KR100794305B1 - Optical element and its manufacturing method - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device and a method of manufacturing the same, and more electrically than ordinary metals used as an ohmic contact layer on a group III p- type nitride-based semiconductor. Thermally decomposed nitride exhibiting excellent ohmic contact behavior and optical light transmission, ie nickel nitride (Ni-N), copper nitride (Cu-N), zinc nitride (Zn-N), indium nitride (In-N) The present invention relates to an optical element using tin nitride (Sn-N) as a high-transparent, ohmic contact layer, and a method of manufacturing the same.

Group III nitride-based optical devices are typically substrates, n- type nitride cladding layers, nitride-based active layers, and nitrides A p- type nitride cladding layer and a multi-layered p- type ohmic contact layer are sequentially stacked, and the multi-type ohmic contact layer is a transparent conductive thin film and has excellent electrical and optical properties. Multi-layered thin film layer having at least one layer of pyrolytic nitride-based thin film, or metal, alloy, solid solution, or general conductive oxide in addition to the above-mentioned pyrolytic nitride for controlling electrical and optical properties. oxide, transparent conducting oxide (TCO), transparent conducting nitride (TCN), or transparent conducting nitrogen oxide (tran) It also includes a layered layer combined with phases that are advantageous for forming an ohmic contact interface on an upper layer of a nitride-based semiconductor such as sparent conducting oxynitride (TCNO).

According to the nitride-based light emitting device using the transparent conductive multi-type ohmic contact layer developed according to the present invention and a method of manufacturing the same, the interfacial property of the p- type nitride cladding layer is improved. In addition to excellent current-voltage (IV) characteristics, high light transmittance can increase the external light emitting efficiency of the light emitting device.

Copper nitride, nickel nitride, zinc nitride, indium nitride, tin nitride, pyrolytic nitride, transparent conductive oxide, transparent conductive nitride, transparent conductive nitrogen oxide, multi-type ohmic contact layer, group III nitride-based cladding layer, nitride-based light emitting device

Description

Optical device and method of manufacturing the same

 FIG. 1 is a cross-sectional view illustrating a top-emitting light emitting diode (TELED) to which a multi-layered ohmic contact electrode structure according to a first embodiment of the present invention is applied.

  FIG. 2 is a cross-sectional view illustrating a top-emitting light emitting diode (TELED) to which the multi-layered ohmic contact electrode structure according to the second embodiment of the present invention is applied.

3 is a cross-sectional view illustrating various stacked shapes of p- type multi ohmic contact layers formed on an upper layer of a nitride-based cladding layer according to first and second embodiments of the present invention.

4 is a p- type multi ohmic contact electrode structure formed after introducing nanometer scale particles into an upper layer of a nitride-based clad layer according to the first and second embodiments of the present invention. This is a cross-sectional view showing various stacked forms of layers).

The present invention relates to an optical device and a method of manufacturing the same, more specifically, the normal metal used in the group III nitride-based semiconductor pihyeong (group Ⅲ p -type nitride-based semiconductor) the upper contact layer (ohmic contact layer) Ohmic Thermally decomposed nitrides with excellent electrical ohmic contact behavior and optical light transmission, ie nickel nitrides (Ni-N), copper nitrides (Cu-N), zinc nitrides (Zn-N), and indium nitrides (In- N) or tin nitride (Sn-N) is applied to a highly transparent ohmic contact layer, and an optical element and a method of manufacturing the same.

  Currently, transparent conducting thin films are widely used in the optoelectronic field, the display field, and the energy industry. In the field of semiconductor light emitting devices such as light emitting diodes (LEDs) and laser diodes (LDs), in addition to electrical characteristics such as smooth carrier injection and current spreading, the semiconductor light emitting device active layer It should be a material that has both optical properties so that photons generated in the active layer can be emitted as much as possible to the outside. In particular, many domestic and overseas research institutes related to group III nitride light emitting diodes (III nitride LEDs), which are spotlighted as next generation lighting sources, are actively researching to develop high quality transparent conductive thin films for light emitting devices. have. As a result, transparent conductive materials such as well-known indium tin oxide (ITO) and doped zinc oxide (ZnO) have been recently used directly as electrodes of nitride-based light emitting diodes (LEDs). have.

  Among the various transparent conductive oxides (TCO), the most actively researched materials are indium oxide (In2O3), tin oxide (SnO2), cadmium oxide (CdO), zinc oxide (ZnO), and indium tin oxide (ITO). In addition, since they have relatively small work function values and rapid light transmittance reduction characteristics in the wavelength range of visible and ultraviolet light, they have many problems when used as transparent electrodes of nitride-based light emitting diodes (LEDs). The problems experienced by these materials, which are currently partly used in nitride based light emitting diodes, are as follows.

First, the conventional transparent conductive oxide (TCO) or nitride (TCN) has a much smaller work function than the work function of the p- type nitride-based cladding layer. When used as a p- type ohmic contact layer, a high energy barrier to carrier flow is formed at the interface, making it difficult to inject holes smoothly. There are many difficulties in implementing a nitride based light emitting diode (LED).

  Second, the conventional transparent conductive oxide (TCO) or nitride (TCN) has a low light transmittance below the wavelength range with blue light among the light generated and emitted from the nitride-based LED, so it is applied to the LED emitting light in the short wavelength region Difficult to do

  Third, conventional transparent conductive oxides (TCOs) or nitrides (TCNs) have a large value near the refractive index of light, which is about 2, so that they can be emitted into the air through these transparent conductive oxide electrodes. There is difficulty.

  Currently, nitride semiconductors are used to commercialize optical devices such as transistors, light emitting diodes (LEDs), and laser diodes (LDs), which are widely used. In order to implement a device, contact control, which is an interface property between a group III nitride semiconductor and an electrode, is very important.

  A light emitting diode (LED) using a nitride semiconductor composed of gallium nitride (GaN), indium nitride (InN), and aluminum nitride (AlN) is a top-emitting light emitting diode (TELED) and a flip chip. It is classified as a flip-chip light emitting diode (FCLED).

Currently widely used TELED is formed so that the light generated through the p- type ohmic contact layer ( p- type ohmic contact layer) in contact with the nitride nitride-based cladding layer. On the other hand, FCLED, which is manufactured with large area and high-capacity light emitting device by using heat dissipation that is relatively easy to generate when driving, compared with TELED, uses high reflective type ohmic contact layer to generate light generated from active layer, as opposed to TELED. It emits light through a transparent sapphire substrate. Light emitting diodes using group III-nitride semiconductors have a low hole concentration in the nitride-based cladding layer, which makes it difficult to transport holes that are easily carriers in all directions in the nitride-based cladding layer. In order to make a high quality optoelectronic device using a nitride-based cladding layer, a good quality ohmic contact layer having excellent current spreadability is absolutely required. In other words, in order to realize a high quality next-generation light emitting diode using a group III nitride semiconductor, it has excellent current spreading in the lateral direction and hole injection in the vertical direction, and at the same time in the visible and short wavelength region An ohmic contact electrode structure having excellent optical properties (light transmittance or light reflectance) with respect to light should be developed / formed.

  Currently, the ohmic contact layer for TELED, which is most widely used, is formed of nickel / gold (Ni / Au) oxidized on the nitride nitride clad layer upper layer. A thin film layer of Ni / Au is sequentially deposited on the upper layer of the nitride-based clad layer using an e-beam evaporator, and then heat-treated in an oxygen (O2) atmosphere to obtain a specific contact resistance of about 10-3 to 10-4 Ω㎠. It is known to form a semi-transparent ohmic contact layer with specific ohmic contact resistance. The oxidized nickel-gold ohmic contact layer has a low light transmittance of 75% or less at 460 nanometers (nm) or less, which is a wavelength range of blue light, and thus is not suitable for the next type ohmic layer for nitride-based light emitting diodes.

  The low specific contact resistance of the semi-transparent nickel-gold ohmic contact layer is a gallium nitride (GaN) and an ohmic contact layer which forms a nitride nitride cladding layer when heat treated at a temperature of about 500 to 600 degrees and an oxygen (O 2) gas atmosphere. In the contact interface with the applied nickel metal, nickel oxide (NiO), which is a semiconductor oxide, is formed in an island shape, and at the same time, a structure covering the upper layer and between the nickel oxide where gold (Au) metal is distributed in an island shape is formed. It was found to have. In particular, nickel oxide is formed when the thinly deposited nickel-gold on the upper layer of the nitride-based cladding layer is heat-treated in an oxygen atmosphere, which is used to form a Schottky barrier height & width between gallium nitride (GaN) and the electrode. width: SBH & SBW) is reduced and the carrier is easily supplied to the device when an external voltage is applied through this electrode. As described above, the reason why the thin Ni / Au thin film layer exhibits excellent ohmic behavior, which is an excellent electrical property, is not only a role of nickel oxide, which leads to reduction of SBH & SBW, but also a gold (Au) metal which leads to the improvement of current spreading in the lateral direction. Ingredient.

  In addition to the mechanism for the ohmic behavior of the Ni / Au thin film layer, a thin nickel-gold thin film layer is formed on the upper layer of the nitride-based cladding layer, and then heat treated to form an effective hole concentration (net effective) in the nitride-based cladding layer. This effective hole on the surface of the nitride-based cladding layer is removed through a reactivation process that removes the Mg-H intermetallic compound that limits the hole concentration, thereby increasing the magnesium dopant concentration on the surface of the nitride-based cladding layer. It is understood that a concentration of 1018 or more causes tunneling transport between the nitride-based cladding layer and the nickel contact-containing ohmic contact layer, thereby exhibiting ohmic behavior with low specific contact resistance.

  However, TELED using a translucent type ohmic contact layer formed of oxidized Ni / Au contains gold (Au) metal component that inhibits light transmittance, that is, absorbs a large amount of light generated in the LED active layer. The low efficiency limits the application of large-area and high-capacity high-brightness LED applications in the future.

  In order to overcome some of the limitations of the devices of the top-emit type and flip chip light emitting diodes in recent years, transparent conductive oxides having excellent light transmittance, for example, than the semi-transparent nickel-gold structure used as the conventional ohmic contact layer, for example, The research aimed at using ITO is described in T. Margalith et al., Appl. Phys. Lett. Vol. 74. p3930 (1999). Recently, the use of the ITO ohmic contact layer to implement TELED exhibiting improved output power compared to the conventional nickel-gold structure is described in Solid-State Electronics vol.47. p849 (2003). However, the ohmic contact layer of such a structure can increase the output of the light emitting diode, but has a problem of showing a relatively high operating voltage. The root cause is relatively small compared to the work function value of the nitride-based semiconductor as described above. Because of the high value, a high Schottky barrier is formed at the interface between the nitride-based cladding layer and the ITO ohmic contact layer, which makes it difficult to inject a carrier smoothly, causing a large amount of heat generation and a short device life.

  As described above, when TCOs such as ITO and ZnO are directly deposited / contacted on the upper layer of the nitride-based cladding layer, high and thick SBH and SBW are generated, respectively, and do not form an ohmic contact layer. The GIST research group inserts a thin second TCO layer between the type nitride-based cladding layer and the TCOs and heats them to form particles of less than 100 nanometers (nm) in order to produce a high quality ohmic contact layer. The results of the formation were announced. The nanoparticles generated at these interfaces generate an electric field at the interface, and this induced electric field lowers the height and width of the schottky barrier and converts the TCO electrode exhibiting the schottky behavior into ohmic behavior. Analyzed.

As described above, the present invention was devised to fabricate a nitride-based light emitting device having a high-quality, high-transparent conductivity p- type multi ohmic contact layer. Group III p- type nitride-based semiconductors compared to general transparent conductive oxides (TCO) such as zinc oxide (ZnO) or transparent conductive nitrides (TCN) such as titanium nitride (TiN) ) Thermally decomposed nitride, nickel nitride (Ni-N), copper nitride (Cu-N), and zinc nitride (Zn-), which have excellent advantages in terms of contact interface characteristics in the vertical and horizontal directions in the upper layer. N), Indium Nitride (In-N) or Tin Nitride (Sn-N), a unique high quality transparent conductive type multi-ohmic contact electrode structure that can provide low contact resistance and high light transmittance The purpose of the present invention is to provide an optical device and a method of manufacturing the same, and applying the same.

In order to achieve the above object, a nitride-based light emitting device according to an embodiment of the present invention includes a nitride-based nitride layer between an n- type nitride cladding layer and a p- type nitride cladding layer. In a nitride-based light emitting device (especially a light emitting diode and a laser diode) having a nitride-based active layer, a plurality of correlated multiple layers including at least one or more thermally decomposed nitride on the upper part of the clad nitride-based clad layer A multi p- type ohmic contact layer, wherein the thermally decomposed nitride is nickel (Ni), copper (Cu), zinc (Zn), indium (In), or tin (Sn). The metal refers to a material in which at least one metal component and nitrogen (N) component are necessarily bonded.

  The pyrolytic nitride deposited on the upper part of the nitride-based cladding layer is decomposed into metal and nitrogen (N) components during heat treatment, and the decomposed nitrogen (N) component is present in a large amount on the upper part of the nitride-based cladding layer. It removes the nitrogen vacancy that adversely affects the formation of the ohmic electrode, and at the same time, the metal component from decomposition decomposes the gallium (Ga) component and the intermetallic compound in the upper layer of the clad layer. It can be advantageously formed to form an ohmic electrode.

  Preferably, the pyrolytic nitride may further include other metal components as dopants to control electrical properties. Here, the metals applied as dopants are applied with elements classified as metals on the periodic table of elements.

  According to another aspect of the present invention, the highly transparent multi-type ohmic contact electrode structure as described above, in addition to the pyrolytic nitride, metals and metals which are advantageous for forming an ohmic contact electrode structure on the upper part of the nitride-based cladding layer are as follows. Grafting regardless of stacking order with alloy / solid solution, common conducting oxide, transparent conductive oxide (TCO), transparent conductive nitride (TCN), transparent conductive nitrogen oxide (TCON), etc. Can be formed.

  Metals and alloys / solid solutions based on these metals: platinum (Pt), palladium (Pd), nickel (Ni), gold (Au), rhodium (Rh), ruthenium ( Ru, iridium (Ir), silver (Ag), zinc (Zn), magnesium (Mg), beryllium (Be), copper (Cu), cobalt (Co), tin (Sn), rare earth metals ), Or an alloy / solid solution based on these metals.

  The general conducting oxide: nickel oxide (Ni-O), rhodium oxide (Rh-O), ruthenium oxide (Ru-O), iridium oxide (Ir-O), copper oxide (Cu-O), Cobalt oxide (Co-O), tungsten oxide (WO), or titanium oxide (Ti-O).

  The transparent conductive oxide (TCO): indium oxide (In2O3), tin oxide (SnO2), indium tin oxide (ITO), zinc oxide (ZnO), magnesium (MgO), cadmium oxide (CdO), magnesium zinc oxide (MgZnO ), Indium zinc oxide (InZnO), indium tin oxide (InSnO), copper aluminum oxide (CuAlO2), silver oxide (Ag2O), gallium oxide (Ga2O3), zinc tin oxide (ZnSnO), zinc indium tin oxide (ZITO), Or other oxides to which these transparent conductive oxides are combined.

  The transparent conductive nitride (TCN): titanium nitride (TiN), chromium nitride (CrN), tungsten (WN), tantalum (TaN), or niobium (NbN).

  The transparent conductive nitrogen oxide (TCON): indium (In), tin (Sn), zinc (Zn), cadmium (Cd), gallium (Ga), aluminum (Al), magnesium (Mg), titanium (Ti), molybdenum Ium (Mo), nickel (Ni), copper (Cu), silver (Ag), gold (Au), platinum (Pt), rhodium (Rh), iridium (Ir), ruthenium (Ru), or palladium (Pd ) A substance formed by combining at least one of metals as a main component and oxygen (O) and nitrogen (N) must be bonded at the same time.

  More preferably, a third material, ie, a dopant, may be added to the above oxides and nitrides in order to improve the electrical properties of these materials.

In order to achieve the above object, a method of manufacturing a group III nitride light emitting device according to an embodiment of the present invention includes an n- type nitride cladding layer and a p- type nitride cladding layer. In the manufacturing method of the nitride-based light emitting device having a nitride active layer (nitride active layer) between the layers,

end. A multi-layered ohmic contact including at least the above thermally decomposed nitride in an upper portion of the nitride-based cladding layer of the light emitting structure in which an en-type nitride-based cladding layer, an active layer and a nitride-based cladding layer are sequentially stacked on the substrate. Forming an electrode structure;

I. And a heat treatment step of forming a high quality ohmic contact layer on the multi-electrode structure laminated through the step of adding, wherein the thermally decomposed nitride is nickel (Ni), copper (Cu), It refers to a material formed by combining at least one metal component and nitrogen (N) among metals such as zinc (Zn), indium (In), or tin (Sn).

  The heat treatment performed in step B is preferably performed at 100 to 800 degrees for 10 seconds to 3 hours.

  In addition, the heat treatment step is a gas containing at least one of nitrogen (N2), oxygen (O2), hydrogen (H2), air, argon (Ar), or helium (He) gas in the reactor containing the ohmic contact electrode body. Perform in the atmosphere.

  Hereinafter, with reference to the accompanying drawings will be described in detail a preferred group group III nitride-based light emitting device and a method of manufacturing the same.

  In the drawings referred to in the following description, elements having the same function are denoted by the same reference numerals.

  1 is a cross-sectional view showing a light emitting diode to which the multi-type ohmic contact electrode structure according to the first embodiment of the present invention is applied.

  In detail, FIG. 1 (a) is a cross-sectional view showing a group III nitride-based top-emitting type light emitting diode (TELED) stacked / grown on an upper layer of sapphire 10, which is an insulating growth substrate, whereas FIG. Electrically conductive substrates, namely silicon carbide (SiC), zinc oxide (ZnO), silicon (Si), gallium arsenide (GaAs), or electroplating / bonding transfers known in many literatures, etc. A cross-sectional view showing a group III nitride-based top-emitting light emitting diode (TELED) formed on an upper layer of a conductive material layer such as metal (Cu, Ni, Al, etc.) or alloy formed by the method.

  Referring to FIG. 1, the light emitting device includes a substrate 10, a low temperature nucleation layer 20, a nitride buffer layer 30, an N-type nitride cladding layer 40, a nitride active layer 50, and a nitride-based cladding layer. 60 and the ohmic contact layer 70 are laminated in this order. Reference numeral 80 denotes a shaped electrode pad, and 90 denotes an N-type electrode pad.

  Here, the substrate 10 to the nitride-based cladding layer 60 corresponds to the light emitting structure, and the structure stacked on the upper portion of the nitride-based cladding layer 60 corresponds to the electrode structure.

  The substrate 10 may be formed of sapphire (Al 2 O 3), silicon carbide (SiC), zinc oxide (ZnO), silicon (Si), gallium arsenide (GaAs), or an electroplating / bonding transfer known in many literatures. It is preferably formed of any one of materials such as metal (Cu, Ni, Al, etc.) or alloy (alloy) formed by a bonding transfer method.

  The low temperature nucleation layer 20 is preferably amorphous gallium nitride (GaN) or aluminum nitride (AlN) formed at a low temperature of 700 degrees or less, and may be omitted in some cases.

  Each layer from the nitride buffer layer 30 to the nitride nitride cladding layer 60 is formed on the basis of any compound selected from AlxInyGazN (x, y, z: integer), which is a general formula of a group III nitride compound, The dopant is added to the nitride cladding layer 40 and the nitride nitride cladding layer 60.

  In addition, the nitride-based active layer 50 is a variety of known, such as monolayer, multi quantum well (MQW), multi quantum dot / wire, or a layer mixed with quantum dots / lines and wells Can be configured in a manner.

  For example, when a gallium nitride (GaN) compound is applied, the buffer layer 30 is formed of GaN, and the N-type nitride cladding layer 40 is formed by adding Si, Ge, Se, Te, etc. to GaN as an n-type dopant. The active layer is formed of InGaN / GaN MQW or AlGaN / GaN MQW, and the nitride-based cladding layer 60 is formed by adding Mg, Zn, Ca, Sr, Ba, etc. to GaN as a dopant.

  An en-type ohmic contact layer (not shown) may be interposed between the en-type nitride cladding layer 40 and the en-type electrode pad 90, and the en-type ohmic contact layer is formed by sequentially stacking titanium (Ti) and aluminum (Al). Various known structures such as a layer structure can be applied.

  As described above, the core multi-ohmic contact layer 70, which is the core technology of the present invention, has at least one or more thermally decomposed nitrides, that is, nickel (Ni) and copper (Cu), on the upper layer of the nitride-based cladding layer 60. ), Nitride (Zn), indium (In), or tin (Sn), such as at least one or more of the metal and nitrogen (N) is a material in which a nitride material is necessarily bonded.

  Preferably, the pyrolytic nitride may further include other metal components as dopants to control electrical properties. Herein, the metals applied as dopants are applied with elements classified as metals on the periodic table of elements.

  According to another aspect of the present invention, the highly transparent multi-type ohmic contact electrode structure as described above, in addition to the pyrolytic nitride, metals and metals which are advantageous for forming an ohmic contact electrode structure on the upper part of the nitride-based cladding layer are as follows. Grafting regardless of stacking order with alloy / solid solution, common conducting oxide, transparent conductive oxide (TCO), transparent conductive nitride (TCN), transparent conductive nitrogen oxide (TCON), etc. Can be formed.

  Metals and alloys / solid solutions based on these metals: platinum (Pt), palladium (Pd), nickel (Ni), gold (Au), rhodium (Rh), ruthenium ( Ru, iridium (Ir), silver (Ag), zinc (Zn), magnesium (Mg), beryllium (Be), copper (Cu), cobalt (Co), tin (Sn), rare earth metals ), Or an alloy / solid solution based on these metals.

  The general conducting oxide: nickel oxide (Ni-O), rhodium oxide (Rh-O), ruthenium oxide (Ru-O), iridium oxide (Ir-O), copper oxide (Cu-O), Cobalt oxide (Co-O), tungsten oxide (WO), or titanium oxide (Ti-O).

  The transparent conductive oxide (TCO): indium oxide (In2O3), tin oxide (SnO2), indium tin oxide (ITO), zinc oxide (ZnO), magnesium (MgO), cadmium oxide (CdO), magnesium zinc oxide (MgZnO ), Indium zinc oxide (InZnO), indium tin oxide (InSnO), copper aluminum oxide (CuAlO2), silver oxide (Ag2O), gallium oxide (Ga2O3), zinc tin oxide (ZnSnO), zinc indium tin oxide (ZITO), Or other oxides to which these transparent conductive oxides are combined.

  The transparent conductive nitride (TCN): titanium nitride (TiN), chromium nitride (CrN), tungsten (WN), tantalum (TaN), or niobium (NbN).

  The transparent conductive nitrogen oxide (TCON): indium (In), tin (Sn), zinc (Zn), cadmium (Cd), gallium (Ga), aluminum (Al), magnesium (Mg), titanium (Ti), molybdenum Ium (Mo), nickel (Ni), copper (Cu), silver (Ag), gold (Au), platinum (Pt), rhodium (Rh), iridium (Ir), ruthenium (Ru), or palladium (Pd ) A substance formed by combining at least one of metals as a main component and oxygen (O) and nitrogen (N) must be bonded at the same time.

  More preferably, a third material, ie, a dopant, may be added to the above oxides and nitrides in order to improve the electrical properties of these materials.

  In addition, the multi-ohmic contact layer 70 is preferably formed to a thickness of 1 nanometer to 1000 nanometers.

  In addition, the deposition temperature applied to form the formed multiple ohmic contact layer 70 is in the range of 20 degrees to 1500 degrees, and the pressure in the evaporator is performed at atmospheric pressure to about 10-12 torr.

  In addition, it is preferable to undergo an annealing process after the formation of the multilayered ohmic contact layer 70. Annealing is performed at a temperature in the reactor at 100 to 800 degrees for 10 seconds to 3 hours in a vacuum or gas atmosphere. At least one gas of nitrogen, argon, helium, oxygen, hydrogen, or air may be applied to the gas introduced into the reactor during the heat treatment.

  The electrode pad 80 is formed of nickel (Ni) / gold (Au), silver (Ag) / gold (Au), titanium (Ti) / gold (Au), nickel (Ni) / gold (Au), and palladium (Pd). A layer structure in which) / gold (Au), or chromium (Cr) / gold (Au) is sequentially stacked may be applied.

  The method of forming each layer is physical such as electron beam or thermal evaporator, pulsed laser deposition using laser energy source, dual-type thermal evaporator sputtering, etc. It is formed by chemical vapor deposition (CVD) using chemical reactions such as physical vapor deposition (PVD), electroplating, and metal-organic chemical vapor deposition.

  2 is a cross-sectional view illustrating a light emitting diode to which the multi-type ohmic contact electrode structure according to the second embodiment of the present invention is applied.

  In detail, FIG. 2 (a) is a cross-sectional view illustrating a group III-nitride-based top-emitting type light emitting diode (TELED) laminated / grown on an upper layer of sapphire 10, which is an insulating growth substrate, whereas FIG. Electrically conductive substrates such as silicon carbide (SiC), zinc oxide (ZnO), silicon (Si), gallium arsenide (GaAs), or already known electroplating / bonding transfers in many documents. A cross-sectional view showing a group III-nitride-based top-emitting light emitting diode (TELED) formed on an upper layer of a conductive material layer such as metal (Cu, Ni, Al, etc.) or alloy formed by the method.

  First of all, the laminated structure in which the tunnel junction layer 100 is inserted before the formation of the nitride-based cladding (type 60 ohmic contact layer 70 on the upper 60 layer) is a layer structure significantly different from the above-described first embodiment. Have

The tunnel junction layer 100 thus introduced is a compound represented by Al a In b Ga c N x P y As z (a, b, c, x, y, z; integer) composed of group 3-5 elements. Based on any compound selected, a single layer, preferably a bi-layer, tri-layer, or more stacked structure formed to a thickness of 50 nanometers or less may be formed. Can be.

  Preferably, the superlattice structure already known in the literature is referred to as the tunnel junction layer 100. For example, a thin lamination structure formed of Group 3-5 elements such as InGaN / GaN, AlGaN / GaN, AlInN / GaN, AlGaN / InGaN, AlInN / InGaN, AlN / GaN, or AlGaAs / InGaAs, and the like, and have a maximum of 30 pairs repeatedly. Up to 30 pairs can be laminated.

  More preferably, it refers to a single crystal, poly-crystal, or amorphous material layer to which group group elements (Mg, Be, Zn) or group group elements (Si, Ge) are added.

  Referring to FIG. 2, the light emitting device includes a substrate 10, a low temperature nucleation layer 20, a nitride buffer layer 30, an N-type nitride cladding layer 40, a nitride active layer 50, and a nitride-based cladding layer. 60, the ohmic contact layer 70, and the tunnel junction layer 100 are sequentially stacked. Reference numeral 80 denotes a shaped electrode pad, and 90 denotes an N-type electrode pad.

  The substrate 10 to the nitride nitride cladding layer 60 correspond to the light emitting structure, and the structure stacked on the upper portion of the nitride nitride cladding layer 60 corresponds to the electrode structure.

  The substrate 10 may be formed of sapphire (Al 2 O 3), silicon carbide (SiC), zinc oxide (ZnO), silicon (Si), gallium arsenide (GaAs), or an electroplating / bonding transfer known in many literatures. It is preferably formed of any one of materials such as metal (Cu, Ni, Al, etc.) or alloy (alloy) formed by a bonding transfer method.

  The low temperature nucleation layer 20 is preferably amorphous gallium nitride (GaN) or aluminum nitride (AlN) formed at a low temperature of 700 degrees or less, and may be omitted in some cases.

  Each layer from the nitride buffer layer 30 to the nitride nitride cladding layer 60 is formed on the basis of any compound selected from AlxInyGazN (x, y, z: integer), which is a general formula of a group III nitride compound, The dopant is added to the nitride cladding layer 40 and the nitride nitride cladding layer 60.

  In addition, the nitride-based active layer 50 is a variety of known, such as monolayer, multi quantum well (MQW), multi quantum dot / wire, or a layer mixed with quantum dots / lines and wells Can be configured in a manner.

  For example, when a gallium nitride (GaN) compound is applied, the buffer layer 30 is formed of GaN, and the N-type nitride cladding layer 40 is formed by adding Si, Ge, Se, Te, etc. to GaN as an n-type dopant. The active layer is formed of InGaN / GaN MQW or AlGaN / GaN MQW, and the nitride-based cladding layer 60 is formed by adding Mg, Zn, Ca, Sr, Ba, etc. to GaN as a dopant.

  An en-type ohmic contact layer (not shown) may be interposed between the en-type nitride cladding layer 40 and the en-type electrode pad 90, and the en-type ohmic contact layer is formed by sequentially stacking titanium (Ti) and aluminum (Al). Various known structures such as a layer structure can be applied.

  As described above, the core multi-ohmic contact layer 70, which is the core technology of the present invention, has at least one or more thermally decomposed nitrides, that is, nickel (Ni) and copper (Cu), on the upper layer of the nitride-based cladding layer 60. ), Nitride (Zn), indium (In), or tin (Sn), such as at least one or more of the metal and nitrogen (N) is a material in which a nitride material is necessarily bonded.

  Preferably, the pyrolytic nitride may further include other metal components as dopants to control electrical properties. Herein, the metals applied as dopants are applied with elements classified as metals on the periodic table of elements.

  According to another aspect of the present invention, the highly transparent multi-type ohmic contact electrode structure as described above, in addition to the pyrolytic nitride, metals and metals which are advantageous for forming an ohmic contact electrode structure on the upper part of the nitride-based cladding layer are as follows. Grafting regardless of stacking order with alloy / solid solution, common conducting oxide, transparent conductive oxide (TCO), transparent conductive nitride (TCN), transparent conductive nitrogen oxide (TCON), etc. Can be formed.

  Metals and alloys / solid solutions based on these metals: platinum (Pt), palladium (Pd), nickel (Ni), gold (Au), rhodium (Rh), ruthenium ( Ru, iridium (Ir), silver (Ag), zinc (Zn), magnesium (Mg), beryllium (Be), copper (Cu), cobalt (Co), tin (Sn), rare earth metals ), Or an alloy / solid solution based on these metals.

  The general conducting oxide: nickel oxide (Ni-O), rhodium oxide (Rh-O), ruthenium oxide (Ru-O), iridium oxide (Ir-O), copper oxide (Cu-O), Cobalt oxide (Co-O), tungsten oxide (WO), or titanium oxide (Ti-O).

  The transparent conductive oxide (TCO): indium oxide (In2O3), tin oxide (SnO2), indium tin oxide (ITO), zinc oxide (ZnO), magnesium (MgO), cadmium oxide (CdO), magnesium zinc oxide (MgZnO ), Indium zinc oxide (InZnO), indium tin oxide (InSnO), copper aluminum oxide (CuAlO2), silver oxide (Ag2O), gallium oxide (Ga2O3), zinc tin oxide (ZnSnO), zinc indium tin oxide (ZITO), Or other oxides to which these transparent conductive oxides are combined.

   The transparent conductive nitride (TCN): titanium nitride (TiN), chromium nitride (CrN), tungsten (WN), tantalum (TaN), or niobium (NbN).

   The transparent conductive nitrogen oxide (TCON): indium (In), tin (Sn), zinc (Zn), cadmium (Cd), gallium (Ga), aluminum (Al), magnesium (Mg), titanium (Ti), molybdenum Ium (Mo), nickel (Ni), copper (Cu), silver (Ag), gold (Au), platinum (Pt), rhodium (Rh), iridium (Ir), ruthenium (Ru), or palladium (Pd ) A substance formed by combining at least one of metals as a main component and oxygen (O) and nitrogen (N) must be bonded at the same time.

  More preferably, a third material, ie, a dopant, may be added to the above oxides and nitrides in order to improve the electrical properties of these materials.

  In addition, the multi-ohmic contact layer 70 is preferably formed to a thickness of 1 nanometer to 1000 nanometers.

  In addition, the deposition temperature applied to form the shaped multiple ohmic contact layer 70 is in the range of 20 degrees to 1500 degrees, and the pressure in the evaporator is performed at atmospheric pressure to about 10-12 torr.

  In addition, it is preferable to undergo an annealing process after the formation of the multilayered ohmic contact layer 70. Annealing is performed at a temperature in the reactor at 100 to 800 degrees for 10 seconds to 3 hours in a vacuum or gas atmosphere. At least one gas of nitrogen, argon, helium, oxygen, hydrogen, or air may be applied to the gas introduced into the reactor during the heat treatment.

  The electrode pad 80 is formed of nickel (Ni) / gold (Au), silver (Ag) / gold (Au), titanium (Ti) / gold (Au), nickel (Ni) / gold (Au), and palladium (Pd). A layer structure in which) / gold (Au), or chromium (Cr) / gold (Au) is sequentially stacked may be applied.

  The method of forming each layer is physical such as electron beam or thermal evaporator, pulsed laser deposition using laser energy source, dual-type thermal evaporator sputtering, etc. It is formed by chemical vapor deposition (CVD) using chemical reactions such as physical vapor deposition (PVD), electroplating, and metal-organic chemical vapor deposition.

  FIG. 3 is a cross-sectional view illustrating various stacked shapes of the multiple-type ohmic contact electrode structure 70 formed on the upper portion of the nitride-based cladding layer 60 according to the first and second embodiments of the present invention.

  The multi-ohmic contact electrode structure 70 applied in the present invention is, as described above, metals such as nickel (Ni), copper (Cu), zinc (Zn), indium (In), tin (Sn), and the like. Among them, it is preferable to form at least one or more layers of at least one thermally decomposed nitride in which at least one component and nitrogen (N) are necessarily bonded, and to form a single layer or multiple layers of two or more layers.

  More preferably, metal, alloy, solid solution, general conductive oxide, transparent conductive oxide (TCO), transparent conductive nitride, rather than being formed of transparent conductive nitrogen oxide (TCON) single layer 70a, as shown in FIG. Alternatively, multiple forms such as 3 (b), 3 (c), 3 (d), or the like, which are grafted irrespective of the stacking order such as transparent conductive nitrogen oxide (TCON) and the like, may be used.

4 is a p- type multi ohmic contact electrode structure formed after introducing nanometer scale particles into an upper layer of a nitride-based cladding layer according to the first and second embodiments of the present invention. This is a cross-sectional view showing various stacked forms of layers).

  Carrier at the interface between the group III-nitride semiconductor cladding layer 60 and the electrode structure 70 before the formation of the multi-ohmic contact electrode structure 70 applied in the present invention to the upper layer of the nitride-based cladding layer 60. Metals, alloys, solid solutions and common conducting oxides to control the Schottky barrier height and width to control their charge transport , Nanometer size particles composed of transparent conductive oxide (TCO), transparent conductive nitride (TCN), transparent conductive nitrogen oxide (TCON), or pyrolytic nitride, and then form nickel (Ni), copper (Cu) as described above. ), At least one or more layers of pyrolytic nitride in which at least one metal component and nitrogen (N) component are necessarily combined among metals such as zinc (Zn), indium (In), or tin (Sn). It is preferable to form in the above multiple forms.

  More preferably, metal, alloy, solid solution, general conductive oxide, transparent conductive oxide (TCO), transparent conductive nitride, rather than being formed of transparent conductive nitrogen oxide (TCON) single layer 70a, as shown in FIG. Alternatively, multiple forms such as Fig. 4 (b), 4 (c), or 4 (d) may be used, such as transparent conductive nitrogen oxide (TCON) or the like, regardless of the stacking order.

  Examples of preferred multi-type ohmic contact layers 70 include nickel nitride (Ni-N) / indium tin oxide (ITO) or zinc oxide (ZnO), nickel nitride (Ni-N) / indium tin nitrogen oxide (ITON) or Zinc Nitrogen Oxide (ZnON), Copper Nitride (Cu-N) / Ruthenium (Ru) / Indium Tin Nitrogen Oxide (ITON) or Zinc Nitrogen Oxide (ZnON), Tin Nitride (Sn-N) / Iridium (Ir) / Indium Tin Nitrogen Oxide (ITON) or Zinc Nitrogen Oxide (ZnON), Nickel Nitride (Ni-N) / Silver (Ag) / Indium Tin Nitrogen Oxide (ITON) or Zinc Nitrogen Oxide (ZnON), Zinc Nitride (Zn-N) / Ruthenium Oxide (Ru-O) / Indium Tin Nitrogen Oxide (ITON) or Zinc Nitrogen Oxide (ZnON), Tin Nitride (Sn-N) / Iridium Oxide (Ir-O) / Indium Tin Nitrogen Oxide (ITON) or Zinc Nitrogen Oxide (ZnON), nickel nitride (Ni-N) / silver (Ag) or gold (Au) / indium tin oxide (ITO) or zinc oxide (ZnO), tin nitride (Sn-N) / rucenium (Ru) / Silver (Ag) or Gold (Au) / Indium Tin Nitrogen Oxide (ITON) or Zinc Nitrogen Oxidation (ZnON), copper nitride (Cu-N) / iridium (Ir) / silver (Ag) or gold (Au) / indium tin nitrous oxide (ITON) or zinc nitrous oxide (ZnON), nickel nitride (Ni-N) / Nickel Oxide (Ni-O) / Silver (Ag) or Gold (Au) / Indium Tin Nitrogen Oxide (ITON) or Zinc Nitrogen Oxide (ZnON), Tin Nitride (Sn-N) / Ruenium Oxide (Ru-O) / Silver (Ag) or Gold (Au) / Indium Tin Nitrogen Oxide (ITON) or Zinc Nitrogen Oxide (ZnON), Zinc Nitride (Zn-N) / Iridium Oxide (Ir-O) / Silver (Ag) or Gold (Au ) / Indium Tin Nitrogen Oxide (ITON) or Zinc Nitrogen Oxide (ZnON), Copper Nitride (Cu-N) / Indium Tin Oxide (ITO) or Zinc Oxide (ZnO) / Indium Tin Nitrogen Oxide (ITON) or Zinc Nitrogen Oxide ( ZnON), nickel nitride (Ni-N) / indium tin nitrous oxide (ITON) or zinc nitrous oxide (ZnON) / indium tin oxide (ITO) or zinc oxide (ZnO) has various laminated structures.

  The electrode structure composed of the high-transparent, multi-ohmic contact layer designed and proposed in the present invention is not limited to the Group III nitride-based upper light emitting diode formed on the upper layer of the sapphire substrate, which is an insulating material, and is not an electrically insulating substrate material. That is, the present invention can also be applied to a group III-nitride-type vertical top light emitting diode formed on a substrate such as Si, SiC, GaAs, ZnO, or MgZnO.

As described so far, according to the Group III nitride-based light emitting device according to the embodiment of the present invention and a method of manufacturing the same, the electrical and optical characteristics are much higher than those of the transparent conductive thin film electrode using the general metal, transparent conductive oxide or nitride. Thermally decomposed nitride, which has better nitride-based ohmic electrode characteristics, is applied as a type ohmic electrode of a group III nitride-based upper light emitting diode to dramatically improve the ohmic contact interface property with the nitride-based cladding layer. In addition to exhibiting current-voltage characteristics, the high-light transmittance that the transparent electrode must have makes it possible to fabricate a high-efficiency, high-brightness group III-nitride top light emitting device.

Claims (17)

An optical structure including an active layer, an N-type nitride cladding layer formed under the active layer, and a P-type nitride cladding layer formed on the active layer; And Is formed on top of the nitride-based cladding layer, and comprises a contact layer having at least one pyrolysis nitride layer, The pyrolytic nitride layer includes at least one of nickel, copper, zinc, indium, and tin. The method of claim 1, The pyrolytic nitride layer includes nickel nitride (Ni-N), copper nitride (Cu-N), zinc nitride (Zn-N), indium nitride (In-N), or tin nitride (Sn-N). Optical element made into. The method of claim 1, The pyrolytic nitride layer includes nitride formed of at least two alloys of nickel (Ni), copper (Cu), zinc (Zn), indium (In), and tin (Sn). device. The method of claim 1, The pyrolytic nitride layer is an optical element, characterized in that the element further classified as a dopant on the periodic table as a metal. The method of claim 1, The corrugated contact layer is a metal, an alloy or solid solution based on the metal, a conducting oxide, a transparent conducting oxide (TCO), and a transparent grafted nitride layer. Optical device further comprises at least one of a conductive nitride (TCN). The method of claim 5, The metal is platinum (Pt), palladium (Pd), nickel (Ni), gold (Au), rhodium (Rh), ruthenium (Ru), iridium (Ir), silver (Ag), zinc (Zn), magnesium (Mg), beryllium (Be), copper (Cu), cobalt (Co), tin (Sn), and rare earth metals; The conducting oxide is nickel oxide (Ni-O), rhodium oxide (Rh-O), ruthenium oxide (Ru-O), iridium oxide (Ir-O), copper oxide (Cu-O), cobalt At least one of an oxide (Co-O), a tungsten oxide (WO), and a titanium oxide (Ti-O), The transparent conductive oxide (TCO) is indium oxide (In2O3), tin oxide (SnO2), zinc oxide (ZnO), magnesium oxide (MgO), cadmium oxide (CdO), magnesium zinc oxide (MgZnO), indium zinc oxide ( InZnO), indium tin oxide (InSnO), copper aluminum oxide (CuAlO2), silver oxide (Ag2O), gallium oxide (Ga2O3), zinc tin oxide (ZnSnO), and zinc indium tin oxide (ZITO) , The transparent conductive nitride (TCN) includes at least one of titanium nitride (TiN), chromium nitride (CrN), tungsten nitride (WN), tantalum nitride (TaN), and niobium nitride (NbN). . The method of claim 6, Is introduced onto the clad nitride-based cladding layer and grafted to the clad contact layer, wherein the metal, an alloy or solid solution based on the metal, the conducting oxide, and the transparent conductivity And an nanometer size particle formed of at least one of an oxide (TCO) and the transparent conductive nitride (TCN). The method of claim 1, A tunnel junction layer formed between the clad nitride-based cladding layer and the clad contact layer and having a compound represented by AlaInbGacNxPyAsz (a, b, c, x, y, z; integer) composed of group 3-5 elements. Optical device comprising a further. Forming an optical structure including an active layer, an N-type nitride cladding layer formed under the active layer, and a P-type nitride cladding layer formed on the active layer ; And Forming a contact layer having at least one pyrolytic nitride layer on the top of the nitride-based cladding layer, The pyrolytic nitride layer comprises at least one of nickel, copper, zinc, indium, and tin. The method of claim 9, The pyrolytic nitride layer includes nickel nitride (Ni-N), copper nitride (Cu-N), zinc nitride (Zn-N), indium nitride (In-N), or tin nitride (Sn-N). The manufacturing method of the optical element made into. The method of claim 9, The pyrolytic nitride layer includes nitride formed of at least two alloys of nickel (Ni), copper (Cu), zinc (Zn), indium (In), and tin (Sn). Method of manufacturing the device. The method of claim 9, The pyrolytic nitride layer is a method of manufacturing an optical device, characterized in that the element further classified as a metal on the periodic table as a dopant. The method of claim 9, The corrugated contact layer is a metal, an alloy or solid solution based on the metal, a conducting oxide, a transparent conducting oxide (TCO), and a transparent grafted nitride layer. The method of manufacturing an optical device, characterized in that it further comprises at least one of a conductive nitride (TCN). The method of claim 13, The metal is platinum (Pt), palladium (Pd), nickel (Ni), gold (Au), rhodium (Rh), ruthenium (Ru), iridium (Ir), silver (Ag), zinc (Zn), magnesium (Mg), beryllium (Be), copper (Cu), cobalt (Co), tin (Sn), and rare earth metals; The conducting oxide is nickel oxide (Ni-O), rhodium oxide (Rh-O), ruthenium oxide (Ru-O), iridium oxide (Ir-O), copper oxide (Cu-O), cobalt At least one of an oxide (Co-O), a tungsten oxide (WO), and a titanium oxide (Ti-O), The transparent conductive oxide (TCO) is indium oxide (In2O3), tin oxide (SnO2), zinc oxide (ZnO), magnesium oxide (MgO), cadmium oxide (CdO), magnesium zinc oxide (MgZnO), indium zinc oxide ( InZnO), indium tin oxide (InSnO), copper aluminum oxide (CuAlO2), silver oxide (Ag2O), gallium oxide (Ga2O3), zinc tin oxide (ZnSnO), and zinc indium tin oxide (ZITO) , The transparent conductive nitride (TCN) includes at least one of titanium nitride (TiN), chromium nitride (CrN), tungsten nitride (WN), tantalum nitride (TaN), and niobium nitride (NbN). Method of preparation. The method of claim 14, Is introduced onto the clad nitride-based cladding layer and grafted to the clad contact layer, wherein the metal, an alloy or solid solution based on the metal, the conducting oxide, and the transparent conductivity And a nanometer size particle formed of at least one of an oxide (TCO) and the transparent conductive nitride (TCN). The method of claim 9, The method of manufacturing an optical device, characterized in that it further comprises the step of heat treatment after forming the contact layer. The method of claim 16, The heat treatment step is 10 seconds to 3 to 100 to 800 degrees in an atmosphere containing at least one of nitrogen (N 2), oxygen (O 2), hydrogen (H 2), air, argon (Ar), and helium (He) gas. Method for producing an optical element, characterized in that carried out for a time.

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