Electromagnetic wave detector and electromagnetic wave detector assembly

Abstract

The electromagnetic wave detector comprises: a semiconductor layer (4) having a step portion (40) and having sensitivity to a detection wavelength; an insulating film (3) arranged on the step portion (40) and having an opening portion (3a) for exposing a portion of the step portion (40); a two-dimensional material layer (1) arranged on the insulating film (3) and the opening portion (3a) and having a connection area (1c) electrically connected to the semiconductor layer (4) at the opening portion (3a); a first electrode portion (2a) arranged on the insulating film (3) and electrically connected to the two-dimensional material layer (1); and a second electrode portion (2b) arranged on the semiconductor layer (4) and electrically connected to the first electrode portion (2a) via the connection area (1c) of the two-dimensional material layer (1).

Description

Technical Field

[0001] The present disclosure relates to an electromagnetic wave detector and an electromagnetic wave detector assembly. Background Art

[0002] In the past, as a material for the electromagnetic wave detection layer used in the next generation of electromagnetic wave detectors, graphene with extremely high mobility as an example of a two-dimensional material layer is known. The absorptivity of graphene is as low as 2.3%. Therefore, a high sensitivity technique in an electromagnetic wave detector using graphene has been proposed. For example, in the specification of U.S. Patent Application Publication No. 2015 / 0243826, a detector with the structure described below is proposed. That is, in the specification of U.S. Patent Application Publication No. 2015 / 0243826, more than two dielectric layers are provided on the n-type semiconductor layer. A graphene layer is formed on the two dielectric layers and on the surface portion of the n-type semiconductor layer located between the two dielectric layers. Source and drain electrodes connected to the two ends of the graphene layer are arranged on the dielectric layer. The gate electrode is connected to the n-type semiconductor layer.

[0003] In the above detector, a voltage is applied to the graphene layer as a channel via the source and drain electrodes. As a result, the photocarriers generated in the n-type semiconductor layer are amplified, thereby increasing the sensitivity of the detector. In addition, when a voltage is applied to the gate electrode and the source electrode or the drain electrode, a shutdown operation can be performed through the Schottky connection between the graphene and the n-type semiconductor layer.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: U.S. Patent Application Publication No. 2015 / 0243826 Summary of the invention

[0007] However, in the above detector, a transistor action is performed when a high sensitivity action of applying source and drain voltages to graphene is performed, so it is difficult to perform a shutdown action of the detector. In addition, in a Schottky action of applying voltages to the gate electrode and the source electrode or the drain electrode, the sensitivity of the detector depends on the quantum efficiency of the semiconductor layer. Therefore, it is impossible to amplify sufficient photocarriers, and it is difficult to achieve high sensitivity of the detector. In this way, in the previous detectors using two-dimensional material layers such as graphene, high sensitivity and shutdown actions have not been achieved at the same time.

[0008] The main object of the present disclosure is to provide an electromagnetic wave detector using a two-dimensional material layer and an electromagnetic wave detector assembly that has high detection sensitivity and can perform a shutdown operation.

[0009] The electromagnetic wave detector involved in the present disclosure comprises: a semiconductor layer, which is formed with at least one step portion and has sensitivity to the detection wavelength; an insulating film, which is arranged on the at least one step portion and is provided with at least one opening portion that exposes a portion of the at least one step portion; a two-dimensional material layer, which is arranged on the insulating film and the at least one opening portion, and has a connection area electrically connected to the semiconductor layer in the at least one opening portion; a first electrode portion, which is arranged on the insulating film and electrically connected to the two-dimensional material layer; and a second electrode portion, which is arranged on the semiconductor layer and electrically connected to the first electrode portion via the connection area of ​​the two-dimensional material layer.

[0010] According to the present disclosure, it is possible to provide an electromagnetic wave detector using a two-dimensional material layer that has high detection sensitivity and is capable of performing a shutdown operation, and an electromagnetic wave detector assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic plan view of the electromagnetic wave detector according to the first embodiment.

[0012] Figure 2 yes Figure 1 Schematic cross-sectional view at line segment II-II in .

[0013] Figure 3 This is a flowchart for explaining the method for manufacturing the electromagnetic wave detector according to the first embodiment.

[0014] Figure 4 This is a schematic cross-sectional view showing a first modified example of the electromagnetic wave detector according to the first embodiment.

[0015] Figure 5 This is a schematic cross-sectional view showing a second modified example of the electromagnetic wave detector according to the first embodiment.

[0016] Figure 6 This is a schematic cross-sectional view showing a third modified example of the electromagnetic wave detector according to the first embodiment.

[0017] Figure 7 This is a schematic cross-sectional view showing a fourth modified example of the electromagnetic wave detector according to the first embodiment.

[0018] Figure 8 This is a schematic cross-sectional view showing a fifth modified example of the electromagnetic wave detector according to the first embodiment.

[0019] Fig. 9 This is a schematic plan view of the inside of the electromagnetic wave detector showing an example of the arrangement of the step portions of the fifth modified example of the electromagnetic wave detector according to the first embodiment.

[0020] Fig.10 This is a schematic plan view of the inside of another example of the arrangement of the step portions of the fifth modified example of the electromagnetic wave detector according to the first embodiment.

[0021] Fig.11 This is a schematic plan view showing a sixth variation of the electromagnetic wave detector of embodiment 1.

[0022] Fig.12 This is a schematic plan view showing the seventh variation of the electromagnetic wave detector of embodiment 1.

[0023] Fig.13 This is a schematic plan view showing an eighth variation of the electromagnetic wave detector of embodiment 1.

[0024] Fig.14 This is a schematic plan view showing a ninth modified example of the electromagnetic wave detector according to the first embodiment.

[0025] Fig.15 This is a schematic cross-sectional view showing a tenth modified example of the electromagnetic wave detector according to the first embodiment.

[0026] Fig.16 This is a schematic cross-sectional view showing an eleventh modified example of the electromagnetic wave detector according to the first embodiment.

[0027] Fig.17 This is a schematic cross-sectional view showing a twelfth modified example of the electromagnetic wave detector according to the first embodiment.

[0028] Fig.18 This is a schematic cross-sectional view of the electromagnetic wave detector according to the second embodiment.

[0029] Fig.19 This is a schematic plan view of the interior of the electromagnetic wave detector according to the second embodiment.

[0030] Fig. 20 This is a schematic cross-sectional view showing a modified example of the electromagnetic wave detector according to the second embodiment.

[0031] Fig.21 This is a schematic cross-sectional view of the electromagnetic wave detector according to the third embodiment.

[0032] Fig. 22 It is a schematic cross-sectional view showing a modified example of the electromagnetic wave detector according to the third embodiment.

[0033] Fig.23 This is a schematic cross-sectional view of the electromagnetic wave detector according to the fourth embodiment.

[0034] Fig.24 This is a schematic plan view of the electromagnetic wave detector according to the fifth embodiment.

[0035] Fig.25 yes Fig.24 Schematic cross-sectional view at line segment XXV-XXV in .

[0036] Fig.26It is a schematic cross-sectional view showing a first modified example of the electromagnetic wave detector according to the fifth embodiment.

[0037] Fig. 27 It is a schematic cross-sectional view showing a second modified example of the electromagnetic wave detector according to the fifth embodiment.

[0038] Fig.28 It is a schematic cross-sectional view showing a third modified example of the electromagnetic wave detector according to the fifth embodiment.

[0039] Fig.29 This is a schematic plan view of the electromagnetic wave detector according to the sixth embodiment.

[0040] Fig.30 yes Fig.29 Schematic diagram of the cross-section at the line segment XXX-XXX in.

[0041] Fig.31 It is a schematic cross-sectional view showing a first modified example of the electromagnetic wave detector according to the sixth embodiment.

[0042] Fig.32 This is a schematic plan view showing an electromagnetic wave detector according to a seventh embodiment.

[0043] Fig.33 yes Fig.32 Schematic cross-sectional view at line segment XXXIII-XXXIII.

[0044] Fig.34 This is a schematic cross-sectional view of the electromagnetic wave detector according to the eighth embodiment.

[0045] Fig.35 This is a schematic cross-sectional view of the electromagnetic wave detector according to the ninth embodiment.

[0046] Fig.36 This is a schematic cross-sectional view of the electromagnetic wave detector according to the tenth embodiment.

[0047] Fig.37 This is a schematic cross-sectional view showing a modified example of the electromagnetic wave detector according to the tenth embodiment.

[0048] Fig.38 This is a schematic cross-sectional view of the electromagnetic wave detector according to embodiment 11.

[0049] Fig.39 This is a schematic plan view of an electromagnetic wave detector according to embodiment 12.

[0050] Fig.40 It is a plan schematic diagram showing a modified example of the electromagnetic wave detector of embodiment 12.

[0051] Explanation of symbols

[0052] 1: two-dimensional material layer; 1a, 1b, 1c, 1d: region; 1e: turbostratic structure part; 2a: first electrode part; 2b: second electrode part; 2c: third electrode part; 2c: electrode part; 2d: connecting conductor; 3: insulating film; 3a: opening; 3b: tapered part; 4: semiconductor layer; 4a: first semiconductor part; 4a1: first part; 4a2: second part; 4ab, 4ab1, 4ab2: bonding interface; 4b, ba: the second semiconductor part; 4ba, 4bc: the junction part; 4c: the semiconductor part; 5: the current cutoff mechanism; 6: the buffer layer; 7: the conductor; 8: the contact layer; 40: the step part; 41, 41a, 41b: the bottom; 42: the side; 43, 43a, 43b: the top; 44: the back part; 100, 200, 201, 202, 203: the electromagnetic wave detector; 1000, 2000: the electromagnetic wave detector assembly. DETAILED DESCRIPTION

[0053] Hereinafter, the embodiments of the present disclosure will be described with reference to the accompanying drawings. In the following drawings, the same reference numerals are given to the same or corresponding parts, and their description will not be repeated.

[0054] In the embodiments described below, the figures are schematic and conceptually illustrate functions or structures. In addition, the present disclosure is not limited to the embodiments described below. Except for the cases specifically described, the basic structure of the electromagnetic wave detector is common in all embodiments. In addition, the structures with the same symbols are the same as described above or equivalent thereto. This is common throughout the entire text of the specification.

[0055] In the embodiments described below, the electromagnetic wave detector is described using a structure for detecting visible light or infrared light, but the present disclosure is not limited to these. The embodiments described below are effective as detectors for detecting radio waves such as X-rays, ultraviolet light, near-infrared light, terahertz (THz) waves, or microwaves, in addition to detecting visible light or infrared light. In addition, in the embodiments of the present disclosure, these lights and radio waves are generally referred to as electromagnetic waves.

[0056] In the embodiments of the present disclosure, the terms p-type graphene or n-type graphene may be used as graphene. In the following embodiments, graphene having more holes than graphene in an intrinsic state is referred to as p-type graphene, and graphene having more electrons is referred to as n-type graphene.

[0057] In addition, in the embodiments of the present disclosure, the terms n-type or p-type are sometimes used with respect to the material of a member in contact with graphene as an example of a two-dimensional material layer. Here, for example, n-type material refers to a material having an electron-donating property, and p-type material refers to a material having an electron-attracting property. In addition, sometimes the charge is biased in the molecule as a whole, and the type in which electrons dominate is called n-type, and the type in which holes dominate is called p-type. As these materials, either organic matter or inorganic matter or a mixture thereof can be used.

[0058] In addition, regarding the plasma resonance phenomenon such as the surface plasmon resonance phenomenon which is the interaction between the metal surface and light, the phenomenon of pseudo surface plasmon resonance which is called the resonance applied to the metal surface outside the visible light region and the near infrared light region, or the phenomenon of metamaterial or plasma metamaterial which is called the operation of a specific wavelength by a structure with a size below the wavelength, they are not particularly distinguished by the name, but are regarded as equivalent in terms of the effect caused by the phenomenon. Here, these resonances are referred to as surface plasmon resonance, plasma resonance, or simply resonance.

[0059] In addition, in the embodiments described below, graphene is used as an example of a material for the two-dimensional material layer, but the material constituting the two-dimensional material layer is not limited to graphene. For example, as a material for the two-dimensional material layer, materials such as transition metal dichalcogenide (TMD), black phosphorus, silicene (a two-dimensional honeycomb structure based on silicon atoms), and germanene (a two-dimensional honeycomb structure based on germanium atoms) can be applied. As transition metal dichalcogenides, for example, transition metal dichalcogenides such as MoS2, WS2, and WSe2 can be cited.

[0060] These materials have a structure similar to that of graphene and are materials in which atoms can be arranged in a single layer in a two-dimensional plane. Therefore, when these materials are applied to a two-dimensional material layer, the same effects as when graphene is applied to a two-dimensional material layer can be obtained.

[0061] Implementation method 1.

[0062] <Structure of electromagnetic wave detector>

[0063] Figure 1 This is a schematic plan view of the electromagnetic wave detector according to the first embodiment. Figure 2 yes Figure 1 A cross-sectional view of the line segment IB-IB. Figure 3 , typical electrical connections of the electromagnetic wave detector 100 are also shown.

[0064] like Figure 1 as well as Figure 2 As shown, the electromagnetic wave detector of the first embodiment mainly includes a semiconductor layer 4 having a step portion, an insulating film 3, a two-dimensional material layer 1, a first electrode portion 2a, and a second electrode portion 2b.

[0065] The semiconductor layer 4 has sensitivity to a predetermined detection wavelength from among the above-mentioned electromagnetic waves. That is, the semiconductor layer 4 has a first conductive side, and is arranged in a manner to generate photocarriers in the semiconductor layer 4 when an electromagnetic wave of a predetermined detection wavelength is incident on the semiconductor layer 4. The semiconductor material constituting the semiconductor layer 4 can be arbitrarily selected according to the detection wavelength to which it should have sensitivity.

[0066] For example, when the detection wavelength range is 0.1 μm and 0.6 μm or less, gallium phosphide (GaP) can be selected as the semiconductor material constituting the semiconductor layer 4. When the detection wavelength range is 0.2 μm and 1.1 μm or less, silicon (Si) can be selected as the above-mentioned semiconductor material. When the detection wavelength range is 0.8 μm and 1.8 μm or less, germanium (Ge) can be selected as the above-mentioned semiconductor material. When the detection wavelength range is 0.7 μm and 2.55 μm or less, indium gallium arsenide (InGaAs) can be selected as the above-mentioned semiconductor material. When the detection wavelength range is 1 μm and 3.1 μm or less, indium arsenide (InAs) can be selected as the above-mentioned semiconductor material. When the detection wavelength range is 1 μm and 5.4 μm or less, indium antimonide (InSb) can be selected as the above-mentioned semiconductor material. When the detection wavelength range is 2 μm and 16 μm or less, mercury cadmium telluride (HgCdTe) can be selected as the above-mentioned semiconductor material.

[0067] In addition, the semiconductor material constituting the semiconductor layer 4 is not limited to the above. The material constituting the semiconductor layer 4 may also be a single body or a combination of materials including Si, Ge, III-V semiconductors or II-V semiconductors, HgCdTe, InSb, lead selenide (PbSe), lead sulfide (PbS), cadmium sulfide (CdS), gallium nitride (GaN), silicon carbide (SiC), gallium phosphide (GaP), InGaAs, InAs or a substrate of quantum wells or quantum dots, Type II superlattice, etc. As long as the material constituting the semiconductor layer 4 is a combination of the above semiconductor materials, multi-wavelength detection can be performed in an electromagnetic wave detector having the semiconductor layer 4.

[0068] A step portion 40 is formed on the semiconductor layer 4. The step portion 40 has a convex shape in which the number of tops 43 is less than the number of bottoms 41, and the total area of ​​the bottom 41 is larger than the total area of ​​the top 43. The step portion 40 has two bottoms 41, one top 43, and two side portions 42. The top 43 protrudes relative to the two bottoms 41 in the thickness direction of the semiconductor layer 4. The two side portions 42 are respectively arranged between the bottom 41 and the top 43. Figure 1 As shown, the top 43 has, for example, a longitudinal direction and a transverse direction. Both ends of the top 43 in the transverse direction are connected to the side portions 42. Each side portion 42 has an upper end connected to one end of the top 43 in the transverse direction and a lower end connected to one end of the bottom 41 in the transverse direction. Each bottom portion 41 has the one end connected to the lower end of the side portion 42 and the other end arranged on the opposite side of the one end in the transverse direction. Figure 2 As shown, the width of one bottom portion 41 a in the lateral width direction of the two bottom portions 41 is wider than the width of the other bottom portion 41 b in the lateral width direction.

[0069] The back surface portion 44 of the semiconductor layer 4 located on the opposite side to the step portion 40 in the thickness direction of the semiconductor layer 4 is configured as, for example, a flat surface.

[0070] The semiconductor layer 4 is prepared, for example, by doping a silicon substrate having the step portion 40 formed thereon with impurities.

[0071] The insulating film 3 is disposed on the semiconductor layer 4. The insulating film 3 is provided with an opening 3a that exposes a part of the step portion 40. The insulating film 3 is disposed, for example, on the entirety of the two bottom portions 41 and the two side portions 42 of the step portion 40 and on a part of the top portion 43. The opening 3a, for example, exposes a part of the top portion 43. The opening 3a, for example, exposes the central part of the top portion 43 in the lateral width direction. The distance between the opening 3a and one end of the top portion 43 in the lateral width direction is equal to the distance between the opening 3a and the other end of the top portion 43 in the lateral width direction. The distance between the opening 3a and one end of the top portion 43 in the lateral width direction and the distance between the opening 3a and the other end of the top portion 43 in the lateral width direction are, for example, constant in the longitudinal direction. The opening 3a, for example, extends from one end to the other end of the top portion 43 in the longitudinal direction. The opening 3a, for example, has a longitudinal direction and a lateral width direction. The longitudinal direction of the opening 3a, for example, is along the longitudinal direction of the top portion 43. The lateral width direction of the opening 3 a is along the lateral width direction of the top portion 43 .

[0072] The material constituting the insulating film 3 is, for example, silicon oxide (SiO2), tetraethyl orthosilicate (Si(OC2H5)4), silicon nitride (Si3N4), hafnium dioxide (HfO2), aluminum oxide (Al2O3), nickel oxide (NiO), tetraethyl orthosilicate (TEOS), barium titanate (BaTiO3), lead zirconate titanate (PbZrTiO3), strontium bismuth tantalate (SrBi2Ta2O9), bismuth ferrite (BFO:BiFeO3), lithium niobate (LiNbO3), lithium tantalate (LiTaO3), boron nitride (BN) or a siloxane series polymer material. The atomic arrangement of BN is similar to that of graphene, so even if it contacts the two-dimensional material layer 1 including graphene, it will not adversely affect the electron mobility of the two-dimensional material layer 1. Therefore, BN is suitable as the insulating film 3 of the base film disposed under the two-dimensional material layer 1.

[0073] Regarding the thickness T of the insulating film 3, there is no particular restriction as long as the two-dimensional material layer 1 and the first electrode portion 2a are electrically insulated from the semiconductor layer 4 and the tunnel current is prevented from being generated between the two-dimensional material layer 1 and the first electrode portion 2a and the semiconductor layer 4. In addition, the thinner the thickness T of the insulating film 3, the greater the degree of change in the electric field of the two-dimensional material layer 1 caused by the photocarriers generated at the interface between the insulating film 3 and the semiconductor layer 4. Therefore, the thickness T of the insulating film 3 is preferably as thin as possible. In addition, the change in the electric field of the two-dimensional material layer 1 caused by the photocarriers generated at the interface between the insulating film 3 and the semiconductor layer 4 is called a grating effect, and its details will be described later.

[0074] The first electrode portion 2a is disposed on the insulating film 3. The first electrode portion 2a is disposed at a position away from the opening 3a. Preferably, the first electrode portion 2a is disposed on the bottom portion 41a. The first electrode portion 2a is electrically connected to the two-dimensional material layer 1.

[0075] The second electrode portion 2b is arranged on the semiconductor layer 4. The second electrode portion 2b is electrically connected to the first electrode portion 2a via the later-described region 1c (connection region) of the two-dimensional material layer 1. The second electrode portion 2b is arranged, for example, on the entire region of the back portion 44 of the semiconductor layer 4 located on the opposite side of the step portion 40 in the thickness direction of the semiconductor layer 4. In this case, the electromagnetic wave that is incident on the electromagnetic wave detector from the step portion 40 side, passes through the semiconductor layer 4 and reaches the back portion 44, is reflected by the second electrode portion 2b. Therefore, the absorption rate of the electromagnetic wave of the semiconductor layer 4 can be improved.

[0076] As the material constituting the first electrode portion 2a and the second electrode portion 2b, any material can be used as long as it is a conductor. For example, the material constituting the first electrode portion 2a and the second electrode portion 2b includes at least one selected from the group consisting of gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr) and palladium (Pd). An unillustrated adhesion layer that improves the adhesion between the first electrode portion 2a and the insulating film 3 may also be formed between the first electrode portion 2a and the insulating film 3. An unillustrated adhesion layer that improves the adhesion between the second electrode portion 2b and the semiconductor layer 4 may also be formed between the second electrode portion 2b and the semiconductor layer 4. The material constituting the adhesion layer includes, for example, a metal material such as chromium (Cr) or titanium (Ti).

[0077] also, Figure 2 The first electrode portion 2a shown is formed at the lower portion of the two-dimensional material layer 1, but the first electrode portion 2a may be formed at the upper portion of the two-dimensional material layer 1. Figure 2 The second electrode portion 2b shown is arranged on the entire area of ​​the back portion 44 of the semiconductor layer 4, but it is not limited to this. The second electrode portion 2b may be arranged on the portion exposed from the insulating film 3 on the bottom 41 or the side 42 of the semiconductor layer 4, for example, and directly connected to the portion. As long as the second electrode portion 2b is not arranged on the back portion 44, it is possible to detect electromagnetic waves irradiated from the back portion 44 side.

[0078] The two-dimensional material layer 1 is arranged on the insulating film 3 and the opening 3a. The two-dimensional material layer 1 extends from the inside of the opening 3a to the insulating film 3. The two-dimensional material layer 1 is electrically connected to the first electrode portion 2a on the insulating film 3, and is electrically connected to the semiconductor layer 4 inside the opening 3a. The two-dimensional material layer 1 is arranged, for example, on a portion of a bottom 41a, a side portion 42, a top portion 43, another side portion 42, and a portion of another bottom 41b.

[0079] From a different point of view, the two-dimensional material layer 1 has a region 1a electrically connected to the first electrode portion 2a, a region 1c electrically connected to the semiconductor layer 4 inside the opening portion 3a (a region located inside the opening portion 3a), and a region 1b opposite to the semiconductor layer 4 via the insulating film 3. The region 1a is directly connected to the first electrode portion 2a, for example. The region 1c is directly connected to the semiconductor layer 4, for example. The region 1a is arranged on a portion of the bottom 41. The region 1c is arranged on a portion of the top 43. The region 1b is arranged on the remaining portion of the top 43 and on two side portions 42. A portion of the region 1b is arranged on one side portion 42 to connect the region 1a and the region 1c. Another portion of the region 1b is arranged on the other side portion 42. Another portion of the region 1b extends from the region 1c to a portion of the insulating film 3 on the side opposite to the side where the first electrode portion 2a is located when viewed from the opening portion 3a of the insulating film 3.

[0080] The two-dimensional material layer 1 is, for example, a single-layer graphene. The single-layer graphene is a single-atom layer of a two-dimensional carbon crystal. In addition, the single-layer graphene has carbon atoms in each chain arranged in a hexagonal shape. Graphene has a higher carrier mobility than semiconductor materials such as Si used in conventional electronic devices, so it has the effect of increasing the light response speed through the electromagnetic wave detector 100.

[0081] The two-dimensional material layer 1 may also be a stack of more than two layers of graphene (hereinafter referred to as multilayer graphene). The orientation of the lattice vectors of the hexagonal lattice of each graphene in the multilayer graphene may be inconsistent or different. In addition, the orientation of the lattice vectors of the hexagonal lattice of each graphene in the multilayer graphene may also be completely consistent. In multilayer graphene, the size of the band gap of the multilayer graphene can be adjusted according to the number of layers of graphene. Therefore, by adjusting the size of the band gap of the multilayer graphene according to the detection wavelength, the two-dimensional material layer 1 is made to function as an electromagnetic wave absorption layer, and an optical filter can also be made unnecessary. Thus, the number of optical components can be reduced, and the loss of incident light caused by passing through an optical filter can be reduced.

[0082] When the material constituting the two-dimensional material layer 1 includes graphene, the graphene may be formed as a nanoribbon (hereinafter referred to as graphene nanoribbon) obtained by cutting a graphene sheet into nanometer-level widths. The two-dimensional material layer 1 may be formed as a graphene nanoribbon monomer, a stack of a plurality of graphene nanoribbons, or a structure in which graphene nanoribbons are periodically arranged on a plane.

[0083] When the two-dimensional material layer 1 includes periodically arranged graphene nanoribbons (graphene metamaterial), plasmon resonance occurs in the two-dimensional material layer 1 , and the electromagnetic wave detection sensitivity based on the two-dimensional material layer 1 is improved.

[0084] When the material constituting the two-dimensional material layer 1 includes graphene, the graphene may be graphene not doped with impurities. In addition, the graphene may be graphene doped with p-type or n-type impurities.

[0085] The material constituting the two-dimensional material layer 1 is, for example, the same in each of the regions 1a, 1b, and 1c. The material constituting the two-dimensional material layer 1 may be different in each of the regions 1a, 1b, and 1c.

[0086] The material constituting the region 1a is, for example, multilayer graphene. The region 1a is doped with carriers from the first electrode portion 2a. For example, when the material of the first electrode portion 2a is gold (Au), holes are doped into the region 1a of the two-dimensional material layer 1 due to the difference in work function between graphene and Au. When the electromagnetic wave detector is driven in this state, due to the influence of holes doped into the region 1a from the first electrode portion 2a, the mobility of carriers flowing through the channel region of the two-dimensional material layer 1 decreases, and the contact resistance between the two-dimensional material layer 1 and the first electrode portion 2a increases. Due to the increase in the contact resistance, the mobility of electrons (carriers) based on the electric field effect in the electromagnetic wave detector decreases, which may cause a decrease in the performance of the electromagnetic wave detector. In particular, when the material constituting the region 1a is a single-layer graphene, the doping amount of carriers injected from the first electrode portion 2a is greater than that when the material constituting the region 1a is a multilayer graphene, and as a result, the above-mentioned decrease in carrier mobility in the electromagnetic wave detector becomes significant. Therefore, from the viewpoint of suppressing the reduction in the above-mentioned carrier mobility and improving the performance of the electromagnetic wave detector, the material constituting the region 1 a is preferably multilayer graphene rather than single-layer graphene.

[0087] The material constituting the region 1b is, for example, a single-layer graphene. The region 1b functions as a so-called channel region. The mobility of electrons in a single-layer graphene is higher than the mobility of electrons in a multilayer graphene. Therefore, from the viewpoint of improving the mobility of electrons in the region 1b and improving the performance of the electromagnetic wave detector, the material constituting the region 1b is preferably a single-layer graphene rather than a multilayer graphene.

[0088] That is to say, by setting the material constituting region 1a to multilayer graphene and the material constituting region 1b to single-layer graphene, the increase in contact resistance between region 1a and the first electrode portion 2a can be suppressed, and the mobility of electrons in region 1b can be increased, thereby improving the performance of the electromagnetic wave detector.

[0089] <Method for manufacturing electromagnetic wave detector>

[0090] Figure 3 1 is a flowchart for explaining the method for manufacturing the electromagnetic wave detector according to the first embodiment. Figure 3 ,illustrate Figure 1 as well as Figure 2 The manufacturing method of the electromagnetic wave detector shown.

[0091] First, implement Figure 3 The preparation step (S1) shown in the figure is as follows. In this step (S1), a flat semiconductor substrate is prepared. The semiconductor material constituting the semiconductor substrate is a semiconductor material having sensitivity to a predetermined detection wavelength.

[0092] Next, a semiconductor layer step portion forming step (S2) is implemented. In this step (S2), first, a protective film is formed on the region of the top 43 where the step portion 40 is to be formed on the semiconductor substrate. The protective film is, for example, a resist. In the protective film, an opening is formed to expose the region where the bottom 41 is to be formed, for example, by photolithography or electron beam (EB) drawing. Next, the semiconductor substrate is etched using the protective film as an etching mask. The etching technique can be selected from any etching selected from wet etching using chemical solutions such as acids and alkalis and dry etching using active species in plasma. After etching, the protective film is removed. In this way, a semiconductor layer 4 having a step portion 40 is formed from the semiconductor substrate.

[0093] Next, an electrode forming step (S3) is performed. In this step (S3), the second electrode portion 2b is formed on the back side of the semiconductor layer 4. Specifically, after forming a protective film on the step portion 40 of the semiconductor layer 4, a metal film is formed. Before forming the second electrode portion 2b, in order to improve the adhesion between the semiconductor layer 4 and the second electrode portion 2b, the above-mentioned adhesion layer may be pre-formed in the region where the semiconductor layer 4 and the second electrode portion 2b are connected.

[0094] Next, an insulating film forming step (S4) is performed. In this step (S4), an insulating film 3 is formed on the step portion 40 of the semiconductor layer 4. Preferably, the insulating film 3 is formed in a manner that adheres to the bottom 41, the side 42 and the top 43 of the step portion 40 without a gap. The film forming method of the insulating film 3 is not particularly limited. In the case where the material constituting the semiconductor layer 4 is Si and the material constituting the insulating film 3 is SiO2, the insulating film 3 can be formed by thermally oxidizing the surface of the semiconductor layer 4. The film forming method of the insulating film 3 can also be a CVD (Chemical Vapor Deposition) method or a sputtering method.

[0095] Furthermore, in order to suppress damage and contamination of the semiconductor layer 4 due to etching in the opening forming step (S6) described later, a barrier film may be formed between the semiconductor layer 4 and the insulating film 3 immediately before the insulating film forming step (S4). The material constituting the barrier film may be a material having higher resistance to the etchant used in the opening forming step (S6) than the material constituting the insulating film 3 (a material having a slow etching rate), such as silicon nitride (SiN), aluminum oxide (Al2O3) or graphene.

[0096] Next, an electrode forming step (S5) is performed. In this step (S5), the first electrode portion 2a is formed on the insulating film 3. Before forming the first electrode portion 2a, in order to improve the adhesion between the insulating film 3 and the first electrode portion 2a, the above-mentioned adhesion layer may be pre-formed in the region of the insulating film 3 connected to the first electrode portion 2a.

[0097] As a method for forming the first electrode portion 2a, for example, the following process can be used. First, a resist mask is formed on the surface of the insulating film 3 using photoengraving or EB drawing. In the resist mask, an opening is formed in the area where the first electrode portion 2a is to be formed. Thereafter, a film of a metal or the like that is to become the first electrode portion 2a is formed on the resist mask. For the formation of the film, a vapor deposition method, a sputtering method, etc. can be used. At this time, the film is formed in a manner extending from the inside of the opening of the resist mask to the upper surface of the resist mask. Thereafter, by removing the resist mask together with a portion of the film, another portion of the film disposed at the opening of the resist mask remains on the surface of the insulating film 3, becoming the first electrode portion 2a. The above method is generally referred to as a stripping method.

[0098] As a method for forming the first electrode portion 2a, other methods may also be used. For example, a film such as a metal film that is to become the first electrode portion 2a is first formed on the surface of the insulating film 3. Thereafter, a resist mask is formed on the film by photolithography. The resist mask is formed in a manner that covers the area where the first electrode portion 2a is to be formed, and on the other hand, is not formed in areas other than the area where the first electrode portion 2a is to be formed. Thereafter, the film is partially removed by wet etching or dry etching using the resist mask as a mask. As a result, a portion of the film remains under the resist mask. A portion of the film becomes the first electrode portion 2a. Thereafter, the resist mask is removed. In this way, the first electrode portion 2a may also be formed.

[0099] Next, an opening forming step (S6) is performed. In this step (S6), an opening 3a is formed in the insulating film 3. Specifically, a resist mask is formed on the insulating film 3 by photolithography or EB drawing. In the resist mask, an opening is formed in the region where the opening 3a of the insulating film 3 is to be formed. Thereafter, the insulating film 3 is etched using the resist mask as an etching mask. The etching technique can be arbitrarily selected from any of the above-mentioned wet etching and the above-mentioned dry etching. After etching, the resist mask is removed. In this way, the opening 3a is formed in the insulating film 3. The above-mentioned step (S6) may also be performed before the step (S5).

[0100] Next, a two-dimensional material layer forming step (S7) is implemented. In this step (S7), a two-dimensional material layer 1 is formed on the step portion 40. The two-dimensional material layer 1 is formed in a manner that covers the entirety of the first electrode portion 2a, the insulating film 3, and the semiconductor layer 4 exposed inside the opening portion 3a of the insulating film 3. The method for forming the two-dimensional material layer 1 is not particularly limited. The two-dimensional material layer 1 can be formed, for example, by epitaxial growth or by screen printing. In addition, the two-dimensional material layer 1 can be formed by transferring a two-dimensional material film that has been previously formed by a CVD method to the step portion 40 and closely adhering to it, or by transferring a thin film of a two-dimensional material film that has been peeled off by mechanical peeling or the like to the step portion 40 and closely adhering to it.

[0101] Then, a resist mask is formed on the two-dimensional material layer 1 by photolithography or EB drawing. The resist mask is formed in a manner that covers the area where the two-dimensional material layer 1 is to be formed and exposes the other areas. Then, the two-dimensional material layer 1 is etched using the resist mask as a mask. The etching method is, for example, dry etching based on oxygen plasma. Then, the resist mask is removed. Thus, a two-dimensional material layer 1 is formed. Figure 1 as well as Figure 2 The two-dimensional material layer 1 is shown.

[0102] Through the above steps (S1 to S7), the Figure 1 as well as Figure 3 The electromagnetic wave detector shown. In addition, in the above-mentioned manufacturing method, the two-dimensional material layer 1 is formed on the first electrode portion 2a, but the two-dimensional material layer 1 can also be formed in advance on the insulating film 3, and the first electrode portion 2a can be formed in a manner overlapping a portion of the two-dimensional material layer 1. However, when using this structure, it is necessary to pay attention to not causing process damage to the two-dimensional material layer 1 when forming the first electrode portion 2a. For example, it is considered to form the first electrode portion 2a in a state where the area other than the area where the first electrode portion 2a is formed overlapping the two-dimensional material layer 1 is pre-covered with a protective film or the like.

[0103] <Operation Principle>

[0104] Next, the operating principle of the electromagnetic wave detector according to this embodiment will be described.

[0105] like Figure 2As shown, a power supply circuit (not shown) is electrically connected between the first electrode portion 2a and the second electrode portion 2b, and a voltage V is applied between the first electrode portion 2a and the second electrode portion 2b. As a result, a current path is formed inside the electromagnetic wave detector in which the first electrode portion 2a, the two-dimensional material layer 1, the semiconductor layer 4 and the second electrode portion 2b are connected in series in sequence, and a current I flows through the two-dimensional material layer 1. An ammeter (not shown) is provided in the power supply circuit to monitor the current I flowing through the two-dimensional material layer 1. In this way, the electromagnetic wave detector is set to a state capable of detecting electromagnetic waves. In addition, the positive and negative voltages are selected according to the conductivity type (doping type) of the semiconductor layer 4. If the conductivity type is p-type, a positive voltage is applied to the first electrode portion 2a, and if the conductivity type is n-type, a negative voltage is applied to the first electrode portion 2a.

[0106] When an electromagnetic wave of a wavelength to which the semiconductor layer 4 is sensitive is incident on the semiconductor layer 4 in the above state, photocarriers are generated inside the semiconductor layer 4. At this time, the photocarriers generated in the semiconductor layer 4 near the opening 3a are injected into the region 1c of the two-dimensional material layer 1, and the current I changes through the region 1b and the region 1c. Hereinafter, the current component that causes a change in the current I due to the irradiation of the electromagnetic wave is referred to as a photocurrent.

[0107] Furthermore, a voltage is applied to the semiconductor layer 4, so a depletion layer is formed at the interface between the semiconductor layer 4 and the insulating film 3. The depletion layer is widely formed at the interfaces between the bottom 41, the side 42 and the top 43 of the step portion 40 and the insulating film 3. When an electromagnetic wave of a wavelength to which the semiconductor layer 4 is sensitive is incident on the semiconductor layer 4, photocarriers are also generated in the depletion layer. The photocarriers generated in the depletion layer exert an electric field effect on the region 1b of the two-dimensional material layer 1 via the insulating film 3. As a result, the resistance value of the region 1b of the two-dimensional material layer 1 changes, and the current I flowing through the two-dimensional material layer 1 changes. In this way, the electric field effect derived from the light irradiation is applied to the region 1b, so that the electrical characteristics of the two-dimensional material layer 1 change. This causes the above-mentioned grating effect.

[0108] The change in the current I is detected via the first electrode portion 2a electrically connected to the region 1a of the two-dimensional material layer 1. Thus, the electromagnetic wave irradiated to the electromagnetic wave detector can be detected.

[0109] Here, the electromagnetic wave detector of this embodiment is not limited to the structure of detecting the change of the current in the two-dimensional material layer 1 as described above. For example, a constant current can be passed between the first electrode portion 2a and the second electrode portion 2b to detect the change of the voltage V between the first electrode portion 2a and the second electrode portion 2b (that is, the change of the voltage value in the two-dimensional material layer 1).

[0110] Next, explain Figure 1 as well as Figure 2Here, the case where the material constituting the two-dimensional material layer 1 is a single-layer graphene, the material constituting the first electrode portion 2a and the second electrode portion 2b is Au, the material constituting the insulating film 3 is Al2O3, and the material constituting the semiconductor layer 4 is n-type InSb is described.

[0111] N-type InSb is sensitive to electromagnetic waves of 1 μm to 5.4 μm or less. Therefore, when electromagnetic waves of 1 μm to 5.4 μm or less are incident on the semiconductor layer 4, photocarriers are generated in the semiconductor layer 4. The photocarriers generated in the semiconductor layer 4 near the opening 3a are injected into the single-layer graphene in the region 1c, causing the current I to change.

[0112] Furthermore, a positive voltage is applied to the second electrode portion 2b or a negative voltage is applied to the first electrode portion 2a in a reverse biased manner relative to the semiconductor layer 4, so that the electrons in the semiconductor layer 4 are attracted to the second electrode portion 2b, and the holes as minority carriers are attracted to the insulating film 3 side. As a result, a depletion layer is formed at the interface between the semiconductor layer 4 and the insulating film 3. The photocarriers generated in the depletion layer produce a grating effect as described above, and an electric field effect is applied to the single-layer graphene constituting the region 1b, so that the mobility of the single-layer graphene constituting the region 1b changes. The magnitude of the electric field effect is related to the amount of photocarriers generated in the depletion layer. That is, when an electromagnetic wave of 1μm and 5.4μm or less is incident on n-type InSb, the photocarriers generated by the n-type InSb are injected into the single-layer graphene constituting the region 1c, thereby generating a photocurrent, and applying a grating effect to the single-layer graphene constituting the region 1b. As a result, the photocurrent is amplified in the region 1b.

[0113] The grating effect does not directly enhance the quantum efficiency of the photoelectric conversion material, but increases the current change based on the incident electromagnetic wave, so the quantum efficiency equivalently calculated from the differential current based on the incident electromagnetic wave can exceed 100%.

[0114] Therefore, the change in current I when the electromagnetic wave is incident on the electromagnetic wave detector of this embodiment is greater than the change in current when the electromagnetic wave is incident on the conventional electromagnetic wave detector where the region 1b is not provided and the grating effect is not exerted. Therefore, the sensitivity of the electromagnetic wave detector of this embodiment is higher than that of the conventional electromagnetic wave detector.

[0115] The larger the area 1b of the two-dimensional material layer 1 that is affected by the electric field effect, the greater the grating effect, and the more sensitive the electromagnetic wave detection can be. Since the two-dimensional material layer 1 is formed of a single atomic layer or a single molecular layer, it can be formed along the structural surface of the electromagnetic wave detector. The two-dimensional material layer 1 in the electromagnetic wave detector of this embodiment is arranged on the bottom 41, the side 42 and the top 43 of the step portion 40, and the area 1b is arranged on a part of the side 42 and the top 43. Therefore, in comparison Figure 1 When the occupied area of ​​the region 1b shown in the electromagnetic wave detector of the present embodiment and the electromagnetic wave detector of the comparative example in which the two-dimensional material layer 1 is not arranged on the step portion 40 are set equally (i.e., the occupied area of ​​the region 1b when viewed from above), the region 1b of the electromagnetic wave detector of the present embodiment is larger than the region 1b that can be formed in the comparative example. As a result, the grating effect played in the electromagnetic wave detector of the present embodiment is improved than the grating effect played in the comparative example. As a result, the detection sensitivity of the electromagnetic wave detector of the present embodiment is higher than that of the electromagnetic wave detector of the comparative example.

[0116] From a different point of view, the occupied area of ​​the region 1b required to achieve a specific detection sensitivity in the electromagnetic wave detector of the present embodiment is smaller than the occupied area of ​​the region 1b required to achieve the specific detection sensitivity in the electromagnetic wave detector of the above-mentioned comparative example. Therefore, in the electromagnetic wave detector of the present embodiment, compared with the electromagnetic wave detector of the above-mentioned comparative example, it is possible to save area. As a result, the electromagnetic wave detector of the present embodiment is suitable for an image sensor in which electromagnetic wave detectors are arranged at a high density.

[0117] In particular, the electromagnetic wave detector of the present embodiment is arranged in such a manner that the portion of region 1b that connects region 1c and region 1a becomes sufficiently long. Specifically, region 1b is arranged at least on the entire side portion 42 that connects the bottom 41a and the top 43 on the step portion 40. Therefore, the length of the portion of region 1b that connects region 1c and region 1a in the electromagnetic wave detector of the present embodiment is longer than the length of the electromagnetic wave detector in which region 1c is arranged on the side portion 42 that connects the bottom 41a and the top 43. As a result, in the electromagnetic wave detector of the present embodiment, compared with the above-mentioned electromagnetic wave detector, when electromagnetic waves are incident, the region where the photocarriers injected from the semiconductor layer 4 into the two-dimensional material layer 1 at the opening 3a are affected by the electric field change of the two-dimensional material layer 1 accompanied by the grating effect becomes larger, so the degree of photocurrent change becomes larger, and electromagnetic wave detection with higher sensitivity can be performed.

[0118] In addition, the two-dimensional material layer 1 outside the photocarrier path between the opening portion 3a and the first electrode portion 2a will be affected by the electric field changes associated with the above-mentioned grating effect as long as there is a region arranged on the semiconductor layer 4 where the electromagnetic wave is incident through the insulating film 3, and will indirectly contribute to the modulation of the photocarriers, thereby being beneficial to the high sensitivity of the electromagnetic wave detector.

[0119] In addition, the two-dimensional material layer 1 and the semiconductor layer 4 are electrically connected at the opening 3a, so the current I can be made zero by adjusting the voltage V. That is, when light is not irradiated, the current I becomes zero, and when light is irradiated, the current derived only from the photocarriers injected into the two-dimensional material layer 1 changes due to the above-mentioned grating effect and is detected as the current I. Therefore, in the electromagnetic wave detector of this embodiment, a shutdown operation can be performed.

[0120] In the case where the two-dimensional material layer 1 is, for example, a single layer of graphene, the thickness of the two-dimensional material layer 1 is extremely thin, as thin as one atomic layer. In addition, the carrier mobility in a single layer of graphene is greater than that of conventional semiconductor materials. Therefore, in the two-dimensional material layer 1, a large current change occurs relative to a slight potential change compared to conventional semiconductor materials. For example, the current change caused by the potential change applied to the two-dimensional material layer 1 due to the electric field change in the semiconductor layer 4 is greater than the current change in a conventional semiconductor. Specifically, when calculated based on the mobility and thickness of the electrons in the two-dimensional material layer 1, the above-mentioned current change in the two-dimensional material layer 1 becomes about several hundred to several thousand times the current change in a conventional semiconductor. Therefore, in the electromagnetic wave detector of the present embodiment, compared with the electromagnetic wave detector that only detects the photocarriers generated in the semiconductor layer 4, a higher sensitivity electromagnetic wave detection can be performed.

[0121] In the electromagnetic wave detector of the present embodiment, in addition to the photocurrent generated in the semiconductor layer 4 accompanying light irradiation, a photocurrent caused by the photoelectric conversion efficiency of the two-dimensional material layer 1 is also generated. Therefore, in the electromagnetic wave detector of the present embodiment, in addition to being able to detect the current generated in the semiconductor layer 4 due to the incidence of electromagnetic waves and the current accompanied by the grating effect, the photocurrent caused by the original photoelectric conversion efficiency of the two-dimensional material layer 1 can also be detected.

[0122] As described above, the detection sensitivity of the electromagnetic wave detector as this embodiment is higher than that of the conventional electromagnetic wave detector and the electromagnetic wave detector of the comparative example, and the shut-off action can be performed. Furthermore, in the electromagnetic wave detector as this embodiment, compared with the conventional electromagnetic wave detector and the electromagnetic wave detector of the comparative example, the area can be saved.

[0123] <Modification>

[0124] Figure 4, Figure 5 as well as Figure 6 Each electromagnetic wave detector shown basically has Figure 2 The electromagnetic wave detector shown in FIG. 1 has the same structure, but the relative positional relationship between the step portion 40 and the opening 3a of the insulating film 3 is different from that of FIG. Figure 2 The electromagnetic wave detectors shown are different.

[0125] (First Modification)

[0126] exist Figure 4 In the electromagnetic wave detector of the first modified example shown, the step portion 40 has a concave shape in which the number of tops 43 is greater than the number of bottoms 41 and the total area of ​​the bottom 41 is smaller than the total area of ​​the top 43. One step portion 40 has one bottom 41, two tops 43, and two side portions 42. The bottom 41 is recessed relative to the two tops 43 in the thickness direction of the semiconductor layer 4. The two side portions 42 are respectively arranged between the bottom 41 and the top 43.

[0127] The insulating film 3 is, for example, disposed on the entirety of the two tops 43 and the two side portions 42 of the step portion 40 and on a portion of the bottom 41. The opening 3a, for example, exposes a portion of the bottom 41. The opening 3a, for example, exposes the central portion of the bottom 41 in the above-mentioned lateral width direction. The distance between the opening 3a and one end of the bottom 41 in the above-mentioned lateral width direction is equal to the distance between the opening 3a and the other end of the bottom 41 in the above-mentioned lateral width direction. The distance between the opening 3a and one end of the bottom 41 in the above-mentioned lateral width direction and the distance between the opening 3a and the other end of the bottom 41 in the above-mentioned lateral width direction are, for example, constant in the above-mentioned longitudinal direction. The opening 3a, for example, extends from one end to the other end of the bottom 41 in the above-mentioned longitudinal direction. The opening 3a, for example, has a longitudinal direction and a lateral width direction. The longitudinal direction of the opening 3a, for example, is along the above-mentioned longitudinal direction of the bottom 41. The lateral width direction of the opening 3a is along the above-mentioned lateral width direction of the bottom 41.

[0128] The first electrode portion 2a is disposed on one of the two top portions 43a in the lateral width direction. The two-dimensional material layer 1 is disposed, for example, on a portion of one top portion 43a, one side portion 42, the bottom portion 41, the other side portion 42, and a portion of the other top portion 43b. Figure 4 In the two-dimensional material layer 1 shown, a region 1 c electrically connected to the semiconductor layer 4 is disposed on the bottom 41 .

[0129] Figure 4 The distance between the region 1c and the second electrode portion 2b is Figure 2 The distance shown is short. Figure 4 In the electromagnetic wave detector shown in FIG. Figure 2Compared with the electromagnetic wave detector shown, among the photocarriers generated in the semiconductor layer 4 due to the electromagnetic waves reflected or scattered by the second electrode portion 2 b , the number of photocarriers that are not injected into the region 1 c of the two-dimensional material layer 1 and deactivated is reduced, and the photocurrent is increased.

[0130] (Second Modification)

[0131] exist Figure 5 In the electromagnetic wave detector of the second variant shown, the opening 3a of the insulating film 3 and the region 1c of the two-dimensional material layer 1 are arranged on the bottom 41b. Therefore, the portion of the region 1b of the two-dimensional material layer 1 that connects the region 1a and the region 1c is arranged on at least the entirety of the two side portions and the entirety of one top portion. Therefore, Figure 4 The length of the portion connecting region 1c and region 1a in region 1b is Figure 2 Length shown is long.

[0132] exist Figure 5 In the electromagnetic wave detector shown in FIG. Figure 2 Compared with the electromagnetic wave detector shown, the region where the photocarriers injected from the semiconductor layer 4 into the two-dimensional material layer 1 are modulated by the grating effect when irradiated with electromagnetic waves increases, and the contribution of the grating effect becomes larger, so the detection sensitivity is high.

[0133] (Third Modification)

[0134] exist Figure 6 In the electromagnetic wave detector of the third variant shown, the opening 3a of the insulating film 3 and the region 1c of the two-dimensional material layer 1 are arranged on one of the two side portions 42 that does not face the first electrode portion 2a. Therefore, the portion of the region 1b of the two-dimensional material layer 1 that connects the region 1a and the region 1c is arranged on at least the entirety of one side portion and the entirety of one top portion. Therefore, Figure 6 The length of the portion connecting region 1c and region 1a in region 1b is Figure 2 Length shown is long.

[0135] In addition, in Figure 5As shown, when the opening 3a of the insulating film 3 is arranged on the bottom 41, the bottom 41 is preferably arranged parallel to the back portion 44 from the viewpoint of accurately and easily forming the opening 3a. In contrast, in the electromagnetic wave detector of the third variant, as long as one side portion 42 is arranged parallel to the other side portion 42, the opening 3a can be accurately and easily formed even if the bottom 41 and the back portion 44 are not arranged parallel. As a result, in the electromagnetic wave detector of the third variant, the area (pixel area) when viewed from above can be made smaller than that of the electromagnetic wave detector of the second variant. As a result, when a plurality of electromagnetic wave detectors are arranged side by side as an electromagnetic wave detector assembly, each electromagnetic wave detector can be arranged at a high density.

[0136] (Fourth Modification)

[0137] Figure 7 The electromagnetic wave detector of the fourth variant shown basically has the same Figure 2 The electromagnetic wave detector shown in FIG. 1 has the same structure as that shown in FIG. 1 , but has a plurality of openings 3a and regions 1c provided with respect to one step portion 40. Figure 2 The electromagnetic wave detectors shown are different.

[0138] In the electromagnetic wave detector of the fourth modification, the area ratio of the bonding surface 4aa between the two-dimensional material layer 1 and the semiconductor layer 4 is Figure 2 The electromagnetic wave detector shown is large. As described above, the material constituting the two-dimensional material layer 1 is different from the material constituting the semiconductor layer 4, so their work functions are also different. As a result, carriers are doped in the region 1c where the two-dimensional material layer 1 contacts the semiconductor layer 4, but the amount of doping in the region 1c is greatly affected by the number and size of the contact regions between the two-dimensional material layer 1 and the semiconductor layer 4. Moreover, the efficiency of extracting the photocarriers generated in the semiconductor layer 4 when the electromagnetic wave is incident to the two-dimensional material layer 1 is greatly affected by the above-mentioned doping amount in the region 1c.

[0139] In the electromagnetic wave detector of the fourth variant, the number and size of the contact regions between the two-dimensional material layer 1 and the semiconductor layer 4 can be adjusted according to the number of openings 3a and the area of ​​each opening. Figure 2 Compared with the electromagnetic wave detector shown in the figure, the efficiency of extracting the photocarriers generated in the semiconductor layer 4 when the electromagnetic wave is incident to the two-dimensional material layer 1 is improved. In addition, in the electromagnetic wave detector of the fourth variant, multiple paths for transmitting photocarriers are formed in the two-dimensional material layer 1, so when defects or abnormalities occur in any path during manufacturing or use, the reduction in yield or the occurrence of failures are suppressed.

[0140] (Fifth Modification)

[0141] Figure 8 ,9 The electromagnetic wave detector of the fifth variant shown in 10 basically has the same Figure 2 The electromagnetic wave detector shown in FIG. 1 has the same structure as that shown in FIG. 1 , but has a plurality of step portions 40 formed therein. Figure 2 The electromagnetic wave detector shown is different. In addition, Fig. 9 , 10 In order to explain the shape and arrangement of the plurality of step portions 40, only the semiconductor layer 4 is shown.

[0142] The plurality of step portions 40 have a plurality of bottom portions 41, a plurality of side portions 42, and a plurality of top portions 43. For example, two or more step portions 40 are disposed between the opening portion 3a of the insulating film 3 and the first electrode portion 2a. Figure 5 As shown, the opening 3a of the insulating film 3 is arranged, for example, on the step portion 40 farthest from the first electrode portion 2a. The opening 3a of the insulating film 3 is arranged, for example, on the top 43 of the step portion 40 farthest from the first electrode portion 2a.

[0143] By doing so, the length of the region 1b extending between the region 1a connected to the first electrode portion 2a and the region 1c connected to the semiconductor layer 4 in the opening 3a is made shorter than Figure 2 as well as Figures 4 to 6 The length of each region 1b shown is long.

[0144] As a result, Figure 5 In the electromagnetic wave detector shown in FIG. Figure 2 as well as Figures 4 to 6 Compared with the electromagnetic wave detector shown, the region where the photocarriers injected from the semiconductor layer 4 into the two-dimensional material layer 1 are modulated by the grating effect when irradiated with electromagnetic waves increases, and the contribution of the grating effect becomes larger, so the detection sensitivity is high.

[0145] In addition, if Fig. 9 , 10 As shown in FIG. 1 , a plurality of step portions are formed in a lattice pattern in the semiconductor layer 4, thereby causing diffraction and interference between electromagnetic waves incident on the semiconductor layer 4. In an example of a lattice pattern, Fig. 9 As shown in FIG. 1 , a plurality of step portions 40 are arranged in a manner that the planar shapes are the same or different from each other, and are arranged at equal intervals in two directions orthogonal to each other. In another example of a lattice pattern, as shown in FIG. Fig.10 As shown in FIG. 1 , the step portions 40 provided so as to have the same or different planar shapes extend in one direction and are arranged at equal intervals in another direction orthogonal to the one direction.

[0146] Thus, only electromagnetic waves of a specific wavelength are transmitted through the semiconductor layer 4 or absorbed by the semiconductor layer 4. Furthermore, in the process where only electromagnetic waves of a specific wavelength are affected by diffraction, they are mutually reinforced and propagate on the surface of the semiconductor layer 4. Therefore, in the electromagnetic wave detector of the fifth modified example, the detection sensitivity of the electromagnetic wave detector can be controlled by the shape and arrangement of the plurality of step portions 40.

[0147] Furthermore, part of the electromagnetic wave incident on the other regions of the semiconductor layer 4 other than the region under the opening 3a is propagated to the region under the opening 3a, and photocarriers can be generated. Fig. 9 , 10 In the case of the lattice pattern shown in FIG. 1 , the plurality of step portions 40 are not formed as Fig. 9 , 10 Compared with the case of the grid pattern shown, the amount of photocarriers injected from the semiconductor layer 4 into the two-dimensional material layer 1 increases, and the sensitivity of the electromagnetic wave photodetector is improved.

[0148] Furthermore, the region 1b of the two-dimensional material layer 1 is arranged on the surface of the step portion 40 where the diffracted electromagnetic wave propagates through the insulating film 3. Therefore, the region 1b absorbs the diffracted electromagnetic wave, thereby increasing the amount of photocarriers generated. In addition, the electric field effect applied to the region 1b also increases. As a result, a plurality of step portions 40 are formed. Fig. 9 , 10 The sensitivity of the electromagnetic wave detector having the lattice pattern shown is higher than that of the detector having the plurality of step portions 40 not formed. Fig. 9 , 10 The lattice pattern shown is high.

[0149] In addition, Figure 8 In the embodiment, only one opening 3a is formed in the insulating film 3, and the opening 3a is arranged on the top 43 of one step portion among the plurality of step portions 40, but the present invention is not limited thereto. A plurality of openings 3a may be formed in the insulating film 3, and each opening 3a may be arranged on a different step portion 40. Furthermore, each opening 3a may be arranged on at least any one of the top 43, the bottom 41, and the side 42 of each step portion 40.

[0150] (Sixth modification, seventh modification, eighth modification, ninth modification)

[0151] Fig.11 , 12 The electromagnetic wave detectors shown in 13 and 14 basically have the same Figure 1 The electromagnetic wave detector shown in FIG. 2 has the same structure, but the planar shape of the region 1c in contact with the semiconductor layer 4 inside the opening 3a in the two-dimensional material layer 1 is different from Figure 1The planar shape of the region 1c in the electromagnetic wave detector shown is different.

[0152] Figures 11 to 14 The area ratio of the contact area of ​​the region 1c shown to the top 43 is Figure 1 The contact area between the region 1c shown in FIG. 2 and the top 43 is small. Figure 11 to Figure 14 In the electromagnetic wave detector shown, the area of ​​the contact region between the region 1c and the top portion 43 is smaller than the sum of the occupied areas of the region 1a (electrode connection region) and the region 1b in a plan view.

[0153] Figures 11 to 14 The regions 1c shown correspond to Figure 1 The region 1c shown is a structure after removing multiple regions separated by intervals in at least the longitudinal direction of the top 43, in other words, in a direction intersecting the direction in which the regions 1a (electrode connection region), the regions 1b, and the regions 1c of the two-dimensional material layer 1 are arranged side by side. Figure 11 to Figure 13 In the example, each of the plurality of regions has a rectangular shape in plan view. Fig.14 In the figure, each of the plurality of regions has a triangular shape in plan view.

[0154] Figures 11 to 14 The planar shapes of the regions 1 c shown are symmetrical with respect to a straight line that passes through the center of the top 43 in the lateral direction and extends in the longitudinal direction. Figures 11 to 14 The planar shapes of the region 1 c shown are symmetrical with respect to a straight line that passes through the center of the top 43 in the longitudinal direction and extends in the lateral direction.

[0155] Fig.11 The planar shape of the region 1c shown is a band shape. Fig.11 In the two-dimensional material layer 1 shown, the width of the region 1 c in the longitudinal direction of the top 43 is narrower than the widths of the regions 1 a and 1 b in the longitudinal direction.

[0156] Fig.12 The planar shape of the region 1c shown is a comb shape (ladder shape). Fig.12 In the two-dimensional material layer 1 shown, the sum of the widths of the region 1c in the longitudinal direction of the top 43 is narrower than the widths of the region 1a and the region 1b in the longitudinal direction. Fig.12 The two-dimensional material layer 1 shown is formed with a plurality of openings that expose the top 43 , and the plurality of openings are arranged side by side in the longitudinal direction of the top 43 .

[0157] Fig.13 The planar shape of the region 1c shown is a grid shape. Fig.13The two-dimensional material layer 1 shown in the figure has a plurality of openings for exposing the top 43, and the plurality of openings are arranged side by side in the longitudinal direction and the lateral direction of the top 43. Fig.13 In the two-dimensional material layer 1 shown, the minimum value of the sum of the widths of the region 1 c in the longitudinal direction of the top 43 is narrower than the minimum widths of the region 1 a and the region 1 b in the longitudinal direction.

[0158] exist Fig.14 In the two-dimensional material layer 1 shown, the width of the region 1c in the longitudinal direction of the top 43 gradually narrows as it moves away from the region 1b in the lateral direction of the top 43, and is narrowest at the center of the lateral direction. In other words, the width of the region 1c in the direction intersecting the arrangement direction of the regions 1a, 1b, and 1c of the two-dimensional material layer 1 gradually narrows as it moves away from the regions 1a and 1b in the arrangement direction. The width of the region 1c in the direction intersecting the arrangement direction of the regions 1a, 1b, and 1c of the two-dimensional material layer 1 is narrowest, for example, at the center of the region 1c in the arrangement direction.

[0159] exist Figures 11 to 14 In the embodiment, the area of ​​the contact region between the two-dimensional material layer 1 and the semiconductor layer 4 is adjusted according to the width of the region 1c in the longitudinal direction of the top 43. Figures 11 to 14 In the electromagnetic wave detector shown, the contact resistance between the two-dimensional material layer 1 and the semiconductor layer 4 and even the resistance of the electromagnetic wave detector can be adjusted. Figures 11 to 14 In the electromagnetic wave detector shown in FIG. Figure 1 Compared with the electromagnetic wave detector shown in 2, the deviation of the characteristics of the electromagnetic wave detector can be reduced, and the dark current can be reduced.

[0160] in addition, Figures 12-14 The sum of the end surfaces of the region 1c shown is greater than Figure 1 The sum of the areas of the end faces of the region 1c shown in FIG. 2 is larger. The end faces of the region 1c are faces extending in the thickness direction of the two-dimensional material layer 1, in other words, in a direction orthogonal to the thin sheet formed by the two-dimensional arrangement of atoms in the two-dimensional material layer 1. In other words, Figures 12-14 The end face area ratio of the two-dimensional crystal structure in each region 1c is Figure 1 As well as the end face area of ​​the two-dimensional crystal structure in region 1c of 2, the end face area increases. Figures 12-14 In each two-dimensional material layer 1, Figure 1 As compared with the two-dimensional material layer 1 shown in FIG. 2, the ratio of unbonded hands (dangling bonds) of the two-dimensional crystal structure increases. As a result, when the carriers generated in the semiconductor layer 4 due to electromagnetic wave irradiation are transported to the first electrode portion 2a via the two-dimensional material layer 1, Figures 12-14 Each two-dimensional material layer 1, and Figure 1Compared with the two-dimensional material layer 1 and 2, the ratio of the change in carrier density becomes larger, the mobility of carriers increases, and the change in current I becomes larger. As a result, Figures 12-14 The sensitivity ratio of each electromagnetic wave detector shown is Figure 1 And the electromagnetic wave detector shown in 2 has high sensitivity.

[0161] In addition, in each variation of the above-mentioned present embodiment, the region 1c of the two-dimensional material layer 1 may also be a graphene nanoribbon. The graphene nanoribbon has a band gap that varies in accordance with its width. Therefore, the wavelength domain of the electromagnetic wave that can be photoelectrically converted in the region 1c can be adjusted according to the width of the above-mentioned longitudinal direction of the region 1c composed of the graphene nanoribbon, for example, it can be made narrower than the wavelength domain of the electromagnetic wave that can be photoelectrically converted in other regions 1a and 1b. In this case, the photocarriers generated by the photoelectric conversion in the region 1c and the photocarriers generated by the photoelectric conversion in other regions 1a and 1b can be detected separately. In addition, by detecting the photocarriers generated by the photoelectric conversion in the region 1c, the sensitivity of the electromagnetic wave detector is improved. In addition, in such an electromagnetic wave detector, the domain 1c composed of the graphene nanoribbon is Schottky-bonded to the semiconductor layer 4, so the dark current is reduced, and the sensitivity is improved by detecting the photocarriers generated by the electromagnetic wave absorbed in the Schottky junction.

[0162] also, Figure 11 to Figure 14 The region 1c shown is disposed on the top 43 of the step portion 40, but is not limited thereto. Figure 4 as well as Figure 5 The planar shape of the region 1c shown can also be Figure 11 to Figure 14 The region 1c shown in any figure is formed in the same manner.

[0163] (10th Modification, 11th Modification, 12th Modification)

[0164] Fig.15 , 16 The electromagnetic wave detector shown in 17 basically has the same Figure 2 The electromagnetic wave detector shown in FIG. 1 has the same structure as that shown in FIG. 1 , but the step portion 40 in the cross section perpendicular to the longitudinal direction of the top portion 43 is tapered. Figure 2 The electromagnetic wave detectors shown are different.

[0165] The interval between the two side portions 42 on the bottom 41 side is different from the interval between the two side portions 42 on the top 43 side. Fig.15 In the tenth variation shown, the interval between the two side portions 42 gradually widens as it approaches the top 43 from the bottom 41. Fig.16In the 11th modification shown, the interval between the two side portions 42 gradually narrows as it approaches the top 43 from the bottom 41. Fig.17 In the twelfth modified example shown, the interval between the two side portions 42 gradually narrows as it approaches the top portion 43 from the bottom portion 41, and the top portion 43 does not form a surface but is provided in a linear shape.

[0166] In these cases, Figure 2 Compared with the case where the shape of the step portion 40 on the cross section perpendicular to the longitudinal direction of the top 43 is a rectangular shape, the region 1b of the two-dimensional material layer 1 extending between the opening 3a and the first electrode portion 2a can be set wider. As a result, in each of the electromagnetic wave detectors of the tenth modification, the eleventh modification, and the twelfth modification, Figure 2 Compared with the electromagnetic wave detector shown, the contribution of the grating effect becomes larger and the detection sensitivity is improved.

[0167] (Other Modifications)

[0168] In addition, the electromagnetic wave detector of embodiment 1 may also be provided with an insulating protective film (not shown) arranged in a manner covering the two-dimensional material layer. The insulating protective film may also be provided on the insulating film 3 in a manner covering the two-dimensional material layer 1, the semiconductor layer 4, and the periphery of the first electrode portion 2a. The material constituting the insulating protective film may be any material having electrical insulation, for example, at least one selected from the group consisting of SiO2, Si3N4, HfO2, Al2O3, and BN.

[0169] In addition, the electromagnetic wave detector of this embodiment can also be used together with an electromagnetic wave detector (not shown) having the same structure as the electromagnetic wave detector of this embodiment and shielding the electromagnetic wave as the detection object, to detect the difference in output between the two electromagnetic wave detectors. By detecting the difference in this way, the influence of changes in characteristics that depend on the ambient temperature can be suppressed, so high-precision detection can be performed.

[0170] In addition, the electromagnetic wave detector of this embodiment can also be integrally formed with an output amplifier circuit (not shown) using graphene. That is, an output amplifier circuit using graphene can also be provided on the semiconductor layer 4 of the electromagnetic wave detector of this embodiment. In the output amplifier circuit using graphene, the operation is faster than the output amplifier circuit using a silicon series semiconductor material, and a high-performance electromagnetic wave detector can be realized. In addition, by using graphene for peripheral circuits such as a readout circuit, high-speed readout and simplified manufacturing process can be achieved.

[0171] Furthermore, the above-mentioned first to twelfth modified examples can also be applied to other embodiments described below.

[0172] Implementation method 2.

[0173] Fig.18 This is a schematic cross-sectional view of the electromagnetic wave detector according to the second embodiment. Fig.19 2 is a plan view of the interior of the electromagnetic wave detector of Embodiment 2. Fig.18 , Fig.19 As shown, the electromagnetic wave detector of the second embodiment has a structure basically the same as that of the electromagnetic wave detector of the first embodiment, and can obtain the same effect, but is different from the electromagnetic wave detector of the first embodiment in that the semiconductor layer 4 includes a current cutoff structure. Fig.19 In order to explain the position of the current interruption mechanism, only the opening 3 a of the insulating film 3 , the semiconductor layer 4 , and the current interruption structure 5 are shown.

[0174] The current interruption structure 5 is a portion capable of interrupting current. Specifically, the current interruption structure 5 is a portion for interrupting the movement of carriers between a region of the semiconductor layer 4 facing the region 1 b via the insulating film 3 and a region connected to the region 1 c.

[0175] like Fig.18 As shown, the current interruption structure 5 is arranged in a region of the semiconductor layer 4 facing the insulating film 3. Fig.19 As shown in FIG. 1 , the current cutoff structure 5 is arranged so as to surround the opening end of the opening 3a in a plan view. When the region 1c and the opening 3a are arranged on the top 43 of the step portion 40, the current cutoff structure 5 is arranged on the top 43. The current cutoff structure 5 has one end exposed from the semiconductor layer 4 at the top 43 and connected to the insulating film 3 and the other end buried in the semiconductor layer 4. The distance (depth) between the one end and the other end of the current cutoff structure 5 and the width in the direction intersecting the distance are not particularly limited as long as they do not hinder the diffusion of carriers.

[0176] The specific structure of the current cutoff structure 5 is not particularly limited as long as it is a structure for cutting off the current. The current cutoff structure 5 may be, for example, a groove formed in the semiconductor layer 4. The interior of the groove may be hollow or filled with an insulator. In addition, the current cutoff structure 5 may be a region doped with impurities at a higher concentration than the semiconductor layer 4 and having a higher conductivity than the semiconductor layer 4. In addition, the current cutoff structure 5 may be a region formed by burying a metal material in the interior of the groove and having a higher conductivity than the semiconductor layer 4.

[0177] In the electromagnetic wave detector of the second embodiment, the photocarriers generated in the semiconductor layer 4 are separated into carriers injected into the region 1c of the two-dimensional material layer 1 and carriers contributing to the grating effect of applying an electric field change to the region 1b of the two-dimensional material layer 1 via the insulating film 3 by using the current cutoff structure 5. For example, when the width of the opening 3a in the insulating film 3 is narrower than the diffusion length of the photocarriers in the semiconductor material constituting the semiconductor layer 4 and the current cutoff structure 5 is not provided, the photocarriers under the insulating film 3 contribute to the grating effect and are injected into the two-dimensional material layer 1. In this case, the amplification of the current change based on the above-mentioned grating effect occurs with a delay relative to the generation of the photocarriers. In contrast, in the electromagnetic wave detector of the second embodiment, the carriers contributing to the grating effect and the carriers injected into the two-dimensional material layer 1 are separated by using the current cutoff structure 5. As a result, the above-mentioned delay is eliminated and the response speed of the electromagnetic wave detector is improved. In addition, when a plurality of electromagnetic wave detectors of the second embodiment are arranged to form an electromagnetic wave detector assembly, each pixel is separated.

[0178] (Variation Example)

[0179] Fig. 20 The electromagnetic wave detector shown has Fig.18 as well as Fig.19 The electromagnetic wave detector of the second embodiment shown has basically the same structure, but is different from the second embodiment in that the current interruption structure 5 is formed so as to penetrate the semiconductor layer 4 and reach the second electrode portion 2 b.

[0180] In addition, each structure of the electromagnetic wave detector of Embodiment 2 and its modification example can also be applied to other embodiments.

[0181] Implementation method 3.

[0182] Fig.21 Schematic cross-sectional view of the electromagnetic wave detector of Embodiment 3. Fig.21 As shown, the electromagnetic wave detector of embodiment 3 has basically the same structure as the electromagnetic wave detector of embodiment 1 and can obtain the same effect, but is different from the electromagnetic wave detector of embodiment 1 in that a buffer layer 6 is arranged between the two-dimensional material layer 1 and the semiconductor layer 4 inside the opening 3a of the insulating film 3.

[0183] The buffer layer 6 electrically connects the region 1c of the two-dimensional material layer 1 to the semiconductor layer 4. Specifically, the buffer layer 6 is provided in such a manner that a tunnel is generated between the region 1c of the two-dimensional material layer 1 and the semiconductor layer 4, so that the region 1c of the two-dimensional material layer 1 and the semiconductor layer 4 are electrically connected by the tunnel current. The material constituting the buffer layer 6 can be any material having electrical insulation, for example, at least one selected from the group consisting of SiO2, Si3N4, HfO2, Al2O3 and BN. The thickness of the buffer layer 6 is set in such a manner that a tunnel current can be generated between the two-dimensional material layer 1 and the semiconductor layer 4 when an electromagnetic wave is incident.

[0184] The thickness of the buffer layer 6 is, for example, 1 nm and less than 10 nm. As for the method for making the buffer layer 6, any method can be adopted, for example, it can be selected from ALD (Atomic Layer Deposition) method, vacuum evaporation method and sputtering method. Alternatively, the buffer layer 6 can also be formed by oxidizing or nitriding the surface of the semiconductor layer 4. Alternatively, the buffer layer 6 can also be a natural oxide film formed on the surface of the semiconductor layer 4.

[0185] The electromagnetic wave detector of embodiment 3 also includes a buffer layer 6. The buffer layer 6 is arranged between the two-dimensional material layer 1 and the semiconductor layer 4 inside the opening 3a. The buffer layer 6 has a thickness that can form a tunnel current between the two-dimensional material layer 1 and the semiconductor layer 4. In this case, the film thickness of the buffer layer 6 is set to a thickness that generates a tunnel injection from the semiconductor layer 4 to the two-dimensional material layer 1, thereby improving the injection efficiency, so that a large photocurrent is injected into the two-dimensional material layer 1, and the sensitivity of the electromagnetic wave detector can be improved. In addition, by using the buffer layer 6 to suppress the leakage current at the bonding interface between the semiconductor layer 4 and the two-dimensional material layer 1, the dark current can be reduced.

[0186] (Variation Example)

[0187] Fig. 22 The electromagnetic wave detector shown has Fig.21 The electromagnetic wave detector of the third embodiment shown has basically the same structure, but is different from the third embodiment in that a third electrode portion 2 c different from the first electrode portion 2 a is further provided on the surface of the insulating film 3 .

[0188] The third electrode portion 2c is preferably arranged in a region opposite to the region where the first electrode portion 2a is located when viewed from the opening portion 3a. The two-dimensional material layer 1 is also connected to the electrode portion 2c. For example, a source-drain voltage Vd is applied between the first electrode portion 2a and the third electrode portion 2c. If this is done, the photocurrent extracted from the two-dimensional material layer 1 can be increased.

[0189] In addition, each structure of the electromagnetic wave detector of Embodiment 3 and its modification example can also be applied to other embodiments.

[0190] Implementation method 4.

[0191] Fig.23 FIG. 4 is a cross-sectional schematic diagram of an electromagnetic wave detector according to Embodiment 4. Fig.23 As shown, the electromagnetic wave detector of embodiment 4 has basically the same structure as the electromagnetic wave detector of embodiment 1 and can obtain the same effect, but is different from the electromagnetic wave detector of embodiment 1 in that a connecting conductor 2d is formed inside the opening 3a of the insulating film 3.

[0192] The connecting conductor 2d electrically connects the semiconductor layer 4 to the region 1c of the two-dimensional material layer 1. It is configured so that the region 1c of the two-dimensional material layer 1 overlaps the upper surface of the connecting conductor 2d. The back surface of the connecting conductor 2d is electrically connected to the surface of the semiconductor layer 4. The two-dimensional material layer 1 is electrically connected to the upper surface of the connecting conductor 2d. From a different point of view, the region 1c of the two-dimensional material layer 1 is electrically connected to the semiconductor layer 4 via the connecting conductor 2d. The position of the upper surface of the connecting conductor 2d is substantially the same as the position of the upper surface of the insulating film 3. The two-dimensional material layer 1 extends in a planar shape from the upper surface of the insulating film 3 to the upper surface of the connecting conductor 2d without bending.

[0193] The connecting conductor 2d is preferably ohmically bonded to the semiconductor layer 4. In addition, the connecting conductor 2d preferably exhibits high transmittance at the wavelength of the electromagnetic wave detected by the electromagnetic wave detector. Preferably, the material constituting the connecting conductor 2d is a material whose properties change due to the irradiation of electromagnetic waves and a change in potential is applied to the two-dimensional material layer 1, for example, including at least one selected from the group consisting of quantum dots, ferroelectric materials, liquid crystal materials, fullerenes, rare earth oxides, semiconductor materials, pn junction materials, metal-semiconductor bonding materials, and metal-insulator-semiconductor bonding materials. For example, as long as the material constituting the connecting conductor 2d is a ferroelectric material having a polarization effect (thermoelectric effect) based on electromagnetic waves, a change in polarization is generated in the ferroelectric by irradiation with electromagnetic waves, and a change in potential can be applied to the two-dimensional material layer 1.

[0194] The electromagnetic wave detector includes a connecting conductor 2d. The connecting conductor 2d electrically connects the semiconductor layer 4 and the two-dimensional material layer 1 inside the opening 3a. The connecting conductor 2d is preferably ohmically bonded to the semiconductor layer 4. In addition, the connecting conductor 2d preferably exhibits high transmittance at the detection wavelength of the electromagnetic wave.

[0195] In the electromagnetic wave detector of embodiment 4, a connecting conductor 2d is provided between the two-dimensional material layer 1 and the semiconductor layer 4, thereby being able to reduce the contact resistance between the two-dimensional material layer 1 and the semiconductor layer 4 compared to the electromagnetic wave detector of embodiment 1, and also being able to suppress the attenuation of the photocurrent which becomes a problem when the junction between the two-dimensional material layer 1 and the semiconductor layer 4 is a Schottky junction.

[0196] In addition, in the electromagnetic wave detector of embodiment 4, it is preferred that the thickness of the connecting conductor 2d is substantially the same as the thickness of the insulating film 3, that is, the position of the upper surface of the connecting conductor 2d is substantially the same as the position of the upper surface of the insulating film 3. In this case, the two-dimensional material layer 1 is not bent but formed horizontally, so the mobility of the carriers of the two-dimensional material layer 1 is improved. The grating effect is proportional to the mobility, so the detection sensitivity of the electromagnetic wave detector is improved.

[0197] In addition, the structure of the electromagnetic wave detector of Embodiment 4 can also be applied to other embodiments.

[0198] Implementation method 5.

[0199] Fig.24 This is a schematic plan view of the electromagnetic wave detector according to the fifth embodiment. Fig.25 yes Fig.24 Schematic cross-sectional view at line segment XXV-XXV.

[0200] like Fig.24 , Fig.25 As shown, the electromagnetic wave detector of embodiment 5 has basically the same structure as the electromagnetic wave detector of embodiment 1 and can obtain the same effect, but is different from the electromagnetic wave detector of embodiment 1 in that the semiconductor layer 4 includes a first semiconductor part 4a having a first conductive type and a second semiconductor part 4b having a second conductive type, and the two are joined inside the opening 3a.

[0201] The first semiconductor portion 4a and the second semiconductor portion 4b are arranged side by side along the above-mentioned lateral width direction of the opening 3a. The first semiconductor portion 4a is doped with carriers opposite to those of the second semiconductor portion 4b. That is, the first semiconductor portion 4a and the second semiconductor portion 4b form a pn junction. The first semiconductor portion 4a, the second semiconductor portion 4b, and the pn junction interface 4ab between the first semiconductor portion 4a and the second semiconductor portion 4b are exposed inside the opening 3a. The bonding interface 4ab extends along the above-mentioned longitudinal direction of the opening 3a. The bonding interface 4ab extends below the opening 3a of the insulating film 3. The opening 3a of the insulating film 3 is arranged, for example, on the top 43.

[0202] The materials constituting the first semiconductor portion 4a and the second semiconductor portion 4b are, for example, the same semiconductor material. In addition, the materials constituting the first semiconductor portion 4a and the second semiconductor portion 4b may also be different semiconductor materials. In this case, the electromagnetic wave detector can be driven in the wavelength band of the electromagnetic wave that can be absorbed by each semiconductor material, so the wavelength range of the electromagnetic wave that can be detected can be expanded and selected.

[0203] The semiconductor layer 4 further includes another semiconductor portion 4c, for example, below the first semiconductor portion 4a and the second semiconductor portion 4b. The other semiconductor portion 4c may have the first conductivity type or the second conductivity type, or may not have any conductivity type. Another electrode portion 2c may also be arranged on the other semiconductor portion 4c.

[0204] The step portion 40 includes at least the first semiconductor portion 4a and the second semiconductor portion 4b. The step portion 40 includes, for example, the first semiconductor portion 4a, the second semiconductor portion 4b, and the other semiconductor portion 4c. One bottom portion 41a, the other bottom portion 41b, the lower portion of one side portion 42, and the lower portion of the other side portion 42 are, for example, composed of the other semiconductor portion 4c. The upper portion of one side portion 42 and the portion of the top portion 43 located on the side of one side portion 42 are composed of the first semiconductor portion 4a. The upper portion of the other side portion 42 and the portion of the top portion 43 located on the side of the other side portion 42 are composed of the second semiconductor portion 4b.

[0205] The second electrode portion 2b is disposed on the bottom portion 41b. The region 1c of the two-dimensional material layer 1 includes a portion electrically connected to the first semiconductor portion 4a and a portion electrically connected to the second semiconductor portion 4b inside the opening 3a. A junction 4ac where the region 1c of the two-dimensional material layer 1 is joined to the first semiconductor portion 4a and a junction 4bc where the region 1c is joined to the second semiconductor portion 4b are disposed inside the opening 3a.

[0206] The two-dimensional material layer 1 includes, in addition to the regions 1a, 1b, and 1c, a region 1d connected to the other portions of the region 1b and disposed on the other bottom portion 41b. The region 1d is electrically connected to the second electrode portion 2b.

[0207] like Fig.25As shown, the pn junction interface 4ab between the first semiconductor portion 4a and the second semiconductor portion 4b is arranged in contact with the two-dimensional material layer 1. Therefore, the photocarriers generated at the pn junction interface 4ab between the first semiconductor portion 4a and the second semiconductor portion 4b by light irradiation can be easily taken out to the two-dimensional material layer 1. Furthermore, the conductivity of the two-dimensional material layer 1 on the pn junction interface 4ab changes due to the influence of the local electric field change at the pn junction generated by the photocarriers. As a result, the detection sensitivity of the electromagnetic wave detector is improved.

[0208] In addition, if Fig.25 As shown, the two-dimensional material layer 1 is configured in a manner that connects the first electrode portion 2a and the second electrode portion 2b. The two-dimensional material layer 1 is connected to the semiconductor layer 4 in the region between the first electrode portion 2a and the second electrode portion 2b. As a result, a voltage can be applied between the first electrode portion 2a and the second electrode portion 2b, and the photocarriers generated in the semiconductor layer 4 can be read out using the two-dimensional material layer 1. At this time, in the two-dimensional material layer 1, the region in contact with the first semiconductor portion 4a and the region in contact with the second semiconductor portion 4b are doped by each semiconductor portion. Therefore, a gradient of charge density is formed in the two-dimensional material layer 1. As a result, the mobility of carriers in the two-dimensional material layer 1 is improved, and the detection sensitivity of the electromagnetic wave detector is improved.

[0209] (Variation Example)

[0210] Fig.26 The electromagnetic wave detector shown has Fig.24 , Fig.25 The same structure as the electromagnetic wave detector shown in the figure can obtain the same effect, but the first semiconductor part 4a is directly connected to the first electrode part 2a, and the second semiconductor part 4b is directly connected to the second electrode part 2b. Fig.24 , Fig.25 The electromagnetic wave detectors shown are different.

[0211] The first semiconductor portion 4a extends from below the opening 3a to a region located below the first electrode portion 2a. The second semiconductor portion 4b extends from below the opening 3a to a region located below the second electrode portion 2b.

[0212] The step portion 40 includes a first semiconductor portion 4a and a second semiconductor portion 4b. The step portion 40 does not include another semiconductor portion 4c. A portion located on the side of one side portion 42 among one bottom portion 41a, one side portion 42, and a top portion 43 is composed of the first semiconductor portion 4a. A portion located on the side of the other side portion 42 among the other bottom portion 41a, the other side portion 42, and the top portion 43 is composed of the second semiconductor portion 4b.

[0213] In the insulating film 3, an additional opening is formed in a region sandwiching the opening 3a and located below the first electrode 2a and the second electrode 2b. The first electrode 2a is directly connected to the first semiconductor portion 4a inside the additional opening. The second electrode 2b is directly connected to the second semiconductor portion 4b inside the additional opening.

[0214] Thus, a voltage V can be applied between the first semiconductor portion 4a and the second semiconductor portion 4b while a voltage can also be applied to the two-dimensional material layer 1. At this time, as long as the photodiode including the first semiconductor portion 4a and the second semiconductor portion 4b is in a saturated state with a reverse bias applied, current flows only in the two-dimensional material layer 1. Thus, a depletion layer is generated in the first semiconductor portion 4a and the second semiconductor portion 4b, and a large voltage change can be applied to the two-dimensional material layer 1, so that a large photocurrent (photocarrier) can be extracted as a result. Furthermore, in the two-dimensional material layer 1, the conductivity of the two-dimensional material layer 1 changes due to the change in the local electric field generated at the pn junction interface, i.e., the junction 4ba, between the first semiconductor portion 4a and the second semiconductor portion 4b. As a result, the detection sensitivity of the electromagnetic wave detector is improved.

[0215] In addition, when a tunnel diode including the first semiconductor portion 4a and the second semiconductor portion 4b is used, a large photocurrent is generated only when light is irradiated. This photocurrent is injected into the two-dimensional material layer 1. Furthermore, a change in conductivity due to the influence of electric field change can be generated in the two-dimensional material layer 1 only when light is irradiated. As a result, a high sensitivity of the electromagnetic wave detector can be achieved.

[0216] In addition, in the electromagnetic wave detector of the fifth embodiment, the other semiconductor portions 4c and the other electrode portions 2c may not be formed.

[0217] Fig. 27 The electromagnetic wave detector shown has Fig.24 , Fig.25 The same structure as the electromagnetic wave detector shown in FIG. 1 can obtain the same effect, but the region 1c of the two-dimensional material layer 1 is cut off between the joint 4ac and the joint 4bc. Fig.24 , Fig.25 The electromagnetic wave detectors shown are different. Fig.28 The electromagnetic wave detector shown has Fig.26 The same structure as the electromagnetic wave detector shown in FIG. 1 can obtain the same effect, but the region 1c of the two-dimensional material layer 1 is cut off between the joint 4ac and the joint 4bc. Fig.26 The electromagnetic wave detectors shown are different.

[0218] In other words, Fig. 27 , 28The region 1 c of the two-dimensional material layer 1 is shown to be interrupted at the bonding interface 4 ab . Fig. 27 , 28 The region 1c of the two-dimensional material layer 1 shown has a first connection region in contact with the first semiconductor portion 4a and a second connection region in contact with the second semiconductor portion 4b. The first connection region and the second connection region are electrically connected not via the two-dimensional material layer 1 but only via the pn junction interface 4ab.

[0219] Fig. 27 as well as Fig.28 The two-dimensional material layer 1 shown includes a first two-dimensional material layer 1 having a first connection region electrically connected to the first semiconductor portion 4a and a second two-dimensional material layer 1 having a second connection region electrically connected to the second semiconductor portion 4b. The first two-dimensional material layer 1 and the second two-dimensional material layer 1 are configured as different components independent of each other. The first two-dimensional material layer 1 and the second two-dimensional material layer 1 are arranged in a manner of facing each other with a bonding interface 4ab sandwiched therebetween. The first two-dimensional material layer 1 and the second two-dimensional material layer 1 are cut off at the bonding interface 4ab.

[0220] exist Fig. 27 In the electromagnetic wave detector shown in FIG. 28, the current I flows sequentially through the second electrode portion 2b, the second two-dimensional material layer 1, the junction 4bc, the second semiconductor portion 4b, the pn junction interface 4ab, the first semiconductor portion 4a, the junction 4ac, the first two-dimensional material layer 1, and the first electrode portion 2a. The junction 4ac and the junction 4bc are Schottky junctions of the two-dimensional material layer 1 and the first semiconductor portion 4a or the second semiconductor portion 4b.

[0221] In such an electromagnetic wave detector, a reverse bias is applied to the junction portion 4ac, so the dark current is reduced.

[0222] In addition, when the material constituting the first semiconductor portion 4a is different from the material constituting the second semiconductor portion 4b, the degree of change in the barrier height relative to the voltage value (reverse bias) of the Schottky junction applied to the junction 4ac is different from the degree of change in the barrier height relative to the voltage value (forward bias) of the Schottky junction applied to the junction 4bc. In the case where the junction 4ac and the junction 4bc are Schottky junctions, the behavior of the dark current and the photocurrent changes according to the barrier height. Therefore, in Fig. 27 as well as Fig.28 In the electromagnetic wave detector shown, the ratio of changes in the dark current and the photocurrent can be freely adjusted according to the voltage value, so that the temperature sensitivity can be improved.

[0223] In addition, the electromagnetic wave detector of Embodiment 5 and each structure of the above-mentioned modification example can also be applied to other embodiments.

[0224] Implementation method 6.

[0225] Fig.29 This is a schematic plan view of the electromagnetic wave detector according to the sixth embodiment. Fig.30 yes Fig.29 The cross-sectional view of the line segment XXX-XXX. Fig.29 as well as Fig.30 As shown, the electromagnetic wave detector of embodiment 6 has basically the same structure as the electromagnetic wave detector of embodiment 5 and can obtain the same effect, but is different from the electromagnetic wave detector of embodiment 5 in that when the semiconductor layer 4 is observed from the opening portion 3a, the first semiconductor portion 4a is configured in a manner that clamps at least a portion of the second semiconductor portion 4b.

[0226] When the semiconductor layer 4 is observed from the opening 3a, the first semiconductor portion 4a includes a first portion 4a1 disposed on one side opposite to the second semiconductor portion 4b in the lateral width direction of the opening 3a and a second portion 4a2 disposed on the other side opposite to the second semiconductor portion 4b in the lateral width direction of the opening 3a. Inside the opening 3a, the second semiconductor portion 4b, the first portion 4a1 of the first semiconductor portion 4a, and the second portion 4a2 of the first semiconductor portion 4a are disposed so as to face the two-dimensional material layer 1. The first portion 4a1 and the second portion 4a2 are respectively bonded to the second semiconductor portion 4b.

[0227] The first portion 4a1 and the second portion 4a2 of the first semiconductor portion 4a, the second semiconductor portion 4b, and the pn junction interface 4ab1 and the pn junction interface 4ab2 between the first portion 4a1 and the second semiconductor portion 4b are exposed in the opening 3a.

[0228] The two-dimensional material layer 1 is connected to the first portion 4a1 and the second portion 4a2 of the first semiconductor portion 4a, the second semiconductor portion 4b, and the pn junction interface 4ab1 and the pn junction interface 4ab2 inside the opening 3a.

[0229] In the electromagnetic wave detector of the sixth embodiment, the pn junction interface between the first semiconductor portion 4a and the second semiconductor portion 4b can be increased compared to the electromagnetic wave detector of the fifth embodiment. Furthermore, by increasing the contact area between the pn junction interface and the two-dimensional material layer 1, the influence of the local electric field change generated at the pn junction interface due to light irradiation on the two-dimensional material layer 1 can be increased. Furthermore, by increasing the contact area between the pn junction interface and the two-dimensional material layer 1, the influence of the local electric field change generated at the pn junction interface due to light irradiation on the two-dimensional material layer 1 can be increased.

[0230] (Variation Example)

[0231] A plurality of second semiconductor portions 4b may also be provided. That is, a plurality of second semiconductor portions 4b may also be arranged in the first semiconductor portion 4a at intervals inside the opening 3a. As a result, the pn junction interface between the first semiconductor portion 4a and the second semiconductor portion 4b can be further increased. Furthermore, by further increasing the contact area between the above-mentioned pn junction interface and the two-dimensional material layer 1, the effect of the local electric field change generated at the pn junction interface due to light irradiation on the two-dimensional material layer 1 can be increased.

[0232] In addition, the first semiconductor portion 4a and the second semiconductor portion 4b can be configured as pnp or npn phototransistors. Fig.31 As shown, the first electrode portion 2a is brought into contact with the first semiconductor portion 4a. Fig.31 The electromagnetic wave detector shown basically has the same Fig.29 as well as Fig.30 The same structure as the electromagnetic wave detector shown in FIG. 1 can obtain the same effect, but the structures of the insulating film 3, the first electrode portion 2a and the electrode portion 2c are different from those of FIG. Fig.29 as well as Fig.30 The electromagnetic wave detector shown is different. That is, Fig.31 In the electromagnetic wave detector shown, the first electrode portion 2a is in contact with the first semiconductor portion 4a. Furthermore, the electrode portion 2c is also in contact with the first semiconductor portion 4a. An additional opening is formed in the insulating film 3 at a position sandwiching the opening 3a and below the first electrode portion 2a and the electrode portion 2c, respectively. The first electrode portion 2a and the electrode portion 2c extend to the inside of the additional opening, respectively. Inside the additional opening, the first electrode portion 2a and the electrode portion 2c are connected to the first semiconductor portion 4a.

[0233] With such a structure, current flows through the transistor including the first semiconductor portion 4a and the second semiconductor portion 4b only when light is irradiated. As a result, the two-dimensional material layer 1 can generate an electric field change, and the sensitivity of the electromagnetic wave detector can be increased.

[0234] Implementation method 7.

[0235] Fig.32 This is a schematic plan view of an electromagnetic wave detector according to a seventh embodiment. Fig.33 yes Fig.32 The cross-sectional view of the line segment XXXIII-XXXIII. Fig.32 as well as Fig.33As shown, the electromagnetic wave detector of embodiment 7 has basically the same structure as the electromagnetic wave detector of embodiment 5 and can obtain the same effect, but is different from the electromagnetic wave detector of embodiment 5 in that the second semiconductor part 4b is buried in the first semiconductor part 4a.

[0236] The second semiconductor portion 4b is arranged below the opening 3a. The second semiconductor portion 4b is buried below the first semiconductor portion 4a connected to the two-dimensional material layer 1 inside the opening 3a. The second semiconductor portion 4b is arranged, for example, inside the step portion 40 at a position below the top 43 and above the bottom 41. The first semiconductor portion 4a is arranged between the top 43 and the second semiconductor portion 4b. In other words, a thin first semiconductor portion 4a is arranged between the two-dimensional material layer 1 and the second semiconductor portion 4b. The thickness of the first semiconductor portion 4a located between the top 43 and the second semiconductor portion 4b is thinner than the thickness of the second semiconductor portion 4b.

[0237] A pn junction is formed by the first semiconductor portion 4a and the second semiconductor portion 4b. As a result, the pn junction is formed just below the two-dimensional material layer 1 located inside the opening 3a. Therefore, the efficiency of extracting the photocurrent from the semiconductor layer 4 to the two-dimensional material layer 1 is improved. Furthermore, the electric field change caused by the semiconductor layer 4 to the two-dimensional material layer 1 becomes larger, so the sensitivity of the electromagnetic wave detector can be increased.

[0238] If you do this, then Fig.33 As shown, a pn junction is formed at the junction interface between the first semiconductor portion 4a and the second semiconductor portion 4b to form a diode. Electromagnetic waves (light) are irradiated to the diode, so that the deactivation of photocarriers generated at the junction interface between the first semiconductor portion 4a and the second semiconductor portion 4b is reduced, and the photocurrent injected into the two-dimensional material layer 1 is increased. As a result, a highly sensitive electromagnetic wave detector can be obtained.

[0239] In addition, in the electromagnetic wave detector of the seventh embodiment, other semiconductor portions 4c and other electrode portions 2c may not be formed.

[0240] In addition, the structure of the electromagnetic wave detector of Embodiment 7 can also be applied to other embodiments.

[0241] Implementation method 8.

[0242] Fig.34 Schematic cross-sectional view of the electromagnetic wave detector of Embodiment 8. Fig.34As shown, the electromagnetic wave detector of embodiment 8 has basically the same structure as the electromagnetic wave detector of embodiment 1 and can obtain the same effect, but is different from the electromagnetic wave detector of embodiment 1 in that a conical portion 3b is formed on the insulating film 3 in which the thickness of the insulating film 3 gradually becomes thinner from the first electrode portion 2a to the opening portion 3a.

[0243] like Fig.34 As shown, between the first electrode portion 2a and the opening portion 3a of the insulating film 3, a tapered portion 3b is formed in which the surface of the insulating film 3 is inclined relative to the side portion 42. The angle formed by the surface of the tapered portion 3b and the surface of the first semiconductor portion 4a only needs to be an acute angle, for example, it can be less than 45° or less than 30°. The surface of the tapered portion 3b is, for example, a plane, but it can also be a curved surface. The tapered portion 3b can be formed by any method. For example, the tapered portion 3b can also be formed by forming an insulating film with the semiconductor layer 4 tilted. Alternatively, the tapered portion 3b can also be formed by dry etching the insulating film 3 pre-formed on the semiconductor layer 4 while the semiconductor layer 4 is tilted.

[0244] In the electromagnetic wave detector of the eighth embodiment, a gradient is provided in the insulating film 3 in the tapered portion 3b, so that when the electromagnetic wave is irradiated to the semiconductor layer 4, a local change in the degree of electric field change in the two-dimensional material layer 1 occurs. That is, when the electromagnetic wave is irradiated to the semiconductor layer 4 and an electric field change is applied to the two-dimensional material layer 1, the degree of the electric field change changes locally in accordance with the change in the thickness of the insulating film 3. As a result, the mobility of carriers in the two-dimensional material layer 1 is improved, and the detection sensitivity of the electromagnetic wave detector is improved.

[0245] In addition, the structure of the electromagnetic wave detector of Embodiment 8 can also be applied to other embodiments.

[0246] Implementation method 9.

[0247] <Structure of electromagnetic wave detector>

[0248] Fig.35 FIG. 1 is a cross-sectional schematic diagram of an electromagnetic wave detector according to Embodiment 9. Fig.35 As shown, the electromagnetic wave detector of embodiment 9 has basically the same structure as the electromagnetic wave detector of embodiment 1 and can obtain the same effect, but is different from the electromagnetic wave detector of embodiment 1 in that the two-dimensional material layer 1 includes a turbostratic structure portion 1e.

[0249] like Fig.35As shown, in the two-dimensional material layer 1, the region corresponding to the channel region is a turbostratic structure portion 1e. Here, the turbostratic structure portion 1e refers to a region where a plurality of graphenes are stacked, which means a structure in which the lattices of the stacked graphenes are stacked in a mismatched state. In addition, the entire two-dimensional material layer 1 may be a turbostratic structure, or only the turbostratic structure portion 1e may be a turbostratic structure.

[0250] The method for producing the turbostratic structure portion 1e may be any method. The turbostratic structure portion 1e may be formed, for example, by transferring a single layer of graphene produced by a CVD method multiple times to stack multiple layers of graphene. In addition, the turbostratic structure portion 1e may be formed, for example, by growing graphene by a CVD method using ethanol or methane as a carbon source on graphene.

[0251] exist Fig.35 In the electromagnetic wave detector shown, in the two-dimensional material layer 1, the portion corresponding to the channel region is a turbostratic structure portion 1e, so the mobility of carriers in the two-dimensional material layer 1 is improved. Here, the usual stacked graphene is called A-B stacking, and the stacked graphenes are stacked in a matched state. However, when the graphene produced by the CVD method is polycrystalline, and graphene is transferred multiple times on the graphene, or when the graphene is stacked on the graphene of the base using the CVD method, a turbostratic structure is formed in which the lattices of the stacked graphenes are not matched.

[0252] The graphene of the turbostratic structure constituting the turbostratic structure portion 1e is less affected by the interaction between the layers and has the same properties as single-layer graphene. Furthermore, the two-dimensional material layer 1 is affected by the carrier scattering in the insulating film 3 as the substrate and the mobility decreases. However, in the turbostratic structure portion 1e, the graphene in contact with the insulating film 3 is affected by the carrier scattering, but the upper graphene stacked on the graphene with a turbostratic structure is less affected by the carrier scattering of the insulating film 3 of the substrate. In addition, in the graphene of the turbostratic structure, the interaction between the layers is less affected, so the conductivity is also improved. Based on the above, the graphene of the turbostratic structure can improve the mobility of carriers. As a result, the sensitivity of the electromagnetic wave detector can be improved.

[0253] In addition, the graphene of the turbostratic structure may be applied only to the portion of the two-dimensional material layer 1 present on the insulating film 3. For example, in the two-dimensional material layer 1, in the region 1a, graphene that is not turbostratic, such as a single-layer graphene, may be used. In this case, the influence of carrier scattering of the insulating film 3 on the two-dimensional material layer 1 can be suppressed without increasing the contact resistance between the first electrode portion 2a and the first semiconductor portion 4a and the two-dimensional material layer 1.

[0254] In addition, the structure of the electromagnetic wave detector of Embodiment 9 can also be applied to other embodiments.

[0255] Implementation method 10.

[0256] Fig.36 This is a schematic cross-sectional view of the electromagnetic wave detector according to the tenth embodiment.

[0257] like Fig.36 As shown, the electromagnetic wave detector of embodiment 10 has basically the same structure as the electromagnetic wave detector of embodiment 1 and can obtain the same effect, but is different from the electromagnetic wave detector of embodiment 1 in that it also has one or more conductors 7 configured in contact with the two-dimensional material layer 1.

[0258] exist Fig.36 In the electromagnetic wave detector shown, a plurality of conductors 7 are arranged in contact with the region 1b of the two-dimensional material layer 1. The plurality of conductors 7 are arranged at intervals from each other. The plurality of conductors 7 are arranged, for example, on the side 42 of the step portion 40. The conductors 7 are floating electrodes. This will be described in detail below.

[0259] like Fig.36 As shown, the electromagnetic wave detector of the tenth embodiment includes a plurality of conductors 7 as floating electrodes on the two-dimensional material layer 1. The material constituting each conductor 7 may be any material having conductivity, for example, at least one selected from the group consisting of gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr) and palladium (Pd). Each conductor 7 is not connected to a power supply circuit, etc., and is floating.

[0260] The plurality of conductors 7 are provided on the region 1b of the two-dimensional material layer 1 between the first electrode portion 2a and the first semiconductor portion 4a. The plurality of conductors 7 have a one-dimensional or two-dimensional periodic structure. For example, as an example of a one-dimensional periodic structure, Fig.36 A structure in which a plurality of conductors 7 are arranged at intervals (periodically) in the horizontal direction on the paper or in the depth direction of the paper. In addition, as an example of a two-dimensional periodic structure, a structure in which conductors 7 are arranged at positions corresponding to lattice points of a square lattice or a triangular lattice when the electromagnetic wave detector is viewed from above can be adopted. In addition, in the case of viewing the electromagnetic wave detector from above, the planar shape of each conductor 7 can also be any shape such as a circle, a triangle, a quadrilateral, a polygon or an ellipse. In addition, the configuration when viewing the conductor 7 from above is not limited to an arrangement having the above-mentioned periodic symmetry, but can also be an arrangement having an asymmetry when viewed from above. Here, the specific method for forming the conductor 7 can adopt any method, for example, the same method as the method for manufacturing the first electrode portion 2a described in Implementation Example 1 can also be used.

[0261] In the electromagnetic wave detector of embodiment 10, a conductor 7 serving as a floating electrode is provided on the two-dimensional material layer 1 corresponding to the channel region. Therefore, photocarriers generated in the semiconductor layer 4 by irradiation with electromagnetic waves travel between the plurality of conductors 7, resulting in a longer lifetime of the photocarriers. Thus, the sensitivity of the electromagnetic wave detector can be improved.

[0262] In addition, the plurality of conductors 7 are arranged to form a one-dimensional periodic structure, and the material of the conductors 7 is set to a material that generates surface plasmon resonance, so that polarization dependence is generated in the conductors 7 by the irradiated electromagnetic waves. As a result, only electromagnetic waves of a specific polarization can be irradiated to the semiconductor layer 4 of the electromagnetic wave detector. In this case, the electromagnetic wave detector of embodiment 10 can detect only specific polarized light.

[0263] In addition, the plurality of conductors 7 are arranged to form a two-dimensional periodic structure, and the material of the conductors 7 is set to a material that generates surface plasmon resonance, so that electromagnetic waves of specific wavelengths can be resonated by the plurality of conductors 7. In this case, only electromagnetic waves with specific wavelengths can be detected by the electromagnetic wave detector. In this case, the electromagnetic wave detector of embodiment 10 can only detect electromagnetic waves of specific wavelengths with high sensitivity.

[0264] In addition, when the plurality of conductors 7 are formed into an asymmetric configuration in a plan view, polarization dependence is generated in the conductors 7 for the irradiated electromagnetic waves, similarly to the case where the plurality of conductors 7 are formed into a one-dimensional periodic structure. As a result, only electromagnetic waves of a specific polarization can be irradiated to the semiconductor layer 4. In this case, the electromagnetic wave detector of embodiment 10 can detect only specific polarized light.

[0265] (Variation Example)

[0266] Fig.37 The electromagnetic wave detector shown has Fig.36 The electromagnetic wave detector shown in FIG. 1 has basically the same structure and can obtain the same effect, but has a conductor 7 disposed under the two-dimensional material layer 1. Fig.36 The electromagnetic wave detector shown is different. That is, Fig.37 In the electromagnetic wave detector shown in FIG. 1 , a plurality of conductors 7 are arranged between the lower surface of the two-dimensional material layer 1 and the upper surface of the insulating film 3. The two-dimensional material layer 1 has a plurality of curved portions (concave and convex portions) along the surface of the plurality of conductors 7. With such a structure, it is also possible to obtain Fig.36 Furthermore, in this case, since the two-dimensional material layer 1 is not damaged when the conductor 7 is formed, the decrease in the mobility of carriers in the two-dimensional material layer 1 can be suppressed.

[0267] In addition, a concavo-convex portion may be formed in the region of the two-dimensional material layer 1 corresponding to the channel region. In this case, the concavo-convex portion of the two-dimensional material layer 1 may also be a periodic structure or an asymmetric structure, similar to the above-mentioned plurality of conductors 7. In this case, the same effect as the case where a plurality of conductors 7 are formed can be obtained.

[0268] in addition, Fig.36 as well as Fig.37 Although each conductor 7 is shown as being formed only on the side portion 42 , it may be formed on at least any one of the top portion 43 , the side portion 42 , and the bottom portion 41 as long as it is in contact with the region 1 b .

[0269] in addition, Fig.36 as well as Fig.37 Although each of the electromagnetic wave detectors shown includes a plurality of conductors 7 , it may include only one conductor 7 .

[0270] In addition, the electromagnetic wave detector of embodiment 10 and each structure of the above-mentioned modification example can also be applied to other embodiments.

[0271] Implementation method 11.

[0272] Fig.38 Schematic cross-sectional view of the electromagnetic wave detector of Embodiment 11. Fig.38 As shown, the electromagnetic wave detector of embodiment 11 has basically the same structure as the electromagnetic wave detector of embodiment 1 and can obtain the same effect, but is different from the electromagnetic wave detector of embodiment 1 in that it also has one or more contact layers 8 configured in contact with the two-dimensional material layer 1.

[0273] exist Fig.38 In the electromagnetic wave detector shown, the contact layer 8 is disposed on the region 1b of the two-dimensional material layer 1. The contact layer 8 is provided in contact with the two-dimensional material layer 1 so as to supply holes or electrons to the two-dimensional material layer 1.

[0274] The material constituting the contact layer 8 is, for example, a composition containing a photosensitizer having a quinonediazide group and a novolac resin, which is called a positive photoresist. In addition, the material constituting the contact layer 8 may also be, for example, a material having a polar group, and more specifically, a material having an electron-attracting group as an example of a material having a polar group. The material having an electron-attracting group has an effect of reducing the electron density of the two-dimensional material layer 1. In addition, the material constituting the contact layer 8 may also be, for example, a material having an electron-donating group as an example of a material having a polar group. The material having an electron-donating group has an effect of increasing the electron density of the two-dimensional material layer 1.

[0275] As the material having an electron-attracting group, for example, there can be mentioned a material having a halogen, nitrile, carboxyl or carbonyl group, etc. In addition, as the material having an electron-donating group, for example, there can be mentioned a material having an alkyl, ethanol, amino or hydroxyl group, etc. In addition, the material constituting the contact layer 8 can also be a material in which the polar group other than the electron-attracting group and the electron-donating group generates a heavy charge in the entire molecule.

[0276] The material constituting the contact layer 8 may be an organic substance, a metal, a semiconductor, an insulator, a two-dimensional material, or a mixture of any of these materials, as long as the charge is unevenly distributed in the entire molecule to generate polarity.

[0277] When the material constituting the contact layer 8 is an inorganic substance, the conductivity type of the two-dimensional material layer 1 doped with the contact layer 8 is p-type when the work function of the contact layer 8 is larger than the work function of the two-dimensional material layer 1, and is n-type when it is smaller. In contrast, when the material constituting the contact layer 8 is an organic substance, the organic substance constituting the contact layer 8 does not have a clear work function. Therefore, as to whether the conductivity type of the doped two-dimensional material layer 1 is p-type or n-type, it is preferable to determine the polarity of the material of the contact layer 8 based on the polarity of the molecules of the organic substance used for the contact layer 8.

[0278] For example, when a composition containing a photosensitizer having a quinonediazide group and a novolac resin, which is called a positive photoresist, is used as the contact layer 8, the region where the resist is formed by the photolithography process on the two-dimensional material layer 1 becomes a p-type two-dimensional material layer region. As a result, it is not necessary to form a mask in contact with 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 simplify the process.

[0279] The electromagnetic wave detector of embodiment 11 has a contact layer 8 formed on the two-dimensional material layer 1. As described above, as the material of the contact layer 8, for example, a material having an electron-attracting group or a material having an electron-donating group is used, so that the state (conductivity type) of the two-dimensional material layer 1 can be intentionally set to n-type or p-type. In this case, the carrier doping of the two-dimensional material layer 1 can be controlled without considering the influence of the carrier doping from the first electrode portion 2a and the first semiconductor portion 4a to the two-dimensional material layer 1. As a result, the performance of the electromagnetic wave detector can be improved.

[0280] In addition, by forming the contact layer 8 only on either the first electrode portion 2a side or the first semiconductor portion 4a side at the upper surface of the two-dimensional material layer 1, a gradient of charge density is formed in the two-dimensional material layer 1. 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.

[0281] In addition, in the electromagnetic wave detector of embodiment 11, the film thickness of the contact layer 8 is preferably thin enough to perform photoelectric conversion when the electromagnetic wave is irradiated to the two-dimensional material layer 1. On the other hand, it is preferred to form the contact layer 8 in a manner having a thickness to the extent that carriers are doped from the contact layer 8 to the two-dimensional material layer 1. As long as carriers such as molecules or electrons are introduced into the two-dimensional material layer 1, the contact layer 8 can be set to any structure. For example, the two-dimensional material layer 1 can also be immersed in a solution, and carriers can be supplied to the two-dimensional material layer 1 at the molecular level, so that the solid contact layer 8 is not formed on the two-dimensional material layer 1, but the carriers are doped into the two-dimensional material layer 1.

[0282] In addition, as the material of the contact layer 8, in addition to the above-mentioned materials, a material that produces a polarity change can also be used. In this case, when the contact layer 8 undergoes a polarity change, the electrons or holes generated during the change are supplied to the two-dimensional material layer 1. Therefore, electron or hole doping occurs in the portion of the two-dimensional material layer 1 that the contact layer 8 contacts. Therefore, even if the contact layer 8 is removed, the portion of the two-dimensional material layer 1 that has been in contact with the contact layer 8 is still doped with electrons or holes. Therefore, in the case of using a material that produces a polarity change as the contact layer 8, the contact layer 8 can also be removed from the two-dimensional material layer 1 after a certain period of time. In this case, the opening area of ​​the two-dimensional material layer 1 is increased compared to the case where the contact layer 8 exists. Therefore, the detection sensitivity of the electromagnetic wave detector can be improved. Here, polarity change refers to the phenomenon that a polar group undergoes a chemical change, for example, it means that an electron-attracting group changes to an electron-donating group or an electron-donating group changes to an electron-attracting group or a polar group changes to a non-polar group or a non-polar group changes to a polar group.

[0283] In addition, the contact layer 8 may also be formed of a material that undergoes a polarity change due to electromagnetic wave irradiation. In this case, a material that undergoes a polarity change at a specific electromagnetic wave wavelength is selected as the material of the contact layer 8, so that a polarity change can occur in the contact layer 8 only when an electromagnetic wave of a specific electromagnetic wave wavelength is irradiated, and doping into the two-dimensional material layer 1 can be performed. As a result, the photocurrent flowing into the two-dimensional material layer 1 can be increased.

[0284] Alternatively, a material that generates a redox reaction when irradiated with electromagnetic waves may be used as the material of the contact layer 8. In this case, the two-dimensional material layer 1 can be doped with electrons or holes generated during the redox reaction.

[0285] The electromagnetic wave detector includes a contact layer 8 in contact with the two-dimensional material layer 1. The contact layer 8 supplies holes or electrons to the two-dimensional material layer 1. In this case, the carrier doping of the two-dimensional material layer 1 can be controlled without considering the influence of the carrier doping from the first electrode portion 2a and the first semiconductor portion 4a. As a result, the performance of the electromagnetic wave detector can be improved.

[0286] also, Fig.38 The contact layer 8 shown is formed only on the side portion, but may be formed on at least any one of the top portion 43 , the side portion 42 , and the bottom portion 41 .

[0287] In addition, the electromagnetic wave detector of embodiment 11 and each structure of the above-mentioned modification example can also be applied to other embodiments.

[0288] Implementation method 12.

[0289] Fig.39 This is a schematic plan view of an electromagnetic wave detector assembly according to a twelfth embodiment.

[0290] like Fig.39 As shown, the electromagnetic wave detector assembly 1000 of the twelfth embodiment is an assembly of a plurality of electromagnetic wave detectors 100. The electromagnetic wave detector assembly 1000 includes a plurality of electromagnetic wave detectors 100 of any of the plurality of embodiments 1 to 11 as detection elements. The electromagnetic wave detector assembly 1000 includes, for example, the electromagnetic wave detector of the first embodiment as the electromagnetic wave detector 100.

[0291] In the electromagnetic wave detector assembly 1000, the detection wavelengths of the plurality of electromagnetic wave detectors 100 are equal. Fig.39 As shown, in the electromagnetic wave detector assembly 1000, 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 intersecting the first direction. Fig.39 In the electromagnetic wave detector assembly 1000 shown, four electromagnetic wave detectors 100 are arranged in a 2×2 array. However, the number of electromagnetic wave detectors 100 arranged is not limited thereto. For example, a plurality of electromagnetic wave detectors 100 may be arranged in a 3 or more×3 or more array.

[0292] In addition, Fig.39 In the electromagnetic wave detector assembly 1000 shown, the plurality of electromagnetic wave detectors 100 are periodically arranged two-dimensionally, but the plurality of electromagnetic wave detectors 100 may be periodically arranged along one direction. In addition, the plurality of electromagnetic wave detectors 100 may be arranged at equal intervals or at different intervals.

[0293] In addition, when a plurality of electromagnetic wave detectors 100 are arranged in an array, the second electrode portion 2b may be set as a common electrode as long as each electromagnetic wave detector 100 can be separated. By setting the second electrode portion 2b as a common electrode, the wiring of pixels can be reduced compared to a structure in which the second electrode portion 2b is independent in each electromagnetic wave detector 100. As a result, the resolution of the electromagnetic wave detector assembly can be increased.

[0294] As a method of separating the electromagnetic wave detectors 100 from each other, for example, the current interruption structure 5 such as the groove structure described in the second embodiment may be provided on the outer periphery of the electromagnetic wave detector 100 .

[0295] In this way, the electromagnetic wave detector assembly 1000 using a plurality of electromagnetic wave detectors 100 can also be used as an image sensor by arranging the plurality of electromagnetic wave detectors 100 in an array.

[0296] The electromagnetic wave detector assembly 1000 may include any of the electromagnetic wave detectors of Embodiments 2 to 11 as the electromagnetic wave detector 100. The electromagnetic wave detector assembly 1000 may include any of the electromagnetic wave detectors of Embodiments 2 to 11 as the electromagnetic wave detector 100.

[0297] The electromagnetic wave detector assembly 1000 may include a plurality of electromagnetic wave detectors according to any one of Embodiments 1 to 11, or may include a plurality of electromagnetic wave detectors according to two or more of Embodiments 1 to 11.

[0298] (Variation Example)

[0299] Fig.40 The electromagnetic wave detector assembly 2000 shown has Fig.39 The electromagnetic wave detector assembly 1000 shown in FIG. 1 has basically the same structure and can obtain the same effect, but is different from the electromagnetic wave detector assembly 1000 in that it includes electromagnetic wave detectors 200, 201, 202, and 203 of different types as a plurality of electromagnetic wave detectors. Fig.39 The electromagnetic wave detector assembly shown is different. That is, Fig.40 In the electromagnetic wave detector assembly 2000 shown, electromagnetic wave detectors 200 , 201 , 202 , and 203 of different types are arranged in an array (matrix).

[0300] exist Fig.40 In the electromagnetic wave detector assembly 2000 shown in FIG. 1 , the electromagnetic wave detectors 200 , 201 , 202 , and 203 are arranged in a 2×2 matrix, but the number of electromagnetic wave detectors arranged is not limited to this. Fig.40In the electromagnetic wave detector assembly 2000 shown, the plurality of electromagnetic wave detectors 200, 201, 202, 203 are periodically arranged in two dimensions, but the plurality of electromagnetic wave detectors 200, 201, 202, 203 may be periodically arranged along one direction. In addition, the intervals between the plurality of electromagnetic wave detectors 200, 201, 202, 203 may be equal intervals or different intervals.

[0301] exist Fig.40 The electromagnetic wave detector assembly 2000 shown can function as an image sensor by arranging electromagnetic wave detectors 200 , 201 , 202 , and 203 of different types according to any of Embodiments 1 to 11 in a one-dimensional or two-dimensional array.

[0302] Electromagnetic wave detectors 200, 201, 202, and 203 are, for example, electromagnetic wave detectors that detect different wavelengths. Specifically, electromagnetic wave detectors 200, 201, 202, and 203 are electromagnetic wave detectors of any of embodiments 1 to 11, and may also be prepared as electromagnetic wave detectors having different detection wavelength selectivities. In this case, the electromagnetic wave detector assembly can detect electromagnetic waves of at least two or more different wavelengths.

[0303] In this way, the electromagnetic wave detectors 200, 201, 202, and 203 having different detection wavelengths are arranged in an array, so that the wavelength of the electromagnetic wave can be identified in any wavelength domain, such as ultraviolet light, infrared light, terahertz wave, and radio wave wavelength domain, similar to the image sensor used in the visible light domain. As a result, for example, different color images can be obtained in which the difference in wavelength is presented as different colors.

[0304] In addition, as the constituent material of the semiconductor layer 4 constituting the electromagnetic wave detector, a semiconductor material having different detection wavelengths may also be used. For example, a semiconductor material having a detection wavelength of visible light and a semiconductor material having a detection wavelength of infrared light may be used as the above-mentioned constituent material. In this case, for example, when the electromagnetic wave detector is applied to a vehicle-mounted sensor, the electromagnetic wave detector can be used as a camera for visible light images during the day. Furthermore, the electromagnetic wave detector can also be used as an infrared camera at night. If this is done, there is no need to separate the camera having an image sensor according to the detection wavelength of the electromagnetic wave.

[0305] In addition, as a use of the electromagnetic wave detector other than an image sensor, for example, even if the number of pixels is small, the electromagnetic wave detector can be used as a position detection sensor capable of detecting the position of an object. For example, by constructing the electromagnetic wave detector assembly, as long as the electromagnetic wave detectors 200, 201, 202, and 203 with different detection wavelengths are used as described above, an image sensor that detects the intensity of electromagnetic waves of multiple wavelengths can be obtained. As a result, it is possible to detect electromagnetic waves of multiple wavelengths and obtain a color image without using a color filter that was previously required in a CMOS image sensor or the like.

[0306] Furthermore, by arraying the electromagnetic wave detectors 200, 201, 202, and 203 with different polarizations, a polarization recognition image sensor can also be formed. For example, four pixels with polarization angles of 0°, 90°, 45°, and 135° are used as a unit, and multiple electromagnetic wave detectors of the unit are configured, so that polarization imaging can be achieved. Through the polarization recognition image sensor, for example, it is possible to achieve recognition of man-made and natural objects, material recognition, recognition of objects of the same temperature in the infrared wavelength domain, recognition of boundaries between objects, or equivalent improvement of resolution, etc.

[0307] As described above, the electromagnetic wave detector assembly 2000 can detect electromagnetic waves in a wide wavelength range. In addition, the electromagnetic wave detector assembly 2000 can detect electromagnetic waves of different wavelengths.

[0308] (Variation Example)

[0309] In the above-mentioned embodiments, as the material of the insulating film 3 , the contact layer 8 , or the first semiconductor portion 4 a and the second semiconductor portion 4 b , it is preferable to use a material whose characteristics change due to irradiation with electromagnetic waves and which applies a change in potential to the two-dimensional material layer 1 .

[0310] Here, as a material whose characteristics change due to irradiation with electromagnetic waves and which applies a change in potential to the two-dimensional material layer 1, for example, quantum dots, ferroelectric materials, liquid crystal materials, fullerenes, rare earth oxides, semiconductor materials, pn junction materials, metal-semiconductor bonding materials, or metal-insulator-semiconductor bonding materials can be used. For example, when a ferroelectric material having a polarization effect (thermoelectric effect) based on electromagnetic waves is used as the ferroelectric material, a change in polarization occurs in the ferroelectric material by irradiation with electromagnetic waves. As a result, a change in potential can be applied to the two-dimensional material layer 1.

[0311] As described above, when the material constituting the insulating film 3, the contact layer 8, the first semiconductor part 4a or the second semiconductor part 4b is a material whose properties change due to irradiation with electromagnetic waves, in the insulating film 3, the contact layer 8, the first semiconductor part 4a or the second semiconductor part 4b, the properties change due to irradiation with electromagnetic waves, and a change in potential can be applied to the two-dimensional material layer 1.

[0312] In addition, an example is described in which a material whose characteristics change due to irradiation with electromagnetic waves and applies a change in potential to the two-dimensional material layer 1 is applied to the insulating film 3, the contact layer 8, the first semiconductor portion 4a, or the second semiconductor portion 4b, but the material whose characteristics change due to irradiation with electromagnetic waves and applies a change in potential to the two-dimensional material layer 1 may be applied to at least one of the above-mentioned components. For example, in the case where a material whose characteristics change due to irradiation with electromagnetic waves and applies a change in potential to the two-dimensional material layer 1 is applied to the contact layer 8, the contact layer 8 does not need to be in direct contact with the two-dimensional material layer 1. For example, as long as a change in potential can be applied to the two-dimensional material layer 1, the contact layer 8 may be provided on the upper surface or the lower surface of the two-dimensional material layer 1 via an insulating film or the like.

[0313] The above-mentioned embodiments can be appropriately modified or omitted. Furthermore, the above-mentioned embodiments can be variously modified in the implementation stage without departing from the scope of the gist thereof. In addition, the above-mentioned embodiments include disclosures at various stages, and various disclosures can be extracted by appropriate combinations of the disclosed multiple structural elements.

[0314] The embodiments disclosed herein should be considered to be illustrative at all points, and not restrictive. As long as there is no contradiction, at least two embodiments in the embodiments disclosed herein may be combined. The scope of the present disclosure is not shown by the above description, but by the claims, and is intended to include all changes within the meaning and scope equivalent to the claims.

Claims

1. An electromagnetic wave detector comprising: The semiconductor layer is formed with at least one step portion and has sensitivity to the detection wavelength; an insulating film disposed on the at least one step portion and having at least one opening portion for exposing a portion of the at least one step portion; a two-dimensional material layer, arranged on the insulating film and the at least one opening, and having a region connected to the semiconductor layer through the insulating film and generating a grating effect and a connection region electrically connected to the semiconductor layer at the at least one opening; a first electrode portion, arranged on the insulating film and electrically connected to the two-dimensional material layer at a position away from the opening of the insulating film; as well as a second electrode portion, which is disposed on the semiconductor layer and is electrically connected to the first electrode portion via the connection region of the two-dimensional material layer; One of the at least one step portion corresponds to the plurality of openings, and the plurality of openings are provided so as to expose a portion of the corresponding one step portion.

2. An electromagnetic wave detector comprising: The semiconductor layer is formed with at least one step portion and has sensitivity to the detection wavelength; an insulating film disposed on the at least one step portion and having at least one opening portion for exposing a portion of the at least one step portion; a two-dimensional material layer, arranged on the insulating film and the at least one opening, and having a region connected to the semiconductor layer through the insulating film and generating a grating effect and a connection region electrically connected to the semiconductor layer at the at least one opening; a first electrode portion, arranged on the insulating film and electrically connected to the two-dimensional material layer at a position away from the opening of the insulating film; as well as a second electrode portion, which is disposed on the semiconductor layer and is electrically connected to the first electrode portion via the connection region of the two-dimensional material layer; The semiconductor layer includes a current cutoff structure located in a region facing the insulating film and arranged so as to surround an outer periphery of the at least one opening.

3. An electromagnetic wave detector comprising: The semiconductor layer is formed with at least one step portion and has sensitivity to the detection wavelength; an insulating film disposed on the at least one step portion and having at least one opening portion for exposing a portion of the at least one step portion; a two-dimensional material layer, arranged on the insulating film and the at least one opening, and having a region connected to the semiconductor layer through the insulating film and generating a grating effect and a connection region electrically connected to the semiconductor layer at the at least one opening; a first electrode portion, arranged on the insulating film and electrically connected to the two-dimensional material layer at a position away from the opening of the insulating film; as well as a second electrode portion, which is disposed on the semiconductor layer and is electrically connected to the first electrode portion via the connection region of the two-dimensional material layer; The semiconductor layer comprises: A first semiconductor portion having a first conductivity type; as well as a second semiconductor portion, which is bonded to the first semiconductor portion and has a second conductivity type, Inside the at least one opening, a portion of a junction between the first semiconductor portion and the second semiconductor portion and a portion of the first semiconductor portion and a portion of the second semiconductor portion connected to the junction are arranged to face the connection region of the two-dimensional material layer. When the semiconductor layer is viewed from the at least one opening, the first semiconductor portion includes a first portion and a second portion which are arranged so as to sandwich at least a portion of the second semiconductor portion. Inside the at least one opening, at least a portion of the second semiconductor portion, the first portion of the first semiconductor portion, and the second portion of the first semiconductor portion are arranged to face the connection region of the two-dimensional material layer.

4. An electromagnetic wave detector comprising: The semiconductor layer is formed with at least one step portion and has sensitivity to the detection wavelength; an insulating film disposed on the at least one step portion and having at least one opening portion for exposing a portion of the at least one step portion; a two-dimensional material layer, arranged on the insulating film and the at least one opening, and having a region connected to the semiconductor layer through the insulating film and generating a grating effect and a connection region electrically connected to the semiconductor layer at the at least one opening; a first electrode portion, arranged on the insulating film and electrically connected to the two-dimensional material layer at a position away from the opening of the insulating film; as well as a second electrode portion, which is disposed on the semiconductor layer and is electrically connected to the first electrode portion via the connection region of the two-dimensional material layer; The semiconductor layer comprises: A first semiconductor portion having a first conductivity type; as well as a second semiconductor portion, which is bonded to the first semiconductor portion and has a second conductivity type, Inside the at least one opening, a portion of a junction between the first semiconductor portion and the second semiconductor portion and a portion of the first semiconductor portion and a portion of the second semiconductor portion connected to the junction are arranged to face the connection region of the two-dimensional material layer. The connection region of the two-dimensional material layer includes a first connection region in contact with the first semiconductor portion and a second connection region in contact with the second semiconductor portion. The two-dimensional material layer includes a first two-dimensional material layer having the first connection region and a second two-dimensional material layer having the second connection region, The first two-dimensional material layer and the second two-dimensional material layer are disconnected at the junction between the first semiconductor portion and the second semiconductor portion.

5. An electromagnetic wave detector comprising: The semiconductor layer is formed with at least one step portion and has sensitivity to the detection wavelength; an insulating film disposed on the at least one step portion and having at least one opening portion for exposing a portion of the at least one step portion; a two-dimensional material layer, arranged on the insulating film and the at least one opening, and having a region connected to the semiconductor layer through the insulating film and generating a grating effect and a connection region electrically connected to the semiconductor layer at the at least one opening; a first electrode portion, arranged on the insulating film and electrically connected to the two-dimensional material layer at a position away from the opening of the insulating film; as well as a second electrode portion, which is disposed on the semiconductor layer and is electrically connected to the first electrode portion via the connection region of the two-dimensional material layer; The semiconductor layer comprises: A first semiconductor portion having a first conductivity type; a second semiconductor portion, which is bonded to the first semiconductor portion and has a second conductivity type; The first semiconductor portion is connected to the connection region of the two-dimensional material layer inside the at least one opening. The second semiconductor portion is buried under the first semiconductor portion connected to the connection region of the two-dimensional material layer in the at least one opening.

6. The electromagnetic wave detector according to any one of claims 1 to 5, wherein: The at least one step portion has a top portion, a bottom portion, and a side portion disposed between the bottom portion and the top portion. The at least one opening is provided so as to expose at least a part of the top portion, the bottom portion, and the side portion.

7. The electromagnetic wave detector according to any one of claims 1 to 5, wherein: The at least one step portion includes a plurality of step portions, The at least one opening is provided so as to expose at least a portion of the plurality of step portions.

8. The electromagnetic wave detector according to any one of claims 1 to 5, wherein: The electromagnetic wave detector further includes a buffer layer disposed inside the at least one opening and between the semiconductor layer and the connection region of the two-dimensional material layer.

9. The electromagnetic wave detector according to claim 8, wherein: The buffer layer has a thickness capable of forming a tunnel current between the connection region of the two-dimensional material layer and the semiconductor layer.

10. The electromagnetic wave detector according to any one of claims 1 to 5, wherein: The electromagnetic wave detector further includes a connection conductor that electrically connects the semiconductor layer and the connection region of the two-dimensional material layer inside the at least one opening.

11. The electromagnetic wave detector according to any one of claims 1 to 5, wherein: The two-dimensional material layer further comprises an electrode connection region, and the electrode connection region is electrically connected to the first electrode portion. A minimum value of a width of the connection region in a direction intersecting a direction in which the connection region and the electrode connection region are arranged side by side is narrower than a minimum value of a width of the electrode connection region.

12. The electromagnetic wave detector according to claim 11, wherein: The width of the connection region in the crossing direction gradually becomes narrower as it moves away from the electrode connection region in the arrangement direction.

13. The electromagnetic wave detector according to claim 4 or 5, wherein: The first electrode portion is directly connected to the first semiconductor portion, The second electrode portion is directly connected to the second semiconductor portion.

14. The electromagnetic wave detector according to any one of claims 1 to 5, wherein: The thickness of the insulating film changes as it approaches the at least one opening from the first electrode portion.

15. The electromagnetic wave detector according to any one of claims 1 to 5, wherein: The electromagnetic wave detector further includes one or more conductors or contact layers arranged in contact with the two-dimensional material layer.

16. The electromagnetic wave detector according to any one of claims 1 to 5, wherein: The two-dimensional material layer includes any material selected from the group consisting of transition metal dichalcogenides, graphene, black phosphorus, silicene, germanene, graphene nanoribbons, and borophene.

17. The electromagnetic wave detector according to any one of claims 1 to 5, wherein: The two-dimensional material layer comprises one or more layers of graphene arranged in a turbostratic structure, The one or more layers of graphene arranged in a turbostratic structure are arranged on a portion located between the at least one opening portion in the insulating film and the first electrode portion.

18. The electromagnetic wave detector according to any one of claims 1 to 5, wherein: The electromagnetic wave detector further includes an insulating protective film disposed so as to cover the two-dimensional material layer.

19. An electromagnetic wave detector assembly, wherein: The electromagnetic wave detector assembly comprises a plurality of electromagnetic wave detectors according to any one of claims 1 to 18, The plurality of electromagnetic wave detectors are arranged to be aligned along at least one of the first direction and the second direction.

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