WO2023112770A1 - 電磁波検出器及び電磁波検出器アレイ - Google Patents

電磁波検出器及び電磁波検出器アレイ Download PDF

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Publication number
WO2023112770A1
WO2023112770A1 PCT/JP2022/044887 JP2022044887W WO2023112770A1 WO 2023112770 A1 WO2023112770 A1 WO 2023112770A1 JP 2022044887 W JP2022044887 W JP 2022044887W WO 2023112770 A1 WO2023112770 A1 WO 2023112770A1
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electromagnetic wave
layer
dimensional material
material layer
wave detector
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English (en)
French (fr)
Japanese (ja)
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昌一郎 福島
政彰 嶋谷
新平 小川
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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Priority to JP2023524448A priority Critical patent/JP7321403B1/ja
Priority to CN202280081335.3A priority patent/CN118369775A/zh
Publication of WO2023112770A1 publication Critical patent/WO2023112770A1/ja
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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
    • H10F30/00—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors
    • H10F30/20—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors
    • H10F30/21—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors the devices being sensitive to infrared, visible or ultraviolet radiation
    • H10F30/22—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors the devices being sensitive to infrared, visible or ultraviolet radiation the devices having only one potential barrier, e.g. photodiodes
    • H10F30/227—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors the devices being sensitive to infrared, visible or ultraviolet radiation the devices having only one potential barrier, e.g. photodiodes the potential barrier being a Schottky barrier

Definitions

  • the present disclosure relates to electromagnetic wave detectors and electromagnetic wave detector arrays.
  • an electromagnetic wave detector equipped with a two-dimensional material layer such as graphene as an electromagnetic wave detection layer is known.
  • Two-dimensional material layers have very high mobilities, but relatively low double-digit efficiencies. 2. Description of the Related Art In recent years, efforts have been made to improve the sensitivity of electromagnetic wave detectors having two-dimensional material layers.
  • Patent Document 1 proposes an electromagnetic wave detector comprising a ferroelectric layer disposed below or above a graphene layer connected between source and drain electrodes. ing.
  • the ferroelectric layer generates a pyroelectric effect when an incident electromagnetic wave, especially an electromagnetic wave in the infrared wavelength region is incident.
  • This pyroelectric effect causes a change in dielectric polarization in the ferroelectric layer, which in turn modulates the gate voltage of the graphene layer. Due to the thickness of the atomic layer and the high charge mobility of the graphene layer, a small change in the gate voltage can produce a huge change in the current response. Such an effect is called an optical gate effect. High sensitivity can be realized by this optical gate effect.
  • a main object of the present disclosure is to provide an electromagnetic wave detector using a two-dimensional material layer that has high detection sensitivity and response speed, and is capable of OFF operation.
  • An electromagnetic wave detector includes a first portion, a second portion spaced apart from the first portion in the first direction, and between the first portion and the second portion in the first direction. a two-dimensional material layer having a third portion that is bridged; a first electrode portion electrically connected to the first portion; and the first, third, and second portions of the two-dimensional material layer. and a ferroelectric layer at least partially disposed on the third portion.
  • an electromagnetic wave detector using a two-dimensional material layer that has high detection sensitivity and response speed and is capable of OFF operation.
  • FIG. 1 is a schematic plan view of an electromagnetic wave detector according to Embodiment 1.
  • FIG. FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. 1;
  • 4 is a flow chart for explaining a manufacturing method of the electromagnetic wave detector according to Embodiment 1;
  • 4A and 4B are diagrams for specifically explaining the principle of operation associated with the pyroelectric effect of the ferroelectric layer in the electromagnetic wave detector according to Embodiment 1;
  • FIG. 4A and 4B are diagrams for specifically explaining the principle of operation associated with the pyroelectric effect and the inverse piezoelectric effect of a ferroelectric layer in the electromagnetic wave detector according to Embodiment 1;
  • FIG. 4 is a schematic plan view showing a first modification of the electromagnetic wave detector according to Embodiment 1;
  • FIG. 7 is a schematic cross-sectional view taken along line VII-VII in FIG. 6;
  • FIG. 8 is a schematic plan view of an electromagnetic wave detector according to Embodiment 2;
  • FIG. 9 is a schematic cross-sectional view along line segment IX-IX in FIG. 8;
  • FIG. 10 is a diagram for explaining changes in wavelength of absorbed electromagnetic waves in a two-dimensional material layer when a voltage is applied at a resonance frequency in the electromagnetic wave detector according to Embodiment 2;
  • FIG. 11 is a schematic cross-sectional view of an electromagnetic wave detector according to Embodiment 3;
  • FIG. 12 is a schematic cross-sectional view along the line segment XII-XII in FIG. 11;
  • FIG. 11 is a schematic cross-sectional view of an electromagnetic wave detector according to Embodiment 4;
  • FIG. 11 is a schematic cross-sectional view of an electromagnetic wave detector according to Embodiment 5;
  • FIG. 11 is a schematic cross-sectional view of an electromagnetic wave detector according to Embodiment 6;
  • FIG. 12 is a schematic plan view of an electromagnetic wave detector according to Embodiment 7;
  • FIG. 20 is a schematic plan view showing a first modified example of the electromagnetic wave detector according to Embodiment 7;
  • FIG. 12 is a schematic plan view of an electromagnetic wave detector according to Embodiment 8;
  • FIG. 19 is a schematic cross-sectional view along the line segment XIX-XIX in FIG. 18;
  • FIG. 20 is a top view of an electromagnetic wave detector array according to Embodiment 9;
  • FIG. 21 is a schematic diagram showing an example of a readout circuit for reading out electric signals obtained from the electromagnetic wave detector array according to the ninth embodiment;
  • FIG. 22 is a top view showing a first modified example of the electromagnetic wave detector array according to Embodiment 9;
  • the configuration of the electromagnetic wave detector when detecting visible light or infrared light will be described. Not limited.
  • a detector that detects radio waves such as X-rays, ultraviolet light, near-infrared light, terahertz (THz) waves, and microwaves is also valid.
  • radio waves such as X-rays, ultraviolet light, near-infrared light, terahertz (THz) waves, and microwaves is also valid.
  • these light and radio waves are collectively referred to as electromagnetic waves.
  • p-type graphene and n-type graphene may be used as graphene.
  • graphene with more holes than the intrinsic graphene is referred to as p-type graphene
  • graphene with more electrons than the intrinsic graphene is referred to as n-type graphene. That is, an n-type material is an electron-donating material.
  • a p-type material is a material having an electron-withdrawing property.
  • n-type when there is a bias in charge in the entire molecule, electrons are sometimes called n-type.
  • a molecule in which holes are dominant when the charge is unevenly distributed over the entire molecule is sometimes called a p-type.
  • Either one of an organic substance and an inorganic substance or a mixture of an organic substance and an inorganic substance may be used as the material of the member that contacts graphene, which is an example of the two-dimensional material layer.
  • a plasmon resonance phenomenon such as surface plasmon resonance, which is an interaction between a metal surface and light, and a phenomenon called quasi-surface plasmon resonance in the sense of resonance on a metal surface outside the visible light range and near-infrared light range.
  • a plasmon resonance phenomenon such as surface plasmon resonance, which is an interaction between a metal surface and light
  • quasi-surface plasmon resonance in the sense of resonance on a metal surface outside the visible light range and near-infrared light range.
  • metamaterials or metasurfaces or metasurfaces or plasmonic metamaterials in the sense of manipulating wavelengths by means of structures of subwavelength dimensions, without specifically distinguishing between them by name, and the effects of the phenomena are treated equally in terms of
  • These resonances are referred to herein as surface plasmon resonances, plasmon resonances, or simply resonances.
  • graphene is used as an example of the material of the two-dimensional material layer, but the material of the two-dimensional material layer is not limited to graphene.
  • materials for the two-dimensional material layer include transition metal dichalcogenide (TMD), black phosphorous, silicene (two-dimensional honeycomb structure with silicon atoms), and germanene (two-dimensional honeycomb structure with germanium atoms).
  • TMD transition metal dichalcogenide
  • Transition metal dichalcogenides include, for example, molybdenum disulfide (MoS 2 ), tungsten disulfide (WS 2 ), and tungsten diselenide (WSe 2 ).
  • the two-dimensional material layer consists of graphene, transition metal dichalcogenide (TMD), black phosphorus, silicene (two-dimensional honeycomb structure with silicon atoms), graphene nanoribbons and borophene. Any material selected from the group may be included, or a plurality of these materials may be laminated.
  • These materials have structures similar to graphene.
  • atoms are arranged in a monolayer in a two-dimensional plane. Therefore, even when these materials are applied to the two-dimensional material layer, the same effects can be obtained as when graphene is applied to the two-dimensional material layer.
  • the two-dimensional material layer may be configured as multilayer graphene in which two or more single-layer graphene layers are laminated.
  • non-doped graphene or graphene doped with p-type or n-type impurities may be used as the two-dimensional material layer.
  • the photoelectric conversion efficiency of the two-dimensional material layer increases, and the sensitivity of the electromagnetic wave detector increases.
  • the lattice vectors of the hexagonal lattices of arbitrary two layers of graphene may or may not match.
  • a bandgap is formed in the two-dimensional material layer.
  • the two-dimensional material layer is less susceptible to carrier scattering from the underlying structure such as the substrate, resulting in a lower noise level. Therefore, an electromagnetic wave detector using multi-layer graphene as a two-dimensional material layer has increased electromagnetic wave absorption, and can improve the detection sensitivity of electromagnetic waves.
  • the two-dimensional material layer when the two-dimensional material layer is in contact with the electrode, carriers are doped from the electrode to the two-dimensional material layer.
  • carriers are doped from the electrode to the two-dimensional material layer.
  • Au gold
  • holes are doped into the two-dimensional material layer near the electrode due to the difference in work function between the two-dimensional material layer and Au.
  • the electromagnetic wave detector is driven in the electron conduction state in this state, the mobility of electrons flowing in the channel region of the two-dimensional material layer decreases due to the influence of holes doped from the electrode to the two-dimensional material layer.
  • the contact resistance between the dimensional material layer and the electrode increases. This increase in contact resistance may reduce the mobility of electrons (carriers) due to the electric field effect in the electromagnetic wave detector, resulting in deterioration of the performance of the electromagnetic wave detector.
  • the doping amount of carriers injected from the electrode is large. Therefore, the decrease in electron mobility in the electromagnetic wave detector is particularly remarkable when single-layer graphene is used as the two-dimensional material layer. Therefore, when all the two-dimensional material layers are formed of monolayer graphene, the performance of the electromagnetic wave detector may be degraded.
  • the contact area with the electrode may be composed of multilayer graphene.
  • Multilayer graphene has less carrier doping from the electrode than single-layer graphene. Therefore, an increase in contact resistance between the two-dimensional material layer and the electrode can be suppressed. As a result, it is possible to suppress the above-described decrease in electron mobility in the electromagnetic wave detector and improve the performance of the electromagnetic wave detector.
  • nanoribbon graphene (hereinafter also referred to as graphene nanoribbon) can also be used as the two-dimensional material layer.
  • the two-dimensional material layer for example, either a single graphene nanoribbon, a composite in which a plurality of graphene nanoribbons are laminated, or a structure in which graphene nanoribbons are periodically arranged on a plane is used.
  • plasmon resonance can be generated in the graphene nanoribbons.
  • the sensitivity of the electromagnetic wave detector can be improved.
  • a structure in which graphene nanoribbons are periodically arranged is sometimes called a graphene metamaterial. Therefore, the electromagnetic wave detector using the graphene metamaterial as the two-dimensional material layer can also obtain the above-described effects.
  • turbostratic lamination which is not AB lamination seen in graphite in the natural state
  • Turbostratic lamination is also called random lamination, turbostratic graphene.
  • the method for producing the turbostratic structure portion may be determined as appropriate.
  • the turbostratic structure portion 1T may be formed by transferring single-layer graphene produced by a CVD method a plurality of times and laminating multilayer graphene.
  • ethanol, methane, or the like may be placed on graphene as a carbon source, and graphene may be grown by a CVD method to form a turbostratic structure portion.
  • an insulating layer is a layer of an insulating film having a thickness that does not cause a tunnel current.
  • the material of the insulating layer is, for example, silicon oxide (SiO 2 ).
  • the material of the insulating layer is not limited to silicon oxide, and includes, for example, tetraethyl orthosilicate (Si( OC2H5 ) 4 ), silicon nitride ( Si3N4 ), hafnium oxide ( HfO2 ), aluminum oxide ( Al2O ) . 3 ), nickel oxide (NiO), boron nitride (BN), and siloxane-based polymer materials.
  • the atomic arrangement of boron nitride (BN) is similar to that of graphene.
  • boron nitride (BN) when boron nitride (BN) is in contact with a two-dimensional material layer made of graphene, a decrease in electron mobility of the two-dimensional material layer is suppressed. Therefore, boron nitride (BN) is suitable for an insulating layer as a base film arranged under a two-dimensional material layer.
  • the material of the ferroelectric layer may be appropriately selected as long as the material causes polarization when an electromagnetic wave having a detection wavelength is incident on the ferroelectric layer.
  • Materials for the ferroelectric layer 5 include, for example, barium titanate (BaTiO 3 ), lithium niobate (LiNbO 3 ), lithium tantalate (LiTaO 3 ), strontium titanate (SrTiO 3 ), lead zirconate titanate (PZT ), strontium bismuthate tantalate (SBT), bismuth ferrite (BFO), zinc oxide (ZnO), hafnium oxide (HfO 2 ) and polyvinylidene fluoride ferroelectrics (PVDF, P(VDF-TrFE) which are organic polymers , P(VDF-TrFE-CTFE), etc.).
  • the ferroelectric layer 5 may be configured by stacking or mixing different ferroelectric materials.
  • the material of the ferroelectric layer is not limited to the above materials as long as it is a pyroelectric substance that produces a pyroelectric effect.
  • the material of the ferroelectric layer may be any ferroelectric that causes a change in polarization in response to a change in thermal energy inside the ferroelectric layer.
  • the electromagnetic wave simply acts as a heat source. Therefore, the pyroelectric effect basically has no wavelength dependence. Therefore, the ferroelectric layer 5 basically has no wavelength dependence. Therefore, the ferroelectric layer is sensitive to broadband electromagnetic waves.
  • Materials constituting the semiconductor layer include, for example, silicon (Si), germanium (Ge), compound semiconductors such as III-V group semiconductors or II-V group semiconductors, cadmium mercury telluride (HgCdTe), iridium antimonide (InSb) , lead selenium (PbSe), lead sulfur (PbS), cadmium sulfur (CdS), gallium nitride (GaN), silicon carbide (SiC), gallium phosphide (GaP), indium gallium arsenide (InGaAs), indium arsenide ( InAs).
  • the semiconductor layer may be a substrate containing quantum wells or quantum dots.
  • the material of the semiconductor layer may be a Type II superlattice.
  • a type II superlattice may have a film configuration called a barrier type.
  • the semiconductor layer may have a multilayer structure, and a pn junction photodiode, pin photodiode, Schottky photodiode, or avalanche photodiode may be used. Alternatively, a phototransistor may be used as the semiconductor layer.
  • the material of the semiconductor layer may be one of the above materials, or may be a combination of the above materials. If the materials constituting the semiconductor layer are a combination of the above-described semiconductor materials, the electromagnetic wave detector provided with the semiconductor layer can detect multiple wavelengths.
  • the semiconductor layer is preferably doped with an impurity so that the semiconductor layer has an electric resistivity of 100 ⁇ cm or less. By doping the semiconductor layer at a high concentration, the moving speed (reading speed) of carriers in the semiconductor layer increases. As a result, the response speed of the electromagnetic wave detector is improved.
  • FIG. 1 is a schematic plan view of an electromagnetic wave detector according to Embodiment 1.
  • FIG. FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. Also shown in FIG. 2 are typical electrical connections for the electromagnetic wave detector 100 .
  • the electromagnetic wave detector shown in FIGS. 1 and 2 includes a two-dimensional material layer 1, a first electrode portion 2a, a second electrode portion 2b, an insulating layer 3, a semiconductor layer 4, and a ferroelectric layer 5. Mainly provide
  • the semiconductor layer 4 has a first surface 41 and a second surface 42 opposite to the first surface 41 .
  • Each of the first surface 41 and the second surface 42 extends along the first direction X and the second direction Y orthogonal to the first direction X. As shown in FIG.
  • the first surface 41 includes a first region 41a, a second region 41b spaced apart from the first region 41a in the first direction X, and a first region 41a and a second region 41b in the first direction X. and a third region 41c arranged between.
  • Each of the first region 41a and the second region 41b is, for example, a plane.
  • the second region 41b is provided so as to be flush with the first region 41a, for example.
  • the semiconductor layer 4 has a recess 43 recessed from each of the first region 41a and the second region 41b.
  • the recess 43 extends along the second direction Y, for example.
  • the third region 41c is the bottom surface of the recess 43, for example.
  • the third region 41c may be provided so as to form the same plane as each of the first region 41a and the second region 41b.
  • the insulating layer 3 is arranged on the first region 41 a of the first surface 41 .
  • the insulating layer 3 is not arranged on the second region 41b and the third region 41c of the first surface 41, and exposes the second region 41b and the third region 41c.
  • the first electrode portion 2a is arranged on part of the upper surface of the insulating layer 3.
  • the first electrode portion 2 a is electrically connected to the first portion 1 a of the two-dimensional material layer 1 .
  • the second electrode portion 2b is arranged on the second surface 42 of the semiconductor layer 4 .
  • the second electrode portion 2 b is electrically connected to the semiconductor layer 4 .
  • the second electrode portion 2 b is electrically connected to the first electrode portion 2 a via the two-dimensional material layer 1 and the semiconductor layer 4 .
  • the two-dimensional material layer 1 is provided on the first electrode portion 2a, the insulating layer 3, and the semiconductor layer 4.
  • the two-dimensional material layer 1 is electrically connected to the first electrode portion 2a.
  • the two-dimensional material layer 1 extends from the upper surface of the first electrode portion 2 a to the upper surface of the insulating layer 3 .
  • the two-dimensional material layer 1 is electrically connected to the semiconductor layer 4 .
  • the two-dimensional material layer 1 mainly includes a first portion 1a, a second portion 1b, a third portion 1c, and a fourth portion 1d.
  • the first portion 1a, the fourth portion 1d, the third portion 1c, and the second portion 1b are continuous in the first direction X in this order.
  • the two-dimensional material layer 1 has a longitudinal direction along the first direction X and a lateral direction along the second direction Y in plan view.
  • the first portion 1 a and the fourth portion 1 d are arranged on the first region 41 a of the first surface 41 of the semiconductor layer 4 .
  • the first portion 1 a is electrically connected to the first electrode portion 2 a on the insulating layer 3 .
  • the first portion 1a is in contact with, for example, the upper surface of the first electrode portion 2a. Note that the first portion 1a may be in contact with the lower surface of the first electrode portion 2a.
  • the fourth portion 1d connects between the first portion 1a and the third portion 1c.
  • the fourth portion 1 d is in contact with the upper surface of the insulating layer 3 .
  • the second portion 1b is spaced apart from the first portion 1a in the first direction X.
  • the second portion 1 b is in contact with the second region 41 b of the first surface 41 of the semiconductor layer 4 .
  • Second portion 1 b is electrically connected to semiconductor layer 4 .
  • second portion 1b is in Schottky junction with semiconductor layer 4 .
  • the third portion 1c is bridged between the first region 41a and the second region 41b of the semiconductor layer 4 in the first direction X.
  • the third portion 1c is arranged on the third region 41c of the first surface 41 of the semiconductor layer 4 . Unlike the first portion 1a and the second portion 1b, the third portion 1c does not contact the first electrode portion 2a, the insulating layer 3, and the semiconductor layer 4 respectively.
  • the third portion 1c is provided, for example, so as to deform when the temperature of the third portion 1c changes.
  • the thicknesses of the first portion 1a, the second portion 1b, the third portion 1c, and the fourth portion 1d of the two-dimensional material layer 1 may be equal to each other.
  • the upper surface of the two-dimensional material layer 1 may be provided with unevenness resulting from the first portion 1a, the second portion 1b, the third portion 1c, and the fourth portion 1d.
  • the ferroelectric layer 5 is arranged on the third portion 1 c of the two-dimensional material layer 1 .
  • the lower surface of ferroelectric layer 5 is in contact with the upper surface of third portion 1c.
  • the ferroelectric layer 5 is electrically connected with the third portion 1 c of the two-dimensional material layer 1 .
  • the upper surface of the ferroelectric layer 5 may be in contact with the lower surface of the third portion 1c.
  • the ferroelectric layer 5 is not in contact with each of the first electrode portion 2a, the insulating layer 3, and the semiconductor layer 4. As shown in FIG. Note that the ferroelectric layer 5 may be in contact with the insulating layer 3 .
  • the ferroelectric layer 5 is sensitive to the wavelength of the electromagnetic wave to be detected by the electromagnetic wave detector 100 (hereinafter also referred to as detection wavelength).
  • detection wavelength the wavelength of the electromagnetic wave to be detected by the electromagnetic wave detector 100
  • the ferroelectric layer 5 is provided so as to deform together with the third portion 1c of the two-dimensional material layer 1 by the inverse piezoelectric effect when the dielectric polarization in the ferroelectric layer 5 changes.
  • the ferroelectric layer 5 deforms the third portion 1c of the two-dimensional material layer 1 to increase the resistance value of the third portion 1c. designed to change.
  • the ferroelectric layer 5 is configured such that the rate of change of dielectric polarization within the ferroelectric layer 5 is as fast as possible.
  • the thickness (film thickness) of the ferroelectric layer 5 is as thin as possible within a range in which a voltage can be applied between the two-dimensional material layer 1 and the semiconductor layer 4 .
  • FIG. 3 is a flowchart for explaining the manufacturing method of the electromagnetic wave detector according to Embodiment 1.
  • FIG. 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 performed.
  • a semiconductor layer 4 which is a flat substrate made of silicon or the like, is prepared.
  • the electrode forming step (S2) is performed.
  • the second electrode portion 2 b is formed on the back surface of the semiconductor layer 4 .
  • a protective film is formed on the surface of the semiconductor layer 4 .
  • a resist is used as the protective film.
  • the second electrode portion 2b is formed on the back surface of the semiconductor layer 4.
  • Metals such as gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), and chromium (Cr) are used as materials for the second electrode portion 2b.
  • an adhesion layer may be formed on the back surface of the semiconductor layer 4 before the second electrode portion 2b is formed.
  • Copper (Cr) or titanium (Ti), for example, is used as the material of the adhesion layer.
  • the step (S2) may be performed after the steps (S3 to S7) as long as the surface of the semiconductor layer 4 is protected.
  • an insulating layer forming step (S3) is performed.
  • the insulating layer 3 is formed on the surface of the semiconductor layer 4 .
  • the insulating layer 3 may be silicon oxide (SiO 2 ) formed by partially thermally oxidizing the surface of the semiconductor layer 4 .
  • an insulating layer may be formed on the surface of the semiconductor layer 4 by CVD (Chemical Vapor Deposition) or sputtering.
  • the electrode forming step (S4) is performed.
  • the first electrode portion 2 a is formed on the insulating layer 3 .
  • Metals such as gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), and the like are used as materials for forming the first electrode portion 2a.
  • an adhesion layer may be formed between the insulating layer 3 and the first electrode portion 2a in order to improve the adhesion between the first electrode portion 2a and the insulating layer 3.
  • the following process is used.
  • a resist mask is formed on the surface of the insulating layer 3 using photolithography, EB drawing, or the like.
  • the resist mask has openings in regions where the first electrode portions 2a are to be formed.
  • a film of metal or the like to be the first electrode portion 2a is formed on the resist mask.
  • a vapor deposition method, a sputtering method, or the like is used to form the film.
  • the film is formed so as to extend from inside 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 layer 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 layer 3 .
  • a resist mask is formed over the film by photolithography.
  • the resist mask is formed so as to cover the region where the first electrode portion 2a is to be formed, but is not formed in regions other than the region where the first electrode portion 2a is to be formed.
  • the film is partially removed by wet etching or dry etching using the resist mask as a mask. As a result, 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.
  • the first electrode portion 2a may be formed.
  • the opening forming step (S5) is performed.
  • this step ( S ⁇ b>5 ) openings are formed in the insulating layer 3 and the semiconductor layer 4 .
  • a resist mask is formed on the insulating layer 3 using photolithography, EB drawing, or the like.
  • the resist mask has openings formed in regions where the openings of the insulating layer 3 are to be formed.
  • the insulating layer 3 is partially removed by wet etching or dry etching using the resist mask as a mask to form an opening.
  • the resist mask is removed.
  • a resist mask is formed on the insulating layer 3 and the semiconductor layer 4 using photolithography, EB drawing, or the like.
  • the resist mask has openings formed in regions where the openings of the semiconductor layer 4 are to be formed. Thereafter, by wet etching or dry etching, the resist mask is used as a mask to partially remove the semiconductor layer 4 to form an opening. Next, the resist mask is removed. Note that the step (S5) may be performed prior to the step (S4).
  • the two-dimensional material layer forming step (S6) is performed.
  • the two-dimensional material layer 1 is formed so as to entirely cover the first electrode portion 2 a , the insulating layer 3 , and the part of the semiconductor layer 4 exposed in the opening of the insulating layer 3 .
  • the material forming the two-dimensional material layer for example, an atomic layer material or a molecular layer material such as graphene may be used.
  • the two-dimensional material layer 1 may be formed by any method.
  • the two-dimensional material layer 1 may be formed by epitaxial growth, or the two-dimensional material layer 1 formed in advance using the CVD method is transferred onto a portion of the first electrode portion 2a, the insulating layer 3 and the semiconductor layer 4.
  • the two-dimensional material layer 1 may be formed using screen printing or the like.
  • the two-dimensional material layer 1 peeled off by mechanical peeling or the like may be transferred onto the above-described first electrode portion 2a and the like.
  • a resist mask is formed on the two-dimensional material layer 1 using photolithography or the like.
  • the resist mask is formed to cover regions where the two-dimensional material layer 1 is to remain, but is not formed in regions where the two-dimensional material layer 1 is not to remain.
  • the two-dimensional material layer 1 is partially removed by etching with oxygen plasma. This removes unnecessary portions of the two-dimensional material layer to form the two-dimensional material layer 1 as shown in FIGS.
  • the resist mask is removed.
  • the area of the fourth portion 1d of the two-dimensional material layer 1 provided as a region in contact with the insulating layer 3 is equal to or larger than the area of the third portion 1c provided as a bridging region.
  • Thermal contraction and expansion occur in the electromagnetic wave detector as the temperature changes during the electromagnetic wave irradiation and voltage application operations.
  • the insulating layer 3 is less deformed due to temperature change and has low thermal conductivity. It is difficult to cause heat conduction, and as a result, it strongly adheres to the two-dimensional material layer 1 .
  • the third portion 1c of the two-dimensional material layer 1 provided in the electromagnetic wave detector according to the present embodiment has a crosslinked structure, and is more likely to be peeled off or broken than other portions supported by the base.
  • the fourth portion 1d as an adhesion layer with the insulating layer 3, it is possible to prevent the two-dimensional material layer 1 from being peeled off or broken, thereby improving the structural strength.
  • a ferroelectric layer forming step (S7) is performed.
  • a ferroelectric layer 5 is formed on the two-dimensional material layer 1 .
  • materials for forming the ferroelectric layer 5 include BaTiO 3 (barium titanate), LiNbO 3 (lithium niobate), LiTaO 3 (lithium tantalate), SrTiO 3 (strontium titanate), PZT (zirconate titanate).
  • the ferroelectric layer 5 may be formed by any method.
  • a polymer film is formed by spin coating or the like, and then processed by photolithography.
  • a film is formed by sputtering, vapor deposition, MOD (Metal Organic Composition) coating, or the like, and then patterned by photolithography.
  • the ferroelectric layer 5 may be formed using an atomic layer deposition method.
  • the number of molecular layers of the ferroelectric layer formed using the atomic layer deposition method is preferably within 1000 layers.
  • the capacitance is improved, the pyroelectric effect is improved, and the detection sensitivity of the electromagnetic wave detector is improved.
  • the ferroelectric layer 5 is formed along with the adsorption of the precursor material to the two-dimensional material layer 1. , the molecular structure of the two-dimensional material layer 1 is not destroyed or distorted. Therefore, it is possible to improve the performance of the electromagnetic wave detector without causing a decrease in detection sensitivity and an increase in noise resulting from a decrease in the electrical properties of the two-dimensional material layer 1 .
  • the step (S7) may be performed prior to the step (S6), and the ferroelectric layer 5 and the two-dimensional material layer 1 may be formed simultaneously in the step (S6).
  • the electromagnetic wave detector shown in FIGS. 1 and 2 is obtained.
  • the two-dimensional material layer 1 is formed on the first electrode portion 2a. You may form the 1st electrode part 2a so that it may overlap.
  • the first electrode portion 2a is formed in a state in which the two-dimensional material layer 1 is previously covered with a protective film or the like other than the region where the first electrode portion 2a is formed. Conceivable.
  • the ferroelectric layer 5 is formed on the two-dimensional material layer 1, but the two-dimensional material layer 1 is formed on the ferroelectric layer 5 previously formed on the insulating layer 3. Also good.
  • the two-dimensional material layer 1 is formed, it is fired to remove residues such as moisture between the ferroelectric layer 5 and the two-dimensional material layer 1, thereby enhancing adhesion. Conceivable.
  • the baking atmosphere, temperature, and other conditions are set so that the moisture and resist are removed while process damage is not given to the first electrode portion 2a, the second electrode portion 2b, the insulating layer 3, and the semiconductor layer 4. It is desirable to For example, firing is performed at 150° C. in an air atmosphere.
  • the area of the fourth portion 1d of the two-dimensional material layer 1 is equal to or larger than the area of the third portion 1c in plan view. A countermeasure such as suppressing peeling of the layer 1 can be considered.
  • the electromagnetic wave detector 100 uses the fourth portion 1d and the third portion 1c of the two-dimensional material layer 1 as a transistor channel, the ferroelectric layer 5 as a gate, and the first electrode portion 2a and the first portion 1a of the two-dimensional material layer 1 as It functions as a field effect transistor using the source, the second electrode portion 2b, and the second portion 1b of the two-dimensional material layer 1 as the drain.
  • a power supply circuit for applying a voltage V is electrically connected between the first electrode portion 2a and the second electrode portion 2b.
  • the layer 4 and the second electrode portion 2b are electrically connected in this order.
  • a voltage V is applied between the first electrode portion 2a and the second electrode portion 2b.
  • the voltage V is set to reverse bias the Schottky junction between the two-dimensional material layer 1 and the semiconductor layer 4 .
  • a current I flows through the two-dimensional material layer 1, which is part of the current path between the first electrode portion 2a and the second electrode portion 2b.
  • An ammeter (not shown) is installed in the power supply circuit, and the current I flowing through the two-dimensional material layer 1 is monitored by the ammeter.
  • FIG. 4 is a schematic diagram for explaining the change in electrical properties of the two-dimensional material layer 1 caused by the pyroelectric effect of the ferroelectric layer 5.
  • 3 is a schematic diagram for explaining changes in gate voltage and source/drain current values in the third portion 1c.
  • FIG. FIG. 5 is a schematic diagram for explaining changes in electrical properties that occur in the two-dimensional material layer 1 due to the pyroelectric effect and the inverse piezoelectric effect of the ferroelectric layer 5.
  • FIG. FIG. 5 shows changes in the source/drain current value and gate voltage dependence accompanying resistance changes in the third portion 1c of the two-dimensional material layer 1 with and without electromagnetic wave irradiation.
  • a polarization change that occurs in the ferroelectric layer 5 due to the pyroelectric effect gives an electric field change to the third portion 1 c of the two-dimensional material layer 1 .
  • the gate voltage Vph is applied to the third portion 1c of the two-dimensional material layer 1, and the source/drain current value in the third portion 1c of the two-dimensional material layer 1 changes.
  • the electromagnetic wave irradiated to the electromagnetic wave detector 100 can be detected.
  • a change in the electrical properties of the material in contact with the two-dimensional material layer 1 gives the two-dimensional material layer 1 an electric field effect, and the effect of changing the electrical properties of the two-dimensional material layer 1 is referred to as an optical gate effect. do.
  • photocarriers generated in the depletion layer formed between the semiconductor layer 4 and the insulating layer 3 due to the irradiation of the electromagnetic wave produce a photogate effect.
  • the semiconductor layer 4 when the semiconductor layer 4 is irradiated with electromagnetic waves to which the semiconductor layer 4 is sensitive, the source-drain current value in the fourth portion 1d of the two-dimensional material layer 1 changes. By detecting this current change amount Iph2, the electromagnetic wave irradiated to the electromagnetic wave detector can be detected.
  • the current change amount Iph1 and the current change amount Iph2 are shown to be equal to each other, but the respective current change amounts may differ from each other.
  • the optical gate effect associated with the pyroelectric effect occurring in the ferroelectric layer 5 occurs regardless of the direction of dielectric polarization in the ferroelectric layer 5 .
  • the extent of the optical gate effect two-dimensional The amount of change in the electrical properties of the material layer 1 changes within the two-dimensional plane of the third portion 1 c of the two-dimensional material layer 1 .
  • the voltage change in the two-dimensional surface of the third portion 1c of the two-dimensional material layer 1 caused by the photogate effect associated with the pyroelectric effect of the ferroelectric layer 5 contributes to the change of the source-drain voltage, and the current value changes. .
  • this current change amount Iph3 the electromagnetic wave irradiated to the electromagnetic wave detector can be detected.
  • the ferroelectric layer 5 when the ferroelectric layer 5 is irradiated with an electromagnetic wave and a change in dielectric polarization occurs inside the ferroelectric layer 5, the inverse piezoelectric effect occurs in the ferroelectric layer 5.
  • power is added by
  • the ferroelectric layer 5 is deformed by the inverse piezoelectric effect
  • the two-dimensional material layer 1 connected with the ferroelectric layer 5 is also deformed.
  • the amount of deformation of the two-dimensional material layer 1 is equivalent to the amount of deformation of the ferroelectric layer 5 .
  • the electrical resistance value of the two-dimensional material layer 1 changes, and the source-drain current value in the third portion 1c of the two-dimensional material layer 1 changes.
  • a pseudo source-drain voltage is applied to the two-dimensional material layer 1 due to the inverse piezoelectric effect generated in the ferroelectric layer 5, and the current value changes.
  • the electromagnetic wave irradiated to the electromagnetic wave detector 100 can be detected.
  • FIG. 5 as a schematic diagram, the current change amount Iph3 and the current change amount Iph4 are shown to be equal to each other, but the respective current change amounts may differ from each other.
  • the semiconductor layer 4 constituting the semiconductor layer 4 is made of p-type material silicon and the two-dimensional material layer 1 is made of n-type material graphene
  • the fourth portion 1d of the two-dimensional material layer 1 and the semiconductor layer 4 are Schottky junction.
  • the current I can be made zero by adjusting the voltage V and applying a reverse bias to the Schottky junction.
  • an electromagnetic wave is applied to the ferroelectric layer 5
  • the dielectric polarization of the ferroelectric layer 5 changes due to the pyroelectric effect, and the Fermi level of the two-dimensional material layer 1 is modulated.
  • the energy barrier of the semiconductor layer 4 is lowered.
  • a current flows through the semiconductor layer 4 and a current I is detected only when electromagnetic waves are applied. That is, the electromagnetic wave detector according to this embodiment can be turned off.
  • the electromagnetic wave detector 100 is not limited to the configuration for detecting changes in current in the two-dimensional material layer 1 as described above.
  • a constant current is passed between the two electrode portions 2b, and a change in the voltage V between the first electrode portion 2a and the second electrode portion 2b (that is, a change in voltage value in the two-dimensional material layer 1) is detected.
  • a change in the voltage V between the first electrode portion 2a and the second electrode portion 2b that is, a change in voltage value in the two-dimensional material layer 1 is detected.
  • the electromagnetic wave detector 100 may be provided so as to detect the frequency change in the value of the current flowing through the third portion 1c between when the electromagnetic wave is not applied and when the electromagnetic wave is applied.
  • the electrical resonance frequency of the third portion 1c of the two-dimensional material layer 1 depends on the light intensity of the irradiated electromagnetic wave, and the inverse piezoelectric effect of the ferroelectric layer 5 and the amount of deformation of the two-dimensional material layer 1 due to temperature changes. depends on Therefore, in a state in which a DC voltage is applied between the first electrode portion 2a and the second electrode portion 2b, the electromagnetic wave can be detected by converting the amount of change in the resonance frequency at the third portion 1c into the amount of light of the electromagnetic wave.
  • two or more electromagnetic wave detectors 100 may be used to detect electromagnetic waves. For example, two or more of the same electromagnetic wave detectors 100 are prepared. One electromagnetic wave detector 100 is arranged in a shielded space where electromagnetic waves are not irradiated. Another electromagnetic wave detector 100 is arranged in a space irradiated with the electromagnetic wave to be measured. Then, the difference between the current I or voltage V of another electromagnetic wave detector 100 irradiated with electromagnetic waves and the current I or voltage V of the electromagnetic wave detector 100 arranged in the shielded space is detected. Electromagnetic waves may be detected in this manner.
  • a reverse bias is applied to the Schottky junction of single-layer graphene and p-type silicon.
  • a voltage is applied, a depletion layer is formed near the junction interface between single-layer graphene and p-type silicon.
  • the detection wavelength range of the electromagnetic wave detector is determined according to the absorption wavelengths of lithium niobate and p-type silicon.
  • lithium niobate When an electromagnetic wave with a detection wavelength is incident on lithium niobate, a change in dielectric polarization occurs in lithium niobate due to the pyroelectric effect. Polarization changes in lithium niobate cause electric field changes in the two-dimensional material layer 1 . This is the optical gate effect described above. As described above, graphene constituting the two-dimensional material layer 1 has high mobility, and a large displacement current can be obtained with a slight change in electric field. Therefore, the pyroelectric effect of lithium niobate greatly changes the Fermi level of the two-dimensional material layer 1, lowering the energy barrier with p-type silicon.
  • the photo-injected current charge extracted from the p-type silicon is due to the photogating effect caused by the pyroelectric effect of lithium niobate in the single-layer graphene and the distribution of the photogating effect occurring in the plane of the single-layer graphene. It is greatly amplified by the resulting source-drain voltage. Therefore, in the electromagnetic wave detector 100 according to the present embodiment, it is possible to achieve a high sensitivity with a quantum efficiency exceeding 100%.
  • the dielectric polarization change rate of lithium niobate is designed to be as short as possible, the time from when the electromagnetic wave enters the electromagnetic wave detector to when the resistance value changes in the single-layer graphene will be shortened. According to such an electromagnetic wave detector, the delay in amplification due to the optical gate effect is eliminated, and the response is speeded up.
  • the electromagnetic wave detector 100 includes a first portion 1a, a second portion 1b spaced from the first portion 1a in the first direction X, and a first portion 1b in the first direction X.
  • a two-dimensional material layer 1 having a third portion 1c bridging between 1a and a second portion 1b, a first electrode portion 2a electrically connected to the first portion 1a, and a two-dimensional material.
  • a second electrode portion 2b electrically connected to the first electrode portion 2a through the first portion 1a, the third portion 1c, and the second portion 1b of the layer 1, and at least a portion thereof on the third portion 1c. and a ferroelectric layer 5 disposed on the .
  • the resistance value of the two-dimensional material layer 1 can change when the dielectric polarization in the ferroelectric layer 5 changes due to the pyroelectric effect. As a result, the conductivity of the two-dimensional material layer 1 is modulated, and as a result the photocurrent can be amplified in the two-dimensional material layer 1 .
  • the amount of change in current in the two-dimensional material layer 1 due to the change in polarization in the ferroelectric layer 5 is larger than the amount of change in current in a normal semiconductor.
  • a large current change occurs with a slight potential change, compared to a normal semiconductor.
  • the thickness of the two-dimensional material layer 1 is one atomic layer, which is extremely thin.
  • the electron mobility in single-layer graphene is large.
  • the amount of current change in the two-dimensional material layer 1, which is calculated from the electron mobility and thickness of the two-dimensional material layer 1, is about several hundred to several thousand times the amount of current change in a normal semiconductor. becomes.
  • the detection current extraction efficiency in the two-dimensional material layer 1 is greatly improved.
  • Such a photogate effect does not directly enhance the quantum efficiency of photoelectric conversion materials such as ordinary semiconductors, but increases current changes due to incident electromagnetic waves. Therefore, the quantum efficiency of the electromagnetic wave detector equivalently calculated from the differential current due to incident electromagnetic waves exceeds 100%. Therefore, the electromagnetic wave detection sensitivity of the electromagnetic wave detector 100 according to the present embodiment is higher than that of conventional semiconductor electromagnetic wave detectors or graphene electromagnetic wave detectors to which the optical gate effect is not applied.
  • the heat capacity of the electromagnetic wave detecting portion is smaller than that of a conventional semiconductor electromagnetic wave detector, the time to reach thermal equilibrium is short, and the response speed is high.
  • this electromagnetic wave detector 100 in addition to the quantum operation of detecting photoelectron-hole pairs in the semiconductor layer 4 and the Schottky junction formed between the semiconductor layer 4 and the two-dimensional material layer 1, temperature change due to electromagnetic wave irradiation is detected. Detecting thermal motion is used as the response principle. It is the carrier mobility of the detector material that predominantly determines the response speed in the quantum operation. Compared to conventional bulk semiconductor materials, the two-dimensional material layer 1 has a high carrier mobility derived from its atomic layer structure, and therefore has a high response speed in quantum-type operation.
  • a third portion 1c of the two-dimensional material layer 1 provided as an electromagnetic wave detection region has a crosslinked structure, and is thermally independent and insulated from the semiconductor layer 4 and the like.
  • the two-dimensional material layer 1 has a monolayer structure and ultimately has a lower heat capacity than conventional bulk semiconductor materials. Therefore, the electromagnetic wave detection speed of the electromagnetic wave detector 100 according to the present embodiment is higher than that of the conventional electromagnetic wave detector using thermal operation.
  • the electromagnetic wave detector 100 further includes an insulating layer 3 that is arranged on the first region 41a of the semiconductor layer 4 and exposes the second region 41b and the third region 41c.
  • the second portion 1b of the two-dimensional material layer 1 is in contact with the second region 41b of the semiconductor layer 4, preferably in Schottky junction.
  • the third portion 1c of the two-dimensional material layer 1 is spaced apart from the third region 41c in the direction orthogonal to the first surface 41 .
  • the electromagnetic wave detector 100 can be turned off.
  • the dielectric polarization direction in the ferroelectric layer 5 is completely orthogonal to the two-dimensional surface of the third portion 1c of the two-dimensional material layer 1
  • the photogate effect accompanying the pyroelectric effect does not occur in the two-dimensional material layer. It changes in the two-dimensional plane of the third portion 1c of 1, and the source-drain voltage changes.
  • the electromagnetic wave detector 100 can be turned off by adjusting the voltage V so that the current does not flow when the electromagnetic wave is not irradiated and the source-drain voltage is not changed.
  • the two-dimensional material layer 1 has the fourth portion 1d arranged on the insulating layer 3, so that the two-dimensional material layer 1 is the fourth portion Compared to the case without 1d, the conductivity of the two-dimensional material layer 1 due to the optical gate effect is more likely to be modulated.
  • the amount of change in the current value I when the electromagnetic wave detector 100 according to the present embodiment is irradiated with an electromagnetic wave is the change in the resistance value of the two-dimensional material layer 1 caused by the pyroelectric effect in the ferroelectric layer 5.
  • the change in current caused by the change in the energy barrier between the two-dimensional material layer 1 and the semiconductor layer 4 , and the photocurrent caused by photoelectric conversion in the two-dimensional material layer 1 are the change in the electromagnetic wave detector according to the present embodiment.
  • the current caused by the above-described optical gate effect, the current caused by the energy barrier change, and the light generated by the photoelectric conversion efficiency inherent in the two-dimensional material layer 1 Each change in current can be detected.
  • the electromagnetic wave detector 100 can realize favorable sensitivity with a quantum efficiency of 100% or higher, high-speed operation, and OFF operation.
  • the electromagnetic wave detector 100 it is possible to form a readout circuit in the semiconductor layer 4 when the material forming the semiconductor layer 4 contains silicon. This makes it possible to read out the signal without forming a circuit outside the device.
  • FIG. 6 is a top view showing a first modification of electromagnetic wave detector 100 according to Embodiment 1.
  • FIG. 7 is a schematic cross-sectional view showing a first modification of the electromagnetic wave detector according to Embodiment 1.
  • FIG. 6 is a top view showing a first modification of electromagnetic wave detector 100 according to Embodiment 1.
  • FIG. 7 is a schematic cross-sectional view showing a first modification of the electromagnetic wave detector according to Embodiment 1.
  • each of the two-dimensional material layer 1, the first electrode portion 2a, the insulating layer 3, the semiconductor layer 4, and the ferroelectric layer 5 is You may have symmetry centering on the 2nd part 1b. In other words, the electromagnetic wave detector 100 may have multiple element structures that are symmetrical with each other.
  • the second portion 1b of the two-dimensional material layer 1 and the second region 41b of the semiconductor layer 4 in contact therewith can be integrated between a plurality of device structures having symmetry with each other, so that the plurality of device structures are independent of each other.
  • the stress applied to the third portion 1c of the two-dimensional material layer 1 can be evenly distributed among the plurality of element structures having symmetry with each other. Peeling and breakage of the dimensional material layer 1 can be suppressed. As a result, the yield and reliability of the electromagnetic wave detector 100 can be improved.
  • each of the two-dimensional material layer 1, the first electrode portion 2a, the insulating layer 3, the semiconductor layer 4, and the ferroelectric layer 5 rotates four times in the circumferential direction around the second portion 1b in plan view. It may have symmetry.
  • FIG. 8 is a schematic plan view of an electromagnetic wave detector according to Embodiment 2.
  • FIG. 9 is a schematic cross-sectional view along line segment IX-IX in FIG.
  • the electromagnetic wave detector shown in FIG. 8 basically has the same configuration as the electromagnetic wave detector shown in FIGS. It differs from the electromagnetic wave detector 100 shown in FIGS. 1 and 2 in that it further includes a three-electrode portion 2c (see FIG. 8). Differences of the electromagnetic wave detector 101 from the electromagnetic wave detector 100 will be mainly described below.
  • the third electrode portion 2c is spaced apart from the third portion 1c of the two-dimensional material layer 1 in the second direction Y in plan view.
  • the third electrode portion 2 c is arranged on the insulating layer 3 .
  • a portion of the second two-dimensional material layer 6 is arranged on the ferroelectric layer 5 .
  • a portion of the second two-dimensional material layer 6 and the third portion 1c of the two-dimensional material layer 1 are arranged so as to sandwich the ferroelectric layer 5 therebetween.
  • the remainder of the second two-dimensional material layer 6 extends along the second direction Y from the part of the second two-dimensional material layer 6 disposed on the ferroelectric layer 5 .
  • the remainder of the second two-dimensional material layer 6 is arranged on the insulating layer 3 .
  • a portion of the remainder of the second two-dimensional material layer 6 is electrically connected to the third electrode portion 2c.
  • a portion of the remainder of the second two-dimensional material layer 6 is arranged on the third electrode portion 2c.
  • the material that constitutes the second two-dimensional material layer 6 can be selected in the same manner as the material that constitutes the two-dimensional material layer 1 .
  • the material forming the second two-dimensional material layer 6 includes, for example, at least one selected from the group consisting of graphene, transition metal dichalcogenide, black phosphorus, silicene, and germanene.
  • the material forming the second two-dimensional material layer 6 is, for example, the same as the material forming the two-dimensional material layer 1, such as graphene.
  • the third electrode portion 2c is provided to apply a voltage Vtg to the third portion 1c of the two-dimensional material layer 1 via the second two-dimensional material layer 6 to modulate the Fermi level of the third portion 1c. ing. ⁇ Operating principle of electromagnetic wave detector> Next, the principle of operation of electromagnetic wave detector 101 according to this embodiment will be described.
  • the electromagnetic wave detector 101 basically has electrical connections similar to those of the electromagnetic wave detector 100 shown in FIG.
  • the second two-dimensional material layer 6 and the ferroelectric layer 5 are electrically connected in this order.
  • a voltage V is applied between the first electrode portion 2a and the second electrode portion 2b, and a voltage Vtg is applied to the ferroelectric layer 5 from the third electrode portion 2c.
  • the electromagnetic wave detector 101 has the fourth portion 1d and the third portion 1c of the two-dimensional material layer 1 as the transistor channel, the second two-dimensional material layer 6 as the second gate, and the ferroelectric layer 5 as the second gate. Functions as a field effect transistor having the first gate, the first electrode portion 2a and the first portion 1a of the two-dimensional material layer 1 as the source, and the second electrode portion 2b and the second portion 1b of the two-dimensional material layer 1 as the drain. .
  • a voltage Vtg is applied to the ferroelectric layer 5 from the third electrode portion 2c via the second two-dimensional material layer 6, causing the ferroelectric layer 5 to generate a piezoelectric effect.
  • the voltage Vtg functions as a gate voltage for modulating the surface charge density using the ferroelectric layer 5 and the third portion 1c of the two-dimensional material layer 1 as channels.
  • the electromagnetic wave absorption rate and detection sensitivity of the two-dimensional material layer 1 can be adjusted.
  • a voltage Vtg from the third electrode portion 2c to the ferroelectric layer 5 By applying a voltage Vtg from the third electrode portion 2c to the ferroelectric layer 5, a field effect is generated and the Fermi level of the third portion 1c of the two-dimensional material layer 1 is modulated.
  • FIG. 10 shows a schematic diagram of the band structure and the Fermi level change in the third portion 1 c when graphene is used for the two-dimensional material layer 1 .
  • Graphene has a zero bandgap structure in which the conductor and the valence band are combined, and the excitation process of photocarriers in response to electromagnetic wave irradiation is different from that of conventional semiconductor materials.
  • the Fermi level of graphene must reach an energy level corresponding to the wavelength of the electromagnetic wave in order for photocarriers to be excited in graphene due to the interband transition between the conduction band and the valence band of graphene.
  • the Fermi level of graphene When the Fermi level of graphene is insufficient with respect to the energy level corresponding to the detection wavelength, even if the electromagnetic wave is incident on the electromagnetic wave detector 101, photocarriers are not excited in the graphene.
  • an electromagnetic wave with a wavelength ⁇ 2, which is longer (lower in energy) than the wavelength ⁇ 1 of the electromagnetic wave having the energy necessary to excite photocarriers in graphene is incident on the electromagnetic wave detector 101. also shows that photocarriers are not excited in graphene.
  • the Fermi level of graphene can be modulated by applying the top gate voltage Vtg.
  • the energy required to excite photocarriers in graphene to which voltage Vtg is applied is smaller than the energy required to excite photocarriers in graphene to which voltage Vtg is not applied. obtain.
  • the energy required to excite photocarriers in graphene to which voltage Vtg is not applied is smaller than the energy required to excite photocarriers in graphene to which voltage Vtg is not applied.
  • the electrical resonance frequency of the third portion 1c of the two-dimensional material layer 1 depends on the light intensity of the irradiated electromagnetic wave.
  • a signal having the same frequency as the resonance frequency of the third portion 1c when the electromagnetic wave of the light quantity to be detected is incident on the electromagnetic wave detector 101 is applied to the third portion 1c as a voltage Vtg, so that only the electromagnetic wave absorption of a specific light quantity is resonated. detectable. That is, by changing the frequency of the voltage Vtg, the amount of light detectable by the electromagnetic wave detector 101 can be adjusted. That is, by changing the frequency of the voltage Vtg, the detection sensitivity of the electromagnetic wave detector 101 can be adjusted and the dynamic range of the electromagnetic wave detector 101 can be improved.
  • FIG. 11 is a schematic plan view of the electromagnetic wave detector 102 according to the third embodiment.
  • 12 is a schematic cross-sectional view taken along line XII-XII in FIG. 11.
  • the electromagnetic wave detector 102 shown in FIGS. 11 and 12 basically has the same configuration as the electromagnetic wave detector 100 shown in FIGS. is not electrically connected to the semiconductor layer 4, unlike the electromagnetic wave detector 100 shown in FIGS. Differences of the electromagnetic wave detector 102 from the electromagnetic wave detector 100 will be mainly described below.
  • the electromagnetic wave detector 102 further comprises a second insulating layer 7 arranged on the second region 41 b of the first surface 41 of the semiconductor layer 4 .
  • the second insulating layer 7 is arranged in the first direction X with the insulating layer 3 separated from the third region 41c.
  • the second electrode portion 2b is arranged on the second insulating layer 7 .
  • the second electrode portion 2 b is not electrically connected to the semiconductor layer 4 .
  • the thickness of the second insulating layer 7 is equal to the thickness of the insulating layer 3, for example.
  • the second insulating layer 7 is manufactured, for example, by the same manufacturing process as the insulating layer 3 .
  • the second portion 1 b of the two-dimensional material layer 1 is arranged on the second insulating layer 7 .
  • the second portion 1 b is electrically connected to the second electrode portion 2 b on the second insulating layer 7 .
  • the second portion 1b is in contact with the second electrode portion 2b.
  • the two-dimensional material layer 1 further includes a fifth portion 1 e arranged on the second insulating layer 7 .
  • the fifth portion 1e connects between the third portion 1c and the second portion 1b.
  • the first portion 1a, the fourth portion 1d, the third portion 1c, the fifth portion 1e, and the second portion 1b are continuous in the first direction X in this order.
  • the fifth portion 1 e is in contact with the upper surface of the second insulating layer 7 .
  • the electromagnetic wave detector 102 may further include a fourth electrode portion 2 d arranged on the second surface 42 of the semiconductor layer 4 .
  • the first electrode portion 2a, the first portion 1a of the two-dimensional material layer 1, the fourth portion 1d, the third portion 1c, the fifth portion 1e, the second portion 1b, and the second electrode portion 2b are electrically connected in this order.
  • a voltage V is applied between the first electrode portion 2a and the second electrode portion 2b.
  • a current I flows through the two-dimensional material layer 1 that forms part of the current path between the first electrode portion 2a and the second electrode portion 2b.
  • An ammeter (not shown) is installed in the power supply circuit, and the current I flowing through the two-dimensional material layer 1 is monitored by the ammeter.
  • the electromagnetic wave detector 102 has the same effects as the electromagnetic wave detector 100 .
  • the two-dimensional material layer 1 and the semiconductor layer 4 are not in Schottky junction.
  • the optical gate due to the pyroelectric effect The effect changes in the two-dimensional plane of the third portion 1c of the two-dimensional material layer 1, and the source-drain voltage changes.
  • the electromagnetic wave detector 102 can also be turned off by adjusting the voltage V so that current does not flow in the state where the electromagnetic wave is not irradiated and the source-drain voltage is not changed.
  • FIG. 13 is a cross-sectional schematic diagram of the electromagnetic wave detector 103 according to the fourth embodiment.
  • the schematic plan view is the same as FIG.
  • the electromagnetic wave detector 103 shown in FIG. 13 basically has the same configuration as the electromagnetic wave detector 100 shown in FIGS. 1 and the electromagnetic wave detector 100 shown in FIG. Differences of the electromagnetic wave detector 103 from the electromagnetic wave detector 100 will be mainly described below.
  • the reflective film 8 is arranged on the semiconductor layer 4 located below the third portion 1 c of the two-dimensional material layer 1 and the ferroelectric layer 5 .
  • Any material can be used for the reflective film 8 as long as it has a reflective characteristic in the wavelength region of the electromagnetic waves absorbed by the two-dimensional material layer 1 and the ferroelectric layer 5 .
  • the material forming the reflective film 8 is selected from the group consisting of gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), and palladium (Pd). At least one selected.
  • the reflective film 8 is arranged on the third region 41 c of the first surface 41 of the semiconductor layer 4 .
  • the reflective film 8 is spaced apart from each of the third portion 1c of the two-dimensional material layer 1 and the ferroelectric layer 5 in the direction orthogonal to the third region 41c of the first surface 41 .
  • the reflective film 8 is provided so as not to hinder deformation of the third portion 1c of the two-dimensional material layer 1 .
  • the reflective film 8 is in contact with the third region 41c, which is the bottom surface of the recess 43, for example.
  • the planar shape of the reflective film 8 may be any shape, such as circular, triangular, quadrangular, polygonal, or elliptical.
  • any method may be used to form the reflective film 8.
  • the method may be the same as the method for forming the first electrode portion 2a in the method for manufacturing the electromagnetic wave detector 100 according to the first embodiment. .
  • the distance between the reflective film 8 and the third portion 1c of the two-dimensional material layer 1 in the direction perpendicular to the third region 41c is set to 1/4 of the detection wavelength.
  • the interval of the reflective film 8 is set to 1/4 of the detection wavelength, interference resonance occurs between the electromagnetic wave incident on the reflective film 8 and the electromagnetic wave reflected from the reflective film 8, and the interval is 1/4 of the detection wavelength.
  • the absorption coefficient increases compared to when it is not set to .
  • the electromagnetic wave detector 103 further includes the reflective film 8 , the electromagnetic wave transmitted through the ferroelectric layer 5 and the third portion 1 c of the two-dimensional material layer 1 among the electromagnetic waves irradiated to the electromagnetic wave detector 103 is reflected by the reflective film 8 . It can be reflected and re-enter each of the third portion 1 c of the two-dimensional material layer 1 and the ferroelectric layer 5 . As a result, each of the third portion 1c of the two-dimensional material layer 1 and the ferroelectric layer 5 easily absorbs electromagnetic waves, so the detection sensitivity of the electromagnetic wave detector 103 is high.
  • the incident light and the reflected light interfere with each other as described above. Because of resonance, the absorption coefficient is high and the detection sensitivity is high compared to the electromagnetic wave detector 103 in which the spacing is not set to 1/4 of the detection wavelength.
  • FIG. 14 is a schematic cross-sectional view of the electromagnetic wave detector 104 according to the fifth embodiment.
  • the schematic plan view is the same as FIG.
  • the electromagnetic wave detector 104 according to Embodiment 5 basically has the same configuration as the electromagnetic wave detector 100 shown in FIGS. It differs from the electromagnetic wave detector 100 shown in FIGS. Differences of the electromagnetic wave detector 104 from the electromagnetic wave detector 100 will be mainly described below.
  • multiple conductors 9 are in contact with the ferroelectric layer 5 .
  • a plurality of conductors 9 are arranged on the third portion 1c in the first direction X at intervals from each other.
  • the plurality of conductors 9 have, for example, a one-dimensional periodic structure.
  • the arrangement of the plurality of conductors 9 in plan view has, for example, periodic symmetry.
  • the plurality of conductors 9 are arranged periodically in one dimension in the first direction X, for example.
  • the plurality of conductors 9 may be arranged one-dimensionally and periodically in the second direction Y (the depth direction of the paper surface of FIG. 14).
  • the plurality of conductors 9 may have a two-dimensional periodic structure.
  • each of the plurality of conductors 9 may be arranged at positions corresponding to grid points such as a square grid or a triangular grid.
  • each of the plurality of conductors 9 may be arranged aperiodically.
  • the arrangement of the plurality of conductors 9 in plan view may be asymmetric.
  • each of the plurality of conductors 9 are, for example, equivalent to each other.
  • the shape and size of each of the plurality of conductors 9 may be different from each other.
  • Each of the plurality of conductors 9 is a floating electrode. Each of the plurality of conductors 9 is not connected to a power supply circuit or the like and is floating.
  • any conductive material may be used as the material for the conductor 9 .
  • the material constituting the conductor 9 is, for example, selected from the group consisting of gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), and palladium (Pd). At least one selected.
  • the material forming the conductor 9 is a material that causes surface plasmon resonance in the conductor 9 .
  • each of the plurality of conductors 9 may be any shape, such as circular, triangular, square, polygonal, or elliptical.
  • each of the plurality of conductors 9 may be any method, but for example, it is equivalent to the method of forming the first electrode portion 2a in the method of manufacturing the electromagnetic wave detector 100 according to the first embodiment. There may be.
  • the electromagnetic wave detector 104 further includes the conductor 9 as a floating electrode on the two-dimensional material layer 1 , the surface carriers generated by the irradiation of the electromagnetic wave in the ferroelectric layer 5 interact with each of the plurality of conductors 9 . can go back and forth. As a result, in the electromagnetic wave detector 104, the lifetime of photocarriers is lengthened and the detection sensitivity is enhanced.
  • the conductors 9 when the plurality of conductors 9 has a one-dimensional periodic structure and the material constituting the conductors 9 is a material that causes surface plasmon resonance, the conductors 9 are polarized with respect to the irradiated electromagnetic waves. Dependencies arise. As a result, the semiconductor layer 4 of the electromagnetic wave detector 104 is irradiated only with electromagnetic waves of specific polarization, so that the electromagnetic wave detector 104 can detect only the specific polarized light with high sensitivity.
  • the plurality of conductors 9 when the plurality of conductors 9 have a two-dimensional periodic structure and the material forming the conductors 9 is a material that causes surface plasmon resonance, the plurality of conductors 9 emit electromagnetic waves of a specific wavelength. Resonate. As a result, the semiconductor layer 4 of the electromagnetic wave detector 104 is irradiated only with electromagnetic waves having a specific wavelength, so that the electromagnetic wave detector 104 can detect only electromagnetic waves with a specific wavelength with high sensitivity.
  • the conductors are responsive to the irradiated electromagnetic waves, as in the case where the plurality of conductors 9 have a one-dimensional periodic structure. 9 gives rise to polarization dependence.
  • the semiconductor layer 4 of the electromagnetic wave detector 104 is irradiated only with electromagnetic waves of specific polarization, so that the electromagnetic wave detector 104 can detect only the specific polarized light with high sensitivity.
  • the plurality of conductors 9 may also be in contact with the third portion 1c of the two-dimensional material layer 1. Also, the plurality of conductors 9 may not be in contact with the ferroelectric layer 5 but may be in contact with the third portion 1c of the two-dimensional material layer 1 . Even with such a configuration, the same effect as that of the electromagnetic wave detector 104 shown in FIG. 14 can be obtained.
  • the plurality of conductors 9 may be arranged under the two-dimensional material layer 1, for example. In this case, since the two-dimensional material layer 1 is not damaged when the conductor 9 is formed, a decrease in carrier mobility in the two-dimensional material layer 1 can be suppressed.
  • the two-dimensional material layer 1 may have an uneven portion.
  • the uneven portions of the two-dimensional material layer 1 may have a periodic structure or an aperiodic structure, like the plurality of conductors 9 described above. Such irregularities act in the same manner as the plurality of conductors 9 .
  • the electromagnetic wave detector 104 may be provided with the two-dimensional material layer 1 in which the uneven portions are formed instead of the plurality of conductors 9 .
  • the concave and convex portions act in the same manner as the plurality of conductors 9, so that the same effects as those of the electromagnetic wave detector 104 can be obtained.
  • Electromagnetic wave detector 104 further comprises one or more electrical conductors 9 .
  • One or more electrical conductors 9 are arranged in contact with the two-dimensional material layer 1 and/or the ferroelectric layer 5 . In this case, the lifetime of photocarriers in the two-dimensional material layer 1 is lengthened. As a result, the detection sensitivity of the electromagnetic wave detector 104 is enhanced.
  • FIG. 15 is a schematic cross-sectional view of the electromagnetic wave detector 105 according to the sixth embodiment.
  • the electromagnetic wave detector 105 shown in FIG. 15 basically has the same configuration as the electromagnetic wave detector 100 shown in FIGS. It differs from the electromagnetic wave detector 100 shown in FIGS. 1 and 2 in that at least one or more contact layers 10 are further provided. Differences of the electromagnetic wave detector 105 from the electromagnetic wave detector 100 will be mainly described below.
  • the contact layer 10 is in contact with the lower surface of the third portion 1c of the two-dimensional material layer 1, for example.
  • the contact layer 10 and the ferroelectric layer 5 are arranged so as to sandwich the third portion 1c of the two-dimensional material layer 1 therebetween.
  • the contact layer 10 may be in contact with the upper surface of the third portion 1c of the two-dimensional material layer 1.
  • the contact layer 10 is arranged, for example, side by side with the ferroelectric layer 5 in the second direction Y (the depth direction of the paper surface of FIG. 15).
  • the contact layer 10 may be in contact with at least one of the second portion 1b, the third portion 1c, and the fourth portion 1d.
  • the contact layer 10 may be in contact with the second portion 1b or the fourth portion 1d.
  • a contact layer 10 is provided to dope the two-dimensional material layer 1 with electrons or holes.
  • the material constituting the contact layer 10 includes, for example, a composition containing a photosensitizer having a quinonediazite group and a novolac resin, which is called a positive photoresist.
  • the material forming the contact layer 10 may be, for example, a material having a polar group.
  • the material forming the contact layer 10 may be, for example, a material having an electron-withdrawing group.
  • Such a contact layer 10 has the effect of reducing the electron density of the two-dimensional material layer 1 .
  • the material forming the contact layer 10 may be, for example, a material having an electron-donating group.
  • Such a contact layer 10 has the effect of increasing the electron density of the two-dimensional material layer 1 .
  • Materials having electron-withdrawing groups include, for example, materials having halogen, nitrile, carboxyl groups, or carbonyl groups.
  • Materials having an electron-donating group include, for example, materials having an alkyl group, an alcohol, an amino group, or a hydroxyl group.
  • the material forming the contact layer 10 may be any material in which a polar group causes an electric charge bias in the entire molecule.
  • the material constituting the contact layer 10 is an organic substance, a metal, a semiconductor, an insulator, a two-dimensional material, or a mixture of any of these materials, and a material that generates polarity due to an uneven charge in the molecule.
  • the conductivity type with which the two-dimensional material layer 1 is doped by the contact layer 10 is the work function of the contact layer 10 and the work function of the two-dimensional material layer 1. Varies depending on size. When the work function of the contact layer 10 is larger than that of the two-dimensional material layer 1, it is p-type, and when it is smaller, it is n-type.
  • the contact layer 10 will dope the two-dimensional material layer 1 because the organic material forming the contact layer 10 does not have a distinct work function.
  • the type is determined by the polarity of the organic molecules that make up the contact layer 10 .
  • the contact layer 10 when a composition containing a photosensitizer having a quinonediazite group and a novolac resin, called a positive photoresist, is used as the contact layer 10, the region of the two-dimensional material layer 1 where the resist is formed by a photolithography process is p becomes a mold two-dimensional material layer region. This eliminates the need for a mask forming process that contacts the surface of the two-dimensional material layer 1 . As a result, it is possible to reduce process damage to the two-dimensional material layer 1 and to simplify the process.
  • a composition containing a photosensitizer having a quinonediazite group and a novolac resin called a positive photoresist
  • the thickness of the contact layer 10 is sufficiently thin so that photoelectric conversion can be performed when the two-dimensional material layer 1 is irradiated with electromagnetic waves.
  • the thickness of the contact layer 10 is such that the two-dimensional material layer 1 is doped with carriers from the contact layer 10 .
  • the electromagnetic wave detector 105 comprises a contact layer 10 in contact with the two-dimensional material layer 1 .
  • the state (conductivity type) of the two-dimensional material layer 1 is intentionally changed to n It can be of type or p-type.
  • the carrier doping of the two-dimensional material layer 1 can be controlled without considering the effect of carrier doping from the polarization of the first electrode portion 2a, the semiconductor layer 4, and the ferroelectric layer 5. FIG. As a result, the performance of the electromagnetic wave detector can be improved.
  • the contact layer 10 by forming the contact layer 10 only on either the first electrode portion 2a side or the semiconductor layer 4 side of the upper surface of the two-dimensional material layer 1, the charge density gradient in the two-dimensional material layer 1 is formed. It 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 composition of the contact layer 10 may be determined accordingly, provided that photocarriers such as molecules or electrons are supplied to the two-dimensional material layer 1 .
  • the two-dimensional material layer 1 is immersed in a solution and photocarriers are supplied to the two-dimensional material layer 1 at the molecular level, without forming a solid contact layer 10 on the two-dimensional material layer 1.
  • the two-dimensional material layer 1 may be doped with photocarriers.
  • a material that causes polarity conversion may be used in addition to the materials described above.
  • the contact layer 10 undergoes polarity conversion, the electrons or holes generated during the conversion are supplied to the two-dimensional material layer 1 . Therefore, doping of electrons or holes occurs in the part of the two-dimensional material layer 1 that is in contact with the contact layer 10 . Therefore, even if the contact layer 10 is removed, the part of the two-dimensional material layer 1 that was in contact with the contact layer 10 remains doped with electrons or holes. Therefore, when a material that causes polarity conversion is used as the contact layer 10, the contact layer 10 may be removed from the two-dimensional material layer 1 after a certain period of time has passed.
  • the polar conversion is a phenomenon in which a polar group is chemically converted.
  • an electron-withdrawing group changes to an electron-donating group
  • an electron-donating group changes to an is changed to a non-polar group
  • a non-polar group is changed to a polar group.
  • the contact layer 10 may be formed of a material that undergoes polarity conversion by electromagnetic wave irradiation.
  • the contact layer 10 by selecting a material that causes polarity conversion at a specific wavelength of the electromagnetic wave as the material of the contact layer 10, the contact layer 10 causes polarity conversion only when the electromagnetic wave of the specific wavelength is irradiated, thereby forming a two-dimensional material layer. Doping to 1 can be done. 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.
  • a plurality of contact layers 10 may be formed on the two-dimensional material layer 1 .
  • the number of contact layers 10 may be three or more and can be any number.
  • a plurality of contact layers 10 may be formed on the two-dimensional material layer 1 located between the first electrode part 2 a and the semiconductor layer 4 . In that case, the materials of the multiple contact layers 10 may be the same material or different materials.
  • FIG. 16 is a schematic plan view of the electromagnetic wave detector 106 according to the seventh embodiment.
  • FIG. 17 is a schematic plan view showing a first modification of the electromagnetic wave detector according to Embodiment 7.
  • FIG. 16 and 17 are the same as FIG. 2.
  • FIG. 16 and 17 are the same as FIG. 2.
  • the electromagnetic wave detector 106 shown in FIG. 16 basically has the same configuration as the electromagnetic wave detector 100 shown in FIGS.
  • the planar shape of portion 1b is different from that of electromagnetic wave detector 100 shown in FIGS.
  • the first portion 1a of the two-dimensional material layer 1 has a first end surface 1as extending in a direction intersecting with the first surface 41 of the semiconductor layer 4 .
  • the first end surface 1as is orthogonal to the first surface 41, for example.
  • the first end surface 1as has a portion facing the first direction X and a portion facing the second direction Y, for example.
  • the second portion 1b of the two-dimensional material layer 1 has a second end surface 1bs extending in a direction crossing the first surface 41 of the semiconductor layer 4.
  • the second end surface 1bs is orthogonal to the first surface 41, for example.
  • the second end surface 1bs has a portion facing the first direction X and a portion facing the second direction Y, for example.
  • the planar shape of the second portion 1b is a comb shape (ladder shape).
  • at least one slit 11 is formed in the second portion 1b.
  • a plurality of slits 11 are formed in the second portion 1b.
  • Each of the plurality of slits 11 extends along the first direction X, for example.
  • Each of the plurality of slits 11 extends, for example, to the boundary between the second portion 1b and the third portion 1c.
  • the second portion 1b is configured as an aggregate of a plurality of minute portions spaced apart from each other in the second direction Y. As shown in FIG.
  • the first direction end of each of the plurality of minute portions is connected to the third portion 1c.
  • the planar shape of each of the plurality of minute portions may be any shape, such as a rectangular shape.
  • Each planar shape of the second portion 1b shown in FIG. 16 is symmetrical with respect to the center line extending along the second direction Y through the center of the semiconductor layer 4 in the first direction X.
  • the planar shape of the second portion 1b shown in FIG. 16 is symmetrical with respect to a stop line extending along the first direction X through the center of the two-dimensional material layer 1 in the second direction Y. As shown in FIG.
  • the second end surface 1bs has a pair of facing surface portions facing each other in the second direction Y, for example.
  • the total area of the second end surfaces 1bs of the second portions 1b is larger than the total area of the first end surfaces 1as of the first portions 1a. From a different point of view, the sum of the widths in the second direction Y of the second portions 1b is smaller than the sum of the widths in the second direction Y of the first portions 1a in plan view.
  • the area occupied by second portion 1b when electromagnetic wave detector 106 is viewed in plan is smaller than the area occupied by second portion 1b when electromagnetic wave detector 100 is viewed in plan.
  • the area of the contact surface between second portion 1 b and semiconductor layer 4 in electromagnetic wave detector 106 is smaller than the area of the contact surface between second portion 1 b and semiconductor layer 4 in electromagnetic wave detector 100 .
  • the minimum sum of the widths of the second portions 1b in the second direction Y is narrower than the minimum widths of the first portion 1a, the fourth portion 1d, and the third portion 1c in the second direction Y.
  • the planar shape of the second portion 1b may be a lattice shape.
  • a plurality of openings 12 are formed to expose the semiconductor layer 4, and the plurality of openings 12 are aligned in the longitudinal direction and the lateral direction of the semiconductor layer 4. are placed.
  • the minimum sum of the widths of the second portions 1b in the second direction Y is narrower than the minimum width of each of 1c.
  • planar shape of the second portion 1b may be an E shape.
  • Each of the plurality of slits 11 does not have to extend, for example, to the boundary between the second portion 1b and the third portion 1c.
  • the electromagnetic wave detector 106 shown in FIGS. 16 and 17 the area of the contact surface between the second portion 1b and the semiconductor layer 4 can be adjusted according to the planar shape of the second portion 1b. Therefore, in the electromagnetic wave detector 106, the contact resistance between the second portion 1b of the two-dimensional material layer 1 and the semiconductor layer 4, and thus the resistance of the electromagnetic wave detector 106 can be adjusted. As a result, the electromagnetic wave detector 106 may have reduced variations in characteristics of the electromagnetic wave detector 106 and a reduced dark current as compared to the electromagnetic wave detector 100 shown in FIGS.
  • the total area of the second end surfaces 1bs of the second portions 1b is larger than the total area of the first end surfaces 1as of the first portions 1a.
  • the second end surface 1bs extends along the thickness direction of the two-dimensional material layer 1, in other words, along the direction orthogonal to the two-dimensional plane in which the atoms are two-dimensionally arranged in the two-dimensional material layer 1. Therefore, the end surface area of the two-dimensional crystal structure in the second portion 1 b of the electromagnetic wave detector 106 is larger than the end surface area of the two-dimensional crystal structure in the second portion 1 b of the electromagnetic wave detector 100 .
  • the electromagnetic wave detector 106 the proportion of dangling bonds in the two-dimensional crystal structure is increased in the second end face 1bs of the second portion 1b compared to the electromagnetic wave detector 100.
  • FIG. 1 when carriers generated in the semiconductor layer 4 by electromagnetic wave irradiation are transported to the first electrode portion 2a through the two-dimensional material layer 1, the two-dimensional material layer 1 of the electromagnetic wave detector 106 does not Compared to the two-dimensional material layer 1, the rate of change in carrier density is increased, the mobility of carriers is increased, and the amount of change in current I is increased. As a result, the sensitivity of electromagnetic wave detector 106 is higher than that of electromagnetic wave detector 100 .
  • the second portion 1b of the two-dimensional material layer 1 may be composed of graphene nanoribbons.
  • Graphene nanoribbons have a bandgap that varies with their width. Therefore, the wavelength range of electromagnetic waves that can be photoelectrically converted in the second portion 1b can be adjusted according to the width in the first direction X of the second portion 1b made of graphene nanoribbons.
  • the wavelength range of electromagnetic waves that can be photoelectrically converted in the second portion 1b can be narrower than the wavelength range of electromagnetic waves that can be photoelectrically converted in each of the first portion 1a, the third portion 1c, and the fourth portion 1d.
  • optical carriers generated by photoelectric conversion in the second portion 1b can be detected separately from optical carriers generated by photoelectric conversion in each of the first portion 1a, the third portion 1c, and the fourth portion 1d. Further, the sensitivity of the electromagnetic wave detector 106 is improved by detecting optical carriers generated by photoelectric conversion in the second portion 1b. In addition, in such an electromagnetic wave detector 106, since the second portion 1b made of graphene nanoribbons and the semiconductor layer 4 form a Schottky junction, the dark current is reduced, and the electromagnetic waves absorbed at the Schottky junction Sensitivity is improved by detecting the generated photocarriers.
  • FIG. 18 is a schematic plan view of electromagnetic wave detector 107 according to the eighth embodiment.
  • 19 is a schematic cross-sectional view along the line segment XIX-XIX in FIG. 18.
  • the electromagnetic wave detector 107 shown in FIGS. 18 and 19 basically has the same configuration as the electromagnetic wave detector 100 shown in FIGS.
  • the electromagnetic wave detector 100 shown in FIGS. 1 and 2 is different from the electromagnetic wave detector 100 shown in FIGS. Differences of the electromagnetic wave detector 107 from the electromagnetic wave detector 100 will be mainly described below.
  • the adhesion layer 13 is arranged so as to be sandwiched between the third portion 1c of the two-dimensional material layer 1 and the ferroelectric layer 5 in a cross-sectional view.
  • the adhesion layer 13 is arranged so as to contact the entirety of each of the third portion 1c of the two-dimensional material layer 1 and the ferroelectric layer 5 .
  • the adhesion layer 13 may be arranged so as to be in contact with a portion of each of the third portion 1 c of the two-dimensional material layer 1 and the ferroelectric layer 5 .
  • the material forming the adhesion layer 13 includes at least one selected from insulating materials formed by an ALD (Atomic Layer Deposition) method, a CVD (Chemical Vapor Deposition) method, and a sputtering method.
  • a material forming the adhesion layer 13 is, for example, alumina formed by the ALD method.
  • the adhesion layer 13 is formed on the two-dimensional material layer third portion 1c before forming the ferroelectric layer 5, for example.
  • the ferroelectric layer 5 is formed on the adhesion layer 13 after the adhesion layer 13 is formed, for example. Note that the adhesion layer 13 and the ferroelectric layer 5 may be formed continuously and then patterned continuously using the same mask pattern.
  • the electromagnetic wave detector 107 is basically electrically connected to the power supply circuit similarly to the electromagnetic wave detector 100 and can operate similarly to the electromagnetic wave detector 100 .
  • the adhesion layer 13 arranged between the third portion 1c of the two-dimensional material layer 1 and the ferroelectric layer 5 allows electromagnetic wave detection without the adhesion layer 13. Adhesion between the third portion 1c and the ferroelectric layer 5 is improved as compared with the container 100. FIG. As a result, variations in characteristics among the electromagnetic wave detectors 107 as detection elements are reduced, and the production yield is improved.
  • the thermal stress corresponding to the difference between the film forming temperature and the driving temperature is It occurs in the body layer 5 and causes deformation and resistance change of the two-dimensional material layer third portion 1c.
  • the electromagnetic wave detector 107 includes the adhesion layer 13, the deformation is suppressed and the change in resistance is reduced, so that the variation in characteristics can be reduced.
  • the production yield in the electromagnetic wave detector 100 without the adhesion layer 13, the third portion 1c of the two-dimensional material layer 1 and the ferroelectric Peeling may occur between the layers 5 .
  • the adhesion layer 13 formed between the third portion 1c of the two-dimensional material layer 1 and the ferroelectric layer 5 controls the charge distribution on the surface of the ferroelectric layer 5. Neutralize. Thereby, in the electromagnetic wave detector 107, separation between the two-dimensional material layer third portion 1c and the ferroelectric layer 5 is suppressed, and the production yield of the electromagnetic wave detector 107 can be improved.
  • Embodiment 9 ⁇ Configuration of electromagnetic wave detector array> 20 is a top view of an electromagnetic wave detector array according to Embodiment 9.
  • FIG. 21 is a schematic diagram showing an example of a readout circuit for reading out electrical signals obtained from the electromagnetic wave detector array according to the ninth embodiment.
  • 22 is a top view showing a first modification of the electromagnetic wave detector array according to Embodiment 9.
  • an electromagnetic wave detector array 1000 according to Embodiment 9 is an assembly of a plurality of electromagnetic wave detectors 100.
  • Electromagnetic wave detector array 1000 has a plurality of electromagnetic wave detectors 100 according to any one of Embodiments 1 to 8 as detection elements.
  • Electromagnetic wave detector array 1000 includes, for example, the electromagnetic wave detector according to Embodiment 1 as electromagnetic wave detector 100 .
  • each detection wavelength of the plurality of electromagnetic wave detectors 100 is the same.
  • a plurality of electromagnetic wave detectors 100 are arranged in an array in two-dimensional directions. In other words, the plurality of electromagnetic wave detectors 100 are arranged side by side in a first direction and a second direction crossing the first direction.
  • four electromagnetic wave detectors 100 are arranged in a 2 ⁇ 2 array.
  • the number of electromagnetic wave detectors 100 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.
  • the plurality of electromagnetic wave detectors 100 are arranged periodically two-dimensionally, but the plurality of electromagnetic wave detectors 100 are arranged periodically along one direction. may have been Also, the intervals between the plurality of electromagnetic wave detectors 100 may be equal intervals or may be different intervals.
  • 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 number of wirings of pixels compared to the configuration in which the second electrode portion 2b is independent in each electromagnetic wave detector 100. FIG. As a result, it is possible to increase the resolution of the electromagnetic wave detector array.
  • the opening structure of the semiconductor layer 4 described in the first embodiment may be provided on the outer periphery of the electromagnetic wave detectors 100 .
  • the electromagnetic wave detector array 1000 including a plurality of electromagnetic wave detectors 100 in this manner can also be used as an image sensor by arranging the plurality of electromagnetic wave detectors 100 in an array.
  • Electromagnetic wave detector array 1000 may include any one of the electromagnetic wave detectors according to Embodiments 2 to 7 as electromagnetic wave detector 100 . Electromagnetic wave detector array 1000 may include any one of the electromagnetic wave detectors according to Embodiments 2 to 8 as electromagnetic wave detector 100 .
  • the electromagnetic wave detector array 1000 may include a plurality of electromagnetic wave detectors according to any one of Embodiments 1 to 8, or two or more of Embodiments 1 to 8. A plurality of electromagnetic wave detectors may be provided.
  • a detection circuit such as a readout circuit or a matrix selection circuit for reading the electric signal obtained from each electromagnetic wave detector 100.
  • a detection circuit such as a readout circuit or a matrix selection circuit may be provided on another semiconductor chip and electrically connected to the electromagnetic wave detector array 1000 by bumps or the like.
  • FIG. 21 is a schematic diagram showing an example of such a detection circuit, indicated generally at 300.
  • the electromagnetic wave detectors 100 forming the electromagnetic wave detector array 1000 are also called pixels.
  • the detection circuit 300 includes a vertical scanning circuit 20 that vertically scans the pixels 100 of the electromagnetic wave detector array 1000, a horizontal scanning circuit 21 that horizontally scans the pixels 100, and a power supply circuit 22 that supplies a bias voltage to each circuit. and an output circuit 23 for outputting the signal from the horizontal scanning circuit 21 to the outside of the electromagnetic wave detector array 1000 .
  • the detection circuit 300 detects the response of the electromagnetic wave detector 100 for each pixel. Specifically, a voltage is applied to the vertical scanning circuit 20 to select one row, and a voltage is applied to the horizontal scanning circuit 21 to select one column, thereby reading the response of one pixel. By fixing a row selected by the vertical scanning circuit 20 and sequentially applying voltages to the horizontal scanning circuit 21, all pixel responses of the row are read out. After that, similarly, by applying a voltage to the vertical scanning circuit 20 to select another row and sequentially applying a voltage to the horizontal scanning circuit 21, all the pixel responses of the other row are read out. By repeating this, the responses of all pixels can be read out.
  • the method of reading the response for each pixel using the vertical scanning circuit 20 and the horizontal scanning circuit 21 has been described, but the method is not limited to this, and the response may be read for each row or column. However, other methods may be used.
  • the electromagnetic wave detector array 2000 shown in FIG. 22 has basically the same configuration as the electromagnetic wave detector array 1000 shown in FIG. 20, and can obtain similar effects. It differs from the electromagnetic wave detector array shown in FIG. 20 in that different electromagnetic wave detectors 200, 201, 202, and 203 are provided.
  • Each of electromagnetic wave detectors 200, 201, 202, and 203 is an electromagnetic wave detector according to any one of the first to seventh embodiments described above.
  • the electromagnetic wave detectors 200, 201, 202, and 203 include, for example, two groups of electromagnetic wave detectors with mutually different detection wavelengths.
  • the electromagnetic wave detector array 2000 can detect electromagnetic waves of at least two or more different wavelengths.
  • electromagnetic wave detector array 2000 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.
  • the plurality of electromagnetic wave detectors 200, 201, 202, 203 are arranged periodically in two dimensions. 203 may be arranged periodically along one direction. Also, the intervals between the plurality of electromagnetic wave detectors 200, 201, 202, and 203 may be equal intervals or may be different intervals.
  • the electromagnetic wave detectors 200, 201, 202, and 203 of different types are arranged in an array, so that it can function as an image sensor.
  • the electromagnetic wave detectors 200, 201, 202, and 203 having different detection wavelengths in an array in this way, similar to an image sensor used in the visible light range, for example, ultraviolet light, infrared light, terahertz waves, and radio waves can be detected.
  • the wavelength of electromagnetic waves can be identified in any wavelength range such as the wavelength range of .
  • a colorized image can be obtained, for example, in which wavelength differences are indicated as color differences.
  • semiconductor materials with different detection wavelengths may be used as the constituent material of the semiconductor layer 4 that constitutes the electromagnetic wave detector.
  • a semiconductor material whose detection wavelength is a visible light wavelength and a semiconductor material whose detection wavelength is an infrared wavelength 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 visible light image camera during the daytime. Furthermore, the electromagnetic wave detector can also be used as an infrared camera at night. In this way, there is no need to use different cameras having image sensors depending on the detection wavelength of electromagnetic waves.
  • 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, for example.
  • the electromagnetic wave detectors 200, 201, 202, and 203 having different detection wavelengths according to the structure of the electromagnetic wave detector array, an image sensor that detects the intensity of electromagnetic waves of multiple wavelengths can be obtained.
  • a color filter which is conventionally required in a CMOS image sensor or the like.
  • a polarization identification image sensor can be formed.
  • polarization imaging can be performed by arranging a plurality of electromagnetic wave detectors of one unit, with four pixels having detection polarization angles of 0°, 90°, 45°, and 135° as one unit.
  • Polarization-sensitive image sensors allow, for example, man-made and natural object identification, material identification, same-temperature object identification in the infrared wavelength range, boundary identification between objects, or equivalent resolution enhancement.
  • the electromagnetic wave detector array 2000 can detect electromagnetic waves in a wide wavelength range. Also, the electromagnetic wave detector array 2000 can detect electromagnetic waves of different wavelengths.
  • the insulating layer 3, the semiconductor layer 4, the ferroelectric layer 5, the conductor 9, and the contact layer 10 are made from It is preferable to use a material that provides a change in potential.
  • examples of materials whose characteristics are changed by irradiation with electromagnetic waves and which give a change in potential to the two-dimensional material layer 1 include quantum dots, ferroelectric materials, liquid crystal materials, fullerenes, rare earth oxides, semiconductor materials, pn A bonding material, a metal-semiconductor bonding material, or a metal-insulator-semiconductor bonding material can be used.
  • a ferroelectric material having a polarization effect (pyroelectric effect) due to electromagnetic waves is used as the ferroelectric material, the polarization of the ferroelectric material changes due to the irradiation of the electromagnetic waves. As a result, a change in potential can be applied to the two-dimensional material layer 1 .
  • the materials constituting the insulating layer 3, the semiconductor layer 4, the ferroelectric layer 5, the conductor 9, and the contact layer 10 are materials whose characteristics change when irradiated with electromagnetic waves, the insulating layer 3, The semiconductor layer 4 , the ferroelectric layer 5 , the conductor 9 , and the contact layer 10 change their characteristics when irradiated with an electromagnetic wave, and the two-dimensional material layer 1 can be given a change in potential.
  • the contact layer 10 may be made of a material whose characteristics change when irradiated with an electromagnetic wave and which gives the two-dimensional material layer 1 a change in potential.
  • the contact layer 10 when a material whose properties change when irradiated with an electromagnetic wave and which changes the potential of the two-dimensional material layer 1 is applied to the contact layer 10, the contact layer 10 must be in direct contact with the two-dimensional material layer 1. no.
  • the contact layer 10 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 as long as a change in potential can be applied to the two-dimensional material layer 1 .

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WO2025109660A1 (ja) * 2023-11-20 2025-05-30 三菱電機株式会社 ガス検出器及びガス検出器アレイ
WO2025163982A1 (ja) * 2024-01-31 2025-08-07 太陽誘電株式会社 光センサおよび光センサの製造方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160305824A1 (en) * 2013-12-05 2016-10-20 National University Of Singapore Pyroelectric detector using graphene electrode
CN107342345A (zh) * 2017-06-27 2017-11-10 重庆大学 一种基于铁电栅介质和薄层二硫化钼沟道的光电晶体管
WO2021002070A1 (ja) * 2019-07-04 2021-01-07 三菱電機株式会社 電磁波検出器

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160305824A1 (en) * 2013-12-05 2016-10-20 National University Of Singapore Pyroelectric detector using graphene electrode
CN107342345A (zh) * 2017-06-27 2017-11-10 重庆大学 一种基于铁电栅介质和薄层二硫化钼沟道的光电晶体管
WO2021002070A1 (ja) * 2019-07-04 2021-01-07 三菱電機株式会社 電磁波検出器

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