JP5459554B2 - Sensor device - Google Patents

Description

  The present invention relates to a sensor device, and more particularly to a sensor device using a transistor having a porous insulating layer.

  Conventionally, various sensors have been researched and developed. Sensors have spread widely from industrial to medical or from homes, and are indispensable in modern society. The sensors are classified according to, for example, a measurement object, a signal conversion function, or a constituent material, and the signal conversion function can be roughly classified into a physical sensor, a chemical sensor, or a biosensor.

Among these, a biosensor is a measurement device that imitates or directly uses an excellent molecular recognition ability of a living body, and is expected to be applicable to a wide range of applications. In particular, research on various biochips aimed at application in the fields of drug discovery, clinical testing, and medical research is being actively promoted.

These biochips use changes in physical properties (physical properties exhibited by the substance) such as fluorescence, refractive index, mass, oxidation / reduction current, and chemiluminescence to detect specific reactions of biomolecules.
In 2003, when the entire base sequence of the human genome was completely deciphered, gene function analysis was performed based on the results, and the specific charges (carriers) of biomolecules were subjected to specific reactions using the electric field effect. Research into biotransistors that detect directly is underway.

Furthermore, with the aim of realizing future tailor-made medicine, the development of DNA chips for genetic testing is also progressing, and it is expected as a technology that can easily examine individual differences in genomic DNA sequences. Among them, gene bases related to diseases and drug metabolism are attracting attention, and by examining the types of individual bases, the effectiveness and side effects of drugs are predicted and matched to the individual's constitution The provision of medical care is being promoted.

FIG. 1 shows a schematic cross-sectional view of an element and an electric circuit diagram for explaining a conventional biotransistor.
Insulated Gate Field Effect Transistor (IGFET) is a biological insulating gate field effect transistor (IGFET) in which molecular recognition materials such as DNA, RNA, antigens / antibodies, and proteins are immobilized on the surface of a gate insulating film. Soaked.

In the IGFET, the potential of the solution is controlled by a reference electrode, and the charge density by molecular recognition of the molecular recognition material on the surface of the gate insulating film is measured through the reference electrode.
In the silicon (Si) surface, the electron density of the channel (between the source electrode and the drain electrode) changes in response to the charge density on the surface of the gate insulating film. It is possible to detect only a signal based on the amount of electric charge displacement due to (for example, see Non-Patent Documents 1 and 2).

Here, the measurement of DNA potential using IGFET will be described.
As shown in FIG. 1, the oligonucleotide probe is immobilized on the surface of the gate insulating film of the IGFET and immersed in the solution together with the reference electrode. The potential of the solution is controlled by a reference electrode. Thus, the change in charge density due to molecular recognition on the surface of the gate insulating film is measured through the reference electrode. Among these, when a sample solution containing the target DNA is introduced into the surface of the gate insulating film, double-stranded DNA is formed by hybridization. Since DNA molecules have a negative charge due to phosphate ions in an aqueous solution, it is possible to realize a state in which the DNA molecules and electrons in the silicon substrate interact electrostatically.
Accordingly, since the electron density of the silicon surface (channel) changes in response to the change in the charge density of DNA molecules on the surface of the gate insulating film, the current between the source (S) and the drain (D) is measured in principle. DNA hybridization can be detected.
However, since the IGFET shown in FIG. 1 is based on a horizontal field effect transistor structure, there is a limit to high sensitivity detection and high speed detection.

In recent years, the use of organic semiconductor materials for electronics has been proposed because of the need for reduced environmental impact, lighter equipment, portability, and flexibility. For this reason, various transistors using organic semiconductor materials have been proposed. Yes. Most of the transistors using inorganic semiconductor materials are lateral transistors, and few inorganic vertical transistors are used. However, in transistors using organic semiconductor materials, the organic semiconductor materials are high resistance and low mobility materials. Therefore, vertical transistors are attracting attention because they are easier to operate at higher currents and higher speeds than horizontal transistors.

As a vertical transistor using an organic semiconductor, a transistor in which CuPc (copper phthalocyanine) is sandwiched between a source electrode and a drain electrode and a slit-like aluminum thin film is embedded in a CuPc layer in a gate electrode has been reported (for example, Non-Patent Document 3).

When compared with a horizontal field effect transistor such as a MOS (Metal Oxide Semiconductor), the vertical type field effect transistor has a current flowing in the horizontal direction of the conductive layer, whereas the vertical type has a conductive layer. Since the current flows in the vertical direction, the vertical field effect transistor can shorten the channel length (distance between the source and the drain) that is the current path of the transistor to the thickness of the conductive layer, and Since a large drain current can be obtained, the transistor can be operated at a high speed. Further, since the element structure is simple, the element size can be reduced.

Since the vertical transistor has such a feature, for example, when used as a control element (also referred to as a switching element) of a light emitting layer such as an organic EL layer, an organic EL layer is used. Since a display device is required to have a high response speed and a relatively large current, it is more suitable than a horizontal transistor. As described above, it has been found that the vertical organic transistor can be used overwhelmingly advantageously compared to the case where the horizontal organic transistor is used, and now, it is aimed at realizing a flexible sheet display. There is active research and development.
However, no high-performance vertical biotransistor has been provided.

The present invention has been made in view of the above points, and the present invention eliminates the conventional drawbacks by using a vertical field effect transistor structure for measurement of biomolecules, and achieves high accuracy and high speed. An object is to provide a high-sensitivity and high-performance sensor device (biotransistor) that can be operated and can be miniaturized.

The present invention is solved by the following (1) to (8).
(1) A porous insulating layer formed of a porous insulating material, a first electrode having a first opening formed on one surface of the porous insulating layer, and the porous insulating layer A second electrode having a second opening corresponding to a hole from the first opening formed on the other surface; between the first electrode and the second electrode; and the porous And a third electrode disposed on the insulating layer.
(2) a low resistance substrate having a first opening; a first electrode formed on a lower surface of the low resistance substrate; an insulating layer formed on an upper surface of the low resistance substrate; A third electrode formed on the insulating layer; a second insulating layer formed on the third electrode; a porous insulating layer formed on the second insulating layer; And a second electrode having a second opening corresponding to a hole from the first opening formed on the porous insulating layer.
(3) The sensor device according to (1) or (2), wherein the third electrode is entirely covered with an insulating material.
(4) A current value that flows by immersing all of the first electrode, the second electrode, and the porous insulating layer in a solution, and applying a voltage between the first electrode and the second electrode. And measuring a property of the solution or a substance contained in the solution or a physical property amount of the contained material based on the current value, according to any one of (1) to (3), Sensor device.
(5) All of the first electrode, the second electrode, the third electrode, and the porous insulating layer are immersed in a solution, a constant voltage is applied to the third electrode, and the first electrode A current value flowing by applying a voltage between an electrode and the second electrode is detected, and the property of the solution or the material contained in the solution or the physical property amount of the contained material is measured based on the current value. The sensor device according to any one of (1) to (3), wherein the sensor device is performed.
(6) The sensor according to any one of (1) to (5), wherein the porous insulating layer is provided with a plurality of holes communicating from the one surface to the other surface. device.
(7) The porous insulating layer includes a metal oxide, and the metal oxide includes (a) zinc oxide, titanium oxide, tin oxide, indium oxide, aluminum oxide, niobium oxide, tantalum pentoxide, and barium titanate. And one metal oxide selected from strontium titanate, or (b) one metal oxide selected from nickel oxide, cobalt oxide, iron oxide, manganese oxide, chromium oxide, and bismuth oxide, or impurities. The sensor device according to any one of (1) to (6), wherein the sensor device is a metal oxide described in (a) or (b) formed by doping.
(8) Either the first electrode or the second and third electrodes is made of chromium, tantalum, titanium, copper, aluminum, molybdenum, tungsten, nickel, gold, palladium, platinum, silver, tin , magnesium, indium tin oxide, characterized in that it comprises conductive metal oxides of the zinc oxide, conductive polyaniline, conductive polypyrrole, conductive polythiazyl, at least one material selected from the group consisting of a conductive polymer The sensor device according to any one of (1) to (7).

  As will be understood from the following detailed and specific description, according to the present invention, the vertical biotransistor according to the present invention can be used for, for example, DNA sequencing, thereby enabling high-sensitivity and high-speed signal detection. A small, low-cost and high-performance sensor device can be provided.

It is the element schematic sectional drawing and electric circuit diagram for demonstrating the conventional biotransistor. It is sectional drawing and the electric circuit diagram which showed typically the vertical type biotransistor single element of this invention. It is a figure which shows the vertical type | mold biotransistor of this invention in a biosensor array. It is a figure which shows the manufacturing method of a vertical type biotransistor. It is a figure which shows the definition of the hole diameter and cell period of the porous insulating layer of this invention. It is the figure which showed the manufacturing method of the porous insulating layer of this invention typically, and the figure which shows the form of the surface of a porous insulating film, and a cross section.

The sensor device of the present invention will be described in detail with reference to the drawings.
<Vertical biotransistor single element>
FIG. 2 is a cross-sectional view and an electric circuit diagram schematically showing a vertical biotransistor single element of the present invention. As shown in FIG. 2, in the vertical biotransistor (10), the source electrode (20) having the first opening (63) is formed on one surface of the porous portion, and the other surface of the porous portion is formed. Between the drain electrode (40) having the second opening (64), the insulating layer (50) formed under the drain electrode (40), and the source electrode (20) and the drain electrode (40). And it is comprised by the gate electrode (30) provided in the porous part vicinity.

The middle diagram of FIG. 3 shows the vertical biotransistor (10) of the present invention in the biosensor array (11) shown in the lower diagram of FIG. The upper view (enlarged view) of FIG. 3 displayed in a circle in the cross section of the single element is a cross-sectional view of the porous portion (60). The porous alumina (porous Al ₂ O ₃ ) formed in the porous portion (60) is a porous insulating layer (50), and a large number of holes (65) penetrating vertically are formed.
That is, the porous alumina (50) is provided with a plurality of holes (65) communicating from the surface on which the source electrode (20) is formed to the surface on which the drain electrode (40) is formed (see FIG. In the figure, one communicating hole is drawn as a representative). The pores of the porous alumina have a spatial gap that penetrates up and down. In the figure, A, T, G, and C linked in a single strand form 4 bases of DNA. This will be described later.

The porous alumina (50) is provided between the source electrode (20) and the drain electrode (40), and the porous alumina has a first opening (63) that is not covered with the source electrode (20). And a second opening (64) which is not covered with the drain electrode. The openings in the first opening and the second opening correspond to each other, and are formed in, for example, a rectangle, a circle, or an ellipse.

The source electrode (20) uses silicon (Si), which is a low resistance substrate, but a conductive material such as aluminum (Al) may be disposed on the Si substrate by vacuum deposition or the like. A source electrode as a first electrode to be electrically connected is provided, and is formed, for example, in a rectangular shape, a circular shape, or an elliptical shape on the peripheral edge portion of the first opening on one surface of the porous alumina (50). Is done. Similarly, a drain electrode (40) as a second electrode is formed at the peripheral edge of the second opening on the other surface of the porous alumina (50). An insulating layer (50) is formed immediately below the drain electrode.
The gate electrode (30) is formed between the source electrode and the drain electrode and serves as a third electrode. This gate electrode is covered with an insulating film such as silicon oxide.
In the configuration described above, when electric charge moves from the source electrode to the drain electrode, the electrical conductivity between the source and drain electrodes increases (resistance becomes small), and current flows efficiently between the source and drain electrodes. It becomes possible.

Next, the sensor device of the present invention will be described with reference to an enlarged view of FIG. 3, taking DNA as an example.
The upper diagram of FIG. 3 shows a state where single-stranded DNA (left in the figure) and folded DNA (right in the figure) moving through a plurality of communicating holes are trapped in the holes. An example of the base sequence of single-stranded DNA is shown on the leftmost side.
This is explained as a molecular passage phenomenon using a force generated by a pressure flow of a biological material solution represented by DNA and an electric field between the source and drain. As a result, the first electrode, the second electrode, and the porous insulating layer are all immersed in the solution, and a voltage is applied between the first electrode and the second electrode. The value of the current flowing between the second electrodes can be detected, and the characteristics of the substance contained in the solution or the physical properties of the contained material can be measured.
Furthermore, selective and more efficient molecular passage can be realized by controlling the Debye length using the third electrode.

With regard to DNA sequencing, a description will be added. DNA sequencing is to determine the binding order (base sequence) of nucleotides constituting DNA.
DNA is a molecule responsible for almost all genetic information of an organism, and is basically encoded in the form of a base sequence. For this reason, DNA sequencing has become a basic means for analyzing genetic information. For this reason, it is actively applied in biotaxonomy and ecology. In the medical field, it is useful for diagnosis and treatment of genetic diseases and infectious diseases, and for drug discovery. The DNA sequencing method which is currently mainstream is a method in which a DNA fragment is prepared in a base-dependent manner and the base order (sequence) is determined by comparing the lengths.
For example, the base of DNA consists of 4 bases, but adenine (A), guanine (G), cytosine (C), thymine (T), 4 bases, each corresponding to each base is cleaved once, The base sequence can be determined by rearranging the short fragments and reading them in the order of the cleaved bases.

DNA is a nucleic acid composed of deoxyribose, phosphate and base. The aforementioned four bases are combined with deoxyribose to form a nucleoside, and this nucleoside having a phosphate bonded thereto is called a nucleotide. Although this nucleotide is the smallest unit of nucleic acid, DNA is a polymer of deoxynucleotides. Nucleotide molecules are linked by a phosphate-mediated bond to form a chain-like molecular structure.
Therefore, the DNA strand has a double helix structure as a whole through hydrogen bonding with complementary bases (A and T, G and C). Base complementarity is a property in which if one of the four types of bases A, T, G, and C is determined, the other is linked with a hydrogen bond. From this, it is obtained by processing a chain double helix structure into a single-stranded DNA by a chemical reaction. If the base sequence of this single-stranded DNA is determined, all the base sequences are revealed.

In the present invention, the principle of a field effect transistor is utilized by utilizing the fact that the size of a nucleotide molecule of single-stranded DNA varies depending on the base to which it is bound, and that the nucleotide molecule retains a unique negative charge. Depending on the application, it enables DNA sequencing.
The different sizes of nucleotide molecules are used as follows. That is, nucleotide molecules can be supplemented by controlling the Debye length by the voltage applied to the gate electrode with the diameter of the communicating hole. At this time, DNA sequencing can be performed by measuring the current between the source and the drain.

The DNA sequencing using the vertical biotransistor of the present invention will be described.
DNA sequencing can be performed by detecting changes in threshold voltage and drain current when a constant gate voltage is applied.
The vertical biotransistor shown in FIG. 2 is used, for example, by being immersed in a DNA solution.
That is, the current is detected in a state where all of the source electrode, drain electrode, and gate electrode in the vertical biotransistor are immersed in the solution, and the characteristics of the solution or the material contained in the solution are included based on the value of the current. Measure physical properties of materials.
In the vertical biotransistor, the charge moving from the source electrode to the drain electrode moves through the spatial gap between the holes in the first opening and the second opening in the porous alumina. The distance of movement is shortened and the resistance is reduced. At this time, if the gate voltage is set to 0 V without applying the gate voltage, the DNA is transported by the electric field gradient between the source electrode and the drain electrode and passes through the hole, so that the negative charge inherent to the nucleotide molecule can be measured.

In addition, the current is detected in a state where all of the source electrode, drain electrode, and gate electrode in the vertical biotransistor are immersed in the solution, and the characteristics of the solution or the material contained in the solution are included based on the value of the current. Measurement of physical properties of materials can be performed.
In a vertical biotransistor, the resistance is reduced because the distance of charge moving from the source electrode to the drain electrode is short. DNA is transported from the first opening to the second opening due to the electric field gradient between the source electrode and the drain electrode and passes through the hole, and in addition, a constant voltage is applied to the gate electrode to thereby increase the Debye length. Each time the nucleotide molecule is captured in the porous part by the control, the negative charge inherent to the nucleotide molecule can be measured with higher accuracy. When the measurement is completed, the DNA depletes the gap between the holes formed in the porous alumina by applying a gate voltage corresponding to the applied voltage between the source electrode and the drain electrode of the vertical biotransistor. It moves from the first opening to the second opening through a layer controlled effective spatial gap.
By repeating this, the vertical biotransistor according to the present invention enables highly sensitive measurement for DNA sequencing.

As another application other than DNA sequencing, for example, if a glucose degrading enzyme is used as a molecular recognition material and a calibration curve for the change in ion concentration is obtained in advance, the vertical biotransistor according to the present invention can be used according to the amount of glucose. It can also be used as a test sensor for changing diabetes or the like.
That is, the vertical biotransistor is based on the generation of water (H ₂ O) and oxygen ions (O ⁻ ) accompanying the generation of H ₂ O ₂ by the redox reaction of glucose by glucose oxidase (GOD), which is a glucose degrading enzyme. It can be used as a glucose sensor by detecting a change in the amount of charge. It goes without saying that other physical properties can be detected using other molecular recognition materials.

In addition, with the same sensor structure described above, it is possible to function as a sensor by physical adsorption, chemical adsorption, and adsorption in which physical adsorption and chemical adsorption are combined. The biosensor includes a functional membrane, and changes as a result of various reactions in the functional membrane are converted into electrical signals by an electrical signal converter, and functions as a sensor by detecting the electrical signals. Reactions in functional membranes include functional membranes and reactions such as physical adsorption, chemical adsorption, molecular adsorption, enzyme reaction, antigen-antibody reaction, microorganisms, electrochemical reaction, DNA, etc. Needless to say, the combination and selectivity to be generated are sufficient, and if a functional film is arranged on the porous inner wall or in the vicinity thereof, it functions as a sensor.

<Vertical biotransistor manufacturing method>
Next, the manufacturing method of the vertical biotransistor of the present invention will be described using FIG. 4 as an example.
First, in the step shown in FIG. 4I, an oxide is formed on a silicon (Si) substrate by thermal oxidation or the like, for example. For example, a Si oxide having a thickness of about 500 nm is formed on a Si substrate having a plane orientation (001) of about 200 μm thickness which is a low resistance. Thereafter, titanium (Ti) or platinum (Pt) is formed by sputtering or vacuum deposition. The film thickness is about 100 nm. Further thereon, a Si oxide is formed by sputtering or CVD. Thereafter, aluminum (Al) is formed to a thickness of about 1 μm by using a vacuum deposition method at room temperature under vacuum conditions of about 1.3 to about 3.9 × 10 ⁻³ Pa.

Next, in the step shown in FIG. 4 (II), for example, Al is treated by anodic oxidation. The anodizing conditions are, for example, solution: sulfuric acid aqueous solution (0.5 mol / liter), voltage (15 V), current density of about 3 to 7 mA / cm ² , and liquid temperature (10 ° C.). Depending on the anodizing conditions, the pore diameter can be controlled to 5 to 450 nm and the cell period to 10 to 500 nm. FIG. 5 shows the definition of the hole diameter and the cell period in the present invention.

Next, in the process shown in FIG. 4 (III), Si is removed so as to become a forward mesa of about 54.7 ° with a potassium hydroxide (KOH) solution diluted with water, for example. Thereby, the second opening is formed.
Next, in the step shown in FIG. 4 (IV), after forming a resist pattern by, for example, photolithography, gold (Au) is deposited on porous alumina to a thickness of 30 nm, and then the resist pattern is removed. This forms the window opening in a rectangular, circular or elliptical shape.
Next, FIG. 4 (V) shows the manufactured vertical biotransistor.

The porous part and the insulating layer contain a metal oxide, and the metal oxide in the porous part is (a) zinc oxide, titanium oxide, tin oxide, indium oxide, aluminum oxide, niobium oxide, tantalum pentoxide, titanic acid. It is selected from barium and strontium titanate.
The metal oxide of the insulating layer is selected from (b) nickel oxide, cobalt oxide, iron oxide, manganese oxide, chromium oxide, and bismuth oxide.
Alternatively, this metal oxide is made of a material formed by doping impurities into the metal oxide described in (a) or (b).
As the porous metal oxide material, for example, an alumina (Al ₂ O ₃ ) or zinc oxide (ZnO) layer according to anodizing conditions for aluminum is preferably used. According to the anodizing treatment conditions, a uniform porosity is formed, so that a vertical biotransistor with high carrier mobility and high sensitivity is realized.

  Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to such specific embodiments, and various modifications may be made within the scope of the gist of the present invention described in the claims. Can be changed.

A 200 μm thick Si substrate was thermally oxidized to form a 500 nm thick Si oxide film. Thereafter, a titanium (Ti) film having a thickness of 100 nm was formed by sputtering. Further thereon, a Si oxide was formed by sputtering, and aluminum (Al) having a thickness of 1 μm was vapor-deposited at room temperature under a reduced pressure of 3.0 × 10 ⁻³ Pa.
Next, Al was anodized under conditions of sulfuric acid aqueous solution (0.5 mol / liter), voltage (15 V), current density 5 mA / cm ² , and liquid temperature (10 ° C.), with a pore diameter of about 15 nm and a cell cycle of about 50 nm. A porous layer was formed.
Next, Si was removed with a potassium hydroxide (KOH) solution diluted with water so as to obtain a forward mesa of about 54.7 °, thereby forming a second opening.
Next, after forming a resist pattern by photolithography, gold (Au) was deposited on porous alumina to a thickness of 30 nm, and then the resist pattern was removed to form a first opening.

In FIG. 6, the manufacturing method of the porous alumina produced in Example 1, the surface morphology of the produced porous alumina, and the SEM observation result of a cross section are shown.
In the figure, a sulfuric acid aqueous solution having a predetermined concentration is placed in a beaker, graphite or platinum is placed as a cathode, and aluminum is placed on the anode side so as to face this. Anodization is performed under the voltage and current conditions described above. As shown in the SEM observation results, it can be confirmed that high-density holes (about 10 to 20 nm in diameter) are formed.
The typical size of a nucleotide molecule is about 5 to 10 nm, whereas the Debye length in a physiological salt solution is about several nm. Therefore, the vertical biotransistor of the present invention allows DNA sequencing. Although it is speculated that it is possible, it was confirmed by using a plurality of commercially available standard solutions that it actually operates as a biotransistor.

In the process for producing the vertical biotransistor of Example 1, instead of porous alumina, a zinc oxide film was formed to form a source electrode, a drain electrode, and a gate electrode, respectively. Even in this case, the same operation as that of Example 1 was confirmed.

In the process of manufacturing the vertical biotransistor of Example 2, instead of zinc oxide, a cobalt oxide film was formed to form a source electrode, a drain electrode, and a gate electrode, respectively. Even in this case, the same operation as in the above-described embodiment was confirmed.

In the process of manufacturing the vertical biotransistor of Example 1, a source electrode was formed using aluminum (Al) instead of Au. Also in this case, the same operation as in the above-described embodiment was confirmed.

In the process of manufacturing the vertical biotransistor of Example 1, a source electrode was formed using Pd instead of Au. Also in this case, the same operation as in the above-described embodiment was confirmed.

In the process of manufacturing the vertical biotransistor of Example 1, a source electrode was formed using zinc oxide doped with aluminum (Al) instead of Au. Also in this case, the same operation as in the above-described embodiment was confirmed.

In the process of manufacturing the vertical biotransistor of Example 1, a source electrode was formed using conductive polyaniline instead of Au. In this case, the same operation was confirmed.

Further, the current-voltage characteristics of the vertical biotransistors shown in Examples 1 to 7 were measured in the same manner as the vertical biotransistor described in Example 1. As a result, a measurement result almost the same as or higher than that of the vertical biotransistor according to Example 1 was obtained, and it was confirmed that the effect was obtained.

In addition, the metal oxide of the insulating layer described above is silicon oxide, tantalum oxide, titanium oxide, aluminum oxide, hafnium oxide, zircon oxide, lanthanum oxide, scandium oxide, praseodymium oxide, bismuth oxide. It is also suitable for a configuration including at least one material selected from the group consisting of oxides, niobium oxides, tungsten oxides, yttrium oxides, and silicon nitrides.

As described above, according to the present invention, it is possible to provide a high-performance sensor device having a novel structure and exhibiting sensor characteristics characterized by using a vertical biotransistor.
In addition, according to the present invention, it is possible to provide a low-cost sensor device and circuit configuration with high carrier mobility, a steep rise signal of an output current (source-drain current), a high operating speed, and a low cost. Can do.

10 Vertical biotransistor
20 Source electrode
30 Gate electrode
40 Drain electrode 50 Insulating layer 60 Porous portion 63 First opening 64 Second opening 65 Hole

T. SAKATA, M. KAMAHORI, Y. MIYAHARA: Mater. Sci. And Eng. C 24 (2004) p.827-832 T. SAKATA, M. KAMAHORI, Y. MIYAHARA: Jpn. J. Appl. Phys, 44, 4B, (2005) p. 2854-2859 K. Kudo et.al: T. IEE Japan, Vol. 118-A, No. 10, (1998) p. 1166-1171

Claims (7)

A porous insulating layer formed of a porous insulating material; a first electrode having a first opening formed on one surface of the porous insulating layer; and the other surface of the porous insulating layer A second electrode having a second opening corresponding to a hole from the first opening formed between the first electrode and the second electrode, and the porous insulating layer And a third electrode disposed on the sensor device. A low resistance substrate having a first opening; a first electrode formed on a lower surface of the low resistance substrate; an insulating layer formed on an upper surface of the low resistance substrate; A third electrode formed thereon, a second insulating layer formed on the third electrode, a porous insulating layer formed on the second insulating layer, and the porous insulation And a second electrode having a second opening corresponding to the hole from the first opening formed on the layer. The sensor device according to claim 1, wherein the third electrode is entirely covered with an insulating material. The current value flowing is detected by immersing all of the first electrode, the second electrode, and the porous insulating layer in a solution, and applying a voltage between the first electrode and the second electrode. 4. The sensor device according to claim 1, wherein the sensor device measures a characteristic of the solution or a substance contained in the solution or a physical property amount of the contained material based on the current value. 5. All of the first electrode, the second electrode, the third electrode, and the porous insulating layer are immersed in a solution, a constant voltage is applied to the third electrode, and the first electrode and the Detecting a value of a flowing current by applying a voltage between the second electrode and measuring a property of the solution or a material contained in the solution or a physical property amount of the contained material based on the current value. The sensor device according to claim 1, wherein the sensor device is a device. The sensor device according to claim 1, wherein the porous insulating layer is provided with a plurality of holes communicating from the one surface to the other surface. The porous insulating layer includes a metal oxide, and the metal oxide includes (a) zinc oxide, titanium oxide, tin oxide, indium oxide, aluminum oxide, niobium oxide, tantalum pentoxide, barium titanate, and One metal oxide selected from strontium titanate, or (b) one metal oxide selected from nickel oxide, cobalt oxide, iron oxide, manganese oxide, chromium oxide, bismuth oxide, or an impurity. The sensor device according to claim 1, wherein the sensor device is a metal oxide described in (a) or (b) .

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