Electromagnetic wave detector, electromagnetic wave detector array, and method for manufacturing electromagnetic wave detector

Abstract

The electromagnetic wave detector (100A) comprises: a semiconductor substrate (1); a first insulating film (2) arranged on the semiconductor substrate and formed in a manner that exposes a portion of the semiconductor substrate; a first electrode (3) arranged on the first insulating film; a two-dimensional material layer (5) having a joint (12) that is Schottky-bonded to a portion of the semiconductor substrate, and extending from the joint to the first electrode via the first insulating film; a second electrode (6) in contact with the semiconductor substrate; and a control electrode (7) that is arranged on at least a portion of the periphery of the joint when viewed from above and is Schottky-bonded to the semiconductor substrate.

Description

Technical Field

[0001] The present disclosure relates to an electromagnetic wave detector, an electromagnetic wave detector array, and a method for manufacturing the electromagnetic wave detector. Background Art

[0002] In the past, as a material for the electromagnetic wave detection layer used in the next generation electromagnetic wave detector, graphene with extremely high mobility as an example of a two-dimensional material layer is known. Furthermore, as the next generation electromagnetic wave detector, an electromagnetic wave detector using a graphene field effect transistor using a single layer or multiple layers of graphene in the channel of the field effect transistor is known.

[0003] Since the band gap of graphene is zero or very small, the graphene field effect transistor has a problem that the current (dark current) is large when no electromagnetic wave is irradiated.

[0004] U.S. Patent Application Publication No. 2015 / 0243826 (Patent Document 1) discloses a structure in which graphene and a silicon substrate are directly contacted in an opening formed in an insulating film covering the surface of a silicon substrate in order to reduce the dark current of a graphene field effect transistor.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: U.S. Patent Application Publication No. 2015 / 0243826 Summary of the invention

[0008] However, in the electromagnetic wave detector having the above-described structure disclosed in Patent Document 1, it is difficult to suppress the variation in dark current of each electromagnetic wave detector (pixel).

[0009] For example, in the manufacturing process of the electromagnetic wave detector, foreign matter such as moisture or resist may remain at the bonding interface between the silicon substrate and the graphene. In such an electromagnetic wave detector, leakage current is generated and the dark current is not sufficiently reduced. As a result, it is difficult to fully suppress the deviation of the dark current of each electromagnetic wave detector in the above-mentioned electromagnetic wave detector.

[0010] A main object of the present disclosure is to provide an electromagnetic wave detector, an electromagnetic wave detector array, and a method for manufacturing the electromagnetic wave detector in which variations in dark current of each electromagnetic wave detector are suppressed.

[0011] The electromagnetic wave detector involved in the present disclosure comprises: a semiconductor substrate; a first insulating film, which is arranged on the semiconductor substrate and formed in a manner that exposes a portion of the semiconductor substrate; a first electrode, which is arranged on the first insulating film; a two-dimensional material layer, which has a joint portion that is Schottky-bonded to the semiconductor substrate at a portion of the semiconductor substrate, and extends from the joint portion to the first electrode via the first insulating film; a second electrode, which is in contact with the semiconductor substrate; and a control electrode, which is arranged on at least a portion of the periphery of the joint portion when viewed from above, and is Schottky-bonded to the semiconductor substrate.

[0012] According to the present disclosure, it is possible to provide an electromagnetic wave detector, an electromagnetic wave detector array, and a method of manufacturing the electromagnetic wave detector in which variations in dark current of each electromagnetic wave detector are suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic plan view of the electromagnetic wave detector according to the first embodiment.

[0014] Figure 2 is along Figure 1 Schematic diagram of the cross section of line segment II-II in FIG.

[0015] Figure 3 This is a flowchart for explaining the method for manufacturing the electromagnetic wave detector according to the first embodiment.

[0016] Figure 4 This is a schematic cross-sectional view showing an operation example of the electromagnetic wave detector according to the first embodiment.

[0017] Figure 5 This is a graph showing an operation example of the electromagnetic wave detector according to the first embodiment.

[0018] Figure 6 This is a schematic cross-sectional view showing a first modified example of the electromagnetic wave detector according to the first embodiment.

[0019] Figure 7 is along Figure 6 Schematic diagram of the cross-section of line segment VII-VII in FIG.

[0020] Figure 8 It is a schematic cross-sectional view showing a second modified example of the electromagnetic wave detector according to the first embodiment.

[0021] Fig. 9 is along Figure 8 Schematic diagram of the cross-section of line segment IX-IX in FIG.

[0022] Fig.10 This is a schematic plan view of the electromagnetic wave detector involved in Embodiment 2.

[0023] Fig.11is along Fig.10 Schematic cross-sectional view of line segment XI-XI in FIG.

[0024] Fig.12 This is a schematic plan view of the electromagnetic wave detector involved in the third embodiment.

[0025] Fig.13 is along Fig.12 Schematic diagram of the cross section of line segment XIII-XIII in FIG.

[0026] Fig.14 It is a schematic cross-sectional view showing a first modified example of the electromagnetic wave detector according to the third embodiment.

[0027] Fig.15 It is a schematic cross-sectional view showing a second modified example of the electromagnetic wave detector according to the third embodiment.

[0028] Fig.16 is along Fig.15 Schematic diagram of the cross section of line segment XVI-XVI in .

[0029] Fig.17 It is a schematic cross-sectional view showing the electromagnetic wave detector involved in the fourth embodiment.

[0030] Fig.18 is along Fig.17 Schematic diagram of the cross section of line segment XVIII-XVIII in FIG.

[0031] Fig.19 It is a schematic cross-sectional view showing the electromagnetic wave detector involved in Embodiment 5.

[0032] Fig. 20 is along Fig.19 Schematic diagram of the cross section of line segment XX-XX in .

[0033] Fig.21 It is a schematic cross-sectional view showing the electromagnetic wave detector involved in Embodiment 6.

[0034] Fig. 22 is along Fig.21 Schematic diagram of the cross section of line segment XXII-XXII in FIG.

[0035] Fig.23 is along Fig.21 Schematic cross-sectional view of line segment XXIII-XXIII in FIG.

[0036] Fig.24 It is a schematic cross-sectional view showing the electromagnetic wave detector involved in the seventh embodiment.

[0037] Fig.25 is along Fig.24Schematic diagram of the cross section of line segment XXV-XXV in FIG.

[0038] Fig.26 is along Fig.24 Schematic diagram of the cross section of line segment XXVI-XXVI in FIG.

[0039] Fig. 27 It is a schematic plan view showing a modified example of the electromagnetic wave detector involved in the seventh embodiment.

[0040] Fig.28 is along Fig. 27 Schematic diagram of the cross section of line segment XXVIII-XXVIII in FIG.

[0041] Fig.29 This is a schematic plan view showing the electromagnetic wave detector involved in the eighth embodiment.

[0042] Fig.30 is along Fig.29 Schematic diagram of the cross section of line segment XXX-XXX in .

[0043] Fig.31 This is a schematic plan view showing the electromagnetic wave detector involved in Embodiment 9.

[0044] Fig.32 is along Fig.31 Schematic diagram of the cross section of line segment XXXII-XXXII in FIG.

[0045] Fig.33 This is a schematic plan view showing the electromagnetic wave detector involved in the tenth embodiment.

[0046] Fig.34 is along Fig.33 Schematic diagram of the cross section of line segment XXXIV-XXXIV in FIG.

[0047] Fig.35 This is a schematic top view of the electromagnetic wave detector array involved in embodiment 11.

[0048] Fig.36 This is a schematic plan view showing a modified example of the electromagnetic wave detector array involved in the eleventh embodiment.

[0049] (Explanation of symbols)

[0050] 1: semiconductor substrate; 1A: first surface; 1B: second surface; 2: first insulating film; 2A: end face; 2B, 2C: opening; 3: first electrode; 4: exposed portion; 5: two-dimensional material layer; 6: second electrode; 7: control electrode; 7A, 7B: end; 8: electrode; 9: pn diode; 9n, 9p: polysilicon thin film; 10: ammeter; 11, 14: power supply; 12: junction; 13: ground node; 15: second insulating film; 100, 100A, 100B, 100C, 101, 101B, 102A, 102B, 102C, 103, 104, 105, 106, 106A, 106B, 107, 108, 109: electromagnetic wave detector; 200, 201: electromagnetic wave detector array. DETAILED DESCRIPTION

[0051] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and their description will not be repeated.

[0052] In the embodiments described below, the figures are schematic drawings, conceptually illustrating functions or structures. In addition, the present invention is not limited to the embodiments described below. Except for the cases specifically described, the basic structure of the electromagnetic wave detector is common to all embodiments. In addition, the parts with the same symbols are the same as described above or equivalent thereto. This is common throughout the entire text of the specification.

[0053] In the embodiments described below, the electromagnetic wave detector is described using a structure for detecting visible light or infrared light, but the present invention is not limited to these. The embodiments described below are also effective as detectors for detecting radio waves such as X-rays, ultraviolet light, near-infrared light, terahertz (THz) waves, or microwaves in addition to visible light or infrared light. In addition, in the embodiments of the present invention, these lights and radio waves are collectively referred to and recorded as electromagnetic waves.

[0054] In the embodiments of the present invention, the term 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.

[0055] In addition, in the embodiment of the present invention, the term n-type or p-type is used for the material of the component in contact with graphene as an example of a two-dimensional material layer. Here, for example, n-type material means a material with electron donating properties, and p-type material means a material with electron attracting properties. In addition, there is a case where a shift is observed in the charge of the molecule as a whole, and the material in which electrons become dominant is called n-type, and the material in which holes become dominant is called p-type. As these materials, any one of organic and inorganic substances or a mixture thereof can be used.

[0056] In addition, in the embodiments described below, graphene is used as an example of a material for a two-dimensional material layer, but the material constituting the two-dimensional material layer is not limited to graphene. For example, as a material for a 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, molybdenum sulfide (MoS2), tungsten sulfide (WS2), and tungsten selenide (WSe2) can be cited. These materials have a structure similar to that of graphene and are materials that can arrange atoms in a single layer in a two-dimensional plane. Therefore, when these materials are applied to a two-dimensional material layer, the same effect as when graphene is applied to a two-dimensional material layer can be obtained.

[0057] Implementation method 1.

[0058] like Figure 1 as well as Figure 2 As shown, the electromagnetic wave detector 100A according to the first embodiment mainly includes a semiconductor substrate 1 , a first insulating film 2 , a first electrode 3 , a two-dimensional material layer 5 , a second electrode 6 , and a control electrode 7 .

[0059] The semiconductor substrate 1 has a first surface 1A and a second surface 1B. The second surface 1B is located on the opposite side to the first surface 1A. The first surface 1A and the second surface 1B are, for example, flat surfaces.

[0060] The semiconductor substrate 1 has sensitivity to a detection wavelength predetermined from the above-mentioned electromagnetic waves. The semiconductor substrate 1 has an n-type or p-type conductivity type and is arranged in a manner to generate photocarriers in the semiconductor substrate 1 when an electromagnetic wave of a predetermined detection wavelength is incident on the semiconductor substrate 1. The semiconductor material constituting the semiconductor substrate 1 can be arbitrarily selected according to the detection wavelength to which sensitivity should be provided.

[0061] The semiconductor material constituting the semiconductor substrate 1 includes, for example, at least one selected from the group consisting of silicon (Si), germanium (Ge), compound semiconductors such as 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), indium gallium arsenide (InGaAs), and indium arsenide (InAs). The semiconductor substrate 1 may be, for example, a substrate including quantum wells or quantum dots composed of two or more semiconductor materials selected from the above group, a substrate including a type II superlattice, or a substrate combining them.

[0062] The first insulating film 2 is arranged on the first surface 1A of the semiconductor substrate 1. The first electrode 3 is arranged on the first insulating film 2. The first insulating film 2 is formed in a manner that a portion of the first surface 1A of the semiconductor substrate 1 is exposed. In other words, a portion of the first surface 1A of the semiconductor substrate 1 is configured as an exposed portion 4 exposed from the first insulating film 2. The first insulating film 2 is formed to be spaced apart from a portion of the first insulating film 2 overlapping the first electrode 3 when viewed from above, and has an end face 2A extending in a direction intersecting the first surface 1A. The material constituting the first insulating film 2 and the thickness of the first insulating film 2 are selected in a manner to prevent the generation of a tunnel current between the semiconductor substrate 1 and the first electrode 3.

[0063] The material constituting the first insulating film 2 includes, for example, at least one selected from the group consisting of silicon oxide (SiO 2 ), silicon nitride (Si 3 N 4 ), hafnium oxide (HfO 2 ), aluminum oxide (Al 2 O 3 ), nickel oxide (NiO) and boron nitride (BN).

[0064] The first electrode 3 is disposed on the first insulating film 2 at a position away from the end surface 2A. The first electrode 3 is electrically connected to the two-dimensional material layer 5. The second electrode 6 is in contact with the semiconductor substrate 1. For example, the second electrode 6 is in contact with the second surface 1B of the semiconductor substrate 1. Preferably, the second electrode 6 is ohmically bonded to the semiconductor substrate 1. Figure 2 As shown, the first electrode 3 and the second electrode 6 are electrically connected to a power circuit. The power circuit includes a power supply 11 for applying a voltage between the first electrode 3 and the second electrode 6, and an ammeter 10 for measuring a current flowing between the first electrode 3 and the second electrode 6.

[0065] The material constituting the first electrode 3 and the second electrode 6 may be any conductive body, but is preferably a material that is ohmically bonded to the semiconductor substrate 1, 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). An unillustrated adhesion layer that improves the adhesion between the first electrode 3 and the first insulating film 2 may also be formed between the first electrode 3 and the first insulating film 2. An unillustrated adhesion layer that improves the adhesion between the second electrode 6 and the semiconductor substrate 1 may also be formed between the second electrode 6 and the semiconductor substrate 1. The material constituting the adhesion layer includes, for example, a metal material such as chromium (Cr) or titanium (Ti).

[0066] The two-dimensional material layer 5 has a junction 12 that is Schottky-bonded to at least a portion of the exposed portion 4. Hereinafter, the Schottky junction between the two-dimensional material layer 5 and the semiconductor substrate 1 is referred to as a first Schottky junction. The two-dimensional material layer 5 is in contact with, for example, a portion of the exposed portion 4. The two-dimensional material layer 5 extends from the junction 12 to the first electrode 3 via the first insulating film 2.

[0067] The two-dimensional material layer 5 has, for example, a length direction and a width direction intersecting the length direction. One end of the two-dimensional material layer 5 in the length direction forms the bonding portion 12. The entire width direction of one end of the two-dimensional material layer 5 in the length direction forms the bonding portion 12. The other end of the two-dimensional material layer 5 in the length direction is electrically connected to the first electrode 3.

[0068] The two-dimensional material layer 5 is, for example, a single-layer graphene or a multi-layer graphene. The two-dimensional material layer 5 may also include, for example, a graphene nanoribbon. The two-dimensional material layer 5 may also include a turbostratic stacked graphene composed of a plurality of single-layer graphenes. As described above, the material constituting the two-dimensional material layer 5 may also include at least one selected from the group consisting of graphene, transition metal dichalcogenides, black phosphorus, silicene, and germanene. In addition, the two-dimensional material layer 5 may also have a heterogeneous stacked structure combining two or more materials selected from the above group.

[0069] A protective film (not shown) may be formed on the two-dimensional material layer 5. The material constituting such a protective film includes, for example, at least one selected from the group consisting of SiO2, Si3N4, HfO2, Al2O3, NiO, and BN.

[0070] The control electrode 7 is arranged at a part of the periphery of the joint portion 12 when viewed from above, and is Schottky-jointed to the semiconductor substrate 1. Hereinafter, the Schottky junction between the control electrode 7 and the semiconductor substrate 1 is referred to as the second Schottky junction. The control electrode 7 is in contact with the first surface 1A of the semiconductor substrate 1. The control electrode 7 is, for example, arranged at a distance from the joint portion 12. The control electrode 7 is, for example, covered by the first insulating film 2. The control electrode 7 is not in direct contact with the two-dimensional material layer 5. The control electrode 7 is not connected to a power source.

[0071] The two-dimensional material layer 5 and the control electrode 7 are arranged in such a manner that the depletion layer of the second Schottky junction is connected to the depletion layer formed at the first Schottky junction when a reverse bias is applied to the first Schottky junction. The two-dimensional material layer 5 and the control electrode 7 are arranged in such a manner that the depletion layer formed by connecting the depletion layer of the second Schottky junction to the depletion layer formed at the first Schottky junction when a reverse bias is applied to the first Schottky junction entirely covers the entire interface of the first Schottky junction.

[0072] The control electrode 7 is, for example, arranged on the side opposite to the first electrode 3 relative to the joint portion 12 in the length direction of the two-dimensional material layer 5. The control electrode 7 has, for example, a length direction and a width direction intersecting the length direction. The length direction of the control electrode 7 is, for example, along the width direction of the two-dimensional material layer 5. The width direction of the control electrode 7 is, for example, along the length direction of the two-dimensional material layer 5. The width of the control electrode 7 in the length direction is greater than the width of the two-dimensional material layer 5 in the width direction. The width of the control electrode 7 in the length direction is, for example, wider than the width of the two-dimensional material layer 5 in the width direction. The width of the joint portion 12 in the length direction of the two-dimensional material layer 5 is, for example, wider than the width of the control electrode 7 in the width direction.

[0073] The material constituting the control electrode 7 includes a metal material that forms a Schottky bond with the semiconductor substrate 1. When the semiconductor substrate 1 has an n-type conductivity, the material constituting the control electrode 7 is a metal having a larger work function than the semiconductor material constituting the semiconductor substrate 1.

[0074] Preferably, the material constituting the control electrode 7 is a metal selected in such a way that the barrier height of the second Schottky junction (the difference between the work function of the material constituting the control electrode 7 and the electron affinity of the material constituting the semiconductor substrate 1) is higher than the barrier height of the first Schottky junction (the difference between the work function of the material constituting the two-dimensional material layer 5 and the electron affinity of the material constituting the semiconductor substrate 1). In the case where the semiconductor substrate 1 is an n-type Si substrate, the material constituting the control electrode 7 includes, for example, at least one of Au and Ni. In the case where the semiconductor substrate 1 has a p-type conductivity type, the material constituting the control electrode 7 is a metal having a smaller work function than the semiconductor material constituting the semiconductor substrate 1. In the case where the semiconductor substrate 1 is a p-type Si substrate, the material constituting the control electrode 7 includes, for example, at least one of indium (In) and tin (Sn).

[0075] <Method for manufacturing electromagnetic wave detector>

[0076] 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 2The manufacturing method of the electromagnetic wave detector shown.

[0077] First, implement Figure 3 The preparation step (S1) shown in the figure. In this step (S1), a flat semiconductor substrate 1 is prepared. The semiconductor substrate 1 has a first surface 1A and a second surface 1B. The semiconductor material constituting the semiconductor substrate 1 is a semiconductor material having sensitivity to a predetermined detection wavelength.

[0078] Next, a control electrode forming step (S2) is performed. In this step (S2), a control electrode 7 is formed on the first surface 1A of the semiconductor substrate 1. The method for forming the control electrode 7 is not particularly limited, and includes, for example, film forming processing using a vapor deposition method or a sputtering method, a photolithography process, and an etching process.

[0079] Next, a second electrode forming step (S3) is performed. In this step (S3), the second electrode 6 is formed on the second surface 1B of the semiconductor substrate 1. The method for forming the second electrode 6 is not particularly limited, and includes, for example, film forming by evaporation or sputtering, photolithography, and etching. Before forming the second electrode 6, in order to improve the adhesion between the semiconductor substrate 1 and the second electrode 6, the above-mentioned adhesion layer may be pre-formed in the region of the semiconductor substrate 1 connected to the second electrode 6.

[0080] Next, an insulating film forming step (S4) is performed. In this step (S4), a first insulating film 2 is formed on the first surface 1A of the semiconductor substrate 1. The film forming method of the first insulating film 2 is not particularly limited, and for example, a plasma CVD (Chemical Vapor Deposition) method or an atomic layer deposition method (ALD) method is used.

[0081] Furthermore, in order to suppress damage and contamination of the semiconductor substrate 1 caused by etching in the exposed portion forming step (S6) described later, a barrier film may be formed between the semiconductor substrate 1 and the first insulating film 2 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 exposed portion forming step (S6) than the material constituting the first insulating film 2 (a material having a slower etching rate), such as silicon nitride (SiN), aluminum oxide (Al2O3) or graphene.

[0082] Next, a first electrode forming step (S5) is performed. In this step (S5), the first electrode 3 is formed on the first insulating film 2. The method for forming the first electrode 3 is not particularly limited, and includes, for example, film forming by evaporation or sputtering, photolithography, and etching. Before forming the first electrode 3, in order to improve the adhesion between the first insulating film 2 and the first electrode 3, the above-mentioned adhesion layer may be pre-formed in the region of the first insulating film 2 connected to the first electrode 3.

[0083] Next, an exposed portion forming step (S6) is implemented. In this step (S6), an exposed portion 4 exposed from the first insulating film 2 is formed on the semiconductor substrate 1 by removing a portion of the first insulating film 2. Specifically, a resist mask is formed on the first insulating film 2 by photoengraving or EB drawing. The resist mask is formed in a manner that covers the area where the first insulating film 2 is to be formed and exposes the area where the exposed portion 4 is to be formed. Thereafter, the first insulating film 2 is etched using the resist mask as an etching mask. The etching method can be arbitrarily selected from any etching including wet etching using hydrofluoric acid or the like and dry etching using reactive ion etching or the like. After etching, the resist mask is removed. In this way, the exposed portion 4 is formed. The above step (S6) can also be implemented before step (S5).

[0084] Next, a two-dimensional material layer forming step (S7) is performed. In this step (S7), a two-dimensional material layer 5 is formed on at least a portion of each of the first insulating film 2 and the exposed portion 4. The method for forming the two-dimensional material layer 5 is not particularly limited, and includes film formation using an epitaxial growth method, photolithography, and etching.

[0085] Through the above steps (S1 to S7), the Figure 1 as well as Figure 2 The electromagnetic wave detector 100A is shown.

[0086] In addition, the exposed portion forming step (S6) may be performed before the first electrode forming step (S5). That is, in the manufacturing method of the electromagnetic wave detector 100A, the above step (S1), the above step (S2), the above step (S3), the above step (S4), the above step (S6), the above step (S5), and the above step (S7) may be performed in sequence.

[0087] <Action>

[0088] Next, the operation of the electromagnetic wave detector according to this embodiment will be described.

[0089] Figure 4 1 is a cross-sectional schematic diagram showing an operation example of the electromagnetic wave detector 100A. Figure 4As shown, a power circuit (not shown) is electrically connected between the first electrode 3 and the second electrode 6. The power circuit includes: a power supply 11 for applying a voltage V between the first electrode 3 and the second electrode 6; and an ammeter 10 for measuring a current I flowing in the power circuit. The positive and negative voltages are selected according to the conductivity type (doping type) of the semiconductor substrate 1 in a manner that applies a reverse bias to the first Schottky junction. The voltage applied by the power supply 11 to both electrodes is set to a positive voltage in such a manner that the potential of the first electrode 3 is higher than the potential of the second electrode 6. If the conductivity type is p-type, then Figure 4 As shown, a positive voltage is applied between the first electrode 3 and the second electrode 6. If the conductivity type is n-type, a negative voltage is applied between the first electrode 3 and the second electrode 6. In this way, the electromagnetic wave detector 100A becomes capable of detecting electromagnetic waves of a wavelength to which the semiconductor substrate 1 has sensitivity.

[0090] The electromagnetic wave detector 100A applies a reverse bias to the first Schottky junction in a state capable of detecting electromagnetic waves. Therefore, the depletion layer at the interface of the first Schottky junction extends around it and connects to the depletion layer of the second Schottky junction. As a result, in the electromagnetic wave detector 100A having the first Schottky junction and the second Schottky junction, the dark current is reduced compared to the electromagnetic wave detector having only the first Schottky junction.

[0091] Figure 5 : is a graph showing an operation example of the electromagnetic wave detector 100A. Figure 5 The horizontal axis represents the voltage (unit: V) applied by the power supply 11 to the first Schottky junction. Figure 5 The vertical axis represents the current value (unit: A) measured by the ammeter 10 . Figure 5 The solid line in φ represents a state where the electromagnetic wave detector 100A is not irradiated with electromagnetic waves and is in a state capable of detecting electromagnetic waves. Figure 5 The dotted line in φ represents a state where electromagnetic waves are irradiated to the electromagnetic wave detector 100A which is in a state capable of detecting electromagnetic waves.

[0092] like Figure 5 As shown by the solid line, when the electromagnetic wave detector 100A is not irradiated with electromagnetic waves, the dark current is suppressed to a low level. Figure 5 As shown by the dotted line, when the electromagnetic wave detector 100A is irradiated with electromagnetic waves, photocarriers are generated in the depletion layer of the semiconductor substrate 1. The photocarriers generated by the semiconductor substrate 1 near the junction 12 flow into the two-dimensional material layer 5, the reverse current increases, and the current I changes. In this way, the current component that causes the change in the current I due to the electromagnetic wave irradiation is called photocurrent. In addition, when the conductivity type of the semiconductor substrate 1 is n-type, the reverse current increases by the flow of holes into the two-dimensional material layer 5, and the current I changes.

[0093] Furthermore, in a state where a reverse bias is applied to the first Schottky junction, a depletion layer is also formed at the interface between the semiconductor substrate 1 and the first insulating film 2. When an electromagnetic wave is incident on the semiconductor substrate 1, photocarriers (for example, holes when the conductivity type of the semiconductor substrate 1 is n-type) are also generated in the depletion layer and accumulated at the interface between the semiconductor substrate 1 and the first insulating film 2. The photocarriers accumulated at the interface modulate the carrier density of the two-dimensional material layer 5 that acts as a channel via the first insulating film 2, similarly to the gate voltage of the transistor. As a result, the conductivity of the two-dimensional material layer 5 changes, and the current I flowing through the two-dimensional material layer 5 changes. This effect is called a grating effect. The current generated by the photocarriers generated in the photoelectric conversion of the semiconductor substrate 1 by the grating effect is amplified, so the quantum efficiency calculated from the photocurrent becomes an extremely large value. Therefore, the detection sensitivity of the electromagnetic wave detector 100A is high.

[0094] <Effects>

[0095] As described above, in the electromagnetic wave detector described in Patent Document 1 in which the second Schottky junction is not formed but only the Schottky junction of graphene and silicon substrate is formed, there is a case where the dark current is not sufficiently reduced due to residual moisture and foreign matter such as photoresist at the bonding interface between graphene and silicon substrate. In addition, there is a case where the Fermi level of graphene is modulated by the above-mentioned foreign matter, and the Schottky barrier height becomes lower. For such reasons, in the electromagnetic wave detector described in Patent Document 1, it is difficult to fully suppress the deviation of the dark current of each electromagnetic wave detector (pixel). The deviation of the dark current of each electromagnetic wave detector (pixel) becomes a problem because it reduces the manufacturing yield of the electromagnetic wave detector array, especially when multiple electromagnetic wave detectors are connected to form an electromagnetic wave detector array.

[0096] In the electromagnetic wave detector 100A, a second Schottky junction between the control electrode 7 and the semiconductor substrate 1 is formed around the first Schottky junction between the two-dimensional material layer 5 and the semiconductor substrate 1. Therefore, in the electromagnetic wave detector 100A, by applying a predetermined reverse bias to the first Schottky junction, the depletion layer of the interface of the first Schottky junction can be connected to the depletion layer of the second Schottky junction. In the electromagnetic wave detector 100A having the first Schottky junction and the second Schottky junction, the dark current in the first Schottky junction is reduced compared to the electromagnetic wave detector having only the first Schottky junction.

[0097] Furthermore, in the manufacturing method of the electromagnetic wave detector 100A, the two-dimensional material layer forming step (S7) is performed after the insulating film forming step (S4) and the exposed portion forming step (S6), and in contrast, the control electrode forming step (S2) is performed before the insulating film forming step (S4) and the exposed portion forming step (S6). Therefore, the above-mentioned foreign matter is difficult to remain in the area on the first surface 1A where the control electrode 7 should be formed in the control electrode forming step (S2) compared to the area on the first surface 1A where the two-dimensional material layer 5 should be formed in the two-dimensional material layer forming step (S7). Therefore, in the electromagnetic wave detector 100A, the deviation of the barrier height of the second Schottky junction (the difference between the work function of the material constituting the control electrode 7 and the electron affinity of the material constituting the semiconductor substrate 1) of each electromagnetic wave detector 100A is reduced compared to the deviation of the barrier height of the first Schottky junction (the difference between the work function of the material constituting the two-dimensional material layer 5 and the electron affinity of the material constituting the semiconductor substrate 1) of each electromagnetic wave detector 100A. As a result, in the electromagnetic wave detector 100A, the variation in dark current among the electromagnetic wave detectors 100A is reduced compared to the electromagnetic wave detector in which only the first Schottky junction is formed.

[0098] Furthermore, the material constituting the control electrode 7 is a metal material, so the bonding interface of the second Schottky junction between the control electrode 7 and the semiconductor substrate 1 can easily suppress the residue of the above-mentioned foreign matter compared to the bonding interface of the first Schottky junction between the two-dimensional material layer 5 and the semiconductor substrate 1. Furthermore, the Fermi level of the metal material constituting the control electrode 7 is difficult to modulate compared to the Fermi level of the material constituting the two-dimensional material layer 5. Therefore, in the electromagnetic wave detector 100A, the deviation of the barrier height of the second Schottky junction of each electromagnetic wave detector 100A is reduced compared to the deviation of the barrier height of the first Schottky junction of each electromagnetic wave detector 100A. As a result, in the electromagnetic wave detector 100A, the deviation of the dark current of each electromagnetic wave detector 100A is reduced compared to the electromagnetic wave detector formed with only the first Schottky junction.

[0099] In addition, in the electromagnetic wave detector 100A, the barrier height of the second Schottky junction can be made higher than the barrier height of the first Schottky junction. In such an electromagnetic wave detector 100A, the voltage range in which the dark current is reduced is ( Figure 4 That is, in the electromagnetic wave detector 100A, a larger negative voltage can be applied between the first electrode 3 and the second electrode 6 than in the electromagnetic wave detector having only the first Schottky junction. Therefore, in the electromagnetic wave detector 100A, the depletion layer extends to a deeper region relative to the first surface 1A than in the electromagnetic wave detector having only the first Schottky junction, so that more photocarriers generated by irradiation with electromagnetic waves can be taken out.

[0100] For example, when the semiconductor substrate 1 is an n-type Si substrate, the two-dimensional material layer 5 is a single-layer graphene, and the material constituting the control electrode 7 is Ni, the difference between the work function of the material constituting the two-dimensional material layer 5 and the electron affinity of the material constituting the semiconductor substrate 1 is 0.95 eV, and the difference between the work function of the material constituting the control electrode 7 and the electron affinity of the material constituting the semiconductor substrate 1 is 1.17 eV. Using the proportionality constant K, the Boltzmann constant k, the temperature T, and the barrier height The number of electrons IMS traveling from the metal to the semiconductor in the Schottky junction is expressed as follows.

[0101] [Mathematical formula 1]

[0102]

[0103] Therefore, when the barrier height of the second Schottky junction is 0.22 eV higher than the barrier height of the first Schottky junction, the number of electrons IMS estimated from the barrier height of the former is about 4 orders of magnitude smaller than the number of electrons IMS estimated from the barrier height of the latter. Therefore, in the electromagnetic wave detector 100A in which the barrier height of the second Schottky junction is higher than the barrier height of the first Schottky junction, the dark current can be reduced compared to the electromagnetic wave detector 100A in which only the first Schottky junction is formed and the barrier height of the second Schottky junction is equal to the barrier height of the first Schottky junction.

[0104] Furthermore, in the electromagnetic wave detector 100A, the amount of photocarriers stored at the interface between the semiconductor substrate 1 and the first insulating film 2 in the region overlapping with the two-dimensional material layer 5 when viewed from above, that is, the region directly below the two-dimensional material layer 5, is greater than that of the electromagnetic wave detector in which only the first Schottky junction is formed. Therefore, in the electromagnetic wave detector 100A, the grating effect is amplified, and the photocurrent increases, compared with that of the electromagnetic wave detector in which only the first Schottky junction is formed.

[0105] As described above, in the electromagnetic wave detector 100A, the variation of the dark current is reduced and the photocurrent is increased compared to the electromagnetic wave detector having only the first Schottky junction, so the variation of the photocurrent is increased and the detection sensitivity is high.

[0106] <Modification>

[0107] Figure 6 as well as Figure 7 1 is a diagram showing an electromagnetic wave detector 100B which is a modified example of the electromagnetic wave detector 100A. Figure 6 as well as Figure 7As shown, in the electromagnetic wave detector 100B, the second electrode 6 is in contact with the first surface 1A. The second electrode 6 is, for example, arranged on the side opposite to the control electrode 7, the two-dimensional material layer 5 and the first electrode 3. In other words, the control electrode 7 is arranged between the junction 12 of the two-dimensional material layer 5 and the second electrode 6. The width of the control electrode 7 in the longitudinal direction is, for example, wider than the width of the second electrode 6 in the longitudinal direction. In this way, the arrangement of the second electrode 6 is not particularly limited as long as it is in contact with the semiconductor substrate 1.

[0108] Figure 8 as well as Fig. 9 100A is a diagram showing an electromagnetic wave detector 100C as a modified example of the electromagnetic wave detector 100A. Figure 8 as well as Fig. 9 As shown, in the electromagnetic wave detector 100C, the control electrode 7 is arranged on the exposed portion 4 of the semiconductor substrate 1. The control electrode 7 is exposed from the first insulating film 2. It is also possible that a part of the control electrode 7 is covered by the first insulating film 2, and another part of the control electrode 7 is exposed from the first insulating film 2. The first insulating film 2 is formed in a manner that does not generate a tunnel current at least between the first electrode 3 and the semiconductor substrate 1 and between the part of the two-dimensional material layer 5 located between the junction 12 and the first electrode 3 and the semiconductor substrate 1. That is, in the electromagnetic wave detectors 100A, 100B, and 100C, most of the first surface 1A of the semiconductor substrate 1 may be configured as the exposed portion 4.

[0109] Implementation method 2.

[0110] Fig.10 as well as Fig.11 1 is a diagram showing an electromagnetic wave detector 101 according to Embodiment 2. Fig.10 as well as Fig.11 As shown, the electromagnetic wave detector 101 has basically the same structure as the electromagnetic wave detector 100A, but is different from the electromagnetic wave detector 100A in that the control electrode 7 is arranged around the joint portion 12 so as to sandwich the joint portion 12 in a plan view.

[0111] The electromagnetic wave detector 101B includes a control electrode 7 formed in a ring shape when viewed from above. When viewed from above, the control electrode 7 is arranged around the joint 12 in a manner that surrounds the entire periphery of the joint 12. When viewed from above, the control electrode 7 is arranged around the joint 12 in a manner that sandwiches the joint 12 in each direction of the length direction and the width direction of the two-dimensional material layer 5.

[0112] A pair of portions of the control electrode 7 that are arranged so as to sandwich the junction 12 in the length direction of the two-dimensional material layer 5 are, for example, in a line-symmetric relationship with respect to the junction 12. A pair of portions of the control electrode 7 that are arranged so as to sandwich the junction 12 in the width direction of the two-dimensional material layer 5 are, for example, in a line-symmetric relationship with respect to the junction 12.

[0113] The control electrode 7 is covered with, for example, the first insulating film 2. The control electrode 7 is disposed around the bonding portion 12 so as to surround, for example, the entire periphery of the exposed portion 4 in a plan view.

[0114] In a plan view, a portion of the control electrode 7 is arranged to overlap a portion of the two-dimensional material layer 5 located between the junction 12 and the first electrode 3. In other words, a portion of the control electrode 7 is arranged directly below a portion of the two-dimensional material layer 5 located between the junction 12 and the first electrode 3.

[0115] The electromagnetic wave detector 101 has basically the same structure as that of the electromagnetic wave detector 100A, and thus can produce the same effects as those of the electromagnetic wave detector 100A.

[0116] Furthermore, in the electromagnetic wave detector 101, the control electrode 7 and the depletion layer of the second Schottky junction of the semiconductor substrate 1 are arranged in a manner that sandwiches the depletion layer of the first Schottky junction of the semiconductor substrate 1 and the two-dimensional material layer 5, so that the depletion layer formed when the reverse bias is applied to the first Schottky junction can more reliably cover the entire interface of the first Schottky junction. Therefore, in the electromagnetic wave detector 101, the deviation of the dark current of each electromagnetic wave detector 100A is more stably reduced compared to the electromagnetic wave detector 100A.

[0117] <Modification>

[0118] The electromagnetic wave detector 101 may also include a plurality of control electrodes 7 that are spaced apart from each other in a circumferential direction surrounding the junction 12. When viewed from above, the plurality of control electrodes 7 include, for example, a pair of control electrodes 7 that are arranged in a manner that sandwiches the junction 12 in the length direction of the two-dimensional material layer 5 and a pair of control electrodes 7 that are arranged in a manner that sandwiches the junction 12 in the width direction of the two-dimensional material layer 5.

[0119] The electromagnetic wave detector 101 may include a plurality of control electrodes 7 formed in a ring shape in plan view. For example, in plan view, the plurality of control electrodes 7 include a first control electrode disposed innermost and a second control electrode disposed to surround the junction portion 12 and the first control electrode.

[0120] The electromagnetic wave detector 101 may have the same structure as the electromagnetic wave detectors 100B and 100C except that the control electrode 7 is arranged around the joint portion 12 so as to sandwich the joint portion 12 in a plan view.

[0121] Implementation method 3.

[0122] Fig.12 as well as Fig.13 1 is a diagram showing an electromagnetic wave detector 102A according to Embodiment 3. Fig.13 as well as Fig.14 As shown, the electromagnetic wave detector 102A has a structure basically the same as the electromagnetic wave detector 101 involved in Embodiment 2, but is different from the electromagnetic wave detector 101 in that the control electrode 7 is arranged in a region that does not overlap with the two-dimensional material layer 5 when viewed from above. In other words, the control electrode 7 is not arranged directly below the two-dimensional material layer 5.

[0123] like Fig.13 As shown, in a plan view, the control electrode 7 has a C-shape, for example, in a manner surrounding a portion of the periphery of the bonding portion 12. In a plan view, the control electrode 7 has, for example, an end portion 7A and an end portion 7B arranged in a manner sandwiching the two-dimensional material layer 5 in the width direction of the two-dimensional material layer 5. In the width direction of the two-dimensional material layer 5, the interval between the end portions 7A and the end portions 7B is, for example, narrower than the width of the exposed portion 4.

[0124] like Fig.11 In the electromagnetic wave detector 101 shown, when the control electrode 7 is arranged so as to overlap with the two-dimensional material layer 5 in a plan view, photocarriers are not accumulated at the interface between the control electrode 7 and the semiconductor substrate 1. Therefore, the above-mentioned grating effect does not appear in the portion of the two-dimensional material layer 5 arranged on the first insulating film 2 and arranged on the control electrode 7.

[0125] In contrast, in the electromagnetic wave detector 102A, the control electrode 7 is arranged in a region that does not overlap with the two-dimensional material layer 5 when viewed from above, so the above-mentioned grating effect appears in the entire two-dimensional material layer 5 arranged on the first insulating film 2. Therefore, in the electromagnetic wave detector 102A, the amplification factor of the photocurrent based on the grating effect is higher than that of the electromagnetic wave detector 101.

[0126] In addition, in the electromagnetic wave detector 101, the first insulating film 2 is arranged between the two-dimensional material layer 5 and the control electrode 7 arranged directly below it. In this case, the portion of the first insulating film 2 arranged on the control electrode 7 protrudes by the thickness of the control electrode 7 relative to the portion arranged on the semiconductor substrate 1. That is, a convex portion caused by the control electrode 7 is formed on the upper surface of the first insulating film 2. In the case where the two-dimensional material layer 5 is formed on such a first insulating film 2, there is a possibility that the adhesion between the two-dimensional material layer 5 and the first insulating film 2 is partially reduced, and a portion that does not contact the first insulating film 2, in other words, a portion that floats relative to the upper surface of the first insulating film 2 is formed in the two-dimensional material layer 5. In this case, the grating effect cannot be provided to the portion of the two-dimensional material layer 5 that does not contact the first insulating film 2, so the amplification factor of the photocurrent is limited. In addition, there is also a possibility that the two-dimensional material layer 5 is damaged by the above-mentioned convex portion of the first insulating film 2.

[0127] In contrast, in the electromagnetic wave detector 102A, the control electrode 7 is not disposed directly below the two-dimensional material layer 5, so the first insulating film 2 disposed between the two-dimensional material layer 5 and the semiconductor substrate 1 is flat. Therefore, in the electromagnetic wave detector 102A, the problem caused by the protrusion of the first insulating film 2 as described above does not occur.

[0128] The electromagnetic wave detector 102A can achieve the same effects as the electromagnetic wave detector 101 in addition to the above-mentioned effects.

[0129] <Modification>

[0130] Fig.14 1 is a diagram showing an electromagnetic wave detector 102B which is a modified example of the electromagnetic wave detector 102A. Fig.14 As shown, the electromagnetic wave detector 102B includes a plurality of control electrodes 7. The plurality of control electrodes 7 are arranged around the junction 12 so as to sandwich the junction 12 in at least one direction. For example, the plurality of control electrodes 7 are arranged so as to sandwich the junction 12 in the width direction of the two-dimensional material layer 5.

[0131] The plurality of control electrodes 7 are covered, for example, by the first insulating film 2. The plurality of control electrodes 7 are arranged around the bonding portion 12, for example, so as to sandwich the exposed portion 4.

[0132] Each control electrode 7 has, for example, a length direction and a width direction. The length direction of each control electrode 7 is, for example, along the length direction of the two-dimensional material layer 5. The width of each control electrode 7 in the length direction is, for example, wider than the width of the joint 12 in the direction. One end of each control electrode 7 in the length direction is, for example, arranged closer to the first electrode 3 than the joint 12.

[0133] Fig.15 as well as Fig.161 is a diagram showing an electromagnetic wave detector 102C as a modified example of the electromagnetic wave detector 102A. Fig.15 as well as Fig.16 As shown, in the electromagnetic wave detector 102C, most of the first surface 1A of the semiconductor substrate 1 is configured as an exposed portion 4. The first insulating film 2 is formed between the first electrode 3 and the semiconductor substrate 1 and between the portion of the two-dimensional material layer 5 located between the junction 12 and the first electrode 3 and the semiconductor substrate 1 in a manner that does not generate a tunnel current. The control electrode 7 is arranged on the exposed portion 4. In other words, the control electrode 7 is exposed from the first insulating film 2.

[0134] The electromagnetic wave detector 102A may have the same structure as the electromagnetic wave detectors 100B and 100C, except that the control electrode 7 is arranged in a region that does not overlap with the two-dimensional material layer 5 in a plan view.

[0135] Implementation method 4.

[0136] Fig.17 as well as Fig.18 This is a diagram showing an electromagnetic wave detector 103 according to the fourth embodiment. Fig.17 as well as Fig.18 The electromagnetic wave detector 103 shown has basically the same structure as the electromagnetic wave detector 101 according to the second embodiment, but is different from the electromagnetic wave detector 101 in that the control electrode 7 is grounded.

[0137] In the electromagnetic wave detector 103 , the control electrode 7 is electrically connected to the ground node 13 . For example, a portion of the control electrode 7 is exposed from the first insulating film 2 , and the portion of the control electrode 7 is electrically connected to a ground line electrically connected to the ground node 13 .

[0138] In the electromagnetic wave detector 103, the potential of the control electrode 7 is fixed. Therefore, even when a relatively large voltage is applied between the first electrode 3 and the second electrode 6, the potential of the control electrode 7 does not increase, and the barrier height of the second Schottky junction between the control electrode 7 and the semiconductor substrate 1 does not decrease.

[0139] Therefore, in the electromagnetic wave detector 103 , even when a relatively large voltage is applied between the first electrode 3 and the second electrode 6 , the dark current can be reduced.

[0140] Furthermore, in an electromagnetic wave detector array having a structure in which a plurality of electromagnetic wave detectors 103 are connected to each other, the control electrode 7 of each electromagnetic wave detector 103 may be electrically connected to the ground node 13 individually. Furthermore, in an electromagnetic wave detector array having a structure in which a plurality of electromagnetic wave detectors 103 are connected to each other, the control electrodes 7 of each electromagnetic wave detector 103 may be electrically connected to each other to form a part of a ground line, and a part of the ground line may be electrically connected to the ground node 13. In the latter electromagnetic wave detector array, the integration degree of the electromagnetic wave detectors 103 can be improved compared to the former electromagnetic wave detector array.

[0141] The electromagnetic wave detector 103 can achieve the same effects as the electromagnetic wave detector 101 in addition to the above-mentioned effects.

[0142] <Modification>

[0143] The electromagnetic wave detector 103 may have the same structure as the electromagnetic wave detectors 100A, 100B, 100C, 102A, 102B, and 102C except that the control electrode 7 is grounded.

[0144] Implementation method 5.

[0145] Fig.19 as well as Fig. 20 1 is a diagram showing an electromagnetic wave detector 104 according to Embodiment 5. Fig.19 as well as Fig. 20 As shown, the electromagnetic wave detector 104 has basically the same structure as the electromagnetic wave detector 101 according to the second embodiment, but is different from the electromagnetic wave detector 101 in that the control electrode 7 is connected to the power supply 14 .

[0146] The electromagnetic wave detector 104 includes a power supply 11 (first power supply) that applies a voltage (first voltage) between the first electrode 3 and the second electrode 6 , and a power supply 14 (second power supply) that applies a voltage (second voltage) to the control electrode 7 .

[0147] In the electromagnetic wave detector 104, the potential of the control electrode 7 can be arbitrarily set by the power supply 14, so the barrier height of the second Schottky junction between the control electrode 7 and the semiconductor substrate 1 can be arbitrarily set. For example, the barrier height is set in such a way that a low dark current region is formed stably with respect to the voltage applied to the first electrode 3. As a result, in the electromagnetic wave detector 104, the deviation of the dark current is reduced and the photoelectric current is increased compared to the electromagnetic wave detector 101, so the variation of the photocurrent becomes larger and the detection sensitivity is high.

[0148] In addition, in the electromagnetic wave detector 104, by applying a voltage to the control electrode 7, the internal electric field of the depletion layer formed at the interface between the first insulating film 2 and the semiconductor substrate 1 directly below the two-dimensional material layer 5 can be increased compared to the electromagnetic wave detector 101. The larger the internal electric field of the depletion layer, the more photocarriers accumulated at the above interface. Therefore, in the electromagnetic wave detector 104, the amplification factor of the photocurrent based on the grating effect is higher than that of the electromagnetic wave detector 101.

[0149] The electromagnetic wave detector 104 can achieve the same effects as those of the electromagnetic wave detector 100A in addition to the above-mentioned effects.

[0150] <Modification>

[0151] The electromagnetic wave detector 104 may have the same structure as the electromagnetic wave detectors 100A, 100B, 100C, 102A, 102B, and 102C except that the control electrode 7 is connected to the power source 14 .

[0152] Implementation method 6.

[0153] Figure 21 to Figure 23 1 is a diagram showing an electromagnetic wave detector 105 according to Embodiment 6. Figure 21 to Figure 23 As shown, the electromagnetic wave detector 105 has basically the same structure as the electromagnetic wave detector 101 according to the second embodiment, but is different from the electromagnetic wave detector 101 in that the control electrode 7 and the first electrode 3 are electrically connected.

[0154] The control electrode 7 is electrically connected to the first electrode 3, for example, via the extraction electrode 8. The extraction electrode 8 is arranged on the first insulating film 2 and the control electrode 7. The first insulating film 2 is formed with an opening 2B that exposes the exposed portion 4 of the semiconductor substrate 1 and an opening 2C that exposes a portion of the control electrode 7. In a plan view, the opening 2C is arranged, for example, at a distance from the opening 2B.

[0155] In the manufacturing method of the electromagnetic wave detector 105, for example, the above-mentioned step (S1), the above-mentioned step (S2), the above-mentioned step (S3), the above-mentioned step (S4), the above-mentioned step (S6), the above-mentioned step (S5), and the above-mentioned step (S7) are sequentially performed. The opening 2B and the opening 2C are simultaneously formed in the exposed portion forming step (S6), for example. The first electrode 3 and the extraction electrode 8 are simultaneously formed in the first electrode forming step (S5) performed after the exposed portion forming step (S6).

[0156] In the electromagnetic wave detector 105, the potential of the control electrode 7 is kept constant. Therefore, even when a relatively large voltage is applied between the first electrode 3 and the second electrode 6, the potential of the control electrode 7 does not increase, and the barrier height of the second Schottky junction between the control electrode 7 and the semiconductor substrate 1 does not decrease. Therefore, in the electromagnetic wave detector 105, even when a relatively large voltage is applied between the first electrode 3 and the second electrode 6, dark current can be reduced.

[0157] The electromagnetic wave detector 105 can achieve the same effects as the electromagnetic wave detector 101 in addition to the above-mentioned effects.

[0158] <Modification>

[0159] The electromagnetic wave detector 105 may have the same structure as the electromagnetic wave detectors 100A, 100B, 100C, 102A, 102B, and 102C except that the control electrode 7 and the first electrode 3 are electrically connected.

[0160] Implementation method 7.

[0161] Figure 24 to Figure 26 1 is a diagram showing an electromagnetic wave detector 106A according to Embodiment 7. Figure 24 to Figure 26 As shown, the electromagnetic wave detector 106A has basically the same structure as the electromagnetic wave detector 105 involved in embodiment 6, but is different from the electromagnetic wave detector 105 in that it also has a pn diode 9 including a cathode electrode electrically connected to the control electrode 7 and an anode electrode electrically connected to the first electrode 3.

[0162] The cathode electrode of the pn diode 9 is, for example, a polycrystalline silicon thin film 9n having an n-type conductivity type. The anode electrode of the pn diode 9 is, for example, a polycrystalline silicon thin film 9p having a p-type conductivity type. The polycrystalline silicon thin film 9n and the polycrystalline silicon thin film 9p are arranged in a longitudinal direction of the two-dimensional material layer 5 to form a pn junction. The polycrystalline silicon thin film 9n is electrically connected to the control electrode 7 via the extraction electrode 8. The polycrystalline silicon thin film 9p is electrically connected to the first electrode 3 via the extraction electrode 8. The pn diode 9 is arranged on the first insulating film 2.

[0163] The pn diode 9 may be formed, for example, in the first electrode forming step ( S5 ), or may be formed after the first electrode forming step ( S5 ) and before the two-dimensional material layer forming step ( S7 ).

[0164] In the electromagnetic wave detector 106A, the potential of the control electrode 7 is higher than the potential of the first electrode 3 by the built-in potential of the pn diode 9. Therefore, it is possible to increase the barrier height of the second Schottky junction between the control electrode 7 and the semiconductor substrate 1 without increasing the voltage applied to the first electrode 3. As a result, in the electromagnetic wave detector 106A, the dark current can be reduced compared to the electromagnetic wave detector 105, and the dark current deviation of each electromagnetic wave detector 106A can be suppressed.

[0165] Furthermore, the pn diode 9 is connected in a direction that blocks the inflow of photocarriers (holes when the conductivity type of the semiconductor substrate 1 is n-type) from the semiconductor substrate 1. Thus, by irradiating the electromagnetic wave detector 106A with electromagnetic waves, the photocarriers generated in the depletion layer of the semiconductor substrate 1 cannot flow into the control electrode 7, but flow into the junction 12. Therefore, in the electromagnetic wave detector 106A, the extraction efficiency of photocarriers is improved compared to the electromagnetic wave detector 105, and a large photocurrent can be obtained.

[0166] The electromagnetic wave detector 106A can achieve the same effects as the electromagnetic wave detector 101 in addition to the above-mentioned effects.

[0167] <Modification>

[0168] Fig. 27 as well as Fig.28 1 is a diagram showing an electromagnetic wave detector 106B which is a modified example of the electromagnetic wave detector 106A. Fig. 27 as well as Fig.28 As shown, in the electromagnetic wave detector 106B, the polysilicon thin film 9n is in contact with the control electrode 7. The polysilicon thin film 9n is electrically connected to the control electrode 7 without passing through the extraction electrode 8. In addition, the pn diode 9 may be arranged at any position on the current path electrically connecting the control electrode 7 and the first electrode 3.

[0169] The electromagnetic wave detector 106A may have the same structure as the electromagnetic wave detectors 100A, 100B, 100C, 102A, 102B, and 102C except that it further includes the pn diode 9 .

[0170] Implementation method 8.

[0171] Fig.29 as well as Fig.30 1 is a diagram showing an electromagnetic wave detector 107 according to Embodiment 8. Fig.29 as well as Fig.30 As shown, the electromagnetic wave detector 107 has basically the same structure as the electromagnetic wave detector 101 according to the second embodiment, but is different from the electromagnetic wave detector 101 in that it further includes a second insulating film 15 arranged between the semiconductor substrate 1 and the control electrode 7 .

[0172] The control electrode 7 forms a MIS (Metal-Insulator-Semiconductor) type Schottky junction with the semiconductor substrate 1 via the second insulating film 15 .

[0173] The material constituting the second insulating film 15 includes, for example, at least one selected from the group consisting of silicon oxide (SiO2), silicon nitride (Si3N4), hafnium oxide (HfO2), aluminum oxide (Al2O3), nickel oxide (NiO), and boron nitride (BN). The material constituting the second insulating film 15 may be, for example, the same as the material constituting the first insulating film 2. There is no particular limitation on the thickness of the second insulating film 15 as long as a MIS (Metal-Insulator-Semiconductor) type Schottky junction can be formed between the control electrode 7 and the semiconductor substrate 1.

[0174] The second insulating film 15 is formed before the control electrode forming step ( S2 ).

[0175] In the electromagnetic wave detector 107, the second insulating film 15 prevents photocarriers from flowing into the control electrode 7. Therefore, by irradiating the electromagnetic wave detector 106A with electromagnetic waves, photocarriers generated in the depletion layer of the semiconductor substrate 1 flow into the junction 12. As a result, in the electromagnetic wave detector 107, the extraction efficiency of photocarriers is improved compared to the electromagnetic wave detector 101, and a large photocurrent can be obtained.

[0176] The electromagnetic wave detector 107 can achieve the same effects as the electromagnetic wave detector 101 in addition to the above-mentioned effects.

[0177] <Modification>

[0178] The electromagnetic wave detector 107 may have the same structure as the electromagnetic wave detectors 100A, 100B, 100C, 102A, 102B, 102C, 103 , 104 , 105 , and 106 , except that it further includes the second insulating film 15 .

[0179] Implementation method 9.

[0180] Fig.31 as well as Fig.32 1 is a diagram showing an electromagnetic wave detector 108 according to Embodiment 9. Fig.31 as well as Fig.32 As shown, the electromagnetic wave detector 108 has basically the same structure as the electromagnetic wave detector 101 according to the second embodiment, but is different from the electromagnetic wave detector 101 in that the two-dimensional material layer 5 is arranged to cover the control electrode 7 via the first insulating film 2 .

[0181] The two-dimensional material layer 5 is arranged to cover the exposed portion 4, for example. The two-dimensional material layer 5 is Schottky-bonded to the entire exposed portion 4 of the semiconductor substrate 1. The outer edge of the two-dimensional material layer 5 is arranged outside the outer edge of the control electrode 7, for example, in a plan view.

[0182] In the electromagnetic wave detector 108, the voltage applied to the first electrode 3 is applied to the control electrode 7 via the two-dimensional material layer 5 and the first insulating film 2. Therefore, even when a relatively large voltage is applied between the first electrode 3 and the second electrode 6, the potential of the control electrode 7 does not increase, and the barrier height of the second Schottky junction between the control electrode 7 and the semiconductor substrate 1 does not decrease.

[0183] Therefore, in the electromagnetic wave detector 108 , even when a relatively large voltage is applied between the first electrode 3 and the second electrode 6 , the dark current can be reduced.

[0184] The electromagnetic wave detector 108 can achieve the same effects as the electromagnetic wave detector 101 in addition to the above-mentioned effects.

[0185] <Modification>

[0186] Furthermore, the electromagnetic wave detector 108 may have the same structure as the electromagnetic wave detectors 100A, 100B, 100C, 103, 104, 105, and 106 except that the control electrode 7 is grounded.

[0187] Implementation method 10.

[0188] Fig.33 as well as Fig.34 1 is a diagram showing an electromagnetic wave detector 109 according to Embodiment 10. Fig.33 as well as Fig.34 As shown, the electromagnetic wave detector 109 has basically the same structure as the electromagnetic wave detector 101 according to the second embodiment, but is different from the electromagnetic wave detector 101 in that the control electrode 7 is in contact with the two-dimensional material layer 5 .

[0189] At least a portion of the control electrode 7 is exposed from the first insulating film 2 . In other words, at least a portion of the control electrode 7 is disposed on the exposed portion 4 . At least a portion of the control electrode 7 exposed from the first insulating film 2 is in contact with the two-dimensional material layer 5 .

[0190] like Fig.33 as well as Fig.34 As shown, for example, the entire control electrode 7 is exposed from the first insulating film 2. In a plan view, the control electrode 7 has, for example, a pair of portions arranged so as to sandwich the junction portion 12 in the longitudinal direction of the two-dimensional material layer 5. The two-dimensional material layer 5 is in contact with, for example, a portion of the pair of portions of the control electrode 7.

[0191] In the electromagnetic wave detector 109, the voltage applied to the first electrode 3 is applied to the control electrode 7 via the two-dimensional material layer 5. Therefore, even when a relatively large voltage is applied between the first electrode 3 and the second electrode 6, the potential of the control electrode 7 does not increase, and the barrier height of the second Schottky junction between the control electrode 7 and the semiconductor substrate 1 does not decrease.

[0192] Therefore, in the electromagnetic wave detector 109 , even when a relatively large voltage is applied between the first electrode 3 and the second electrode 6 , the dark current can be reduced.

[0193] The electromagnetic wave detector 109 can achieve the same effects as the electromagnetic wave detector 101 in addition to the above-mentioned effects.

[0194] <Modification>

[0195] The electromagnetic wave detector 108 may have the same structure as the electromagnetic wave detectors 100A, 100B, 100C, 102A, 102B, 102C, 103, 104, 105, 106, and 107 except that the control electrode 7 is grounded.

[0196] Implementation method 11.

[0197] Fig.35 1 is a diagram showing an electromagnetic wave detector array 200 according to Embodiment 11. Fig.35 As shown, the electromagnetic wave detector array 200 includes a plurality of detection elements. Each detection element has the same structure as each other and is composed of any of the electromagnetic wave detectors 100A, 100B, 100C, 101, 101B, 102A, 102B, 102C, 103, 104, 105, 106, 106A, 106B, 107, 108, and 109 involved in Embodiments 1 to 10. For example, the electromagnetic wave detector array 200 includes a plurality of electromagnetic wave detectors 100A.

[0198] In the electromagnetic wave detector array 200, the detection wavelengths of the plurality of electromagnetic wave detectors 100A are equal. Fig.35 As shown, in the electromagnetic wave detector array 200, a plurality of electromagnetic wave detectors 100A are arranged in an array in a two-dimensional direction. In other words, the plurality of electromagnetic wave detectors 100A are arranged in a first direction and in a second direction intersecting the first direction. Fig.35 In the electromagnetic wave detector array 200 shown, four electromagnetic wave detectors 100A are arranged in a 2×2 array. However, the number of electromagnetic wave detectors 100A to be arranged is not limited thereto. For example, a plurality of electromagnetic wave detectors 100A may be arranged in a 3×3 array.

[0199] In addition, Fig.35 In the electromagnetic wave detector array 200 shown, the plurality of electromagnetic wave detectors 100A are periodically arranged two-dimensionally, but the plurality of electromagnetic wave detectors 100A may be periodically arranged in one direction. The plurality of electromagnetic wave detectors 100A may be arranged at equal intervals or at different intervals.

[0200] In addition, when a plurality of electromagnetic wave detectors 100A are arranged in an array, the second electrode 6 may be used as a common electrode as long as the electromagnetic wave detectors 100 are separated. By making the second electrode 6 a common electrode, the wiring of pixels can be reduced compared to a structure in which the second electrode 6 is independent in each electromagnetic wave detector 100A. As a result, the electromagnetic wave detector array can have a higher resolution.

[0201] The electromagnetic wave detector array 200 including the plurality of electromagnetic wave detectors 100A can be used as an image sensor, a line sensor, or a position sensor for determining the position of an object by arranging the plurality of electromagnetic wave detectors 100A in an array.

[0202] <Modification>

[0203] The electromagnetic wave detector array 200 may include any of the plurality of electromagnetic wave detectors 100B, 100C, 101 , 101B, 102A, 102B, 102C, 103 , 104 , 105 , 106 , 106A, 106B, 107 , 108 , and 109 .

[0204] The electromagnetic wave detector array 200 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.

[0205] Fig.36 The electromagnetic wave detector array 201 shown has Fig.35 The electromagnetic wave detector array 200 shown in FIG. 1 has basically the same structure and can obtain the same effect, but has different types of electromagnetic wave detectors as the plurality of electromagnetic wave detectors. Fig.35 The electromagnetic wave detector array shown is different. That is, Fig.36 In the electromagnetic wave detector array 201 shown, electromagnetic wave detectors of different types are arranged in an array (matrix).

[0206] exist Fig.36The electromagnetic wave detector array 201 shown can be used as an image sensor, a line sensor, or a position sensor for determining the position of an object by arranging electromagnetic wave detectors of different types according to any of Embodiments 1 to 10 in a one-dimensional or two-dimensional array.

[0207] In addition, each electromagnetic wave detector included in the electromagnetic wave detector array 201 may be, for example, an electromagnetic wave detector having different detection wavelengths. Specifically, each electromagnetic wave detector may be prepared as an electromagnetic wave detector involved in any of embodiments 1 to 10 and having different detection wavelength selectivity. In this case, the electromagnetic wave detector array can detect electromagnetic waves of at least two different wavelengths.

[0208] By arranging a plurality of electromagnetic wave detectors having different detection wavelengths in an array, it is possible to identify the wavelength of electromagnetic waves in any wavelength domain, such as ultraviolet light, infrared light, terahertz waves, and radio waves, similar to an image sensor used in the visible light domain. As a result, for example, a colorized image can be obtained in which the difference in wavelength is represented as a difference in color.

[0209] The above-mentioned embodiments can be appropriately deformed or omitted. Furthermore, the above-mentioned embodiments can be variously deformed in the implementation stage without departing from the gist thereof. In addition, the above-mentioned embodiments include inventions at various stages, and various inventions can be extracted by appropriate combinations of the disclosed multiple constituent elements.

[0210] The embodiments disclosed herein are illustrative and non-restrictive in all aspects. At least two of the embodiments disclosed herein may be combined as long as there is no contradiction. The scope of the present invention 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: Semiconductor substrates; a first insulating film disposed on the semiconductor substrate and formed so as to expose a portion of the semiconductor substrate; a first electrode disposed on the first insulating film; a two-dimensional material layer having a junction portion that is Schottky-bonded to the semiconductor substrate at a portion of the semiconductor substrate, and extending from the junction portion to the first electrode via the first insulating film; a second electrode in contact with the semiconductor substrate; as well as The control electrode is disposed at least partially around the junction portion in a plan view and is Schottky-bonded to the semiconductor substrate.

2. The electromagnetic wave detector according to claim 1, wherein: The control electrode does not contact the two-dimensional material layer.

3. The electromagnetic wave detector according to claim 1, wherein: The control electrode contacts the two-dimensional material layer.

4. The electromagnetic wave detector according to any one of claims 1 to 3, wherein: The control electrode is arranged around the entire periphery of the junction portion in a plan view.

5. The electromagnetic wave detector according to any one of claims 1 to 3, wherein: The two-dimensional material layer is arranged so as to cover the control electrode via the first insulating film.

6. The electromagnetic wave detector according to claim 1 or 2, wherein: The control electrode is arranged in a region that does not overlap with the two-dimensional material layer in a plan view.

7. The electromagnetic wave detector according to any one of claims 1 to 3, wherein: The control electrode is connected to a ground node.

8. The electromagnetic wave detector according to any one of claims 1 to 3, wherein: The control electrode is electrically connected to the first electrode.

9. The electromagnetic wave detector according to claim 8, wherein: A pn diode including a cathode electrode electrically connected to the control electrode and an anode electrode electrically connected to the first electrode is further provided.

10. The electromagnetic wave detector according to any one of claims 1 to 3, wherein: Also available: a first power source for applying a voltage between the first electrode and the second electrode; and The second power supply applies a voltage to the control electrode.

11. The electromagnetic wave detector according to any one of claims 1 to 3, wherein: further comprising a second insulating film disposed between the semiconductor substrate and the control electrode, The control electrode is Schottky-bonded to the semiconductor substrate via the second insulating film.

12. The electromagnetic wave detector according to any one of claims 1 to 3, wherein: The material constituting the control electrode includes metal.

13. An electromagnetic wave detector array, wherein: A device comprising a plurality of electromagnetic wave detectors according to any one of claims 1 to 12, The plurality of electromagnetic wave detectors are arranged in a row along at least one of the first direction and the second direction.

14. A method for manufacturing an electromagnetic wave detector, comprising: A process for preparing a semiconductor substrate; A step of forming a control electrode that is Schottky-bonded to the semiconductor substrate; forming an insulating film on the semiconductor substrate so as to expose a portion of the semiconductor substrate; forming a first electrode on the insulating film; forming a second electrode in contact with the semiconductor substrate; as well as forming a two-dimensional material layer having a junction portion that is Schottky-bonded to the semiconductor substrate at a portion of the semiconductor substrate, and extending from the junction portion to the first electrode via the insulating film, By forming the two-dimensional material layer, the control electrode is arranged at least partially around the junction portion in a plan view.

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