WO2021124609A1 - 電磁波検出器および電磁波検出器集合体 - Google Patents

電磁波検出器および電磁波検出器集合体 Download PDF

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Publication number
WO2021124609A1
WO2021124609A1 PCT/JP2020/029339 JP2020029339W WO2021124609A1 WO 2021124609 A1 WO2021124609 A1 WO 2021124609A1 JP 2020029339 W JP2020029339 W JP 2020029339W WO 2021124609 A1 WO2021124609 A1 WO 2021124609A1
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Prior art keywords
electromagnetic wave
wave detector
semiconductor
dimensional material
material layer
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PCT/JP2020/029339
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English (en)
French (fr)
Japanese (ja)
Inventor
昌一郎 福島
政彰 嶋谷
聡志 奥田
新平 小川
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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Priority to US17/774,482 priority Critical patent/US12199113B2/en
Priority to CN202080085891.9A priority patent/CN114846628B/zh
Priority to JP2021565327A priority patent/JP7374222B2/ja
Publication of WO2021124609A1 publication Critical patent/WO2021124609A1/ja
Anticipated expiration legal-status Critical
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    • 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
    • H10F39/80—Constructional details of image sensors
    • H10F39/802—Geometry or disposition of elements in pixels, e.g. address-lines or gate electrodes
    • H10F39/8027—Geometry of the photosensitive area
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/02—Details
    • 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
    • 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
    • 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
    • H10F39/18—Complementary metal-oxide-semiconductor [CMOS] image sensors; Photodiode array image sensors
    • 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
    • H10F39/80—Constructional details of image sensors
    • H10F39/806—Optical elements or arrangements associated with the image sensors
    • H10F39/8067—Reflectors

Definitions

  • This disclosure relates to an electromagnetic wave detector and an assembly of electromagnetic wave detectors.
  • a voltage is applied to the graphene layer as a channel via the source / drain electrodes.
  • the sensitivity of the detector is increased by amplifying the optical carriers generated in the n-type semiconductor layer.
  • the OFF operation is enabled by the Schottky connection between the graphene and the n-type semiconductor layer.
  • the transistor operates during the high-sensitivity operation in which the source / drain voltage is applied to the graphene.
  • the sensitivity of the detector depends on the quantum efficiency of the semiconductor layer. Therefore, it is not possible to sufficiently amplify the optical carrier, and it is difficult to increase the sensitivity of the detector.
  • the conventional detector using a two-dimensional material layer such as graphene cannot achieve both high sensitivity and OFF operation at the same time.
  • a main object of the present disclosure is to provide an electromagnetic wave detector and an electromagnetic wave detector aggregate using a two-dimensional material layer, which has high detection sensitivity and can be turned off.
  • the electromagnetic wave detector according to the present disclosure has a semiconductor layer having at least one step portion formed and having sensitivity to a detection wavelength, and a part of the at least one step portion arranged on the at least one step portion. It has an insulating film provided with at least one opening for exposing, and a connecting region arranged on the insulating film and at least one opening and electrically connected to the semiconductor layer at the at least one opening.
  • the first electrode is arranged on the dimensional material layer, the first electrode portion arranged on the insulating film and electrically connected to the two-dimensional material layer, and the first electrode is arranged on the semiconductor layer and passed through the connecting region of the two-dimensional material layer.
  • a second electrode portion electrically connected to the portion is provided.
  • FIG. It is a plane schematic diagram of the electromagnetic wave detector which concerns on Embodiment 1.
  • FIG. It is sectional drawing of the line segment II-II in FIG. It is a flowchart for demonstrating the manufacturing method of the electromagnetic wave detector which concerns on Embodiment 1.
  • FIG. It is sectional drawing which shows the 2nd modification of the electromagnetic wave detector which concerns on Embodiment 1.
  • FIG. It is sectional drawing which shows the 3rd modification of the electromagnetic wave detector which concerns on Embodiment 1.
  • FIG. It is sectional drawing which shows the 4th modification of the electromagnetic wave detector which concerns on Embodiment 1.
  • FIG. 5 is a schematic plan view showing a sixth modification of the electromagnetic wave detector according to the first embodiment. It is a plane schematic diagram which shows the 7th modification of the electromagnetic wave detector which concerns on Embodiment 1. FIG. It is a plane schematic diagram which shows the 8th modification of the electromagnetic wave detector which concerns on Embodiment 1.
  • FIG. FIG. 5 is a schematic plan view showing a sixth modification of the electromagnetic wave detector according to the first embodiment. It is a plane schematic diagram which shows the 7th modification of the electromagnetic wave detector which concerns on Embodiment 1.
  • FIG. It is a plane schematic diagram which shows the 8th modification of the electromagnetic wave detector which concerns on Embodiment 1.
  • FIG. 5 is a schematic plan view showing a ninth modification of the electromagnetic wave detector according to the first embodiment. It is sectional drawing which shows the tenth modification of the electromagnetic wave detector which concerns on Embodiment 1. FIG. It is sectional drawing which shows the eleventh modification of the electromagnetic wave detector which concerns on Embodiment 1. FIG. It is sectional drawing which shows the twelfth modification of the electromagnetic wave detector which concerns on Embodiment 1. FIG. It is sectional drawing of the electromagnetic wave detector which concerns on Embodiment 2. FIG. It is a plane internal schematic diagram of the electromagnetic wave detector which concerns on Embodiment 2. FIG. It is sectional drawing which shows the modification of the electromagnetic wave detector which concerns on Embodiment 2. FIG. It is sectional drawing of the electromagnetic wave detector which concerns on Embodiment 3. FIG.
  • FIG. 5 is a schematic cross-sectional view of the electromagnetic wave detector according to the fourth embodiment.
  • FIG. 5 is a schematic plan view of an electromagnetic wave detector according to a fifth embodiment. It is sectional drawing of the line segment XXV-XXV in FIG. 24. It is sectional drawing which shows the 1st modification of the electromagnetic wave detector which concerns on Embodiment 5. It is sectional drawing which shows the 2nd modification of the electromagnetic wave detector which concerns on Embodiment 5.
  • FIG. It is sectional drawing which shows the 3rd modification of the electromagnetic wave detector which concerns on Embodiment 5.
  • FIG. It is a plane schematic diagram of the electromagnetic wave detector which concerns on Embodiment 6.
  • FIG. 5 is a schematic cross-sectional view taken along the line segment XXX-XXX in FIG. 29. It is sectional drawing which shows the 1st modification of the electromagnetic wave detector which concerns on Embodiment 6. It is a plane schematic diagram which shows the electromagnetic wave detector which concerns on Embodiment 7. It is sectional drawing of the line segment XXXIII-XXXIII of FIG. 32.
  • FIG. 5 is a schematic cross-sectional view of the electromagnetic wave detector according to the eighth embodiment.
  • FIG. 5 is a schematic cross-sectional view of the electromagnetic wave detector according to the ninth embodiment.
  • FIG. 5 is a schematic cross-sectional view of the electromagnetic wave detector according to the tenth embodiment. It is sectional drawing which shows the modification of the electromagnetic wave detector which concerns on embodiment 10.
  • FIG. 5 is a schematic cross-sectional view of the electromagnetic wave detector according to the eleventh embodiment. It is a plane schematic diagram of the electromagnetic wave detector which concerns on Embodiment 12. It is a plane schematic diagram which shows the modification of the electromagnetic wave detector which concerns on Embodiment 12.
  • the figure is schematic and conceptually describes the function or structure. Further, the present disclosure is not limited by the embodiments described below. Unless otherwise specified, the basic configuration of the electromagnetic wave detector is common to all embodiments. Further, those having the same reference numerals are the same or equivalent as described above. This is common throughout the specification.
  • the electromagnetic wave detector will be described using a configuration for detecting visible light or infrared light, but the present disclosure is not limited thereto.
  • the embodiments described below are detectors that detect radio waves such as X-rays, ultraviolet light, near-infrared light, terahertz (THz) waves, or microwaves in addition to visible light or infrared light. It is also effective as.
  • these light and radio waves are collectively referred to as electromagnetic waves.
  • p-type graphene or n-type graphene may be used as graphene.
  • graphene having more holes than graphene in the intrinsic state is called p-type graphene
  • graphene having more electrons is called n-type graphene.
  • the n-type or p-type term may be used for the material of the member in contact with graphene, which is an example of the two-dimensional material layer.
  • the n-type material is a material having an electron donating property
  • the p-type material is a material having an electron attracting property.
  • the charge is biased in the whole molecule, and the one in which electrons are dominant is called n-type, and the one in which holes are dominant is called p-type.
  • these materials either one of organic substances and inorganic substances or a mixture thereof can be used.
  • plasmon resonance phenomena such as surface plasmon resonance, which is the interaction between the metal surface and light, and pseudo-surface plasmon resonance in the sense of resonance on the metal surface outside the visible and near-infrared regions.
  • these resonances are referred to as surface plasmon resonance, plasmon resonance, or simply resonance.
  • graphene is used as an example of the material of the two-dimensional material layer, but the material constituting the two-dimensional material layer is not limited to graphene.
  • the materials of the two-dimensional material layer include transition metal dichalcogenide (TMD), black phosphorus (Black Phosphorus), silicene (two-dimensional honeycomb structure with silicon atoms), and germanene (two-dimensional honeycomb structure with germanium atoms).
  • TMD transition metal dichalcogenide
  • Black Phosphorus Black Phosphorus
  • silicene two-dimensional honeycomb structure with silicon atoms
  • germanene two-dimensional honeycomb structure with germanium atoms
  • transition metal dichalcogenide include transition metal dichalcogenides such as MoS 2 , WS 2 , and WSe 2 .
  • These materials have a structure similar to graphene, and are materials that allow atoms to be arranged in a single layer in a two-dimensional plane. Therefore, even when these materials are applied to the two-dimensional material layer, the same action and effect as when graphene is applied to the two-dimensional material layer can be obtained.
  • FIG. 1 is a schematic plan view of the electromagnetic wave detector according to the first embodiment.
  • FIG. 2 is a schematic cross-sectional view of the line segment IB-IB of FIG.
  • FIG. 3 also shows a typical electrical connection of the electromagnetic wave detector 100.
  • the electromagnetic wave detector according to the first embodiment includes a semiconductor layer 4 having a stepped portion, an insulating film 3, a two-dimensional material layer 1, and a first electrode portion 2a. And a second electrode portion 2b are mainly provided.
  • the semiconductor layer 4 has sensitivity to a predetermined detection wavelength from the above-mentioned electromagnetic waves. That is, the semiconductor layer 4 has a first conductive side, and is provided so that an optical carrier is generated in the semiconductor layer 4 when an electromagnetic wave having a predetermined detection wavelength is incident on the semiconductor layer 4.
  • the semiconductor material constituting the semiconductor layer 4 can be arbitrarily selected according to the detection wavelength that should have sensitivity.
  • gallium phosphide GaP
  • silicon Si
  • germanium Ge
  • indium gallium arsenide InGaAs
  • indium arsenide InAs
  • indium antimonide InSb
  • mercury cadmium tellurium HgCdTe
  • the semiconductor material constituting the semiconductor layer 4 is not limited to the above.
  • the material constituting the semiconductor layer 4 is a compound semiconductor such as Si, Ge, III-V group semiconductor or II-V group semiconductor, HgCdTe, InSb, lead selenium (PbSe), lead sulfur (PbS), cadmium sulfur (CdS). , Gallium Nitride (GaN), Silicon Carbide (SiC), Gallium Phosphide (GaP), InGaAs, InAs, or Substrates Containing Quantum Wells or Quantum Dots, Type II Super Lattice, etc. There may be. If the material constituting the semiconductor layer 4 is a combination of the above-mentioned semiconductor materials, the electromagnetic wave detector provided with the semiconductor layer 4 can detect multiple wavelengths.
  • the stepped portion 40 has a convex shape in which the number of top portions 43 is smaller than the number of bottom portions 41 and the total area of the bottom portion 41 is larger than the total area of the top portion 43.
  • the step portion 40 has two bottom portions 41, one top portion 43, and two side portions 42.
  • the top 43 projects with respect to the two bottoms 41 in the thickness direction of the semiconductor layer 4.
  • Each of the two side portions 42 is located between the bottom 41 and the top 43.
  • the top 43 has, for example, a longitudinal direction and a lateral direction. Both ends of the top 43 in the lateral direction are connected to the side 42.
  • Each side portion 42 has an upper end connected to one end of the top portion 43 in the lateral direction and a lower end connected to one end of the bottom portion 41 in the lateral direction.
  • Each bottom portion 41 has the one end connected to the lower end of the side portion 42 and the other end arranged on the opposite side to the one end in the lateral direction. As shown in FIG. 2, the width of one of the two bottoms 41 in the lateral direction is wider than the width of the other bottom 41b in the lateral direction.
  • the back surface portion 44 of the semiconductor layer 4 located on the side opposite to the step portion 40 in the thickness direction of the semiconductor layer 4 is configured as, for example, a flat surface.
  • the semiconductor layer 4 is prepared, for example, by doping a silicon substrate on which a step portion 40 is formed with impurities.
  • the insulating film 3 is arranged on the semiconductor layer 4.
  • the insulating film 3 is provided with an opening 3a that exposes a part of the step portion 40.
  • the insulating film 3 is arranged, for example, on the entire two bottom portions 41 and the two side portions 42 of the step portion 40, and on a part of the top portion 43.
  • the opening 3a exposes, for example, a part of the top 43.
  • the opening 3a exposes the central portion of the top 43, for example, in the lateral direction.
  • the distance between the opening 3a and one end of the top 43 in the lateral direction is equal to the distance between the opening 3a and the other end of the top 43 in the lateral direction.
  • the distance between the opening 3a and one end of the top 43 in the lateral direction and the distance between the opening 3a and the other end of the top 43 in the lateral direction are constant, for example, in the longitudinal direction.
  • the opening 3a extends from one end to the other end of the top 43, for example, in the longitudinal direction.
  • the opening 3a has, for example, a longitudinal direction and a lateral direction.
  • the longitudinal direction of the opening 3a is, for example, along the longitudinal direction of the top 43.
  • the lateral direction of the opening 3a is along the lateral direction of the top 43.
  • the material constituting the insulating film 3 is, for example, silicon oxide (SiO 2 ) such as NSG (None-topped Silicone Glass), PSG (Phospho silicate glass), BPSG (Boro-phossilicate glass), tetraethyl orthosilicate (Si (Si)).
  • silicon oxide SiO 2
  • NSG Non-topped Silicone Glass
  • PSG Phospho silicate glass
  • BPSG Bo-phossilicate glass
  • tetraethyl orthosilicate Si (Si)
  • the BN Since BN has an atomic arrangement similar to that of graphene, contact with the two-dimensional material layer 1 made of graphene does not adversely affect the electron mobility of the two-dimensional material layer 1. Therefore, the BN is suitable for the insulating film 3 as the base film arranged under the two-dimensional material layer 1.
  • the thickness T of the insulating film 3 is such that the two-dimensional material layer 1 and the first electrode portion 2a are electrically insulated from the semiconductor layer 4, and the tunnel current is the two-dimensional material layer 1 and the first electrode portion 2a and the semiconductor. There is no particular limitation as long as it is prevented from occurring between the layer 4 and the layer 4.
  • the electric field change of the two-dimensional material layer 1 caused by the optical carrier generated at the interface between the insulating film 3 and the semiconductor layer 4 is called an optical gate effect, and the details thereof will be described later.
  • the first electrode portion 2a is arranged on the insulating film 3.
  • the first electrode portion 2a is arranged at a position away from the opening 3a.
  • the first electrode portion 2a is arranged on the bottom portion 41a.
  • the first electrode portion 2a is electrically connected to the two-dimensional material layer 1.
  • the second electrode portion 2b is arranged on the semiconductor layer 4.
  • the second electrode portion 2b is electrically connected to the first electrode portion 2a via a region 1c (connection region) described later in the two-dimensional material layer 1.
  • the second electrode portion 2b is arranged on the entire back surface portion 44 of the semiconductor layer 4, which is located on the side opposite to the step portion 40 in the thickness direction of the semiconductor layer 4, for example. In this case, among the electromagnetic waves incident on the electromagnetic wave detector from the step portion 40 side, the electromagnetic waves that have passed through the semiconductor layer 4 and reached the back surface portion 44 are reflected by the second electrode portion 2b. Therefore, the absorption rate of electromagnetic waves of the semiconductor layer 4 is increased.
  • the materials constituting the first electrode portion 2a and the second electrode portion 2b any material can be used as long as it is a conductor.
  • the materials constituting the first electrode portion 2a and the second electrode portion 2b are gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), and It comprises at least one selected from the group consisting of palladium (Pd).
  • An adhesion layer (not shown) that enhances the adhesion between the first electrode portion 2a and the insulating film 3 may be formed between the first electrode portion 2a and the insulating film 3.
  • An adhesion layer (not shown) that enhances the adhesion between the second electrode portion 2b and the semiconductor layer 4 may be formed between the second electrode portion 2b and the semiconductor layer 4.
  • the material constituting the adhesion layer includes, for example, a metal material such as chromium (Cr) or titanium (Ti).
  • the first electrode portion 2a shown in FIG. 2 is formed in the lower part of the two-dimensional material layer 1, the first electrode portion 2a may be formed in the upper part of the two-dimensional material layer 1.
  • the second electrode portion 2b shown in FIG. 2 is arranged in the entire area of the back surface portion 44 of the semiconductor layer 4, but is not limited to this.
  • the second electrode portion 2b may be arranged on a portion exposed from the insulating film 3 on the bottom portion 41 or the side portion 42 of the semiconductor layer 4, and may be directly connected to the portion. If the second electrode portion 2b is not arranged on the back surface portion 44, the electromagnetic wave emitted from the back surface portion 44 side can be detected.
  • the two-dimensional material layer 1 is arranged on the insulating film 3 and the opening 3a.
  • the two-dimensional material layer 1 extends from the inside of the opening 3a to the insulating film 3.
  • the two-dimensional material layer 1 is electrically connected to the first electrode portion 2a on the insulating film 3 and is electrically connected to the semiconductor layer 4 inside the opening 3a.
  • the two-dimensional material layer 1 is arranged, for example, on a part of one bottom portion 41a, one side portion 42, a top portion 43, the other side portion 42, and a part of the other bottom portion 41b.
  • the two-dimensional material layer 1 has a region 1a that is electrically connected to the first electrode portion 2a and a region 1c (which is electrically connected to the semiconductor layer 4 inside the opening 3a). It has a region (region located inside the opening 3a) and a region 1b that faces the semiconductor layer 4 via the insulating film 3.
  • the region 1a is directly connected to, for example, the first electrode portion 2a.
  • the region 1c is directly connected to, for example, the semiconductor layer 4.
  • the region 1a is arranged on a part of the bottom 41.
  • Region 1c is located on a portion of top 43.
  • Region 1b is located on the rest of the top 43 and two side portions 42.
  • a part of the region 1b is arranged on one side portion 42 and connects the region 1a and the region 1c.
  • the other portion of the region 1b is located on the other side portion 42.
  • the other part of the region 1b extends from the region 1c to the portion of the insulating film 3 on the side opposite to the side where the first electrode portion 2a is located when viewed from the opening 3a of the insulating film 3. ..
  • the two-dimensional material layer 1 is, for example, a single layer of graphene.
  • Single-layer graphene is a monoatomic layer of two-dimensional carbon crystals.
  • single-layer graphene has carbon atoms in each chain arranged in a hexagonal shape. Since graphene has a higher carrier mobility than semiconductor materials such as Si used in conventional electronic devices, the electromagnetic wave detector 100 has an effect of improving the optical response speed.
  • the two-dimensional material layer 1 may be a laminated body of two or more layers of graphene (hereinafter referred to as multilayer graphene).
  • the orientations of the lattice vectors of the hexagonal lattices of each graphene in the multilayer graphene may not match or may differ.
  • the orientations of the lattice vectors of the hexagonal lattices of each graphene in the multilayer graphene may be completely the same.
  • the size of the band gap of multi-layer graphene can be adjusted by the number of layers of graphene.
  • the two-dimensional material layer 1 can act as an electromagnetic wave absorption layer, and further, an optical filter can be eliminated. As a result, the number of optical components can be reduced, and the loss of incident light due to passing through the optical filter can be reduced.
  • the graphene may be configured as a nanoribbon (hereinafter referred to as graphene nanoribbon) obtained by cutting out a graphene sheet with a width of nanoorder.
  • the two-dimensional material layer 1 may be configured as a single graphene nanoribbon, a laminate of a plurality of graphene nanoribbons, or a structure in which graphene nanoribbons are periodically arranged on a plane.
  • the two-dimensional material layer 1 contains a graphene nanoribbon (graphene metamaterial) in which the two-dimensional material layer 1 is periodically arranged, plasmon resonance occurs in the two-dimensional material layer 1 and the electromagnetic wave detection sensitivity by the two-dimensional material layer 1 is improved.
  • graphene nanoribbon graphene metamaterial
  • the graphene may be undoped graphene doped with impurities. Further, the graphene may be graphene doped with p-type or n-type impurities.
  • the material constituting the two-dimensional material layer 1 is, for example, uniform in each of the region 1a, the region 1b, and the region 1c.
  • the materials constituting the two-dimensional material layer 1 may be different in each of the region 1a, the region 1b, and the region 1c.
  • the material constituting the region 1a is, for example, multi-layer graphene.
  • the region 1a is doped with carriers from the first electrode portion 2a.
  • the material of the first electrode portion 2a is gold (Au)
  • holes are doped in the region 1a of the two-dimensional material layer 1 due to the difference in work functions between graphene and Au.
  • the electromagnetic wave detector is driven in this state, the carrier mobility flowing in the channel region of the two-dimensional material layer 1 decreases due to the influence of the holes doped in the region 1a from the first electrode portion 2a, and the two-dimensional material The contact resistance between the layer 1 and the first electrode portion 2a increases.
  • the material constituting the region 1a is single-layer graphene
  • the doping amount of the carrier injected from the first electrode portion 2a is larger than that when the material constituting the region 1a is multi-layer graphene.
  • the decrease in carrier mobility in the electromagnetic wave detector becomes remarkable. Therefore, from the viewpoint of suppressing the above-mentioned decrease in carrier mobility and improving the performance of the electromagnetic wave detector, the material constituting the region 1a is preferably multi-layer graphene rather than single-layer graphene.
  • the material constituting the region 1b is, for example, single-layer graphene.
  • the region 1b acts as a so-called channel region.
  • the electron mobility in single-layer graphene is higher than the electron mobility in multi-layer graphene. Therefore, from the viewpoint of increasing the mobility of electrons in the region 1b and improving the performance of the electromagnetic wave detector, the material constituting the region 1b is preferably single-layer graphene rather than multi-layer graphene.
  • the region 1a and the first electrode portion 2a can be suppressed from increasing in contact resistance.
  • the mobility of electrons in 1b can be increased, and the performance of the electromagnetic wave detector can be improved.
  • FIG. 3 is a flowchart for explaining a method of manufacturing the electromagnetic wave detector according to the first embodiment. A method of manufacturing the electromagnetic wave detector shown in FIGS. 1 and 2 will be described with reference to FIG.
  • the preparation step (S1) shown in FIG. 3 is carried out.
  • a flat semiconductor substrate is prepared.
  • the semiconductor material constituting the semiconductor substrate is a semiconductor material having sensitivity to a predetermined detection wavelength.
  • the semiconductor layer stepped portion forming step (S2) is carried out.
  • a protective film is formed on the region where the top 43 of the step portion 40 is to be formed in the semiconductor substrate.
  • the protective film is, for example, a resist.
  • the protective film is formed with an opening that exposes the area where the bottom 41 should be formed, for example by photoengraving or electron beam (EB) drawing.
  • the semiconductor substrate is etched using the protective film as an etching mask.
  • the etching method can be selected from either wet etching using a chemical solution such as acid or alkali, or dry etching using a reactive species in plasma. After etching, the protective film is removed. In this way, the semiconductor layer 4 having the stepped portion 40 is formed from the semiconductor substrate.
  • the electrode forming step (S3) is carried out.
  • the second electrode portion 2b is formed on the back surface of the semiconductor layer 4. Specifically, after forming a protective film on the stepped portion 40 of the semiconductor layer 4, a metal film is formed.
  • the above-mentioned adhesion layer is formed in the region connected to the second electrode portion 2b in the semiconductor layer 4. May be formed in advance.
  • the insulating film forming step (S4) is carried out.
  • the insulating film 3 is formed on the stepped portion 40 of the semiconductor layer 4.
  • the insulating film 3 is formed so as to be in close contact with the entire bottom portion 41, side portions 42, and top portion 43 of the step portion 40 without gaps.
  • the film forming method of the insulating film 3 is not particularly limited.
  • the insulating film 3 can be formed by thermally oxidizing the surface of the semiconductor layer 4.
  • the film forming method of the insulating film 3 may be a CVD (Chemical Vapor Deposition) method or a sputtering method.
  • a barrier film is formed between the semiconductor layer 4 and the insulating film 3 immediately before the insulating film forming step (S4). May be formed.
  • the material constituting the barrier film may be a material having higher resistance to the etchant used in the opening forming step (S6) than the material constituting the insulating film 3 (a material having a slow etching rate), for example, nitriding. Silicon (SiN), aluminum oxide (Al 2 O 3 ), or graphene.
  • the electrode forming step (S5) is carried out.
  • the first electrode portion 2a is formed on the insulating film 3.
  • the above-mentioned adhesion layer is formed in the region of the insulating film 3 connected to the first electrode portion 2a. May be formed in advance.
  • the following process can be used.
  • a resist mask is formed on the surface of the insulating film 3 by photoengraving or EB drawing.
  • the resist mask has an opening formed in a region where the first electrode portion 2a should be formed.
  • a film such as metal to be the first electrode portion 2a is formed on the resist mask.
  • a thin-film deposition method, a sputtering method, or the like can be used to form the film.
  • the film is formed so as to extend from the inside of the opening of the resist mask to the upper surface of the resist mask.
  • the other part of the film arranged in the opening of the resist mask remains on the surface of the insulating film 3 and becomes the first electrode portion 2a. ..
  • the method described above is generally called lift-off.
  • a film such as a metal film to be the first electrode portion 2a is first formed on the surface of the insulating film 3. Then, a resist mask is formed on the film by a photolithography method. The resist mask is formed so as to cover the region where the first electrode portion 2a should be formed, but is not formed in a region other than the region where the first electrode portion 2a should be formed. Then, the film is partially removed by wet etching or dry etching using a resist mask as a mask. As a result, a part of the film remains under the resist mask. A part of this film becomes the first electrode portion 2a. After that, the resist mask is removed. In this way, the first electrode portion 2a may be formed.
  • the opening forming step (S6) is carried out.
  • the opening 3a is formed in the insulating film 3.
  • a resist mask is formed on the insulating film 3 by photoengraving or EB drawing.
  • an opening is formed in a region where the opening 3a of the insulating film 3 is to be formed.
  • the insulating film 3 is etched using the resist mask as an etching mask.
  • the etching method can be arbitrarily selected from either the wet etching or the dry etching. After etching, the resist mask is removed. In this way, the opening 3a is formed in the insulating film 3.
  • the above step (S6) may be performed before the step (S5).
  • the two-dimensional material layer forming step (S7) is carried out.
  • the two-dimensional material layer 1 is formed on the step portion 40.
  • the two-dimensional material layer 1 is formed so as to cover the entire semiconductor layer 4 exposed inside the first electrode portion 2a, the insulating film 3, and the opening 3a of the insulating film 3.
  • the method for forming the two-dimensional material layer 1 is not particularly limited.
  • the two-dimensional material layer 1 may be formed by, for example, epitaxial growth, or may be formed by a screen printing method.
  • the two-dimensional material layer 1 may be formed by transferring and attaching a two-dimensional material film previously formed by a CVD method onto the step portion 40, or may be in the form of a film peeled off by mechanical peeling or the like. It may be formed by transferring and pasting the two-dimensional material film of No. 1 on the step portion 40.
  • a resist mask is formed on the two-dimensional material layer 1 by photoengraving or EB drawing.
  • the resist mask is formed so as to cover the region where the two-dimensional material layer 1 should be formed and to expose the other regions.
  • the resist mask is used as a mask to etch the two-dimensional material layer 1.
  • the etching method is, for example, dry etching with oxygen plasma. After that, the resist mask is removed. As a result, the two-dimensional material layer 1 shown in FIGS. 1 and 2 is formed.
  • the electromagnetic wave detectors shown in FIGS. 1 and 3 are manufactured.
  • the two-dimensional material layer 1 was formed on the first electrode portion 2a, but the two-dimensional material layer 1 was formed in advance on the insulating film 3 and partially above the two-dimensional material layer 1.
  • the first electrode portion 2a may be formed so as to overlap with the first electrode portion 2a.
  • care must be taken not to give process damage to the two-dimensional material layer 1 when the first electrode portion 2a is formed.
  • a power supply circuit (not shown) is electrically connected between the first electrode portion 2a and the second electrode portion 2b, and a voltage is applied between the first electrode portion 2a and the second electrode portion 2b. V is applied.
  • a current path in which the first electrode portion 2a, the two-dimensional material layer 1, the semiconductor layer 4, and the second electrode portion 2b are connected in series in this order is formed inside the electromagnetic wave detector, and the two-dimensional material layer is formed.
  • a current I flows through 1.
  • An ammeter (not shown) is installed in the power supply circuit to monitor the current I flowing through the two-dimensional material layer 1. In this way, the electromagnetic wave detector is in a state where it can detect electromagnetic waves.
  • the positive or negative voltage is selected according to the conductive type (doping type) of the semiconductor layer 4. If the conductive type is p-type, a positive voltage is applied to the first electrode portion 2a, and if the conductive type is n-type, a negative voltage is applied to the first electrode portion 2a.
  • the optical carriers generated in the semiconductor layer 4 in the vicinity of the opening 3a are injected into the region 1c of the two-dimensional material layer 1 and cause a change in the current I through the region 1b and the region.
  • the current component that causes a change in the current I due to electromagnetic wave irradiation is referred to as a photocurrent.
  • a depletion layer is formed at the interface between the semiconductor layer 4 and the insulating film 3.
  • the depletion layer is widely formed at the bottom 41, the side 42, and the interface between the top 43 and the insulating film 3 of the step 40.
  • an electromagnetic wave having a wavelength having a sensitivity of the semiconductor layer 4 is incident on the semiconductor layer 4, optical carriers are also generated in the depletion layer.
  • the optical carriers generated in the depletion layer give an electric field effect to the region 1b of the two-dimensional material layer 1 via the insulating film 3.
  • the resistance value of the region 1b of the two-dimensional material layer 1 changes, and the current I flowing through the two-dimensional material layer 1 changes.
  • the electric field effect derived from the light irradiation is applied to the region 1b, so that the electrical characteristics of the two-dimensional material layer 1 are changed.
  • the optical gate effect described above is thus triggered.
  • the change in the current I is detected via the first electrode portion 2a electrically connected to the region 1a of the two-dimensional material layer 1. This makes it possible to detect the electromagnetic wave radiated to the electromagnetic wave detector.
  • the electromagnetic wave detector according to the present embodiment is not limited to the configuration for detecting the change in the current in the two-dimensional material layer 1 as described above, and is, for example, the first electrode portion 2a and the second electrode portion 2a.
  • a constant current may be passed between the electrode portion 2b and the change in the voltage V between the first electrode portion 2a and the second electrode portion 2b (that is, the change in the voltage value in the two-dimensional material layer 1) may be detected.
  • the material constituting the two-dimensional material layer 1 is single-layer graphene
  • the material constituting the first electrode portion 2a and the second electrode portion 2b is Au
  • the material constituting the insulating film 3 is Al 2 O 3
  • the semiconductor layer is Al 2 O 3
  • the material constituting 4 is n-type InSb
  • N-type InSb is sensitive to electromagnetic waves of 1 ⁇ m or more and 5.4 ⁇ m or less. Therefore, when an electromagnetic wave of 1 ⁇ m or more and 5.4 ⁇ m or less is incident on the semiconductor layer 4, optical carriers are generated in the semiconductor layer 4. The optical carriers generated in the semiconductor layer 4 in the vicinity of the opening 3a are injected into the single-layer graphene in the region 1c to cause a change in the current I.
  • the electrons in the semiconductor layer 4 are seconded. It is attracted to the electrode portion 2b, and holes, which are minority carriers, are attracted to the insulating film 3 side. As a result, a depletion layer is formed at the interface between the semiconductor layer 4 and the insulating film 3.
  • the optical carriers generated in the depletion layer generate an optical gate effect as described above, apply an electric field effect to the single-layer graphene constituting the region 1b, and change the mobility of the single-layer graphene constituting the region 1b.
  • the magnitude of this field effect correlates with the amount of photocarriers generated in the depletion layer. That is, when an electromagnetic wave of 1 ⁇ m or more and 5.4 ⁇ m or less is incident on the n-type InSb, a photocurrent is generated by injecting the photocarrier generated by the n-type InSb into the single-layer graphene constituting the region 1c, and the region 1b is generated. The optical gate effect is given to the single-layer graphene that composes. As a result, the photocurrent is amplified in region 1b.
  • the optical gate effect does not directly enhance the quantum efficiency of the photoelectric conversion material, but increases the current change due to the incident of electromagnetic waves. Therefore, the quantum efficiency calculated equivalently from the differential current due to the incident of electromagnetic waves exceeds 100%. Can be done.
  • the amount of change in the current I when the electromagnetic wave is incident on the electromagnetic wave detector according to the present embodiment is the same as that of the conventional electromagnetic wave detector in which the region 1b is not provided and the optical gate effect is not exhibited. Is larger than the amount of change in the current when is incident. Therefore, the electromagnetic wave detector according to the present embodiment has high sensitivity as compared with the conventional electromagnetic wave detector.
  • the above-mentioned optical gate effect increases as the region 1b of the two-dimensional material layer 1 subject to the electric field effect increases, enabling more sensitive electromagnetic wave detection.
  • the two-dimensional material layer 1 is formed of a monoatomic layer or a monomolecular layer, it is possible to form a film along the structural surface of the electromagnetic wave detector.
  • the two-dimensional material layer 1 in the electromagnetic wave detector according to the present embodiment is arranged on the bottom portion 41, the side portion 42, and the top portion 43 of the step portion 40, and the region 1b is one of the side portion 42 and the top portion 43. It is placed on the department. Therefore, the electromagnetic wave detector and the two-dimensional material layer 1 according to the present embodiment, in which the occupied area of the region 1b shown in FIG.
  • the electromagnetic wave detector according to the present embodiment When compared with the electromagnetic wave detector as a comparative example that is not arranged, the area 1b of the electromagnetic wave detector according to the present embodiment is wider than the area 1b that can be formed in the above comparative example. As a result, the optical gate effect produced by the electromagnetic wave detector according to the present embodiment is enhanced as compared with the optical gate effect produced in the above comparative example. As a result, the electromagnetic wave detector according to the present embodiment has higher detection sensitivity than the electromagnetic wave detector of the above comparative example.
  • the occupied area of the region 1b required to realize the specific detection sensitivity in the electromagnetic wave detector according to the present embodiment is the specific detection sensitivity in the electromagnetic wave detector of the comparative example. It is smaller than the occupied area of the region 1b required to realize the above. Therefore, the area of the electromagnetic wave detector according to the present embodiment can be reduced as compared with the electromagnetic wave detector of the above comparative example. As a result, the electromagnetic wave detector according to the present embodiment is suitable for an image sensor in which the electromagnetic wave detector is arranged at a high density.
  • the electromagnetic wave detector according to the present embodiment is provided so that the portion of the region 1b that connects the region 1c and the region 1a is sufficiently long.
  • the region 1b is arranged on the entire one side portion 42 connecting the bottom portion 41a and the top portion 43 at least on the step portion 40. Therefore, in the electromagnetic wave detector according to the present embodiment, the length of the portion of the region 1b that connects the region 1c and the region 1a is such that the region 1c connects the bottom 41a and the top 43. It is longer than that of the electromagnetic wave detector arranged on the side portion 42 of the.
  • the optical carriers injected from the semiconductor layer 4 to the two-dimensional material layer 1 at the opening 3a at the time of electromagnetic wave incident have an optical gate effect. Since the region affected by the electric field change of the two-dimensional material layer 1 is widened, the degree of the photocurrent change becomes large, and electromagnetic wave detection with higher sensitivity becomes possible.
  • the current I can be reduced to zero by adjusting the voltage V. That is, when light is not irradiated, the current I becomes zero, and when light is irradiated, only the current derived from the optical carrier injected into the two-dimensional material layer 1 is detected as the current I after being changed by the above-mentioned optical gate effect. Therefore, the electromagnetic wave detector according to the present embodiment can be turned off.
  • the thickness of the two-dimensional material layer 1 is as thin as one atomic layer.
  • the carrier mobility of single-layer graphene is higher than that of conventional semiconductor materials. Therefore, the two-dimensional material layer 1 causes a large current change with respect to a slight potential change as compared with the conventional semiconductor material. For example, the amount of current change due to the potential change applied to the two-dimensional material layer 1 due to the change in the electric field in the semiconductor layer 4 is larger than the amount of current change in a normal semiconductor.
  • the electromagnetic wave detector according to the present embodiment can detect electromagnetic waves with higher sensitivity than the electromagnetic wave detector that detects only the optical carriers generated in the semiconductor layer 4.
  • the electromagnetic wave detector according to the present embodiment in addition to the photocurrent generated in the semiconductor layer 4 due to light irradiation, a photocurrent due to the photoelectric conversion efficiency of the two-dimensional material layer 1 is also generated. Therefore, in the electromagnetic wave detector according to the present embodiment, in addition to the current generated in the semiconductor layer 4 and the current associated with the optical gate effect due to the incident of the electromagnetic wave, the original photoelectric conversion efficiency of the two-dimensional material layer 1 is obtained. The resulting photocurrent can also be detected.
  • the electromagnetic wave detector of the present embodiment has higher detection sensitivity than the conventional electromagnetic wave detector and the electromagnetic wave detector of the above-mentioned comparative example, and can be turned off. Further, in the electromagnetic wave detector of the present embodiment, the area can be reduced as compared with the conventional electromagnetic wave detector and the electromagnetic wave detector of the above-mentioned comparative example.
  • Each electromagnetic wave detector shown in FIGS. 4, 5 and 6 basically has the same configuration as the electromagnetic wave detector shown in FIG. 2, but has a stepped portion 40 and an opening 3a of the insulating film 3. The relative positional relationship of is different from that of the electromagnetic wave detector shown in FIG.
  • the step portion 40 has a recess in which the number of tops 43 is larger than the number of bottoms 41 and the total area of the bottom 41 is smaller than the total area of the top 43. It has a shape.
  • One step 40 has one bottom 41, two tops 43, and two side 42s. The bottom portion 41 is recessed with respect to the two top portions 43 in the thickness direction of the semiconductor layer 4. Each of the two side portions 42 is located between the bottom 41 and the top 43.
  • the insulating film 3 is arranged, for example, on the entire two tops 43 and two side portions 42 of the step portion 40, and on a part of the bottom portion 41.
  • the opening 3a exposes, for example, a part of the bottom 41.
  • the opening 3a exposes the central portion of the bottom portion 41, for example, in the lateral direction.
  • the distance between the opening 3a and one end of the bottom 41 in the lateral direction is equal to the distance between the opening 3a and the other end of the bottom 41 in the lateral direction.
  • the distance between the opening 3a and one end of the bottom 41 in the lateral direction and the distance between the opening 3a and the other end of the bottom 41 in the lateral direction are constant, for example, in the longitudinal direction.
  • the opening 3a extends from one end to the other end of the bottom 41 in the longitudinal direction, for example.
  • the opening 3a has, for example, a longitudinal direction and a lateral direction.
  • the longitudinal direction of the opening 3a is, for example, along the longitudinal direction of the bottom 41.
  • the lateral direction of the opening 3a is along the lateral direction of the bottom 41.
  • the first electrode portion 2a is arranged on one of the two top portions 43a in the lateral direction.
  • the two-dimensional material layer 1 is arranged, for example, on a part of one top 43a, one side 42, a bottom 41, the other side 42, and a part of the other top 43b.
  • the region 1c electrically connected to the semiconductor layer 4 is arranged on the bottom portion 41.
  • the distance between the region 1c shown in FIG. 4 and the second electrode portion 2b is shorter than that shown in FIG. Therefore, in the electromagnetic wave detector shown in FIG. 4, two of the optical carriers generated in the semiconductor layer 4 by the electromagnetic waves reflected or scattered by the second electrode portion 2b are compared with the electromagnetic wave detector shown in FIG. The number of photocarriers that are not injected into the region 1c of the dimensional material layer 1 and are deactivated is reduced, and the light current is increased.
  • the region in which the optical carriers injected from the semiconductor layer 4 to the two-dimensional material layer 1 are modulated by the optical gate effect during electromagnetic wave irradiation is located.
  • the detection sensitivity is high because the contribution of the optical gate effect increases.
  • the opening 3a of the insulating film 3 and the region 1c of the two-dimensional material layer 1 do not face the first electrode portion 2a of the two side portions 42. It is arranged on one side portion 42. Therefore, in the region 1b of the two-dimensional material layer 1, the portion connecting the region 1a and the region 1c is arranged on the entire at least one side portion and the entire one top portion. Therefore, the length of the portion of the region 1b shown in FIG. 6 that connects the region 1c and the region 1a is longer than that shown in FIG.
  • the bottom 41 is referred to as the back surface 44 from the viewpoint of accurately and easily forming the opening 3a. It is preferable that they are provided in parallel.
  • the electromagnetic wave detector according to the third modification if one side portion 42 and the other side portion 42 are provided in parallel, the bottom portion 41 is not provided in parallel with the back surface portion 44. Also, the opening 3a can be formed accurately and easily. As a result, the electromagnetic wave detector according to the third modification can have a smaller area (pixel area) when viewed in a plan view than the electromagnetic wave detector according to the second modification. As a result, when a plurality of electromagnetic wave detectors are arranged side by side to form an electromagnetic wave detector aggregate, each electromagnetic wave detector can be arranged at a high density.
  • the electromagnetic wave detector according to the fourth modification shown in FIG. 7 basically has the same configuration as the electromagnetic wave detector shown in FIG. 2, but has a plurality of openings 3a and a plurality of openings 3a for one step portion 40. It differs from the electromagnetic wave detector shown in FIG. 2 in that the region 1c is provided.
  • the area of the joint surface 4aa of the two-dimensional material layer 1 and the semiconductor layer 4 is larger than that of the electromagnetic wave detector shown in FIG.
  • the material constituting the two-dimensional material layer 1 is different from the material constituting the semiconductor layer 4, their work functions are also different.
  • carriers are doped into the region 1c of the two-dimensional material layer 1 in contact with the semiconductor layer 4, but the amount of doping to the region 1c is the number of contact regions between the two-dimensional material layer 1 and the semiconductor layer 4. And is greatly affected by size.
  • the efficiency of extracting the optical carriers generated in the semiconductor layer 4 to the two-dimensional material layer 1 when an electromagnetic wave is incident is greatly affected by the amount of doping in the region 1c.
  • the number and size of the contact region between the two-dimensional material layer 1 and the semiconductor layer 4 can be adjusted by the number of openings 3a and each opening area.
  • the efficiency of extracting the optical carriers generated in the semiconductor layer 4 to the two-dimensional material layer 1 when the electromagnetic wave is incident is higher than that in the electromagnetic wave detector shown in FIG. Is enhanced.
  • the electromagnetic wave detector according to the fourth modification since a plurality of paths for transmitting optical carriers are formed in the two-dimensional material layer 1, defects or defects are formed in either path during manufacturing or use. Even when an abnormality occurs, the decrease in yield or the occurrence of failure is suppressed.
  • the electromagnetic wave detector according to the fifth modification shown in FIGS. 8, 9 and 10 basically has the same configuration as the electromagnetic wave detector shown in FIG. 2, but has a plurality of stepped portions 40 formed therein. In that respect, it differs from the electromagnetic wave detector shown in FIG. In FIGS. 9 and 10, only the semiconductor layer 4 is shown in order to explain the shapes and arrangements of the plurality of stepped portions 40.
  • the plurality of stepped portions 40 have a plurality of bottom portions 41, a plurality of side portions 42, and a plurality of top portions 43.
  • two or more stepped portions 40 are arranged between the opening portion 3a of the insulating film 3 and the first electrode portion 2a.
  • the opening 3a of the insulating film 3 is arranged on, for example, the step portion 40 farthest from the first electrode portion 2a.
  • the opening 3a of the insulating film 3 is arranged on, for example, the top 43 of the step portion 40 farthest from the first electrode portion 2a.
  • FIGS. 2 and 2 the length of the region 1b extending between the region 1a connected to the first electrode portion 2a and the region 1c connected to the semiconductor layer 4 in the opening 3a is shown in FIGS. 2 and 2. It is longer than the length of each region 1b shown in FIGS. 4 to 6.
  • the optical carriers injected from the semiconductor layer 4 into the two-dimensional material layer 1 at the time of electromagnetic wave irradiation are present.
  • the detection sensitivity is high because the region modulated by the optical gate effect increases and the contribution of the optical gate effect increases.
  • each step portion 40 provided so as to have the same or different planar shapes extends in one direction, and the one direction thereof. They are evenly spaced in other directions orthogonal to.
  • the detection sensitivity of the electromagnetic wave detector can be controlled by the shape and arrangement of the plurality of stepped portions 40.
  • a part of the electromagnetic wave incident on the region other than the region located below the opening 3a in the step portion 40 of the semiconductor layer 4 can be propagated to the region located below the opening 3a to generate an optical carrier. Therefore, when the plurality of stepped portions 40 are formed as the grid pattern shown in FIGS. 9 and 10, the plurality of stepped portions 40 are not formed as the grid pattern shown in FIGS. 9 and 10. In comparison, the amount of optical carriers injected from the semiconductor layer 4 into the two-dimensional material layer 1 increases, and the sensitivity of the electromagnetic wave photodetector improves.
  • the region 1b of the two-dimensional material layer 1 is arranged on the surface of the step portion 40 through which the diffracted electromagnetic wave propagates via the insulating film 3. Therefore, the amount of optical carriers generated increases by absorbing the electromagnetic waves diffracted by the region 1b. In addition, the electric field effect applied to the region 1b is also enhanced. As a result, the sensitivity of the electromagnetic wave detector in which the plurality of stepped portions 40 are formed as the grid pattern shown in FIGS. 9 and 10, the plurality of stepped portions 40 are formed as the grid pattern shown in FIGS. 9 and 10. Higher than when not.
  • FIG. 8 only one opening 3a is formed in the insulating film 3, and the opening 3a is arranged on the top 43 of one of the plurality of stepped portions 40, but the present invention is limited to this. It's not a thing.
  • a plurality of openings 3a may be formed in the insulating film 3, and each opening 3a may be arranged on different step portions 40. Further, each opening 3a may be arranged at at least one of the top 43, the bottom 41, and the side 42 of each step 40.
  • the electromagnetic wave detectors shown in FIGS. 11, 12, 13 and 14 basically have the same configuration as the electromagnetic wave detectors shown in FIGS. 1 and 2, but inside the opening 3a of the two-dimensional material layer 1.
  • the planar shape of the region 1c in contact with the semiconductor layer 4 is different from the planar shape of the region 1c in the electromagnetic wave detector shown in FIG.
  • the area of the contact area between the region 1c and the top 43 shown in FIGS. 11 to 14 is smaller than the area of the contact area between the region 1c and the top 43 shown in FIGS. 1 and 2.
  • the area of the contact region between the region 1c and the top 43 is smaller than the sum of the occupied areas of the region 1a (electrode connection region) and the region 1b in a plan view.
  • Each region 1c shown in FIGS. 11 to 14 is, from the region 1c shown in FIG. 1, at least the longitudinal direction of the top 43, in other words, the region 1a (electrode connection region), the region 1b, and the region of the two-dimensional material layer 1. Corresponds to the direction in which a plurality of spaced regions are removed in the direction in which 1c is arranged side by side and the direction in which the 1c is arranged side by side. In FIGS. 11 to 13, each plane shape of the plurality of regions is rectangular. In FIG. 14, each plane shape of the plurality of regions is triangular.
  • each planar shape of each region 1c shown in FIGS. 11 to 14 is symmetrical with respect to a straight line extending along the longitudinal direction through the center of the top 43 in the lateral direction.
  • Each planar shape of the region 1c shown in FIGS. 11-14 is symmetrical with respect to a straight line extending along the lateral direction through the longitudinal center of the apex 43.
  • the planar shape of the region 1c shown in FIG. 11 is a ribbon shape.
  • the width of the region 1c in the longitudinal direction of the top 43 is narrower than the width of the regions 1a and 1b in the longitudinal direction.
  • the planar shape of the region 1c shown in FIG. 12 is a comb shape (ladder shape).
  • the sum of the widths of the regions 1c in the longitudinal direction of the top 43 is narrower than the widths of the regions 1a and 1b in the longitudinal direction.
  • a plurality of openings for exposing the top 43 are formed, and the plurality of openings are arranged side by side in the longitudinal direction of the top 43.
  • the planar shape of the region 1c shown in FIG. 13 is a grid shape.
  • a plurality of openings for exposing the top 43 are formed, and the plurality of openings are arranged side by side in each of the longitudinal direction and the lateral direction of the top 43. ..
  • the minimum value of the total width of the region 1c in the longitudinal direction of the top 43 is narrower than the minimum width of the region 1a and the region 1b in the longitudinal direction.
  • the width of the region 1c in the longitudinal direction of the top 43 gradually narrows as the distance from the region 1b in the lateral direction of the top 43 increases, and is the largest at the center in the lateral direction. narrow.
  • the width of the region 1c in the direction intersecting the arrangement direction of each region 1a, 1b, 1c of the two-dimensional material layer 1 gradually narrows as the distance from the region 1a and the region 1b in the arrangement direction increases.
  • the width of the region 1c in the direction intersecting the arrangement direction of each region 1a, 1b, 1c of the two-dimensional material layer 1 is, for example, the narrowest at the center of the region 1c in the arrangement direction.
  • the area of the contact region between the two-dimensional material layer 1 and the semiconductor layer 4 is adjusted according to the width of the region 1c in the longitudinal direction of the top 43. Therefore, in the electromagnetic wave detectors shown in FIGS. 11 to 14, the contact resistance between the two-dimensional material layer 1 and the semiconductor layer 4 and the resistance of the electromagnetic wave detector can be adjusted. In the electromagnetic wave detectors shown in FIGS. 11 to 14, the variation in the characteristics of the electromagnetic wave detectors can be reduced and the dark current can be reduced as compared with the electromagnetic wave detectors shown in FIGS. 1 and 2.
  • the total area of the end faces of the regions 1c shown in FIGS. 12 to 14 is larger than the total area of the end faces of the regions 1c shown in FIGS. 1 and 2.
  • the end face of the region 1c is a plane extending along the thickness direction of the two-dimensional material layer 1, in other words, the direction orthogonal to the sheet in which the atoms are two-dimensionally arranged in the two-dimensional material layer 1.
  • the end face region of the two-dimensional crystal structure in each region 1c of FIGS. 12 to 14 is larger than the end face region of the two-dimensional crystal structure in the regions 1c of FIGS. 1 and 2. Therefore, in each of the two-dimensional material layers 1 of FIGS.
  • the region 1c of the two-dimensional material layer 1 may be a graphene nanoribbon.
  • Graphene nanoribbons have a bandgap that varies with their width. Therefore, the wavelength range of the electromagnetic wave that can be photoelectrically converted in the region 1c can be adjusted according to the width of the region 1c composed of the graphene nanoribbon in the longitudinal direction. For example, the wavelength of the electromagnetic wave that can be photoelectrically converted in the other regions 1a and 1b. It can be narrower than the range. In this case, the optical carriers generated by the photoelectric conversion in the region 1c can be detected separately from the optical carriers generated by the photoelectric conversion in the other regions 1a and 1b.
  • the sensitivity of the electromagnetic wave detector is improved by detecting the optical carriers generated by the photoelectric conversion in the region 1c. Further, in such an electromagnetic wave detector, since the region 1c composed of the graphene nanoribbon and the semiconductor layer 4 are Schottky-bonded, the dark current is reduced and the electromagnetic wave absorbed at the Schottky-junction is generated. Sensitivity is improved by detecting optical carriers.
  • the region 1c shown in FIGS. 11 to 14 is arranged on the top 43 of the step portion 40, but is not limited to this.
  • the planar shape of the region 1c shown in FIGS. 4 and 5 may be formed in the same manner as the region 1c shown in any of FIGS. 11 to 14.
  • the electromagnetic wave detectors shown in FIGS. 15, 16 and 17 basically have the same configuration as the electromagnetic wave detector shown in FIG. 2, but the stepped portion 40 on the cross section of the top 43 perpendicular to the longitudinal direction. Is different from the electromagnetic wave detector shown in FIG. 2 in that the shape of is tapered.
  • the distance between the two side parts 42 on the bottom 41 side is different from the distance between the two side parts 42 on the top 43 side.
  • the distance between the two side portions 42 gradually increases from the bottom portion 41 to the top portion 43.
  • the distance between the two side portions 42 gradually narrows from the bottom portion 41 to the top portion 43.
  • the distance between the two side portions 42 gradually narrows from the bottom portion 41 toward the top portion 43, and the top portion 43 does not form a surface and becomes linear. It is provided.
  • the opening 3a and the first electrode portion 2a The region 1b of the two-dimensional material layer 1 that extends the space can be widely provided.
  • the contribution of the optical gate effect is larger than that of the electromagnetic wave detector shown in FIG. 2, and the detection sensitivity is increased. Can be enhanced.
  • the electromagnetic wave detector according to the first embodiment may further include an insulating protective film (not shown) arranged so as to cover the two-dimensional material layer.
  • the insulating protective film may be provided on the insulating film 3 so as to cover the two-dimensional material layer 1, the semiconductor layer 4, and the first electrode portion 2a.
  • the material constituting the insulating protective film may be any material having electrical insulating properties, and is selected from the group consisting of , for example, SiO 2 , Si 3 N 4 , HfO 2 , Al 2 O 3, and BN. Includes at least one.
  • the electromagnetic wave detector according to the present embodiment has the same structure as the electromagnetic wave detector according to the present embodiment and is used in combination with an electromagnetic wave detector (not shown) shielded from the electromagnetic wave to be detected.
  • the difference in output between the two electromagnetic wave detectors may be detected. By detecting the difference in this way, it is possible to suppress the influence of changes in characteristics depending on the environmental temperature, so that highly accurate detection is possible.
  • the electromagnetic wave detector according to the present embodiment may be configured integrally with an output amplifier circuit (not shown) using graphene. That is, an output amplifier circuit using graphene may be further provided on the semiconductor layer 4 of the electromagnetic wave detector according to the present embodiment.
  • An output amplifier circuit using graphene operates faster than an output amplifier circuit using a silicon-based semiconductor material, and a high-performance electromagnetic wave detector can be realized. Further, by using graphene for peripheral circuits such as a readout circuit, high-speed readout and simplification of the manufacturing process become possible.
  • FIG. 18 is a schematic cross-sectional view of the electromagnetic wave detector according to the second embodiment.
  • FIG. 19 is a plan internal view of the electromagnetic wave detector according to the second embodiment.
  • the electromagnetic wave detector according to the second embodiment has basically the same configuration as the electromagnetic wave detector according to the first embodiment, and the same effect can be obtained.
  • the semiconductor layer 4 is different from the electromagnetic wave detector according to the first embodiment in that the semiconductor layer 4 includes a current cutoff structure.
  • FIG. 19 only the opening 3a of the insulating film 3, the semiconductor layer 4, and the current blocking structure 5 are shown in order to explain the position of the current blocking mechanism.
  • the current cutoff structure 5 is a part capable of cut off the current. Specifically, the current cutoff structure 5 blocks the movement of carriers in the semiconductor layer 4 from a region facing the region 1b via the insulating film 3 to a region connected to the region 1c. It is a part for.
  • the current cutoff structure 5 is arranged in the region of the semiconductor layer 4 facing the insulating film 3. As shown in FIG. 19, in a plan view, the current cutoff structure 5 is arranged so as to surround the opening end of the opening 3a. When the region 1c and the opening 3a are arranged on the top 43 of the step portion 40, the current cutoff structure 5 is arranged on the top 43.
  • the current cutoff structure 5 has one end exposed from the semiconductor layer 4 at the top 43 and connected to the insulating film 3, and the other end embedded in the semiconductor layer 4.
  • the distance (depth) between the one end and the other end of the current cutoff structure 5 and the width in the direction intersecting the distance are not particularly limited as long as the diffusion of carriers can be prevented.
  • the specific structure of the current cutoff structure 5 is not particularly limited as long as it is a structure that cuts off the current.
  • the current cutoff structure 5 may be, for example, a trench formed in the semiconductor layer 4. The inside of the trench may be hollow or may be filled with an insulator. Further, the current cutoff structure 5 may be a region in which impurities having a higher concentration than that of the semiconductor layer 4 are doped, and may be a region in which the conductivity is higher than that of the semiconductor layer 4. Further, the current cutoff structure 5 may be a region having a higher conductivity than the semiconductor layer 4 formed by embedding a metal material inside the trench.
  • the optical carriers generated in the semiconductor layer 4 are injected into the region 1c of the two-dimensional material layer 1 by the current blocking structure 5 and two-dimensionally via the insulating film 3. It is separated into carriers that contribute to the optical gate effect that gives an electric field change to the region 1b of the material layer 1.
  • the optical carriers under the insulating film 3 are provided. Contributes to the optical gate effect and is injected into the two-dimensional material layer 1.
  • the amplification of the current change due to the above-mentioned optical gate effect is caused with a delay with respect to the generation of optical carriers.
  • the carrier contributing to the optical gate effect and the carrier injected into the two-dimensional material layer 1 are separated by the current blocking structure 5. As a result, the delay is eliminated and the response speed of the electromagnetic wave detector is improved. Further, when a plurality of electromagnetic wave detectors according to the second embodiment are arranged to form an electromagnetic wave detector aggregate, each pixel is separated.
  • the electromagnetic wave detector shown in FIG. 20 has basically the same configuration as the electromagnetic wave detector according to the second embodiment shown in FIGS. 18 and 19, but the current cutoff structure 5 penetrates the semiconductor layer 4. It differs from that in that it is formed so as to reach the second electrode portion 2b.
  • FIG. 21 is a schematic cross-sectional view of the electromagnetic wave detector according to the third embodiment.
  • the electromagnetic wave detector according to the third embodiment has basically the same configuration as the electromagnetic wave detector according to the first embodiment, and can obtain the same effect, but is insulated. It differs from the electromagnetic wave detector according to the first embodiment in that the buffer layer 6 is arranged between the two-dimensional material layer 1 and the semiconductor layer 4 inside the opening 3a of the film 3.
  • the buffer layer 6 electrically connects the region 1c of the two-dimensional material layer 1 and the semiconductor layer 4. Specifically, the buffer layer 6 creates a tunnel between the region 1c of the two-dimensional material layer 1 and the semiconductor layer 4, and the region 1c of the two-dimensional material layer 1 and the semiconductor layer 4 are connected by the tunnel current. It is provided so that it is electrically connected.
  • the material constituting the buffer layer 6 may be any material having electrical insulation, and is selected from the group consisting of , for example, SiO 2 , Si 3 N 4 , HfO 2 , Al 2 O 3, and BN. Includes at least one.
  • the thickness of the buffer layer 6 is set so that a tunnel current can be generated between the two-dimensional material layer 1 and the semiconductor layer 4 when an electromagnetic wave is incident.
  • the thickness of the buffer layer 6 is, for example, 1 nm or more and 10 nm or less.
  • the method for producing the buffer layer 6 can be any method, and can be selected from, for example, an ALD (Atomic Layer Deposition) method, a vacuum deposition method, a sputtering method, and the like.
  • the buffer layer 6 may be formed by oxidizing or nitriding the surface of the semiconductor layer 4.
  • the buffer layer 6 may be a natural oxide film formed on the surface of the semiconductor layer 4.
  • the electromagnetic wave detector according to the third embodiment further includes a buffer layer 6.
  • the buffer layer 6 is arranged between the two-dimensional material layer 1 and the semiconductor layer 4 inside the opening 3a.
  • the buffer layer 6 has a thickness capable of forming a tunnel current between the two-dimensional material layer 1 and the semiconductor layer 4.
  • the thickness of the buffer layer 6 is set to such a thickness that tunnel injection occurs from the semiconductor layer 4 to the two-dimensional material layer 1, so that the injection efficiency is improved and a large photocurrent is injected into the two-dimensional material layer 1. Therefore, the sensitivity of the electromagnetic wave detector can be improved. Further, the dark current can be reduced by suppressing the leakage current at the junction interface between the semiconductor layer 4 and the two-dimensional material layer 1 by the buffer layer 6.
  • the electromagnetic wave detector shown in FIG. 22 has basically the same configuration as the electromagnetic wave detector according to the third embodiment shown in FIG. 21, but the first electrode portion 2a is formed on the surface of the insulating film 3. It differs from that in that it further includes another third electrode portion 2c.
  • the third electrode portion 2c is preferably arranged in a region opposite to the region where the first electrode portion 2a is located when viewed from the opening 3a.
  • the two-dimensional material layer 1 is also connected to the electrode portion 2c.
  • a source / drain voltage Vd is applied between the first electrode portion 2a and the third electrode portion 2c. In this way, the photocurrent extracted from the two-dimensional material layer 1 can be increased.
  • FIG. 23 is a schematic cross-sectional view of the electromagnetic wave detector according to the fourth embodiment.
  • the electromagnetic wave detector according to the fourth embodiment has basically the same configuration as the electromagnetic wave detector according to the first embodiment, and can obtain the same effect, but has an insulating film. It differs from the electromagnetic wave detector according to the first embodiment in that the connecting conductor 2d is formed inside the opening 3a of the third embodiment.
  • the connecting conductor 2d electrically connects the semiconductor layer 4 and the region 1c of the two-dimensional material layer 1.
  • the region 1c of the two-dimensional material layer 1 is arranged so as to overlap on the upper surface of the connecting conductor 2d.
  • the back surface of the connecting conductor 2d is electrically connected to the front surface of the semiconductor layer 4.
  • the two-dimensional material layer 1 and the upper surface of the connecting conductor 2d are electrically connected. From a different point of view, the region 1c of the two-dimensional material layer 1 is electrically connected to the semiconductor layer 4 via the connecting conductor 2d.
  • the position of the upper surface of the connecting conductor 2d is substantially the same as the position of the upper surface of the insulating film 3.
  • the two-dimensional material layer 1 extends flatly from the upper surface of the insulating film 3 to the upper surface of the connecting conductor 2d without bending.
  • the connecting conductor 2d is ohmic-bonded to the semiconductor layer 4. Further, it is desirable that the connecting conductor 2d exhibits a high transmittance at the wavelength of the electromagnetic wave detected by the electromagnetic wave detector.
  • the material constituting the connecting conductor 2d is a material whose characteristics are changed by irradiation with electromagnetic waves to give a change in electric potential to the two-dimensional material layer 1, and is, for example, a quantum dot, a dielectric material, a liquid crystal material, or the like. It comprises at least one selected from the group consisting of fullerene, rare earth oxides, semiconductor materials, pn junction materials, metal-semiconductor junction materials, and metal-insulator-semiconductor junction materials.
  • the material constituting the connecting conductor 2d is a ferroelectric material having a polarization effect (pyroelectric effect) due to electromagnetic waves
  • the polarization of the ferroelectric material is changed by irradiation with electromagnetic waves, and the two-dimensional material layer 1 Can be given a change in potential.
  • the electromagnetic wave detector includes a connecting conductor 2d.
  • the connecting conductor 2d electrically connects the semiconductor layer 4 and the two-dimensional material layer 1 inside the opening 3a. It is desirable that the connecting conductor 2d is ohmic-bonded to the semiconductor layer 4. Further, it is desirable that the connecting conductor 2d exhibits a high transmittance at the detection wavelength of the electromagnetic wave.
  • the connecting conductor 2d is provided between the two-dimensional material layer 1 and the semiconductor layer 4, so that the two-dimensional material is compared with the electromagnetic wave detector according to the first embodiment.
  • the contact resistance between the layer 1 and the semiconductor layer 4 can be reduced, and the attenuation of the photocurrent, which becomes a problem when the junction between the two-dimensional material layer 1 and the semiconductor layer 4 is a Schottky junction, can be suppressed.
  • the thickness of the connecting conductor 2d and the thickness of the insulating film 3 are substantially the same, that is, the position of the upper surface of the connecting conductor 2d is the position of the upper surface of the insulating film 3. It is preferably substantially the same as the position.
  • the two-dimensional material layer 1 is formed horizontally without bending, the mobility of carriers in the two-dimensional material layer 1 is improved. Since the optical gate effect is proportional to the mobility, the detection sensitivity of the electromagnetic wave detector is improved.
  • the configuration of the electromagnetic wave detector according to the fourth embodiment can be applied to other embodiments.
  • FIG. 24 is a schematic plan view of the electromagnetic wave detector according to the fifth embodiment.
  • FIG. 25 is a schematic cross-sectional view of the line segment XXV-XXV of FIG. 24.
  • the electromagnetic wave detector according to the fifth embodiment has basically the same configuration as the electromagnetic wave detector according to the first embodiment, and the same effect can be obtained.
  • the semiconductor layer 4 includes a first semiconductor portion 4a having a first conductive type and a second semiconductor portion 4b having a second conductive type, and both are joined inside the opening 3a. It is different from the electromagnetic wave detector according to the first embodiment.
  • the first semiconductor portion 4a and the second semiconductor portion 4b are arranged side by side along the lateral direction of the opening 3a.
  • the first semiconductor portion 4a is doped with a carrier opposite to that of the second semiconductor portion 4b. That is, the first semiconductor portion 4a and the second semiconductor portion 4b are pn-junctioned.
  • the first semiconductor portion 4a, the second semiconductor portion 4b, and the pn junction interface 4ab between the first semiconductor portion 4a and the second semiconductor portion 4b are exposed inside the opening 3a.
  • the joining interface 4ab extends along the longitudinal direction of the opening 3a.
  • the bonding interface 4ab extends below the opening 3a of the insulating film 3.
  • the opening 3a of the insulating film 3 is arranged on, for example, the top 43.
  • the materials constituting the first semiconductor portion 4a and the second semiconductor portion 4b are, for example, the same semiconductor material.
  • the materials constituting the first semiconductor portion 4a and the second semiconductor portion 4b may be different semiconductor materials. In that case, since the electromagnetic wave detector can be driven in the wavelength band of the electromagnetic wave that can be absorbed by each semiconductor material, the wavelength range of the detectable electromagnetic wave can be expanded and selected.
  • the semiconductor layer 4 further includes another semiconductor portion 4c below, for example, the first semiconductor portion 4a and the second semiconductor portion 4b.
  • the other semiconductor portion 4c may or may not have a first conductive type or a second conductive type.
  • Another electrode portion 2c may be arranged on the other semiconductor portion 4c.
  • the step portion 40 includes at least the first semiconductor portion 4a and the second semiconductor portion 4b.
  • the step portion 40 is composed of, for example, a first semiconductor portion 4a, a second semiconductor portion 4b, and another semiconductor portion 4c.
  • One bottom portion 41a, the other bottom portion 41b, the lower portion of one side portion 42, and the lower portion of the other side portion 42 are composed of, for example, another semiconductor portion 4c.
  • the upper portion of one side portion 42 and the portion of the top portion 43 located on the side portion 42 side are composed of the first semiconductor portion 4a.
  • the upper portion of the other side portion 42 and the portion of the top portion 43 located on the other side portion 42 side are composed of the second semiconductor portion 4b.
  • the second electrode portion 2b is arranged on the bottom portion 41b.
  • the region 1c of the two-dimensional material layer 1 includes a portion electrically connected to the first semiconductor portion 4a and a portion electrically connected to the second semiconductor portion 4b inside the opening 3a.
  • the joint portion 4ac in which the region 1c of the two-dimensional material layer 1 and the first semiconductor portion 4a are joined, and the joint portion 4bc in which the region 1c and the second semiconductor portion 4b are joined are inside the opening 3a. Have been placed.
  • the two-dimensional material layer 1 further includes, in addition to the region 1a, the region 1b, and the region 1c, a region 1d that is connected to the other portion of the region 1b and is located on the other bottom 41b.
  • the region 1d is electrically connected to the second electrode portion 2b.
  • the pn junction interface 4ab between the first semiconductor portion 4a and the second semiconductor portion 4b is arranged so as to be in contact with the two-dimensional material layer 1. Therefore, the optical carriers generated at the pn junction interface 4ab between the first semiconductor portion 4a and the second semiconductor portion 4b by light irradiation can be easily taken out to the two-dimensional material layer 1. Further, the conductivity of the two-dimensional material layer 1 on the pn junction interface 4ab changes under the influence of the local electric field change in the pn junction generated by the optical carrier. As a result, the detection sensitivity of the electromagnetic wave detector is improved.
  • the two-dimensional material layer 1 is arranged so as to connect between the first electrode portion 2a and the second electrode portion 2b.
  • the two-dimensional material layer 1 is connected to the semiconductor layer 4 in a region between the first electrode portion 2a and the second electrode portion 2b.
  • a voltage can be applied between the first electrode portion 2a and the second electrode portion 2b, and the optical carriers generated in the semiconductor layer 4 can be read out by the two-dimensional material layer 1.
  • each of the region in contact with the first semiconductor portion 4a and the region in contact with the second semiconductor portion 4b is doped by each semiconductor portion. Therefore, a gradient of charge density is formed in the two-dimensional material layer 1.
  • the mobility of carriers in the two-dimensional material layer 1 is improved, and the detection sensitivity of the electromagnetic wave detector is improved.
  • the electromagnetic wave detector shown in FIG. 26 has the same configuration as the electromagnetic wave detector shown in FIGS. 24 and 25 and can obtain the same effect, but the first semiconductor portion 4a and the first electrode portion 2a It differs from the electromagnetic wave detectors shown in FIGS. 24 and 25 in that it is directly connected and the second semiconductor portion 4b is directly connected to the second electrode portion 2b.
  • the first semiconductor portion 4a extends from below the opening 3a to a region located below the first electrode portion 2a.
  • the second semiconductor portion 4b extends from below the opening 3a to a region located below the second electrode portion 2b.
  • the step portion 40 is composed of a first semiconductor portion 4a and a second semiconductor portion 4b.
  • the step portion 40 does not include the other semiconductor portion 4c.
  • a portion of the bottom portion 41a, the side portion 42, and the top portion 43 located on the side portion 42 side is composed of the first semiconductor portion 4a.
  • the portion of the other bottom portion 41a, the other side portion 42, and the top portion 43 located on the other side portion 42 side is composed of the second semiconductor portion 4b.
  • an additional opening is formed in a region sandwiching the opening 3a and located below each of the first electrode portion 2a and the second electrode portion 2b.
  • the first electrode portion 2a is directly connected to the first semiconductor portion 4a inside the additional opening.
  • the second electrode portion 2b is directly connected to the second semiconductor portion 4b inside the additional opening.
  • the voltage can be applied to the two-dimensional material layer 1 while applying the voltage V between the first semiconductor portion 4a and the second semiconductor portion 4b.
  • the photodiode composed of the first semiconductor portion 4a and the second semiconductor portion 4b is in a saturated state in which a reverse bias is applied, a current flows only in the two-dimensional material layer 1.
  • a depletion layer is generated in the first semiconductor portion 4a and the second semiconductor portion 4b, and a large voltage change can be given to the two-dimensional material layer 1, and as a result, a large photocurrent (optical carrier) is taken out. Can be done.
  • the conductivity of the two-dimensional material layer 1 is affected by the local electric field change generated at the junction 4ba, which is the pn junction interface between the first semiconductor portion 4a and the second semiconductor portion 4b. Change. As a result, the detection sensitivity of the electromagnetic wave detector is improved.
  • a tunnel diode composed of a first semiconductor portion 4a and a second semiconductor portion 4b when used, a large photocurrent is generated only at the time of light irradiation.
  • the photocurrent is injected into the two-dimensional material layer 1.
  • the change in conductivity due to the influence of the change in the electric field can be generated in the two-dimensional material layer 1 only at the time of light irradiation. As a result, the sensitivity of the electromagnetic wave detector can be increased.
  • the other semiconductor portion 4c and the other electrode portion 2c may not be formed.
  • the electromagnetic wave detector shown in FIG. 27 has the same configuration as the electromagnetic wave detectors shown in FIGS. 24 and 25, and the same effect can be obtained, but the region 1c of the two-dimensional material layer 1 is the joint portion 4ac. It differs from the electromagnetic wave detectors shown in FIGS. 24 and 25 in that it is separated from the joint portion 4bc.
  • the electromagnetic wave detector shown in FIG. 28 has the same configuration as the electromagnetic wave detector shown in FIG. 26 and can obtain the same effect, but the region 1c of the two-dimensional material layer 1 is the joint portion 4ac and the joint portion. It differs from the electromagnetic wave detector shown in FIG. 26 in that it is separated from 4 bc.
  • the region 1c of the two-dimensional material layer 1 shown in FIGS. 27 and 28 is divided on the bonding interface 4ab.
  • the region 1c of the two-dimensional material layer 1 shown in FIGS. 27 and 28 has a first connection region in contact with the first semiconductor portion 4a and a second connection region in contact with the second semiconductor portion 4b. doing.
  • the first connection region and the second connection region are electrically connected not via the two-dimensional material layer 1 but only through the pn junction interface 4ab.
  • the two-dimensional material layer 1 shown in FIGS. 27 and 28 includes a first two-dimensional material layer 1 having a first connection region electrically connected to the first semiconductor portion 4a, and a second semiconductor portion 4b. It includes a second two-dimensional material layer 1 having a second connecting region that is electrically connected.
  • the first two-dimensional material layer 1 and the second two-dimensional material layer 1 are configured as separate members independent of each other.
  • the first two-dimensional material layer 1 and the second two-dimensional material layer 1 are arranged so as to face each other with the bonding interface 4ab interposed therebetween.
  • the first two-dimensional material layer 1 and the second two-dimensional material layer 1 are separated on the bonding interface 4ab.
  • the current I is the second electrode portion 2b, the second two-dimensional material layer 1, the junction portion 4bc, the second semiconductor portion 4b, the pn junction interface 4ab, and the first semiconductor portion. It flows in this order through 4a, the junction 4ac, the first two-dimensional material layer 1, and the first electrode portion 2a.
  • the joint portion 4ac and the joint portion 4bc are Schottky joint portions in which the two-dimensional material layer 1 and the first semiconductor portion 4a or the second semiconductor portion 4b are Schottky-bonded.
  • the degree of change in the barrier height with respect to the voltage value (reverse bias) applied to the Schottky junction of the junction portion 4ac. is different from the degree of change in the barrier height with respect to the voltage value (forward bias) applied to the Schottky junction of the junction 4bc.
  • the joint portion 4ac and the joint portion 4bc are Schottky joint portions, the behavior of the dark current and the photocurrent changes according to the barrier height. Therefore, in the electromagnetic wave detectors shown in FIGS. 27 and 28, the rate of change of each of the dark current and the photocurrent can be freely adjusted by the voltage value, so that the temperature sensitivity can be improved.
  • FIG. 29 is a schematic plan view of the electromagnetic wave detector according to the sixth embodiment.
  • FIG. 30 is a schematic cross-sectional view taken along the line segment XXX-XXX of FIG. 29.
  • the electromagnetic wave detector according to the sixth embodiment has basically the same configuration as the electromagnetic wave detector according to the fifth embodiment, and the same effect can be obtained.
  • the electromagnetic wave detector according to the fifth embodiment is different from the electromagnetic wave detector according to the fifth embodiment in that the first semiconductor portion 4a is arranged so as to sandwich at least a part of the second semiconductor portion 4b when the semiconductor layer 4 is viewed from the opening 3a. ..
  • the first semiconductor portion 4a is the first portion 4a1 arranged on one side of the opening 3a with respect to the second semiconductor portion 4b in the lateral direction, and the opening 3a. It has a second portion 4a2 arranged on the other side with respect to the second semiconductor portion 4b in the above-mentioned lateral direction. Inside the opening 3a, the second semiconductor portion 4b, the first portion 4a1 of the first semiconductor portion 4a, and the second portion 4a2 of the first semiconductor portion 4a are arranged so as to face the two-dimensional material layer 1. There is. Each of the first portion 4a1 and the second portion 4a2 is joined to the second semiconductor portion 4b.
  • the pn junction interface 4ab2 with 4b is exposed inside the opening 3a.
  • the two-dimensional material layer 1 is connected to the first portion 4a1 and the second portion 4a2 of the first semiconductor portion 4a, the second semiconductor portion 4b, and the pn junction interface 4ab1 and the pn junction interface 4ab2 inside the opening 3a. Has been done.
  • the pn junction interface between the first semiconductor portion 4a and the second semiconductor portion 4b can be increased as compared with the electromagnetic wave detector according to the fifth embodiment. Further, by increasing the contact region between the pn junction interface and the two-dimensional material layer 1, the influence of the local electric field change generated at the pn junction interface by light irradiation on the two-dimensional material layer 1 can be increased. Further, by increasing the contact region between the pn junction interface and the two-dimensional material layer 1, the influence of the local electric field change generated at the pn junction interface by light irradiation on the two-dimensional material layer 1 can be increased.
  • a plurality of second semiconductor portions 4b may be provided. That is, inside the opening 3a, a plurality of second semiconductor portions 4b may be arranged in the first semiconductor portion 4a at intervals from each other. As a result, the pn junction interface between the first semiconductor portion 4a and the second semiconductor portion 4b can be further increased. Further, by further increasing the contact region between the pn junction interface and the two-dimensional material layer 1, the influence of the local electric field change generated at the pn junction interface by light irradiation on the two-dimensional material layer 1 can be increased.
  • the first semiconductor portion 4a and the second semiconductor portion 4b can be pnp or npn phototransistors.
  • the first electrode portion 2a may be brought into contact with the first semiconductor portion 4a.
  • the electromagnetic wave detector shown in FIG. 31 basically has the same configuration as the electromagnetic wave detectors shown in FIGS. 29 and 30, and the same effect can be obtained, but the insulating film 3 and the first electrode portion
  • the configurations of 2a and the electrode portion 2c are different from those of the electromagnetic wave detectors shown in FIGS. 29 and 30. That is, in the electromagnetic wave detector shown in FIG. 31, the first electrode portion 2a and the first semiconductor portion 4a are in contact with each other.
  • the electrode portion 2c and the first semiconductor portion 4a are also in contact with each other.
  • an additional opening is formed in a region sandwiching the opening 3a and located below each of the first electrode portion 2a and the electrode portion 2c.
  • the first electrode portion 2a and the electrode portion 2c extend inside the additional opening, respectively. Inside the additional opening, the first electrode portion 2a and the electrode portion 2c are connected to the first semiconductor portion 4a.
  • FIG. 32 is a schematic plan view of the electromagnetic wave detector according to the seventh embodiment.
  • FIG. 33 is a schematic cross-sectional view of the line segment XXXIII-XXXIII of FIG. 32.
  • the electromagnetic wave detector according to the seventh embodiment has basically the same configuration as the electromagnetic wave detector according to the fifth embodiment, and the same effect can be obtained. However, it differs from the electromagnetic wave detector according to the fifth embodiment in that the second semiconductor portion 4b is embedded in the first semiconductor portion 4a.
  • the second semiconductor portion 4b is arranged below the opening 3a.
  • the second semiconductor portion 4b is embedded under the first semiconductor portion 4a connected to the two-dimensional material layer 1 inside the opening 3a.
  • the second semiconductor portion 4b is arranged below the top portion 43 and above the bottom portion 41, for example, inside the step portion 40.
  • a first semiconductor portion 4a is arranged between the top portion 43 and the second semiconductor portion 4b.
  • a thin first semiconductor portion 4a is arranged between the two-dimensional material layer 1 and the second semiconductor portion 4b.
  • the thickness of the first semiconductor portion 4a located between the top portion 43 and the second semiconductor portion 4b is thinner than the thickness of the second semiconductor portion 4b.
  • a pn junction is formed by the first semiconductor portion 4a and the second semiconductor portion 4b.
  • the pn junction is formed directly below the two-dimensional material layer 1 located inside the opening 3a. Therefore, the efficiency of extracting the photocurrent from the semiconductor layer 4 to the two-dimensional material layer 1 is improved. Further, since the electric field change given to the two-dimensional material layer 1 by the semiconductor layer 4 becomes large, the sensitivity of the electromagnetic wave detector can be increased.
  • a pn junction is formed at the junction interface between the first semiconductor portion 4a and the second semiconductor portion 4b, and a diode is formed.
  • the diode is irradiated with electromagnetic waves (light)
  • the deactivation of photocarriers generated at the junction interface between the first semiconductor portion 4a and the second semiconductor portion 4b is reduced, and the light injected into the two-dimensional material layer 1 is reduced.
  • the current increases.
  • an electromagnetic wave detector with high sensitivity can be obtained.
  • the other semiconductor portion 4c and the other electrode portion 2c may not be formed.
  • the configuration of the electromagnetic wave detector according to the seventh embodiment can be applied to other embodiments.
  • FIG. 34 is a schematic cross-sectional view of the electromagnetic wave detector according to the eighth embodiment.
  • the electromagnetic wave detector according to the eighth embodiment has basically the same configuration as the electromagnetic wave detector according to the first embodiment, and can obtain the same effect, but is insulated.
  • the film 3 differs from the electromagnetic wave detector according to the first embodiment in that a tapered portion 3b is formed in which the thickness of the insulating film 3 gradually decreases from the first electrode portion 2a toward the opening 3a.
  • a tapered portion 3b in which the surface of the insulating film 3 is inclined with respect to the side portion 42 is formed between the first electrode portion 2a and the opening portion 3a of the insulating film 3.
  • the angle formed by the surface of the tapered portion 3b and the surface of the first semiconductor portion 4a may be an acute angle, for example, 45 ° or less, or 30 ° or less.
  • the surface of the tapered portion 3b is, for example, a flat surface, but may be a curved surface.
  • the tapered portion 3b can be formed by any method.
  • the tapered portion 3b may be formed by inclining the semiconductor layer 4 to form an insulating film.
  • the tapered portion 3b may be formed by dry etching the insulating film 3 previously formed on the semiconductor layer 4 in a state where the semiconductor layer 4 is tilted.
  • the electromagnetic wave detector according to the eighth embodiment since the insulating film 3 is provided with a gradient in the tapered portion 3b, the electric field change in the two-dimensional material layer 1 when the semiconductor layer 4 is irradiated with the electromagnetic wave. There is a degree of local variation. That is, when the semiconductor layer 4 is irradiated with electromagnetic waves and the two-dimensional material layer 1 is subjected to an electric field change, the degree of the electric field change locally changes according to the change in the thickness of the insulating film 3. As a result, the mobility of carriers in the two-dimensional material layer 1 is improved, and the detection sensitivity of the electromagnetic wave detector is improved.
  • the configuration of the electromagnetic wave detector according to the eighth embodiment can be applied to other embodiments.
  • FIG. 35 is a schematic cross-sectional view of the electromagnetic wave detector according to the ninth embodiment.
  • the electromagnetic wave detector according to the ninth embodiment has basically the same configuration as the electromagnetic wave detector according to the first embodiment, and can obtain the same effect, but is two-dimensional. It differs from the electromagnetic wave detector according to the first embodiment in that the material layer 1 includes the irregular layer structure portion 1e.
  • the region corresponding to the channel region in the two-dimensional material layer 1 is the random layer structure portion 1e.
  • the disordered layer structure portion 1e means a region in which a plurality of graphenes are laminated, and a structure in which the lattices of the laminated graphenes are laminated in an inconsistent state.
  • the entire two-dimensional material layer 1 may have a turbulent layer structure, or only the turbulent layer structure portion 1e may have a turbulent layer structure.
  • the method for producing the disordered layer structure portion 1e may be any method.
  • the random layer structure portion 1e can be formed, for example, by transferring a single layer graphene produced by a CVD method a plurality of times and laminating the multilayer graphene.
  • the disordered layer structure portion 1e can be formed, for example, by growing graphene on graphene by a CVD method using ethanol, methane or the like as a carbon source.
  • the portion corresponding to the channel region in the two-dimensional material layer 1 is the irregular layer structure portion 1e, the mobility of carriers in the two-dimensional material layer 1 is improved.
  • ordinary laminated graphene is called AB lamination, and the laminated graphenes are laminated in a aligned state.
  • the graphene produced by the CVD method is polycrystalline, and when the graphene is further transferred onto the graphene multiple times, or when the graphene is laminated on the underlying graphene by the CVD method, the laminated graphenes are deposited with each other. It has a disordered layer structure in which the lattice is in an inconsistent state.
  • the graphene having a random layer structure constituting the disordered layer structure portion 1e is less affected by the interaction between the layers and has the same properties as the single layer graphene. Further, the mobility of the two-dimensional material layer 1 is lowered due to the influence of carrier scattering in the underlying insulating film 3. However, in the irregular layer structure portion 1e, the graphene in contact with the insulating film 3 is affected by carrier scattering, but the graphene in the upper layer laminated on the graphene in the irregular layer structure is affected by the carrier scattering of the underlying insulating film 3. Less susceptible. Further, in graphene having a disordered layer structure, the influence of interaction between layers is small, so that the conductivity is also improved. From the above, the mobility of carriers can be improved in graphene having a disordered layer structure. As a result, the sensitivity of the electromagnetic wave detector can be improved.
  • the graphene having a disordered layer structure may be applied only to the portion of the two-dimensional material layer 1 existing on the insulating film 3.
  • graphene having a non-random layer structure for example, single-layer graphene may be used for the region 1a.
  • the influence of carrier scattering of the insulating film 3 on the two-dimensional material layer 1 can be suppressed without increasing the contact resistance between the first electrode portion 2a and the first semiconductor portion 4a and the two-dimensional material layer 1. ..
  • the configuration of the electromagnetic wave detector according to the ninth embodiment can be applied to other embodiments.
  • FIG. 36 is a schematic cross-sectional view of the electromagnetic wave detector according to the tenth embodiment.
  • the electromagnetic wave detector according to the tenth embodiment has basically the same configuration as the electromagnetic wave detector according to the first embodiment, and can obtain the same effect, but is two-dimensional. It differs from the electromagnetic wave detector according to the first embodiment in that it further includes one or more conductors 7 arranged so as to be in contact with the material layer 1.
  • a plurality of conductors 7 are arranged so as to come into contact with the region 1b of the two-dimensional material layer 1.
  • the plurality of conductors 7 are arranged at intervals from each other.
  • the plurality of conductors 7 are arranged, for example, on the side portion 42 of the step portion 40.
  • the conductor 7 is a floating electrode.
  • the electromagnetic wave detector according to the tenth embodiment includes a plurality of conductors 7 as floating electrodes on the two-dimensional material layer 1.
  • the material constituting each conductor 7 may be any material having conductivity, and for example, gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), and chromium. It comprises at least one selected from the group consisting of (Cr) and palladium (Pd).
  • Each conductor 7 is not connected to a power supply circuit or the like and is floating.
  • the plurality of conductors 7 are provided on the region 1b of the two-dimensional material layer 1 located between the first electrode portion 2a and the first semiconductor portion 4a.
  • the plurality of conductors 7 have a one-dimensional or two-dimensional periodic structure.
  • a one-dimensional periodic structure a structure in which a plurality of conductors 7 are arranged at intervals (periodically) from each other in the horizontal direction on the paper surface or the depth direction of the paper surface in FIG. 36 can be adopted.
  • the plan view of the electromagnetic wave detector in the plan view of the electromagnetic wave detector, a structure in which the conductors 7 are arranged at positions corresponding to lattice points such as a square lattice or a triangular lattice can be adopted.
  • the planar shape of each conductor 7 may be any shape such as a circular shape, a triangular shape, a quadrangular shape, a polygonal shape, or an elliptical shape.
  • the arrangement of the conductors 7 in the plan view is not limited to the above-mentioned arrangement having periodic symmetry, and may be an arrangement having asymmetry in the plan view.
  • any method can be adopted as the specific method for forming the conductor 7, but for example, the same method as the method for manufacturing the first electrode portion 2a described in the first embodiment may be used. ..
  • the conductor 7 which is a floating electrode is provided on the two-dimensional material layer 1 corresponding to the channel region. Therefore, the optical carriers generated by the irradiation of electromagnetic waves in the semiconductor layer 4 can move back and forth between the plurality of conductors 7, and as a result, the life of the optical carriers is extended. As a result, the sensitivity of the electromagnetic wave detector can be increased.
  • the conductor 7 is polarized depending on the irradiated electromagnetic wave. Occurs.
  • the electromagnetic wave detector according to the tenth embodiment can detect only specific polarized light.
  • the plurality of conductors 7 have a specific wavelength. Electromagnetic waves can be resonated. In this case, only the electromagnetic wave having a specific wavelength can be detected by the electromagnetic wave detector. In this case, the electromagnetic wave detector according to the tenth embodiment can detect only electromagnetic waves having a specific wavelength with high sensitivity.
  • the conductors 7 are subjected to the irradiated electromagnetic waves as in the case where the plurality of conductors 7 have a one-dimensional periodic structure. Polarization dependence occurs in.
  • the semiconductor layer 4 can be irradiated with only electromagnetic waves having a specific polarization.
  • the electromagnetic wave detector according to the tenth embodiment can detect only specific polarized light.
  • the electromagnetic wave detector shown in FIG. 37 has basically the same configuration as the electromagnetic wave detector shown in FIG. 36 and can obtain the same effect, but the conductor 7 is provided under the two-dimensional material layer 1. It differs from the electromagnetic wave detector shown in FIG. 36 in that it is arranged. That is, in the electromagnetic wave detector shown in FIG. 37, a plurality of conductors 7 are arranged between the lower surface of the two-dimensional material layer 1 and the upper surface of the insulating film 3.
  • the two-dimensional material layer 1 has a plurality of bent portions (concavo-convex portions) along the surfaces of the plurality of conductors 7. Even with such a configuration, the same effect as that of the electromagnetic wave detector shown in FIG. 36 can be obtained. Further, in this case, since the two-dimensional material layer 1 is not damaged when the conductor 7 is formed, it is possible to suppress a decrease in carrier mobility in the two-dimensional material layer 1.
  • the uneven portion may be formed in the region of the two-dimensional material layer 1 corresponding to the channel region.
  • the uneven portion of the two-dimensional material layer 1 may have a periodic structure or an asymmetrical structure as in the case of the plurality of conductors 7 described above. In this case, the same effect as when a plurality of conductors 7 are formed can be obtained.
  • each conductor 7 shown in FIGS. 36 and 37 is formed only on the side portion 42, at least one of the top portion 43, the side portion 42, and the bottom portion 41 is formed as long as it is in contact with the region 1b. It suffices if it is formed on the top.
  • each electromagnetic wave detector shown in FIGS. 36 and 37 includes a plurality of conductors 7, but may include only one conductor 7.
  • FIG. 38 is a schematic cross-sectional view of the electromagnetic wave detector according to the eleventh embodiment.
  • the electromagnetic wave detector according to the eleventh embodiment has basically the same configuration as the electromagnetic wave detector according to the first embodiment, and can obtain the same effect, but is two-dimensional. It differs from the electromagnetic wave detector according to the first embodiment in that it further includes one or more contact layers 8 arranged so as to be in contact with the material layer 1.
  • the contact layer 8 is arranged on the region 1b of the two-dimensional material layer 1.
  • the contact layer 8 is provided so as to contact the two-dimensional material layer 1 and supply holes or electrons to the two-dimensional material layer 1.
  • the material constituting the contact layer 8 is, for example, a composition called a positive photoresist, which contains a photosensitizer having a quinonediagit group and a novolak resin. Further, the material constituting the contact layer 8 may be, for example, a material having a polar group, or more specifically, a material having an electron attracting group which is an example of a material having a polar group. The material having an electron attracting group has an effect of reducing the electron density of the two-dimensional material layer 1. Further, the material constituting the contact layer 8 may be, for example, a material having an electron donating group, which is an example of a material having a polar group. The material having an electron donating group has an effect of increasing the electron density of the two-dimensional material layer 1.
  • the material having an electron attracting group examples include a material having a halogen, a nitrile, a carboxyl group, a carbonyl group, and the like.
  • the material having an electron donating group examples include a material having an alkyl group, an alcohol, an amino group, a hydroxyl group and the like.
  • the material constituting the contact layer 8 may be a material in which the charge is biased in the entire molecule due to polar groups other than the electron attracting group and the electron donating group.
  • the material constituting the contact layer 8 is an organic substance, a metal, a semiconductor, an insulator, a two-dimensional material, or a mixture of any of these materials, as long as the charge is biased in the entire molecule to generate polarity. You may.
  • the conductive type in which the two-dimensional material layer 1 in contact with the contact layer 8 is doped has a work function of the contact layer 8 rather than a work function of the two-dimensional material layer 1.
  • the function is large, it is p-type, and when it is small, it is n-type.
  • the material constituting the contact layer 8 is an organic substance, the organic substance constituting the contact layer 8 does not have a clear work function. Therefore, it is preferable to determine the polar group of the material of the contact layer 8 based on the polarity of the organic molecule used for the contact layer 8 whether the conductive type to which the two-dimensional material layer 1 is doped becomes the p type or the n type. ..
  • the contact layer 8 when a composition containing a photosensitizer having a quinonediagit group and a novolak resin, which is called a positive photoresist, is used as the contact layer 8, the region where the resist is formed by the photolithography step in the two-dimensional material layer 1 is p. It becomes a mold two-dimensional material layer area. This eliminates the need for a mask forming process that comes into contact with the surface of the two-dimensional material layer 1. As a result, it is possible to reduce the process damage to the two-dimensional material layer 1 and simplify the process.
  • the contact layer 8 is formed on the two-dimensional material layer 1.
  • the state (conductive type) of the two-dimensional material layer 1 is intentionally n. It can be a type or a p type.
  • the carrier doping of the two-dimensional material layer 1 can be controlled without considering the influence of the carrier doping on the two-dimensional material layer 1 from the first electrode portion 2a and the first semiconductor portion 4a. As a result, the performance of the electromagnetic wave detector can be improved.
  • the contact layer 8 by forming the contact layer 8 only on either the first electrode portion 2a side or the first semiconductor portion 4a side on the upper surface of the two-dimensional material layer 1, the charge density can be increased in the two-dimensional material layer 1. A gradient is formed. As a result, the mobility of carriers in the two-dimensional material layer 1 is improved, and the sensitivity of the electromagnetic wave detector can be increased.
  • the film thickness of the contact layer 8 is preferably sufficiently thin so that photoelectric conversion can be performed when the electromagnetic wave is irradiated to the two-dimensional material layer 1.
  • the contact layer 8 may have any configuration as long as carriers such as molecules or electrons are introduced into the two-dimensional material layer 1. For example, by immersing the two-dimensional material layer 1 in a solution and supplying carriers to the two-dimensional material layer 1 at the molecular level, the solid contact layer 8 is not formed on the two-dimensional material layer 1, and the two-dimensional material is not formed. Layer 1 may be doped with carriers.
  • a material that causes a polarity conversion may be used in addition to the material described above.
  • the contact layer 8 undergoes polarity conversion the electrons or holes generated during the conversion are supplied to the two-dimensional material layer 1. Therefore, electron or hole doping occurs in the portion of the two-dimensional material layer 1 in which the contact layer 8 is in contact. Therefore, even if the contact layer 8 is removed, the portion of the two-dimensional material layer 1 that has been in contact with the contact layer 8 remains doped with electrons or holes. Therefore, when a material that causes polarity conversion is used as the contact layer 8, the contact layer 8 may be removed from the two-dimensional material layer 1 after a certain period of time has elapsed.
  • the opening area of the two-dimensional material layer 1 increases as compared with the case where the contact layer 8 is present. Therefore, the detection sensitivity of the electromagnetic wave detector can be improved.
  • the polarity conversion is a phenomenon in which a polar group is chemically converted. For example, an electron attracting group is changed to an electron donating group, an electron donating group is changed to an electron attracting group, or a polar group. Means a phenomenon in which is changed to a non-polar group, or a non-polar group is changed to a polar group.
  • the contact layer 8 may be formed of a material that undergoes polarity conversion by electromagnetic wave irradiation.
  • the contact layer 8 by selecting a material that causes a polarity conversion at a specific electromagnetic wave wavelength as the material of the contact layer 8, the contact layer 8 causes a polarity conversion only when the contact layer 8 is irradiated with an electromagnetic wave having a specific electromagnetic wave wavelength, and the two-dimensional material layer. Doping to 1 can be performed. As a result, the photocurrent flowing into the two-dimensional material layer 1 can be increased.
  • the two-dimensional material layer 1 can be doped with electrons or holes generated during the redox reaction.
  • the electromagnetic wave detector includes a contact layer 8 that comes into contact with the two-dimensional material layer 1.
  • the contact layer 8 supplies holes or electrons to the two-dimensional material layer 1.
  • the carrier doping of the two-dimensional material layer 1 can be controlled without considering the influence of the carrier doping from the first electrode portion 2a and the first semiconductor portion 4a. As a result, the performance of the electromagnetic wave detector can be improved.
  • the contact layer 8 shown in FIG. 38 is formed only on the side portion, it may be formed on at least one of the top portion 43, the side portion 42, and the bottom portion 41.
  • FIG. 39 is a schematic plan view of the electromagnetic wave detector assembly according to the twelfth embodiment.
  • the electromagnetic wave detector aggregate 1000 according to the twelfth embodiment is an aggregate of a plurality of electromagnetic wave detectors 100.
  • the electromagnetic wave detector assembly 1000 has a plurality of electromagnetic wave detectors 100 according to any one of the first to eleventh embodiments as detection elements.
  • the electromagnetic wave detector assembly 1000 includes, for example, the electromagnetic wave detector according to the first embodiment as the electromagnetic wave detector 100.
  • the detection wavelengths of the plurality of electromagnetic wave detectors 100 are the same.
  • a plurality of electromagnetic wave detectors 100 are arranged in an array in the two-dimensional direction.
  • the plurality of electromagnetic wave detectors 100 are arranged side by side in the first direction and the second direction intersecting the first direction.
  • four electromagnetic wave detectors 100 are arranged in a 2 ⁇ 2 array.
  • the number of electromagnetic wave detectors 100 to be arranged is not limited to this.
  • a plurality of electromagnetic wave detectors 100 may be arranged in an array of 3 or more ⁇ 3 or more.
  • a plurality of electromagnetic wave detectors 100 are periodically arranged in two dimensions, but the plurality of electromagnetic wave detectors 100 are periodically arranged in one direction. It may be arranged. Further, the intervals of the plurality of electromagnetic wave detectors 100 may be equal or different.
  • the second electrode portion 2b may be a common electrode as long as each electromagnetic wave detector 100 can be separated.
  • the second electrode portion 2b as a common electrode, it is possible to reduce the wiring of pixels in each electromagnetic wave detector 100 as compared with the configuration in which the second electrode portion 2b is independent. As a result, it is possible to increase the resolution of the electromagnetic wave detector assembly.
  • a current cutoff structure 5 such as the trench structure described in the second embodiment may be provided on the outer periphery of the electromagnetic wave detector 100.
  • the electromagnetic wave detector assembly 1000 using the plurality of electromagnetic wave detectors 100 can also be used as an image sensor by arranging the plurality of electromagnetic wave detectors 100 in an array.
  • the electromagnetic wave detector assembly 1000 may include any of the electromagnetic wave detectors according to the second to eleventh embodiments as the electromagnetic wave detector 100.
  • the electromagnetic wave detector assembly 1000 may include any of the electromagnetic wave detectors according to the second to eleventh embodiments as the electromagnetic wave detector 100.
  • the electromagnetic wave detector assembly 1000 may include a plurality of electromagnetic wave detectors according to any one of the first to eleventh embodiments, or two or more of the first to eleventh embodiments. A plurality of electromagnetic wave detectors according to the form may be provided.
  • the electromagnetic wave detector assembly 2000 shown in FIG. 40 has basically the same configuration as the electromagnetic wave detector assembly 1000 shown in FIG. 39, and can obtain the same effect, but as a plurality of electromagnetic wave detectors. It differs from the electromagnetic wave detector assembly shown in FIG. 39 in that it includes different types of electromagnetic wave detectors 200, 201, 202, and 203. That is, in the electromagnetic wave detector assembly 2000 shown in FIG. 40, different types of electromagnetic wave detectors 200, 201, 202, and 203 are arranged in an array (matrix).
  • the electromagnetic wave detectors 200, 201, 202, and 203 are arranged in a 2 ⁇ 2 matrix, but the number of arranged electromagnetic wave detectors is not limited to this. .. Further, in the electromagnetic wave detector assembly 2000 shown in FIG. 40, a plurality of electromagnetic wave detectors 200, 201, 202, 203 are periodically arranged in two dimensions, but the plurality of electromagnetic wave detectors 200, 201, 202 , 203 may be arranged periodically along one direction. Further, the intervals of the plurality of electromagnetic wave detectors 200, 201, 202, and 203 may be equal or different.
  • electromagnetic wave detector assembly 2000 shown in FIG. 40 different types of electromagnetic wave detectors 200, 201, 202, and 203 according to any one of the first to eleventh embodiments are arranged in a one-dimensional or two-dimensional array. By doing so, it is possible to have a function as an image sensor.
  • the electromagnetic wave detectors 200, 201, 202, and 203 are, for example, electromagnetic wave detectors having different detection wavelengths from each other.
  • the electromagnetic wave detectors 200, 201, 202, and 203 are electromagnetic wave detectors according to any one of the first to eleventh embodiments, and are prepared as electromagnetic wave detectors having different detection wavelength selectivity. May be good.
  • the electromagnetic wave detector assembly can detect at least two or more electromagnetic waves having different wavelengths.
  • the electromagnetic wave detectors 200, 201, 202, and 203 having different detection wavelengths in an array for example, ultraviolet light, infrared light, terahertz wave, and radio wave are arranged in the same manner as the image sensor used in the visible light region.
  • the wavelength of the electromagnetic wave can be identified in any wavelength range such as the wavelength range of. As a result, it is possible to obtain a colorized image showing, for example, a difference in wavelength as a difference in color.
  • semiconductor materials having different detection wavelengths may be used as a constituent material of the semiconductor layer 4 constituting the electromagnetic wave detector.
  • a semiconductor material whose detection wavelength is the wavelength of visible light and a semiconductor material whose detection wavelength is the wavelength of infrared rays may be used as the constituent materials.
  • the electromagnetic wave detector when the electromagnetic wave detector is applied to an in-vehicle sensor, the electromagnetic wave detector can be used as a camera for visible light images in the daytime. Furthermore, the electromagnetic wave detector can also be used as an infrared camera at night. In this way, it is not necessary to properly use a camera having an image sensor depending on the detection wavelength of the electromagnetic wave.
  • the electromagnetic wave detector can be used as a position detection sensor capable of detecting the position of an object even with a small number of pixels.
  • the electromagnetic wave detector assembly if the electromagnetic wave detectors 200, 201, 202, 203 having different detection wavelengths are used as described above, an image sensor that detects the intensity of electromagnetic waves having a plurality of wavelengths can be obtained. As a result, it is possible to detect electromagnetic waves having a plurality of wavelengths and obtain a color image without using a color filter, which has been conventionally required for a CMOS image sensor or the like.
  • the polarization identification image sensor can be formed by arranging the electromagnetic wave detectors 200, 201, 202, and 203 having different polarizations to be detected.
  • polarization imaging can be performed by arranging a plurality of electromagnetic wave detectors of the unit, with four pixels having detection angles of 0 °, 90 °, 45 °, and 135 ° as one unit.
  • the polarization identification image sensor enables, for example, identification of artificial and natural objects, material identification, identification of objects of the same temperature in the infrared wavelength region, identification of boundaries between objects, or equivalent improvement in resolution.
  • the electromagnetic wave detector assembly 2000 can detect electromagnetic waves in a wide wavelength range. Further, the electromagnetic wave detector assembly 2000 can detect electromagnetic waves having different wavelengths.
  • examples of the material whose characteristics are changed by irradiation with electromagnetic waves and which gives the potential change to the two-dimensional material layer 1 include quantum dots, strong dielectric materials, liquid crystal materials, fullerene, rare earth oxides, semiconductor materials, and pn.
  • a bonding material, a metal-semiconductor junction material, a metal-insulator-semiconductor junction material, or the like can be used.
  • the ferroelectric material having a polarization effect (pyroelectric effect) due to electromagnetic waves is used as the ferroelectric material, the polarization of the ferroelectric material is changed by irradiation with electromagnetic waves. As a result, the potential can be changed in the two-dimensional material layer 1.
  • the material constituting the insulating film 3, the contact layer 8, the first semiconductor portion 4a, or the second semiconductor portion 4b is a material whose characteristics change due to irradiation with electromagnetic waves
  • the insulating film 3, the contact layer 8 The characteristics of the first semiconductor portion 4a or the second semiconductor portion 4b are changed by irradiation with electromagnetic waves, and the potential of the two-dimensional material layer 1 can be changed.
  • a material whose characteristics are changed by irradiation of electromagnetic waves and giving a change in potential to the two-dimensional material layer 1 to the insulating film 3, the contact layer 8, the first semiconductor portion 4a, or the second semiconductor portion 4b will be described.
  • a material whose characteristics are changed by irradiation with electromagnetic waves and which gives a change in potential to the two-dimensional material layer 1 may be applied to at least one or more of the above-mentioned members.
  • the contact layer 8 does not necessarily have to be in direct contact with the two-dimensional material layer 1. There is no.
  • the contact layer 8 may be provided on the upper surface or the lower surface of the two-dimensional material layer 1 via an insulating film or the like.
  • each of the above-described embodiments can be appropriately modified or omitted. Further, the above-described embodiment can be variously modified at the implementation stage without departing from the gist thereof. In addition, the above-described embodiment includes various stages of disclosure, and various disclosures can be extracted by an appropriate combination of a plurality of disclosed constituent requirements.

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