on the layer 11a. In this case, since the silver concentration in the crystalline selenium layer 11c can be suppressed lower than that in the crystalline selenium layer 11a, dark current can be suppressed and the photosensitivity can be increased in a wide range of the visible light region.
  • the amorphous selenium layer 11b may be provided, and the amorphous selenium layer 11b may be crystallized in a subsequent heating step to form the crystalline selenium layer 11c.
  • a selenium layer 16 may be provided between the first electrode 15 and the buffer layer 13.
  • the selenium layer 16 is crystallized almost simultaneously in the process of forming the crystalline selenium layer 11a, but may be made amorphous by adding the impurities described above.
  • the selenium layer 16 has a role of electrically separating the pixel electrodes.
  • the structure and material of the first electrode 411 described in Embodiment 1 can be used.
  • the selenium layer 16 may be unnecessary if silver is used for the uppermost layer of the first electrode 15.
  • the hole injection blocking layer 12 is preferably formed of a material having a wide band gap and a light-transmitting property with respect to visible light.
  • a material having a wide band gap and a light-transmitting property with respect to visible light for example, zinc oxide, gallium oxide, indium oxide, tin oxide, or an oxide in which they are mixed can be used. In one embodiment of the present invention, indium-gallium oxide is used.
  • FIG. 12A is a band diagram in the bonding state of the second electrode 14, the hole injection blocking layer 12, and the photoelectric conversion layer 11, where crystalline selenium is used as the photoelectric conversion layer 11 and gallium oxide is used as the hole injection blocking layer 12. It is an example using. Since gallium oxide has a large band gap of about 4.9 eV, the effect of blocking the injection of holes from the second electrode 14 to the photoelectric conversion layer 11 is high. Therefore, the dark current (I dark ) can be kept low.
  • gallium oxide is a material having a low carrier concentration
  • the depletion layer width Wp in the p-type semiconductor layer formed by the pn junction is difficult to increase. Therefore, the incident light cannot be absorbed in the depletion layer and is also absorbed in a region outside the depletion layer.
  • the optical carriers generated in the depletion layer can be efficiently extracted to the outside by the internal electric field, the optical carriers generated in the region outside the depletion layer are deactivated.
  • the depletion layer width Wp can be increased by increasing the carrier concentration of the hole injection blocking layer 12.
  • the second electrode 14 can be connected via a deep level. Holes may be injected into the photoelectric conversion layer 11. Therefore, the hole injection blocking layer 12 is preferably a material having a slightly higher carrier concentration than indium oxide. An example of such a material is indium-gallium oxide.
  • FIG. 12B is a band diagram when indium-gallium oxide is used for the hole injection blocking layer 12.
  • the band gap is about the same as 4.7 eV, and it is estimated that the hole injection blocking function can be maintained.
  • indium-gallium oxide has a higher carrier density than gallium oxide, the depletion layer width Wp can be expanded, and an increase in photocurrent can be estimated.
  • FIG. 13 shows a device C in which the photoelectric conversion layer 11 is an amorphous selenium layer (500 nm), gallium oxide (30 nm) is used for the hole injection blocking layer 12, and indium-gallium oxide ( 30 is a comparison of the dark current (I dark ) of the device D using a light source (I photo ) at the time of light irradiation (wavelength 600 nm: 20 ⁇ W / cm 2 ). Note that the size of the light receiving surface of both the element C and the element D is 2 mm ⁇ 2 mm.
  • the dark current is lower in the element D than in the element C. This is due to the fact that the electron affinity of selenium and gallium oxide is almost the same (about 3.9 eV), whereas the electron affinity of indium-gallium oxide is smaller (about 3.6 eV). Therefore, the energy difference at the lower end of the conduction band of the pn junction interface is larger in the element D, and a barrier for suppressing electron injection is formed, so that the dark current can be made smaller than that in the element C.
  • the device D exhibits a higher photocurrent in light irradiation with a wavelength of 600 nm than the device C. This indicates that light having a relatively long wavelength contributes to the generation of carriers, and at the same time, indicates that the depletion layer width Wp is wide as shown in the band diagram of FIG. ing.
  • FIG. 14 shows a case where the photoelectric conversion layer 11 is a stacked layer of a crystalline selenium layer (50 nm) and an amorphous selenium layer (440 nm), and the thickness of the indium-gallium oxide used for the hole injection blocking layer 12 is changed. It is a figure which shows a dark current and a current gain ( Iphoto / Idark ).
  • the photocurrent (I photo ) uses a value at the time of light irradiation with a wavelength of 450 nm and an irradiance of 20 ⁇ W / cm 2 .
  • FIG. 14 shows a tendency that the dark current is minimum and the current amplification factor is maximum when the hole injection blocking layer 12 is near 10 nm. This tendency can be explained with the band diagrams shown in FIGS.
  • FIG. 15A is a band diagram of the bonding state of the second electrode 14, the hole injection blocking layer 12, and the photoelectric conversion layer 11 when the hole injection blocking layer 12 is relatively thin.
  • the second electrode 14 is preferably formed using a material that transmits visible light, and the structure and material of the second electrode 415 described in Embodiment 1 can be used.
  • a conductive oxide such as indium-tin oxide (ITO) can be used as the second electrode 14.
  • ITO can be typically formed by sputtering, but indium or tin atoms or clusters may be implanted into the base in the initial stage of film formation.
  • the carrier density increases as the number of defects increases.
  • the film thickness t n of the hole injection blocking layer 12 is relatively thin, since the ratio of the region in the film thickness direction is large, the dark current increases due to a leakage current such as a tunnel current.
  • the depletion layer width Wp in the photoelectric conversion layer 11 increases as the carrier concentration of the hole injection blocking layer 12 near the pn junction surface increases. Therefore, the photocurrent tends to increase.
  • FIG. 15B is a band diagram of the bonding state of the second electrode 14, the hole injection blocking layer 12, and the photoelectric conversion layer 11 when the film thickness t n of the hole injection blocking layer 12 is relatively thick. Similar to the case where the thickness t n of the hole injection blocking layer 12 is thin, the hole injection blocking layer 12 is formed with a region in which atoms of indium, tin, or the like are implanted. However, since the distance from the pn junction surface is relatively long, the leakage current due to the tunnel current or the like can be suppressed, and the dark current can be suppressed low. On the other hand, since the carrier concentration of the hole injection blocking layer 12 in the vicinity of the pn junction surface does not change, the depletion layer width Wp in the photoelectric conversion layer 11 is difficult to increase. Therefore, the photocurrent tends to hardly increase.
  • the thickness t n of the hole injection blocking layer 12 is preferably 5nm or more 20nm or less of the hole injection blocking layer 12, and more preferably 10nm and its vicinity.
  • a pn junction photoelectric conversion element As described above, by using a stacked layer of crystalline selenium and amorphous selenium for the photoelectric conversion layer 11 and using indium-gallium oxide for the n-type semiconductor layer, a pn junction photoelectric conversion element with excellent electrical characteristics is formed. be able to.
  • FIG. 16 illustrates a pixel circuit that can be used in the imaging device of one embodiment of the present invention.
  • the pixel circuit includes the transistor 51, the transistor 52, the transistor 53, the transistor 54, and the photoelectric conversion element 10 described in Embodiment 1.
  • One electrode (anode) of the photoelectric conversion element 10 is electrically connected to one of a source and a drain of the transistor 51.
  • One electrode of the photoelectric conversion element 10 is electrically connected to one of a source and a drain of the transistor 52.
  • the other of the source and the drain of the transistor 51 is electrically connected to the gate of the transistor 53.
  • One of the source and the drain of the transistor 53 is electrically connected to one of the source and the drain of the transistor 54.
  • the other electrode (cathode) of the photoelectric conversion element 10 is electrically connected to the wiring 72 (HVDD).
  • a gate of the transistor 51 is electrically connected to the wiring 75 (TX).
  • the other of the source and the drain of the transistor 53 is electrically connected to the wiring 79 (VDD).
  • a gate of the transistor 52 is electrically connected to the wiring 76 (RS).
  • the other of the source and the drain of the transistor 52 is electrically connected to the wiring 73 (GND).
  • the other of the source and the drain of the transistor 54 is electrically connected to the wiring 71 (OUT).
  • a gate of the transistor 54 is electrically connected to the wiring 78 (SE).
  • the wiring 72 (HVDD) is electrically connected to one terminal of the high voltage power supply 56, and the other terminal of the high voltage power supply 56 is electrically connected to the wiring 77 (GND).
  • the wiring 71 (OUT) can function as an output line through which a signal is output from the pixel.
  • the wiring 73 (GND), the wiring 77 (GND), and the wiring 79 (VDD) can function as power supply lines.
  • the wiring 73 (GND) and the wiring 77 (GND) can function as a low potential power supply line
  • the wiring 79 (VDD) can function as a high potential power supply line.
  • the wiring 75 (TX), the wiring 76 (RS), and the wiring 78 (SE) can function as signal lines for controlling on / off of each transistor.
  • the wiring 73 (GND) and the wiring 77 (GND) may be provided as one wiring.
  • the potential of the two wirings is not limited to GND, and may be any potential that is sufficiently lower than the potential supplied to the wiring 79 (VDD).
  • the photoelectric conversion element 10 exhibits high-efficiency photoelectric characteristics when a high voltage potential HVDD is applied.
  • the potential HVDD is higher than the potential VDD supplied to the wiring 79 (VDD).
  • the photoelectric conversion element 10 is preferably a photoelectric conversion element that produces an avalanche multiplication effect in order to increase the light detection sensitivity at low illuminance.
  • a relatively high potential HVDD is required. Therefore, the high voltage power supply 56 has a function of supplying the potential HVDD, and the potential HVDD is supplied to the other electrode of the photoelectric conversion element 10 through the wiring 72 (HVDD).
  • the photoelectric conversion element 10 can be used by applying a potential that does not cause an avalanche multiplication effect.
  • the transistor 51 can function as a transfer transistor for transferring the potential of the charge storage portion (NR) that changes according to the output of the photoelectric conversion element 10 to the charge storage portion (ND).
  • the transistor 52 can function as a reset transistor that initializes the potentials of the charge storage portion (NR) and the charge storage portion (ND).
  • the transistor 53 can function as an amplification transistor that outputs a signal corresponding to the potential of the charge storage portion (ND).
  • the transistor 54 can function as a selection transistor that selects a pixel from which a signal is read.
  • a high breakdown voltage transistor that can withstand the high voltage as a transistor connected to the photoelectric conversion element 10.
  • a transistor including an oxide semiconductor in a semiconductor layer hereinafter referred to as an OS transistor
  • OS transistors are preferably used as the transistor 51 and the transistor 52.
  • the transistors 51 and 52 are desired to have excellent switching characteristics, but the transistor 53 is preferably a transistor with high on-state current because it is desired to have excellent amplification characteristics. Therefore, it is preferable to apply a transistor using silicon as an active layer or an active region (hereinafter, Si transistor) as the transistor 53 and the transistor 54.
  • Si transistor silicon as an active layer or an active region
  • an imaging device with high light detection sensitivity at low illuminance and capable of outputting a signal with little noise can be manufactured.
  • the light detection sensitivity is high, the light capture time can be shortened and imaging can be performed at high speed.
  • the transistor is not limited to the above structure, and an OS transistor may be applied to the transistor 53 and the transistor 54.
  • Si transistors may be applied to the transistors 51 and 52. In any case, the imaging operation of the pixel circuit is possible.
  • the wiring 76 (RS) connected to the gate of the transistor 52 is supplied with HVDD as “H” and GND as “L”.
  • the wiring 75 (TX) connected to the gate of the transistor 51 and the wiring 78 (SE) connected to the gate of the transistor 54 are supplied with VDD as “H” and GND as “L”.
  • the potential of VDD is supplied to the wiring 79 (VDD) connected to the source of the transistor 53. Note that a potential other than the above may be supplied to each wiring.
  • the wiring 76 (RS) is set to “H”
  • the wiring 75 (TX) is set to “H”
  • the potentials of the charge storage portion (NR) and the charge storage portion (ND) are set to the reset potential (GND) (reset) Operation).
  • the potential VDD may be supplied to the wiring 76 (RS) as “H” during the reset operation.
  • the potential of the charge storage portion (NR) changes (accumulation operation).
  • the potential of the charge storage portion (NR) changes from GND to HVDD at the maximum according to the intensity (Bright) of light incident on the photoelectric conversion element 10.
  • the wiring 75 (TX) is set to “H”, and the charge in the charge accumulation portion (NR) is transferred to the charge accumulation portion (ND) (transfer operation).
  • the potential of the charge accumulation unit (ND) changes according to the intensity of light incident on the photoelectric conversion element 10, but VDD is supplied to the gate of the transistor 51, and thus the charge accumulation unit (ND).
  • the transistor 51 is turned off when the potential reaches the VDD. Therefore, the potential of the charge storage portion (ND) changes from the reset potential (GND) to the maximum VDD. In other words, the maximum potential of VDD is applied to the gate of the transistor 53.
  • the wiring 75 (TX) is set to “L” in the accumulation operation, but the wiring 75 (TX) may be set to “H”.
  • the potential of the charge storage unit (ND) also changes with a change in the potential of the charge storage unit (NR).
  • VDD is supplied to the gate of the transistor 51
  • the potential of the charge storage unit (ND) When the voltage reaches VDD, the transistor 51 is turned off. Therefore, the potential of the charge storage portion (ND) changes from the reset potential (GND) to the maximum VDD. That is, even in this case, the maximum potential of VDD is applied to the gate of the transistor 53.
  • the wiring 76 (RS) is set to “L” and the wiring 75 (TX) is set to “L”, and the transfer operation is finished. At this time, the potential of the charge storage portion (ND) is determined.
  • the wiring 76 (RS) is set to “L”
  • the wiring 75 (TX) is set to “L”
  • the wiring 78 (SE) is set to “H”
  • a signal corresponding to the potential of the charge accumulation portion (ND) Output to the wiring 71 (OUT). That is, an output signal corresponding to the intensity of light incident on the photoelectric conversion element 10 in the accumulation operation can be obtained.
  • FIG. 18 illustrates an example of a pixel configuration of an imaging device having the pixel circuit described above.
  • the imaging device may include a layer 31, a layer 32, and a layer 33, each having a region that overlaps with each other.
  • the layer 31 has the configuration of the photoelectric conversion element 10, and includes a pixel electrode 35 corresponding to the first electrode 411 or the first electrode 15, a photoelectric conversion layer 36 corresponding to the photoelectric conversion layer 413 or the photoelectric conversion layer 11,
  • the common electrode 37 corresponding to the second electrode 415 or the second electrode 14 is provided.
  • light (Light) incident on the imaging device is indicated by an arrow.
  • the layer 32 can be, for example, a layer having OS transistors (transistors 51 and 52).
  • OS transistors transistors 51 and 52.
  • the circuit configuration of the pixel shown in FIG. 16 when the intensity of light incident on the photoelectric conversion element 10 is small, the potential of the charge storage portion (ND) is small. Since the OS transistor has an extremely low off-state current, a current corresponding to the gate potential can be accurately output even when the gate potential is extremely small. Therefore, the range of illuminance that can be detected, that is, the dynamic range can be expanded.
  • the period in which charges can be held in the charge storage portion (ND) and the charge storage portion (NR) can be extremely long. Therefore, it is possible to apply a global shutter system in which charge accumulation operation is simultaneously performed in all pixels without complicating a circuit configuration and an operation method.
  • a metal oxide having an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more can be used.
  • a typical example is an oxide semiconductor containing indium.
  • a CAC-OS described later can be used.
  • the semiconductor layer is represented by an In-M-Zn-based oxide containing indium, zinc, and M (metal such as aluminum, titanium, gallium, germanium, yttrium, zirconium, lanthanum, cerium, tin, neodymium, or hafnium). It can be a membrane.
  • the atomic ratio of the metal elements of the sputtering target used for forming the In-M-Zn oxide is In ⁇ M, Zn It is preferable to satisfy ⁇ M.
  • the atomic ratio of the semiconductor layer to be formed includes a variation of plus or minus 40% of the atomic ratio of the metal element contained in the sputtering target.
  • the semiconductor layer an oxide semiconductor with low carrier density is used.
  • the semiconductor layer has a carrier density of 1 ⁇ 10 17 / cm 3 or less, preferably 1 ⁇ 10 15 / cm 3 or less, more preferably 1 ⁇ 10 13 / cm 3 or less, and even more preferably 1 ⁇ 10 11 / cm 3. 3 or less, more preferably less than 1 ⁇ 10 10 / cm 3 , and an oxide semiconductor having a carrier density of 1 ⁇ 10 ⁇ 9 / cm 3 or more can be used.
  • Such an oxide semiconductor is referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor. Accordingly, it can be said that the oxide semiconductor has stable characteristics because the impurity concentration is low and the defect state density is low.
  • the composition is not limited thereto, and a transistor having an appropriate composition may be used depending on required semiconductor characteristics and electrical characteristics (such as field-effect mobility and threshold voltage) of the transistor.
  • the semiconductor layer in order to obtain the required semiconductor characteristics of the transistor, it is preferable that the semiconductor layer have appropriate carrier density, impurity concentration, defect density, atomic ratio of metal element to oxygen, interatomic distance, density, and the like. .
  • the concentration of silicon or carbon in the semiconductor layer is 2 ⁇ 10 18 atoms / cm 3 or less, preferably 2 ⁇ 10 17 atoms / cm 3 or less.
  • the concentration of alkali metal or alkaline earth metal (concentration obtained by secondary ion mass spectrometry) in the semiconductor layer is 1 ⁇ 10 18 atoms / cm 3 or less, preferably 2 ⁇ 10 16 atoms / cm 3 or less.
  • the nitrogen concentration (concentration obtained by secondary ion mass spectrometry) in the semiconductor layer is preferably 5 ⁇ 10 18 atoms / cm 3 or less.
  • the semiconductor layer may have a non-single crystal structure, for example.
  • the non-single crystal structure includes, for example, a CAAC-OS (C-Axis Aligned Crystalline Oxide Semiconductor, or C-Axis Aligned and A-B-plane Annealed Crystalline Structure, a C-axis aligned crystal, and a C-axis aligned crystal structure. Includes a microcrystalline structure or an amorphous structure. In the non-single-crystal structure, the amorphous structure has the highest density of defect states, and the CAAC-OS has the lowest density of defect states.
  • An oxide semiconductor film having an amorphous structure has, for example, disordered atomic arrangement and no crystal component.
  • an oxide semiconductor film with an amorphous structure has, for example, a completely amorphous structure and has no crystal part.
  • the semiconductor layer may be a mixed film including two or more of an amorphous structure region, a microcrystalline structure region, a polycrystalline structure region, a CAAC-OS region, and a single crystal structure region.
  • the mixed film may have a single-layer structure or a stacked structure including any two or more of the above-described regions.
  • CAC Cloud-Aligned Composite
  • the CAC-OS is one structure of a material in which an element included in an oxide semiconductor is unevenly distributed with a size of 0.5 nm to 10 nm, preferably 1 nm to 2 nm, or the vicinity thereof. Note that in the following, in an oxide semiconductor, one or more metal elements are unevenly distributed, and a region including the metal element has a size of 0.5 nm to 10 nm, preferably 1 nm to 2 nm, or the vicinity thereof.
  • the state mixed with is also referred to as a mosaic or patch.
  • the oxide semiconductor preferably contains at least indium.
  • One kind selected from the above or a plurality of kinds may be included.
  • a CAC-OS in In-Ga-Zn oxide is an indium oxide (hereinafter referred to as InO).
  • X1 (X1 is greater real than 0) and.), or indium zinc oxide (hereinafter, in X2 Zn Y2 O Z2 ( X2, Y2, and Z2 is larger real than 0) and a.), gallium An oxide (hereinafter referred to as GaO X3 (X3 is a real number greater than 0)) or a gallium zinc oxide (hereinafter referred to as Ga X4 Zn Y4 O Z4 (where X4, Y4, and Z4 are greater than 0)) to.) and the like, the material becomes mosaic by separate into, mosaic InO X1 or in X2 Zn Y2 O Z2, is a configuration in which uniformly distributed in the film (hereinafter Also referred to as a cloud-like.) A.
  • CAC-OS includes a region GaO X3 is the main component, and In X2 Zn Y2 O Z2, or InO X1 is the main component region is a composite oxide semiconductor having a structure that is mixed.
  • the first region indicates that the atomic ratio of In to the element M in the first region is larger than the atomic ratio of In to the element M in the second region. It is assumed that the concentration of In is higher than that in the second region.
  • IGZO is a common name and may refer to one compound of In, Ga, Zn, and O.
  • ZnO ZnO
  • the crystalline compound has a single crystal structure, a polycrystalline structure, or a CAAC structure.
  • the CAAC structure is a crystal structure in which a plurality of IGZO nanocrystals have c-axis orientation and are connected without being oriented in the ab plane.
  • CAC-OS relates to a material structure of an oxide semiconductor.
  • CAC-OS refers to a region observed in the form of nanoparticles mainly composed of Ga in a material structure including In, Ga, Zn and O, and nanoparticles mainly composed of In.
  • the region observed in a shape is a configuration in which the regions are randomly dispersed in a mosaic shape. Therefore, in the CAC-OS, the crystal structure is a secondary element.
  • the CAC-OS does not include a stacked structure of two or more kinds of films having different compositions.
  • a structure composed of two layers of a film mainly containing In and a film mainly containing Ga is not included.
  • a region GaO X3 is the main component, and In X2 Zn Y2 O Z2 or InO X1 is the main component region, in some cases clear boundary can not be observed.
  • the CAC-OS includes a region that is observed in a part of a nanoparticle mainly including the metal element and a nanoparticle mainly including In.
  • the region observed in the form of particles refers to a configuration in which each region is randomly dispersed in a mosaic shape.
  • the CAC-OS can be formed by a sputtering method, for example, without heating the substrate.
  • a CAC-OS is formed by a sputtering method
  • any one or more selected from an inert gas (typically argon), an oxygen gas, and a nitrogen gas may be used as a deposition gas. Good.
  • the flow rate ratio of the oxygen gas to the total flow rate of the deposition gas during film formation is preferably as low as possible. .
  • the CAC-OS has a feature that a clear peak is not observed when measurement is performed using a ⁇ / 2 ⁇ scan by an out-of-plane method, which is one of X-ray diffraction (XRD) measurement methods. Have. That is, it can be seen from X-ray diffraction that no orientation in the ab plane direction and c-axis direction of the measurement region is observed.
  • XRD X-ray diffraction
  • the CAC-OS in an electron beam diffraction pattern obtained by irradiating an electron beam with a probe diameter of 1 nm (also referred to as a nanobeam electron beam), a ring-shaped high luminance region and a plurality of regions in the ring region are provided. A bright spot is observed. Therefore, it can be seen from the electron beam diffraction pattern that the crystal structure of the CAC-OS has an nc (nano-crystl) structure having no orientation in the planar direction and the cross-sectional direction.
  • nc nano-crystl
  • GaO X3 is a main component by EDX mapping obtained by using energy dispersive X-ray spectroscopy (EDX). It can be confirmed that the region and the region mainly composed of In X2 Zn Y2 O Z2 or InO X1 are unevenly distributed and mixed.
  • EDX energy dispersive X-ray spectroscopy
  • CAC-OS has a structure different from that of an IGZO compound in which metal elements are uniformly distributed, and has a property different from that of an IGZO compound. That is, in the CAC-OS, a region in which GaO X3 or the like is a main component and a region in which In X2 Zn Y2 O Z2 or InO X1 is a main component are phase-separated from each other, and a region in which each element is a main component. Has a mosaic structure.
  • the region containing In X2 Zn Y2 O Z2 or InO X1 as a main component is a region having higher conductivity than a region containing GaO X3 or the like as a main component. That, In X2 Zn Y2 O Z2 or InO X1, is an area which is the main component, by carriers flow, expressed the conductivity of the oxide semiconductor. Therefore, a region where In X2 Zn Y2 O Z2 or InO X1 is a main component is distributed in a cloud shape in the oxide semiconductor, whereby high field-effect mobility ( ⁇ ) can be realized.
  • areas such as GaO X3 is the main component, as compared to the In X2 Zn Y2 O Z2 or InO X1 is the main component area, it is highly regions insulating. That is, a region containing GaO X3 or the like as a main component is distributed in the oxide semiconductor, whereby leakage current can be suppressed and good switching operation can be realized.
  • CAC-OS when CAC-OS is used for a semiconductor element, the insulating property caused by GaO X3 and the like and the conductivity caused by In X2 Zn Y2 O Z2 or InO X1 act complementarily, thereby increasing the An on-current (I on ) and high field effect mobility ( ⁇ ) can be realized.
  • CAC-OS is suitable as a constituent material for various semiconductor devices.
  • the layer 33 can be a supporting substrate or a layer having a Si transistor (transistor 53, transistor 54).
  • the Si transistor can be configured to have a crystalline silicon active layer on an insulating surface such as a glass substrate in addition to a configuration having an active region in a single crystal silicon substrate.
  • FIG. 19 is a block diagram illustrating a circuit configuration of the imaging device of one embodiment of the present invention.
  • the imaging apparatus includes a pixel array 21 having pixels 20 arranged in a matrix, a circuit 22 (row driver) having a function of selecting a row of the pixel array 21, and a correlation double with respect to an output signal of the pixel 20.
  • a circuit 23 (CDS circuit) for performing sampling processing, a circuit 24 (A / D conversion circuit or the like) having a function of converting analog data output from the circuit 23 into digital data, and data converted by the circuit 24
  • a circuit 25 columnumn driver having a function of selecting and reading out. Note that the circuit 23 may be omitted.
  • the elements of the pixel array 21 excluding the photoelectric conversion elements can be provided in the layer 32 in FIG.
  • Elements of the circuits 22 to 25 can be provided in the layer 33.
  • These circuits can be constituted by CMOS circuits using silicon transistors.
  • a transistor suitable for each circuit can be used, and the area of the imaging device can be reduced.
  • FIG. 20A, 20B, and 20C are diagrams illustrating a specific configuration of the imaging device illustrated in FIG.
  • FIG. 20A is a cross-sectional view illustrating the channel length direction of the transistors 51, 52, 53, and 54.
  • 20B is a cross-sectional view taken along dashed-dotted line X1-X2 in FIG. 20A and illustrates a cross section of the transistor 51 in the channel width direction.
  • 20C is a cross-sectional view taken along dashed-dotted line Y1-Y2 in FIG. 20A and illustrates a cross section of the transistor 53 in the channel width direction.
  • the layer 31 can include a partition 82 in addition to the photoelectric conversion element 10.
  • the partition wall 82 is provided at the boundary portion of the pixel electrode 35 between the pixels.
  • the selenium layer used for the photoelectric conversion layer has high resistance and can be configured not to be separated between pixels.
  • the layer 32 is provided with transistors 51 and 52 which are OS transistors. Although the transistors 51 and 52 both have a structure having a back gate 81, any of the transistors 51 and 52 may have a back gate. As shown in FIG. 20B, the back gate 81 may be electrically connected to a front gate of a transistor provided to face the back gate 81. Alternatively, the back gate 81 may be supplied with a fixed potential different from that of the front gate.
  • a self-aligned top gate transistor is illustrated as the OS transistor, but a non-self-aligned transistor may be used as shown in FIG.
  • the layer 33 is provided with a transistor 53 and a transistor 54 which are Si transistors.
  • 20A illustrates the structure in which the Si transistor includes a fin-type semiconductor layer provided over the silicon substrate 300, but may be a planar type as illustrated in FIG. Alternatively, a transistor including a semiconductor layer 310 of a silicon thin film may be used as shown in FIG.
  • the semiconductor layer can be polycrystalline silicon or single crystal silicon of SOI (Silicon on Insulator).
  • the layer 33 can be provided with a circuit for driving the pixel.
  • An insulating layer 80 is provided between the region where the OS transistor is formed and the region where the Si transistor is formed. Hydrogen in the insulating layer provided in the vicinity of the active regions of the transistors 53 and 54 terminates dangling bonds of silicon. Therefore, the hydrogen has an effect of improving the reliability of the transistors 53 and 54. On the other hand, hydrogen in the insulating layer provided in the vicinity of the oxide semiconductor layer which is an active layer of the transistors 51 and 52 is one of the factors that generate carriers in the oxide semiconductor layer. Therefore, the hydrogen may be a factor that decreases the reliability of the transistors 51 and 52.
  • an insulating layer 80 having a function of preventing hydrogen diffusion therebetween it is preferable to provide an insulating layer 80 having a function of preventing hydrogen diffusion therebetween.
  • the reliability of the transistors 53 and 54 can be improved by confining hydrogen in one layer by the insulating layer 80.
  • the reliability of the transistors 51 and 52 can be improved.
  • the insulating layer 80 for example, aluminum oxide, aluminum oxynitride, gallium oxide, gallium oxynitride, yttrium oxide, yttrium oxynitride, hafnium oxide, hafnium oxynitride, yttria-stabilized zirconia (YSZ), or the like can be used.
  • aluminum oxide, aluminum oxynitride, gallium oxide, gallium oxynitride, yttrium oxide, yttrium oxynitride, hafnium oxide, hafnium oxynitride, yttria-stabilized zirconia (YSZ), or the like can be used.
  • FIG. 22A is a cross-sectional view illustrating an example in which a color filter or the like is added to the imaging device of one embodiment of the present invention.
  • a part of a region having a pixel circuit for three pixels is shown.
  • An insulating layer 100 is formed on the layer 31 where the photoelectric conversion element 10 is formed.
  • the insulating layer 100 can be formed using a silicon oxide film having high light-transmitting property with respect to visible light.
  • a silicon nitride film may be stacked as a passivation film.
  • a dielectric film such as hafnium oxide may be laminated as the antireflection film.
  • a light shielding layer 110 may be formed on the insulating layer 100.
  • the light shielding layer 110 has a function of preventing color mixture of light passing through the upper color filter.
  • a metal layer such as aluminum or tungsten can be used for the light shielding layer 110. Further, the metal layer and a dielectric film having a function as an antireflection film may be stacked.
  • An organic resin layer 120 can be provided as a planarization film over the insulating layer 100 and the light shielding layer 110.
  • a color filter 130 (color filter 130a, color filter 130b, and color filter 130c) is formed for each pixel.
  • colors such as R (red), G (green), B (blue), Y (yellow), C (cyan), and M (magenta) are assigned to the color filters 130a, 130b, and 130c.
  • An insulating layer 160 having a light-transmitting property with respect to visible light or the like can be provided over the color filter 130.
  • an optical conversion layer 150 may be used instead of the color filter 130. With such a configuration, an imaging device capable of obtaining images in various wavelength regions can be obtained.
  • an infrared imaging device can be obtained.
  • a far infrared imaging device can be obtained.
  • an ultraviolet imaging device can be obtained.
  • an imaging device that obtains an image that visualizes the intensity of radiation used in an X-ray imaging device or the like can be obtained.
  • radiation such as X-rays transmitted through the subject
  • the scintillator it is converted into light (fluorescence) such as visible light or ultraviolet light by a photoluminescence phenomenon.
  • the photoelectric conversion element 10 detects the light to acquire image data.
  • the imaging device having the configuration may be used for a radiation detector or the like.
  • a scintillator contains a substance that emits visible light or ultraviolet light by absorbing energy when irradiated with radiation such as X-rays or gamma rays.
  • Gd 2 O 2 S Tb
  • Gd 2 O 2 S Pr
  • Gd 2 O 2 S Eu
  • BaFCl Eu
  • distributed to resin or ceramics can be used.
  • the photoelectric conversion element 10 using a selenium-based material can directly convert radiation such as X-rays into electric charges, and thus can be configured to eliminate a scintillator.
  • a microlens array 140 may be provided over the color filter 130a, the color filter 130b, and the color filter 130c. Light passing through the individual lenses of the microlens array 140 passes through the color filter directly below and is irradiated onto the photoelectric conversion element 10. Further, as shown in FIG. 22D, a microlens array 140 may be provided over the optical conversion layer 150.
  • FIG. 23A is an external perspective view of the upper surface side of the package containing the image sensor chip.
  • the package includes a package substrate 210 that fixes the image sensor chip 250, a cover glass 220, and an adhesive 230 that bonds the two together.
  • FIG. 23B is an external perspective view of the lower surface side of the package.
  • the bottom surface of the package has a BGA (Ball grid array) configuration with solder balls as bumps 240.
  • BGA Bit grid array
  • LGA Land grid array
  • PGA Peripheral Component Interconnect
  • FIG. 23C is a perspective view of the package shown with a part of the cover glass 220 and the adhesive 230 omitted
  • FIG. 23D is a cross-sectional view of the package.
  • An electrode pad 260 is formed on the package substrate 210, and the electrode pad 260 and the bump 240 are electrically connected through the through hole 280 and the land 285.
  • the electrode pad 260 is electrically connected to an electrode included in the image sensor chip 250 by a wire 270.
  • FIG. 24A is an external perspective view of the upper surface side of the camera module in which the image sensor chip is housed in a lens-integrated package.
  • the camera module includes a package substrate 211 that fixes the image sensor chip 251, a lens cover 221, a lens 235, and the like. Further, an IC chip 290 having functions such as a drive circuit and a signal conversion circuit of the imaging device is also provided between the package substrate 211 and the image sensor chip 251, and has a configuration as a SiP (System in package). Yes.
  • SiP System in package
  • FIG. 24B is an external perspective view of the lower surface side of the camera module.
  • the package substrate 211 has a QFN (Quad Flat No-Lead Package) configuration in which mounting lands 241 are provided on a lower surface and four side surfaces.
  • the configuration is an example, and may be a QFP (Quad Flat Package), the BGA described above, or the like.
  • FIG. 24C is a perspective view of the module shown with a part of the lens cover 221 and the lens 235 omitted
  • FIG. 24D is a cross-sectional view of the camera module.
  • a part of the land 241 is used as an electrode pad 261, and the electrode pad 261 is electrically connected to electrodes included in the image sensor chip 251 and the IC chip 290 by wires 271.
  • the image sensor chip By mounting the image sensor chip in a package having the above-described form, mounting on a printed board or the like is facilitated, and the image sensor chip can be incorporated into various semiconductor devices and electronic devices.
  • Electronic devices that can use the imaging device according to one embodiment of the present invention include a display device, a personal computer, an image storage device or an image playback device including a recording medium, a mobile phone, a portable game machine, and a portable data terminal , Digital book terminals, video cameras, digital still cameras and other cameras, goggles-type displays (head-mounted displays), navigation systems, sound playback devices (car audio, digital audio players, etc.), copiers, facsimiles, printers, printer multifunction devices Automatic teller machines (ATMs), vending machines, and the like. Specific examples of these electronic devices are shown in FIGS.
  • FIG. 25A illustrates a monitoring camera, which includes a housing 951, a lens 952, a support portion 953, and the like.
  • the imaging device of one embodiment of the present invention can be provided as one of the components for acquiring an image in the monitoring camera.
  • the surveillance camera is an idiomatic name and does not limit the application.
  • a device having a function as a surveillance camera is also called a camera or a video camera.
  • FIG. 25B illustrates a video camera, which includes a first housing 971, a second housing 972, a display portion 973, operation keys 974, a lens 975, a connection portion 976, and the like.
  • the operation key 974 and the lens 975 are provided in the first housing 971, and the display portion 973 is provided in the second housing 972.
  • the imaging device of one embodiment of the present invention can be provided as one of the components for acquiring an image in the video camera.
  • FIG. 25C illustrates a digital camera, which includes a housing 961, a shutter button 962, a microphone 963, a light-emitting portion 967, a lens 965, and the like.
  • the imaging device of one embodiment of the present invention can be provided as one of the components for acquiring an image in the digital camera.
  • FIG. 25D illustrates a wristwatch-type information terminal which includes a housing 931, a display portion 932, a wristband 933, operation buttons 935, a crown 936, a camera 939, and the like.
  • the display unit 932 may be a touch panel.
  • the imaging device of one embodiment of the present invention can be provided as one of the components for acquiring an image in the information terminal.
  • FIG. 25E illustrates an example of a cellular phone, which includes a housing 981, a display portion 982, operation buttons 983, an external connection port 984, a speaker 985, a microphone 986, a camera 987, and the like.
  • the mobile phone includes a touch sensor in the display portion 982. All operations such as making a call or inputting characters can be performed by touching the display portion 982 with a finger, a stylus, or the like.
  • the imaging device of one embodiment of the present invention can be provided as one of the components for acquiring an image in the mobile phone.
  • FIG. 25F illustrates a portable data terminal, which includes a housing 911, a display portion 912, a camera 919, and the like. Information can be input and output by a touch panel function of the display portion 912.
  • the imaging device of one embodiment of the present invention can be provided as one of the components for acquiring an image in the portable data terminal.
  • crystalline selenium according to one embodiment of the present invention was manufactured, and the presence of crystallinity and a film peeling region was evaluated.
  • samples A1 to A10 which are one embodiment of the present invention and comparative samples a1 to a9 which are comparisons.
  • Sample A1 to sample A10 and comparative sample a1 to comparative sample a9 differ in the presence or absence of the underlayer film formation, the film type of the underlayer, the substrate temperature during the selenium layer formation, and the like.
  • the silver film thickness of Sample A1 was 2 nm.
  • the silver film thickness of Sample A2 was 5 nm.
  • Sample A3 had a silver film thickness of 10 nm.
  • Sample A4 had a silver film thickness of 20 nm.
  • the ITSO film thickness of Sample A8 was 200 nm.
  • the film thickness of ITO of sample A9 and sample A10 was 100 nm.
  • the selenium layer of Sample A10 100 ° C.
  • the film thickness of the comparative sample a1 was 20 nm.
  • the film thickness of bismuth of comparative sample a2 was 20 nm.
  • the film thickness of titanium of the comparative sample a3 was 20 nm.
  • Table 2 shows the conditions of each sample.
  • Table 2 shows the film type of the underlayer, the underlayer film formation method, the substrate temperature (Tsub) during underlayer film formation, the underlayer film thickness, the selenium layer formation method, and the selenium layer formation time for each sample.
  • the substrate temperature (Tsub) and the film thickness of the selenium layer are shown.
  • RT indicates that the film was formed at room temperature (RT) without heating the substrate.
  • the column described as “underlayer-selenium layer” indicates whether the underlayer film formation and the selenium layer film formation are performed continuously or discontinuously.
  • the column describing heat treatment indicates whether or not heat treatment was performed after the selenium layer was formed. In this example, none of the samples was subjected to heat treatment.
  • FIGS. 26A and 26B are cross-sectional views illustrating a method for manufacturing a sample.
  • the base layer 63 was formed over the substrate 61 (see FIG. 26A).
  • As the substrate 61 a glass substrate AN100 manufactured by Asahi Glass Co., Ltd. was used.
  • Samples A1 to A6 silver was used for the base layer 63.
  • ITO In Sample A9 and Sample A10, ITO was used for the base layer 63.
  • indium was used for the base layer 63.
  • the base layer 63 was not formed.
  • the formation of the base layer 63 of the samples A1 to A7, the comparative sample a1, and the comparative sample a2 was performed using a vapor deposition chamber of a vapor deposition-sputtering composite apparatus (apparatus model number: VD15-065) manufactured by Shinko Seiki Co., Ltd. Using resistance heating (Ta board), about 0.20 nm / sec. The underlayer was formed at a deposition rate of The pressure during vapor deposition was about 1.0 ⁇ 10 ⁇ 5 Pa.
  • Samples A1 to A6 and comparative sample a1 used silver as a deposition source.
  • Sample A7 and comparative sample a2 used bismuth as a deposition source.
  • the comparative sample a3 used a titanium target, and the film forming gas used was an argon (Ar) gas having a flow rate of 40 sccm. The pressure during film formation was adjusted to 0.4 Pa. The deposition power was 400W.
  • the comparative sample a4 used an indium target, and the film forming gas used was an argon (Ar) gas having a flow rate of 40 sccm. The pressure during film formation was adjusted to 0.4 Pa. The deposition power was 400W.
  • the formation of the foundation layer 63 of the sample A9 and the sample A10 was performed using a sputtering apparatus (equipment model number: E401-S) manufactured by Canon Anelva Engineering.
  • An ITO target was used, and an argon (Ar) gas having a flow rate of 30 sccm and an oxygen (O 2 ) gas having a flow rate of 30 sccm were used as a film forming gas.
  • the pressure during film formation was adjusted to 0.2 Pa.
  • the deposition power was 100W.
  • the selenium layer 65 was continuously formed in vacuum after the base layer 63 was formed. Samples A8 to A10 were once exposed to the air atmosphere after the underlayer 63 was formed, and then the selenium layer 65 was formed.
  • a deposition chamber of a deposition-sputtering composite apparatus (apparatus model number: VD15-065) manufactured by Shinko Seiki Co., Ltd. was used.
  • the deposition of selenium uses resistance heating (Ta board), and is about 0.20 nm / sec.
  • the film was formed at the vapor deposition rate.
  • the pressure during vapor deposition was about 1.0 ⁇ 10 ⁇ 5 Pa.
  • XRD measurement was performed on Samples A1 to A10 and Comparative Samples a1 to a9, and the crystallinity of the selenium layer was evaluated.
  • XRD measurement an X-ray diffractometer D8 DISCOVERHybrid manufactured by Bruker AXS was used, and CuK ⁇ rays having a wavelength of 0.15418 nm were used as an X-ray source.
  • FIG. 27 shows a spectrum obtained by the ⁇ -2 ⁇ scan method, which is a kind of out-of-plane method, and the horizontal axis represents the diffraction angle 2 ⁇ [deg.
  • the vertical axis represents the diffracted X-ray intensity (Intensity) [arbitrary unit (arb. Unit)].
  • the ⁇ -2 ⁇ scan method is a method of measuring the X-ray diffraction intensity by changing the incident angle of the X-ray and setting the angle of the detector provided facing the X-ray source to be the same as the incident angle.
  • the ⁇ -2 ⁇ scan method may be called a powder method.
  • the GIXRD method is a method of measuring the X-ray diffraction intensity by fixing the incident angle of X-rays at a very shallow angle and changing the angle of a detector provided facing the X-ray source.
  • the GIXRD method may be called a 2 ⁇ scan method, a thin film method, or a Seemann-Bohlin method.
  • the X-ray incident angle is set to 0.35 deg. Measured by fixing to
  • FIGS. 27 and 28 also show spectra of Se (ICSD code 40018), Ag (ICSD code 44387), and Ag 2 Se (ICSD code 15213) of the inorganic crystal structure database (ICSD).
  • the peaks observed in the samples A1 to A6 using silver for the underlayer substantially coincide with the peak position of Se (ICSD code 40018), so the samples A1 to A6 It was confirmed that the selenium layer was crystalline selenium. It was found that crystalline selenium can be obtained by using silver for the underlayer and heating selenium to form a film.
  • FIG. 29 shows a spectrum obtained by the ⁇ -2 ⁇ scanning method, and the horizontal axis represents the diffraction angle 2 ⁇ [deg.
  • the vertical axis represents the diffracted X-ray intensity (Intensity) [arbitrary unit (arb. Unit)].
  • FIG. 30 shows a spectrum obtained by the GIXRD method, and the horizontal axis represents the diffraction angle 2 ⁇ [deg.
  • the vertical axis represents the diffracted X-ray intensity (Intensity) [arbitrary unit (arb. Unit)].
  • the X-ray incident angle is set to 0.35 deg. Measured by fixing to
  • ICSD Se inorganic crystal structure database
  • Bi ICSD code 64703
  • Bi 2 Se 3 ICSD code 1652236
  • In 1.94 Sn 0.06 O 3 The spectrum of ICSD code 50847) is also shown.
  • the peak observed in the sample A7 using bismuth for the underlayer almost coincides with the peak position of Se (ICSD code 40018), so the selenium layer of the sample A7 is crystalline selenium. It was confirmed that. It was found that crystalline selenium can be obtained by using bismuth for the underlayer and heating selenium to form a film.
  • FIG. 31 shows a spectrum obtained by the ⁇ -2 ⁇ scan method, and the horizontal axis represents the diffraction angle 2 ⁇ [deg.
  • the vertical axis represents the diffracted X-ray intensity (Intensity) [arbitrary unit (arb. Unit)].
  • FIG. 32 shows a spectrum obtained by the GIXRD method, and the horizontal axis represents the diffraction angle 2 ⁇ [deg.
  • the vertical axis represents the diffracted X-ray intensity (Intensity) [arbitrary unit (arb. Unit)].
  • the X-ray incident angle is set to 0.35 deg. Measured by fixing to
  • FIGS. 31 and 32 show Se (ICSD code 40018), Ag (ICSD code 44387), Ag 2 Se (ICSD code 15213), Bi (ICSD code 64703), Ti (ICSD code 41503) in the inorganic crystal structure database (ICSD). ) And In (ICSD code 171679) spectra are also shown.
  • Comparative sample a1 is a sample in which silver is used for the base layer and a selenium layer is formed at room temperature.
  • the above-described sample A4 is a sample in which silver is used for the base layer and the selenium layer is heated to form a film. In sample A4, a peak attributed to Se was observed, and in comparative sample a1, no peak was observed. Therefore, it has been clarified that crystalline selenium can be obtained after the selenium film is formed by using silver for the underlayer and heating the selenium layer.
  • Comparative sample a2 is a sample in which bismuth is used for the underlayer and a selenium layer is formed at room temperature.
  • the above-mentioned sample A7 is a sample in which bismuth is used for the base layer and the selenium layer is heated to form a film. In sample A7, a peak attributed to Se was observed, and no peak was observed in comparative sample a2. Therefore, it has been clarified that crystalline selenium can be obtained after selenium film formation by heating the selenium layer by using bismuth for the base layer.
  • Comparative sample a3 is a sample in which titanium is used for the base layer and the selenium layer is heated to form a film. Therefore, it has been found that it is difficult to obtain crystalline selenium after selenium film formation even when titanium is used for the base layer and the selenium layer is heated.
  • Comparative sample a4 is a sample in which indium is used for the base layer and the selenium layer is heated to form a film. Therefore, it has been found that it is difficult to obtain crystalline selenium after the selenium film is formed even if indium is used for the base layer and the selenium layer is heated.
  • FIG. 33 shows a spectrum obtained by the ⁇ -2 ⁇ scanning method, and the horizontal axis represents the diffraction angle 2 ⁇ [deg.
  • the vertical axis represents the diffracted X-ray intensity (Intensity) [arbitrary unit (arb. Unit)].
  • FIG. 33 also shows spectra of Se (ICSD code 40018), Ag (ICSD code 44387), and Ag 2 Se (ICSD code 15213) of the inorganic crystal structure database (ICSD).
  • Comparative Samples a5 to a8 no peak attributed to Se was observed.
  • Comparative Sample a9 a peak attributed to Se was observed, but it was a very small peak. Therefore, it was found that the selenium layers of the comparative samples a5 to a9 have low crystallinity.
  • Comparative samples a5 to a9 are samples in which a selenium layer is formed without forming a base layer. Therefore, it was found that a crystalline selenium layer can be obtained by forming the base layer.
  • FIG. 34A is a SEM image of the plane of the sample A1
  • FIG. 34B is a SEM image of the plane of the sample A2
  • FIG. 34C is a SEM image of the plane of the sample A3, and a SEM image of the plane of the sample A4.
  • FIG. 34D shows a planar SEM image of the sample A5
  • FIG. 34F shows a planar SEM image of the sample A6.
  • FIGS. 34A to 34F no film peeling region was observed in any of Samples A1 to A6 in which silver was used for the base layer. It was found that by using silver for the underlayer, crystalline selenium with few film peeling regions can be produced.
  • FIG. 35A shows a plane SEM image of the sample A7
  • FIG. 35B shows a SEM image of the plane of the sample A8
  • FIG. 35C shows a SEM image of the plane of the sample A9
  • FIG. 35C shows a plane SEM image of the sample A10.
  • FIG. 35A in the sample A7 using bismuth for the base layer, no film peeling region was observed. It has been found that by using bismuth for the underlayer, crystalline selenium with few film peeling regions can be produced.
  • FIGS. 35 (B) to 35 (D) film peeling regions were observed in all of samples A8 to A10 using ITO or ITSO for the base layer.
  • the crystalline selenium can be produced by using ITO or ITSO for the underlayer, the generation of the film peeling region could not be suppressed. Note that in FIGS. 35B to 35D, the distorted particles are considered to be crystallized selenium.
  • FIG. 36A shows a planar SEM image of the comparative sample a3
  • FIG. 36B shows a planar SEM image of the comparative sample a4.
  • FIGS. 36A and 36B no film peeling region was observed in the comparative sample a3 and the comparative sample a4 in which titanium or indium was used for the base layer.
  • the comparative sample a3 and the comparative sample a4 had no peak observed by XRD, and the crystallinity of the selenium layer was low.
  • the SEM image of the plane of the comparative sample a5 is FIG. 37A
  • the SEM image of the plane of the comparative sample a6 is FIG. 37B
  • the SEM image of the plane of the comparative sample a8 is FIG. 37C
  • the plane of the comparative sample a9 An SEM image of is shown in FIG. In Comparative Sample a5, no film peeling area was observed.
  • FIG. 37B to FIG. 37D in the comparative sample a6, the comparative sample a8, and the comparative sample a9, film peeling regions were observed, and it was confirmed that selenium was aggregated.
  • no peak was observed in the comparative samples a5 to a8 by XRD.
  • Comparative sample a9 was a very small peak although a peak attributed to Se was observed. Note that in FIG. 37D, the distorted particle is considered to be crystalline selenium, and the smooth particle is considered to be amorphous selenium. As shown in Comparative Samples a5 to a9, it was found that when a selenium layer is heated and formed without providing a base layer, the crystallinity of the selenium layer is low and a film peeling region is likely to occur. Therefore, it was found that the formation of the underlayer is very effective for producing crystalline selenium with few film peeling regions.
  • crystalline selenium according to one embodiment of the present invention was manufactured, and the presence of crystallinity and a film peeling region was evaluated.
  • the samples are a total of 10 samples including sample A4, sample A7, sample A8, and samples B1 to B3 which are one embodiment of the present invention, and comparison sample a3, comparison sample a4, comparison sample b1, and comparison sample b2 that are comparisons.
  • Sample A4, Sample A7, Sample A8, Samples B1 to B3, Comparative sample a3, Comparative sample a4, Comparative sample b1 and Comparative sample b2 are either the film type of the underlayer, the underlayer and the selenium layer are continuously formed, The continuous film formation is different. Note that Sample A4, Sample A7, Sample A8, Comparative Sample a3, and Comparative Sample a4 are the same as the samples described in Example 1.
  • Table 3 shows the conditions of each sample. Table 3 shows the film type of the underlayer, the underlayer film formation method, the substrate temperature (Tsub) during underlayer film formation, the underlayer film thickness, the selenium layer formation method, and the selenium layer formation time for each sample. The substrate temperature (Tsub) and the film thickness of the selenium layer are shown. In the column of the substrate temperature (Tsub), “RT” indicates that the film was formed at room temperature (RT) without heating the substrate. In addition, the column described as “underlayer-selenium layer” indicates whether the underlayer film formation and the selenium layer film formation are performed continuously or discontinuously. The column describing heat treatment indicates whether or not heat treatment was performed after the selenium layer was formed. In this example, none of the samples was subjected to heat treatment.
  • Example preparation method A method for manufacturing each sample will be described with reference to FIGS. Since description of Example 1 can be referred to for Sample A4, Sample A7, Sample A8, Comparative Sample a3, and Comparative Sample a4, description thereof is omitted.
  • the base layer 63 was formed over the substrate 61 (see FIG. 26A).
  • As the substrate 61 a glass substrate AN100 manufactured by Asahi Glass Co., Ltd. was used.
  • titanium was used for the base layer 63.
  • indium was used for the base layer 63.
  • Formation of the base layer 63 of the sample B1 and the sample B2 was performed using a deposition chamber of a deposition-sputtering composite apparatus (apparatus model number: VD15-065) manufactured by Shinko Seiki Co., Ltd. Using resistance heating (Ta board), about 0.20 nm / sec. The underlayer was formed at a deposition rate of The pressure during vapor deposition was about 1.0 ⁇ 10 ⁇ 5 Pa.
  • Sample B1 used silver as a deposition source.
  • Sample B2 used bismuth as a deposition source.
  • Formation of the base layer 63 of the sample B3, the comparative sample b1, and the comparative sample b2 was performed using a sputtering chamber of an evaporation-sputtering composite apparatus (apparatus model number: VD15-065) manufactured by Shinko Seiki Co., Ltd.
  • the sample B3 used an ITSO target, and the deposition gas used was an argon (Ar) gas having a flow rate of 50 sccm and an oxygen (O 2 ) gas having a flow rate of 2 sccm.
  • the pressure during film formation was adjusted to 0.4 Pa.
  • the deposition power was 200W.
  • the comparative sample b1 used a titanium target, and the film forming gas used was an argon (Ar) gas having a flow rate of 40 sccm. The pressure during film formation was adjusted to 0.4 Pa. The deposition power was 400W.
  • the comparative sample b2 used an indium target, and the film forming gas used was an argon (Ar) gas having a flow rate of 40 sccm. The pressure during film formation was adjusted to 0.4 Pa. The deposition power was 400W.
  • Sample B1, Sample B2, Comparative Sample b1, and Comparative Sample b2 were once exposed to the air atmosphere after the underlayer 63 was formed, and then the selenium layer 65 was formed.
  • the selenium layer 65 was continuously formed in a vacuum after forming the base layer 63.
  • the deposition chamber of the Shinko Seiki Co., Ltd. vapor deposition-sputtering composite device (device model number: VD15-065) is used. It was.
  • the deposition of selenium uses resistance heating (Ta board), and is about 0.20 nm / sec. The film was formed at the vapor deposition rate. The pressure during vapor deposition was about 1.0 ⁇ 10 ⁇ 5 Pa.
  • XRD measurement was performed on Sample B1, Sample B2, Sample B3, Comparative Sample b1, and Comparative Sample b2, and the crystallinity of the selenium layer was evaluated.
  • XRD measurement an X-ray diffractometer D8 DISCOVER Hybrid manufactured by Bruker AXS was used, and CuK ⁇ rays having a wavelength of 0.15418 nm were used as an X-ray source.
  • FIG. 38 and 39 show the XRD spectra of Sample B1, Sample B2, and Sample B3.
  • FIG. 38 shows a spectrum obtained by the ⁇ -2 ⁇ scan method, and the horizontal axis represents the diffraction angle 2 ⁇ [deg. The vertical axis represents the diffracted X-ray intensity (Intensity) [arbitrary unit (arb. Unit)].
  • FIG. 39 shows a spectrum obtained by the GIXRD method. The horizontal axis represents the diffraction angle 2 ⁇ [deg. The vertical axis represents the diffracted X-ray intensity (Intensity) [arbitrary unit (arb. Unit)].
  • the X-ray incident angle is set to 0.35 deg. Measured by fixing to
  • Se inorganic crystal structure database (ICSD code 40018)
  • ICSD code 40018 also shows the spectrum of the Ag
  • ICSD code 15213 The spectra of sample A4, sample A7, and sample A8 are also shown.
  • the peaks observed in the sample A4 and the sample B1 using silver for the underlayer almost coincide with the peak position of Se (ICSD code 40018), so the sample A4 and the sample B1 It was confirmed that the selenium layer was crystalline selenium.
  • the sample A4 has a larger XRD peak and higher crystallinity than the sample B1.
  • impurities such as the air atmosphere did not adhere to the surface of the base layer, and a good base layer and selenium layer interface was formed when the selenium layer was formed. It is thought that it became easy to change. It was found that the underlayer and the selenium layer are preferably formed continuously.
  • sample A7 has a larger XRD peak and higher crystallinity than sample B2.
  • impurities such as the air atmosphere did not adhere to the surface of the base layer, and a good base layer and selenium layer interface was formed during the selenium layer formation. It is thought that it became easy to change. It was found that the underlayer and the selenium layer are preferably formed continuously.
  • FIG. 40 and 41 show the XRD spectra of the comparative sample b1 and the comparative sample b2.
  • FIG. 40 shows a spectrum obtained by the ⁇ -2 ⁇ scanning method, and the horizontal axis represents the diffraction angle 2 ⁇ [deg. The vertical axis represents the diffracted X-ray intensity (Intensity) [arbitrary unit (arb. Unit)].
  • FIG. 41 shows a spectrum obtained by the GIXRD method.
  • the horizontal axis represents the diffraction angle 2 ⁇ [deg.
  • the vertical axis represents the diffracted X-ray intensity (Intensity) [arbitrary unit (arb. Unit)].
  • the X-ray incident angle is set to 0.35 deg. Measured by fixing to
  • 40 and 41 also show the spectra of Se (ICSD code 40018), Ti (ICSD code 41503), and In (ICSD code 171679) in the inorganic crystal structure database (ICSD). Moreover, the spectrum of the comparative sample a3 and the comparative sample a4 is also shown.
  • Comparative sample a3 and comparative sample b1 are samples in which titanium is used for the base layer and a selenium layer is heated. Therefore, it has been found that it is difficult to obtain crystalline selenium after selenium film formation even when titanium is used for the base layer and the selenium layer is heated.
  • Comparative sample a4 and comparative sample b2 are samples in which indium is used for the underlayer and the selenium layer is heated. Therefore, it has been found that it is difficult to obtain crystalline selenium after the selenium film is formed even if indium is used for the base layer and the selenium layer is heated.
  • FIG. 42A is a SEM image of the plane of the sample B1
  • FIG. 42B is a SEM image of the plane of the sample B2
  • FIG. 42C is a SEM image of the plane of the sample B3
  • sample A7 and sample B2 both use bismuth for the underlayer, and the difference is whether the underlayer and the selenium layer are formed continuously or discontinuously.
  • sample A7 which is a continuous film formation
  • no film peeling region was observed as shown in FIG.
  • sample B2 which is a discontinuous film formation
  • a film peeling region was observed. Therefore, in sample A7, since the base layer and the selenium layer were continuously formed, impurities such as the air atmosphere did not adhere to the surface of the base layer, and a good base layer and selenium layer interface was formed when the selenium layer was formed.
  • selenium is hard to aggregate and the occurrence of the film peeling area is suppressed. That is, it has been found that by using bismuth for the underlayer and continuously forming the underlayer and the selenium layer, crystalline selenium with few film peeling regions can be produced.
  • crystalline selenium according to one embodiment of the present invention was manufactured, and the presence of crystallinity and a film peeling region was evaluated.
  • the samples are a total of six samples of samples C1 to C6 which are one embodiment of the present invention. Samples C1 to C6 have different heat treatments after the selenium layer is formed.
  • Sample C4 was subjected to 70 ° C. for 3 minutes as the first heat treatment. After the treatment at 150 ° C. for 10 sec. Was processed. Sample C5 was 70 ° C. for 3 min. As the first heat treatment. After the treatment at 200 ° C. for 60 sec. Was processed. The heat treatment of sample C6 was not performed at 70 ° C., but at 200 ° C. for 60 sec. It was only processing of.
  • Tables 4 and 5 show the conditions of each sample.
  • Table 4 shows the film type of the underlayer, the underlayer film formation method, the substrate temperature (Tsub) during underlayer film formation, the underlayer film thickness, the selenium layer formation method, and the selenium layer formation time for each sample.
  • the substrate temperature (Tsub) and the film thickness of the selenium layer are shown.
  • “RT” indicates that the film was formed at room temperature (RT) without heating the substrate.
  • the column described as “underlayer-selenium layer” indicates whether the underlayer film formation and the selenium layer film formation are performed continuously or discontinuously.
  • the column describing heat treatment indicates whether or not heat treatment was performed after the selenium layer was formed.
  • Table 5 shows the conditions of the heat treatment after forming the selenium layer of each sample.
  • FIGS. 43A to 43C are cross-sectional views illustrating a method for manufacturing a sample.
  • the base layer 63 was formed over the substrate 61 (see FIG. 43A).
  • As the substrate 61 a glass substrate AN100 manufactured by Asahi Glass Co., Ltd. was used.
  • Formation of the base layer 63 of the samples C1 to C6 was performed using a deposition chamber of a deposition-sputtering composite apparatus (apparatus model number: VD15-065) manufactured by Shinko Seiki Co., Ltd. Using resistance heating (Ta board), about 0.20 nm / sec. The underlayer was formed at a deposition rate of The pressure during vapor deposition was about 1.0 ⁇ 10 ⁇ 5 Pa. Samples C1 to C6 used silver as a deposition source.
  • Sample C5 was subjected to 70 ° C. for 3 min. As the first heat treatment. After the treatment at 200 ° C. for 60 sec. Was processed. Sample C6 was 200 ° C. 60 sec. Was processed. In this example, heat treatment was performed in a draft chamber.
  • XRD measurement> Next, XRD measurement of samples C1 to C5 was performed, and the crystallinity of the selenium layer was evaluated.
  • XRD measurement an X-ray diffractometer D8 DISCOVER Hybrid manufactured by Bruker AXS was used, and CuK ⁇ rays having a wavelength of 0.15418 nm were used as an X-ray source.
  • FIG. 44 and 45 show XRD spectra of Samples C1 to C5.
  • FIG. 44 shows a spectrum obtained by the ⁇ -2 ⁇ scanning method, and the horizontal axis represents the diffraction angle 2 ⁇ [deg. The vertical axis represents the diffracted X-ray intensity (Intensity) [arbitrary unit (arb. Unit)].
  • FIG. 45 shows a spectrum obtained by the GIXRD method. The horizontal axis represents the diffraction angle 2 ⁇ [deg. The vertical axis represents the diffracted X-ray intensity (Intensity) [arbitrary unit (arb. Unit)].
  • the X-ray incident angle is set to 0.35 deg. Measured by fixing to
  • the peaks observed in the samples C3 to C5 substantially coincide with the peak positions of Se (ICSD code 40018), so the selenium layers of the samples C3 to C5 are crystalline selenium. I was able to confirm that there was. Further, in FIG. 44, it was found that in the order of sample C3, sample C4, and sample C5, the peak height was higher and the peak width was smaller. That is, it was found that the higher the heat treatment temperature, the higher the crystallinity of the selenium layer.
  • FIG. 46A shows a plane SEM image of the sample C1
  • FIG. 46B shows a SEM image of the plane of the sample C2
  • FIG. 46C shows a SEM image of the plane of the sample C3
  • FIG. 46C shows a SEM image of the plane of the sample C4.
  • FIG. 46E shows a planar SEM image of FIG. 46D and sample C5.
  • FIGS. 46A to 46E no film peeling region was observed in any of Samples C1 to C5 in which silver was used for the base layer.
  • peaks were observed by XRD, and the crystallinity of the selenium layer was high. Therefore, it was found that the formation of the underlayer is very effective for producing crystalline selenium with few film peeling regions.
  • FIB focused ion beam
  • composition analysis was performed on the cross sections of the samples C3 to C5 by EDX measurement.
  • FIB processing an FIB-SEM double beam apparatus XVision210DB manufactured by SII Nano Technology was used, the acceleration voltage was 30 kV, and gallium (Ga) was used as irradiation ions.
  • a scanning transmission electron microscope HD-2700 manufactured by Hitachi High-Technologies Corporation was used, the acceleration voltage was 200 kV, and the beam diameter was about 0.4 nm ⁇ .
  • a silicon drift detector Octane T Ultra manufactured by EDAX was used as a detector.
  • the lower limit of detection was about 1 atomic%. Note that the EDX measurement can detect elements from boron (B) with atomic number 5 to uranium (U) with atomic number 92.
  • FIG. 48 (A), FIG. 48 (B), FIG. 49 (A), FIG. 49 (B), FIG. 50 (A), and FIG. 50 (B) show STEM images of the cross section of the sample C3.
  • FIG. 47 is a transmission electron image (TE image: Transmission Electron Image) at a magnification of 50,000 times. As shown in FIG. 47, it was confirmed that the surface of the selenium layer of Sample C3 was substantially flat. A carbon film was provided on the selenium layer as a sample protective film during FIB processing. Furthermore, a platinum film was provided as an antistatic agent during STEM observation.
  • TE image Transmission Electron Image
  • FIG. 48A is a transmission electron image (TE image) with a magnification of 200,000 times.
  • FIG. 48B is a Z contrast image (ZC image: Z Contrast Image) at the same magnification as FIG.
  • ZC image Z Contrast Image
  • a substance with a larger atomic number looks brighter.
  • the density (luminance) of the STEM image in the selenium layer is substantially uniform, and the film quality in the selenium layer of sample C3 is substantially uniform. It could be confirmed.
  • FIG. 49A, 49B, and 50A are transmission electron images (TE images) with a magnification of 3 million times.
  • FIG. 49A is a STEM image near the surface of the selenium layer.
  • the observation location is point 1-1 shown in FIG.
  • FIG. 49B is a STEM image near the center of the selenium layer in the thickness direction.
  • the observation location is point 1-2 shown in FIG.
  • FIG. 50A is a STEM image near the glass substrate of the selenium layer.
  • the observation location is point 1-3 shown in FIG.
  • a crystal lattice image was confirmed. This corresponds to the fact that the sample C3 shows a peak indicating a crystal in the XRD measurement described above.
  • FIG. 52 (A), FIG. 52 (B), FIG. 53 (A), FIG. 53 (B), FIG. 54 (A), and FIG. 54 (B) show STEM images of the cross section of the sample C4.
  • FIG. 51 is a transmission electron image (TE image) with a magnification of 50,000 times. As shown in FIG. 51, it was confirmed that the surface of the selenium layer of Sample C4 was substantially flat.
  • FIG. 52A is a transmission electron image (TE image) with a magnification of 200,000 times.
  • FIG. 52B is a Z-contrast image (ZC image) at a magnification of 200,000 times at the same location as in FIG.
  • the density (luminance) of the STEM image in the selenium layer is substantially uniform, and the film quality in the selenium layer of sample C4 is substantially uniform. It could be confirmed.
  • FIG. 53A, 53B, and 54A are transmission electron images (TE images) with a magnification of 3 million times.
  • FIG. 53A is a STEM image near the surface of the selenium layer.
  • the observation location is point 2-1 shown in FIG.
  • FIG. 53B is a STEM image near the center of the selenium layer in the thickness direction.
  • the observation location is point 2-2 shown in FIG.
  • FIG. 54A is a STEM image near the glass substrate of the selenium layer.
  • the observation location is point 2-3 shown in FIG.
  • a crystal lattice image was confirmed. This corresponds to the fact that the sample C4 shows a peak indicating a crystal in the XRD measurement described above. Further, compared to the sample C3, since the crystal lattice image of the sample C4 can be clearly confirmed, it can be confirmed that the crystallinity is high.
  • FIG. 55, FIG. 56 (A), FIG. 56 (B), FIG. 57 (A), FIG. 57 (B), FIG. 58 (A), and FIG. 58 (B) show STEM images of the cross section of the sample C5.
  • FIG. 55 is a transmission electron image (TE image) with a magnification of 50,000 times. As shown in FIG. 55, it was confirmed that the surface of the selenium layer of Sample C5 was substantially flat.
  • FIG. 56A is a transmission electron image (TE image) with a magnification of 200,000 times.
  • FIG. 56B is a Z-contrast image (ZC image) at a magnification of 200,000 times at the same location as in FIG.
  • the density (luminance) of the STEM image in the selenium layer is substantially uniform, and the film quality in the selenium layer of sample C5 is substantially uniform. It could be confirmed.
  • the sample C5 at 200 ° C. has a more uniform STEM image density (luminance) in the selenium layer. That is, it was found that the film quality in the selenium layer was more uniform.
  • Sample C6 a film peeling region that can be visually confirmed after the heat treatment occurred.
  • Sample C6 was not subjected to heat treatment at 70 ° C., and 200 ° C. for 60 sec. It is a sample that is only heat treatment. It is presumed that silver diffuses in the selenium layer by heat treatment at 70 ° C., and a compound containing selenium and silver is formed. In Sample C6, it is considered that the film peeling region occurred because the selenium layer was crystallized by heat treatment at 200 ° C. before the compound containing selenium and silver was sufficiently formed.
  • the second heat treatment is performed at a temperature higher than the first heat treatment, and the second heat treatment is performed on the selenium layer. It has been found that it is preferable to set the temperature to crystallize (for example, 200 ° C.).
  • FIG. 57A, 57B, and 58A are transmission electron images (TE images) with a magnification of 3 million times.
  • FIG. 57A is a STEM image near the surface of the selenium layer.
  • the observation location is point 3-1 shown in FIG.
  • FIG. 57B is a STEM image near the center of the selenium layer in the thickness direction.
  • the observation location is point 3-2 shown in FIG.
  • FIG. 58A is a STEM image near the glass substrate of the selenium layer.
  • the observation location is point 3-3 shown in FIG.
  • FIGS. 57A, 57B, and 58A a crystal lattice image was confirmed. This corresponds to the fact that the sample C5 shows a peak indicating a crystal in the XRD measurement described above. Moreover, compared with the sample C3 and the sample C4, since the sample C5 can confirm a crystal lattice image clearly, it has confirmed that crystallinity was high.
  • the EDX spectrum will be described.
  • the measurement point was irradiated with an electron beam, the energy of the characteristic X-rays generated and the number of occurrences were measured, and an EDX spectrum was obtained.
  • the obtained spectrum was subjected to peak separation to identify elements.
  • the EDX measurement locations were three in the vicinity of the surface of the selenium layer, in the vicinity of the center in the thickness direction, and in the vicinity of the glass substrate of Samples C3 to C5.
  • FIG. 59 shows the STEM image of the cross section of the sample C3 and the EDX measurement location.
  • EDX spectra are shown in FIGS. 60 (A) to 60 (C).
  • FIG. 60A shows an EDX spectrum near the surface of the selenium layer.
  • the observation location is point 1-4 shown in FIG.
  • FIG. 60B shows an EDX spectrum near the center of the selenium layer in the thickness direction.
  • the observation location is point 1-5 shown in FIG.
  • FIG. 60C shows an EDX spectrum near the glass substrate of the selenium layer.
  • the observation location is point 1-6 shown in FIG.
  • FIG. 61 shows a STEM image of a cross section of the sample C4 and an EDX measurement location.
  • the EDX spectrum is shown in FIGS. 62 (A) to 62 (C).
  • FIG. 62A shows an EDX spectrum near the surface of the selenium layer.
  • the observation location is point 2-4 shown in FIG.
  • FIG. 62B shows an EDX spectrum near the center of the selenium layer in the thickness direction.
  • the observation location is point 2-5 shown in FIG.
  • FIG. 62C shows an EDX spectrum near the glass substrate of the selenium layer.
  • the observation location is point 2-6 shown in FIG.
  • FIG. 63 shows a STEM image of a cross section of the sample C5 and an EDX measurement location.
  • the EDX spectra are shown in FIGS. 64 (A) to 64 (C).
  • FIG. 64A shows an EDX spectrum near the surface of the selenium layer.
  • the observation location is point 3-4 shown in FIG.
  • FIG. 64B is an EDX spectrum near the center of the selenium layer in the thickness direction.
  • the observation location is point 3-5 shown in FIG.
  • FIG. 64C shows an EDX spectrum near the glass substrate of the selenium layer.
  • the observation location is point 3-6 shown in FIG.
  • the horizontal axis represents characteristic X-ray energy (Energy) [keV].
  • the vertical axis represents the characteristic X-ray intensity (Intensity) [counts].
  • any EDX measurement location of Sample C3 to Sample C5 is derived from carbon (C), oxygen (O), silicon (Si), silver (Ag), copper (Cu), gallium (Ga), and selenium (Se).
  • a peak was observed.
  • Table 6 shows atomic concentrations [atomic%] of carbon (C), oxygen (O), silicon (Si), silver (Ag), copper (Cu), gallium (Ga), and selenium (Se).
  • the atomic concentration [atomic%] shown in Table 6 is the number of atoms of carbon (C), oxygen (O), silicon (Si), silver (Ag), copper (Cu), gallium (Ga), and selenium (Se). The ratio of the number of atoms of each element when the sum is 100.0 atomic% is shown.
  • Carbon (C), oxygen (O), silicon (Si), copper (Cu), gallium (Ga), and selenium (Se) were each quantified using peaks derived from electron transition of atoms to the K shell.
  • Silver (Ag) was quantified using the peak derived from the electron transition to the L shell of an atom.
  • Carbon (C), oxygen (O), and silicon (Si) are considered to be derived from the collodion film used for analysis.
  • Copper (Cu) is thought to be due to scattering from the mesh used for the collodion film.
  • Gallium (Ga) is thought to be derived from FIB processing.
  • the ratio of the atomic concentration of silver to selenium (Ag / Se) is shown in Table 7 and FIG. Ag / Se can also be said to be the ratio of the number of silver atoms to selenium.
  • the column described as “Ag / Se” indicates Ag / Se for each EDX measurement location.
  • the column described as “average1” indicates the average value of Ag / Se for each sample.
  • the column described as “average2” indicates the average value of Ag / Se at the EDX measurement locations of all of the samples C3 to C5.
  • sample C3 the minimum value of Ag / Se was 0.119, the maximum value was 0.172, and the average value was 0.141.
  • sample C4 the minimum value of Ag / Se was 0.065, the maximum value was 0.255, and the average value was 0.140.
  • sample C5 the minimum value of Ag / Se was 0.086, the maximum value was 0.144, and the average value was 0.112. The average value of all the measurement points of the samples C3 to C5 was 0.131.
  • the horizontal axis indicates the sample name, and the vertical axis indicates Ag / Se [arbitrary unit (arb. Unit)].
  • Open circles indicate the value of Ag / Se for each EDX measurement location.
  • a broken line with black squares indicates an average value (average1) of Ag / Se for each sample.
  • the alternate long and short dash line indicates the average value (average2) of Ag / Se at the EDX measurement locations of all of the samples C3 to C5.
  • the silver concentration distribution may change locally due to the effects of FIB processing and heat generated by electron beam irradiation in EDX measurement. Therefore, the actual Ag / Se may be lower than the values shown in Table 7 and FIG.
  • Photoelectric conversion element 11 Photoelectric conversion layer 11a Crystalline selenium layer 11b Amorphous selenium layer 11c Crystalline selenium layer 12 Hole injection blocking layer 13 Buffer layer 14 Electrode 15 Electrode 16 Selenium layer 20 Pixel 21 Pixel array 22 Circuit 23 Circuit 24 Circuit 25 Circuit 31 Layer 32 Layer 33 Layer 35 Pixel electrode 36 Photoelectric conversion layer 37 Common electrode 51 Transistor 52 Transistor 53 Transistor 54 Transistor 56 High voltage power source 61 Substrate 63 Selenium layer 67 Selenium layer 71 Wiring 72 Wiring 73 Wiring 75 Wiring 76 Wiring 77 Wiring 78 Wiring 79 Wiring 80 Insulating layer 81 Back gate 82 Partition wall 100 Insulating layer 110 Light shielding layer 120 Organic resin layer 130 Color filter 130a Color filter 130b Color filter 130c Color filter 40 Microlens array 150 Optical conversion layer 160 Insulating layer 210 Package substrate 211 Package substrate 220 Cover glass 221 Lens cover 230 Adhesive 235 Lens 240 Bump 241 Land 250

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Solid State Image Pick-Up Elements (AREA)
  • Recrystallisation Techniques (AREA)
  • Light Receiving Elements (AREA)

Abstract

L'invention concerne un élément de conversion photoélectrique ayant un sélénium cristallin uniforme avec peu de régions de délaminage. L'élément de conversion photoélectrique comprend une première électrode (411), une deuxième électrode (415) et une couche de conversion photoélectrique (413) entre la première électrode (411) et la deuxième électrode (415). La couche de conversion photoélectrique (413) comprend du sélénium et un élément X, l'élément X étant au moins un élément choisi parmi l'argent et le bismuth. La couche de conversion photoélectrique (413) présente un rapport (X/Se) du nombre d'atomes de l'élément X au nombre d'atomes de sélénium dans la région de 0,0010 à 0,70.
PCT/IB2018/050578 2017-02-10 2018-01-31 Élément de conversion photoélectrique, dispositif d'imagerie, dispositif électronique et procédé de production d'un élément de conversion photoélectrique Ceased WO2018146579A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2018566658A JPWO2018146579A1 (ja) 2017-02-10 2018-01-31 光電変換素子、撮像装置、電子機器及び光電変換素子の作製方法

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2017-022896 2017-02-10
JP2017022707 2017-02-10
JP2017022896 2017-02-10
JP2017-022707 2017-02-10

Publications (1)

Publication Number Publication Date
WO2018146579A1 true WO2018146579A1 (fr) 2018-08-16

Family

ID=63108048

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2018/050578 Ceased WO2018146579A1 (fr) 2017-02-10 2018-01-31 Élément de conversion photoélectrique, dispositif d'imagerie, dispositif électronique et procédé de production d'un élément de conversion photoélectrique

Country Status (2)

Country Link
JP (1) JPWO2018146579A1 (fr)
WO (1) WO2018146579A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2022018715A (ja) * 2020-07-16 2022-01-27 日本放送協会 光電変換膜、光電変換膜の製造方法、光電変換素子
CN114899264A (zh) * 2022-04-18 2022-08-12 长江大学 硒自支撑薄膜光电探测器及其制备方法
JP2022548256A (ja) * 2019-09-12 2022-11-17 ザ・リサーチ・ファウンデーション・フォー・ザ・ステイト・ユニヴァーシティ・オブ・ニューヨーク 高利得アモルファスセレン光電子増倍管

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63304551A (ja) * 1986-07-04 1988-12-12 Nippon Hoso Kyokai <Nhk> 撮像管及びその動作方法
JP2001057166A (ja) * 1999-08-18 2001-02-27 Nippon Hoso Kyokai <Nhk> 撮像デバイスとその動作方法
WO2010032802A1 (fr) * 2008-09-18 2010-03-25 富士フイルム株式会社 Cellule solaire
EP2339643A2 (fr) * 2009-12-23 2011-06-29 General Electric Company Cellule photovoltaïque
JP2014216502A (ja) * 2013-04-25 2014-11-17 日本放送協会 光電変換素子及びその製造方法
JP2016532301A (ja) * 2013-08-29 2016-10-13 ユニバーシティー オブ フロリダ リサーチ ファウンデーション，インコーポレイテッドＵｎｉｖｅｒｓｉｔｙ Ｏｆ Ｆｌｏｒｉｄａ Ｒｅｓｅａｒｃｈ Ｆｏｕｎｄａｔｉｏｎ，Ｉｎｃ． 溶液から作製された無機半導体から空気中で安定な赤外線光検出器
JP2016208116A (ja) * 2015-04-16 2016-12-08 株式会社半導体エネルギー研究所 撮像装置および電子機器
JP2017034039A (ja) * 2015-07-30 2017-02-09 日本放送協会 光電変換素子、光電変換素子の製造方法、固体撮像素子

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01192178A (ja) * 1988-01-28 1989-08-02 Hitachi Ltd 受光素子
US8253212B2 (en) * 2008-06-23 2012-08-28 Sunnybrook Health Sciences Centre Photodetector/imaging device with avalanche gain
JP2012154933A (ja) * 2012-02-23 2012-08-16 Fujifilm Corp 放射線検出器
JP6482185B2 (ja) * 2014-05-12 2019-03-13 日本放送協会 固体撮像素子
JP6570417B2 (ja) * 2014-10-24 2019-09-04 株式会社半導体エネルギー研究所 撮像装置および電子機器
US11728356B2 (en) * 2015-05-14 2023-08-15 Semiconductor Energy Laboratory Co., Ltd. Photoelectric conversion element and imaging device

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63304551A (ja) * 1986-07-04 1988-12-12 Nippon Hoso Kyokai <Nhk> 撮像管及びその動作方法
JP2001057166A (ja) * 1999-08-18 2001-02-27 Nippon Hoso Kyokai <Nhk> 撮像デバイスとその動作方法
WO2010032802A1 (fr) * 2008-09-18 2010-03-25 富士フイルム株式会社 Cellule solaire
EP2339643A2 (fr) * 2009-12-23 2011-06-29 General Electric Company Cellule photovoltaïque
JP2014216502A (ja) * 2013-04-25 2014-11-17 日本放送協会 光電変換素子及びその製造方法
JP2016532301A (ja) * 2013-08-29 2016-10-13 ユニバーシティー オブ フロリダ リサーチ ファウンデーション，インコーポレイテッドＵｎｉｖｅｒｓｉｔｙ Ｏｆ Ｆｌｏｒｉｄａ Ｒｅｓｅａｒｃｈ Ｆｏｕｎｄａｔｉｏｎ，Ｉｎｃ． 溶液から作製された無機半導体から空気中で安定な赤外線光検出器
JP2016208116A (ja) * 2015-04-16 2016-12-08 株式会社半導体エネルギー研究所 撮像装置および電子機器
JP2017034039A (ja) * 2015-07-30 2017-02-09 日本放送協会 光電変換素子、光電変換素子の製造方法、固体撮像素子

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2022548256A (ja) * 2019-09-12 2022-11-17 ザ・リサーチ・ファウンデーション・フォー・ザ・ステイト・ユニヴァーシティ・オブ・ニューヨーク 高利得アモルファスセレン光電子増倍管
JP7751567B2 (ja) 2019-09-12 2025-10-08 ザ・リサーチ・ファウンデーション・フォー・ザ・ステイト・ユニヴァーシティ・オブ・ニューヨーク 高利得アモルファスセレン光電子増倍素子
JP2022018715A (ja) * 2020-07-16 2022-01-27 日本放送協会 光電変換膜、光電変換膜の製造方法、光電変換素子
JP7479231B2 (ja) 2020-07-16 2024-05-08 日本放送協会 光電変換膜、光電変換膜の製造方法、光電変換素子
CN114899264A (zh) * 2022-04-18 2022-08-12 长江大学 硒自支撑薄膜光电探测器及其制备方法
CN114899264B (zh) * 2022-04-18 2023-09-29 长江大学 硒自支撑薄膜光电探测器及其制备方法

Also Published As

Publication number Publication date
JPWO2018146579A1 (ja) 2020-01-23

Similar Documents

Publication Publication Date Title
JP7700328B2 (ja) 撮像装置
JP7432644B2 (ja) 撮像装置
JP6811342B2 (ja) 光電変換装置
JP7004469B2 (ja) 撮像装置
JP6960025B2 (ja) 撮像装置
JP2024163178A (ja) 撮像装置
JP2019192939A (ja) 撮像装置
JP7019784B2 (ja) 撮像装置
JP6749781B2 (ja) 撮像装置
JP7114291B2 (ja) 光電変換素子の作製方法
WO2018185587A1 (fr) Dispositif d&#39;imagerie et appareil électronique
WO2018146579A1 (fr) Élément de conversion photoélectrique, dispositif d&#39;imagerie, dispositif électronique et procédé de production d&#39;un élément de conversion photoélectrique
JP2019033239A (ja) 光電変換素子、撮像装置及び電子機器

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 18751923

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2018566658

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 18751923

Country of ref document: EP

Kind code of ref document: A1