Photodetection devices and electronic devices

Abstract

A light detection device (1) of one embodiment of the present disclosure comprises a first electrode (23), a second electrode (26) provided to face the first electrode (23), a photoelectric conversion film (22) provided between the first electrode (23) and the second electrode (26), a first semiconductor layer (25a) provided between the photoelectric conversion film (22) and the second electrode (26), and a second semiconductor layer (25b) provided between the first semiconductor layer (25a) and the second electrode (26). The difference between the energy level at the bottom of the conduction band and the Fermi level in the first semiconductor layer (25a) is smaller than the difference between the energy level at the bottom of the conduction band and the Fermi level in the second semiconductor layer (25b).

Description

Technology Field

[0001] The present disclosure relates to a light detection device and an electronic device. Background Technology

[0002] An imaging device having a plurality of photoelectric conversion layers and photoelectrically converting light of each color has been proposed (Patent Document 1). Prior art literature

[0003] Japanese Patent Publication No. 2017-157816 The problem to be solved

[0004] In light detection devices, it is required to suppress the degradation of signal quality.

[0005] It is desired to provide a light detection device capable of suppressing the degradation of signal quality. means of solving the problem

[0006] A light detection device of one embodiment of the present disclosure comprises a first electrode, a second electrode arranged to face the first electrode, a photoelectric conversion film arranged between the first electrode and the second electrode, a first semiconductor layer arranged between the photoelectric conversion film and the second electrode, and a second semiconductor layer arranged between the first semiconductor layer and the second electrode. The difference between the energy level at the bottom of the conduction band and the Fermi level in the first semiconductor layer is smaller than the difference between the energy level at the bottom of the conduction band and the Fermi level in the second semiconductor layer.

[0007] An electronic device of one embodiment of the present disclosure comprises an optical system and a light detection device that receives light transmitted through the optical system. The light detection device comprises a first electrode, a second electrode provided to face the first electrode, a photoelectric conversion film provided between the first electrode and the second electrode, a first semiconductor layer provided between the photoelectric conversion film and the second electrode, and a second semiconductor layer provided between the first semiconductor layer and the second electrode. The difference between the energy level at the bottom of the conduction band and the Fermi level in the first semiconductor layer is smaller than the difference between the energy level at the bottom of the conduction band and the Fermi level in the second semiconductor layer. Brief explanation of the drawing

[0008] FIG. 1 is a block diagram showing an example of a schematic configuration of an imaging device, which is an example of a light detection device according to a first embodiment of the present disclosure. FIG. 2 is a drawing showing an example of a pixel portion of an imaging device according to a first embodiment of the present disclosure. FIG. 3 is a drawing for explaining an example of a cross-sectional configuration of an imaging device according to a first embodiment of the present disclosure. FIG. 4 is a drawing for explaining an example of the circuit configuration of a pixel of an imaging device according to a first embodiment of the present disclosure. FIG. 5 is a drawing for explaining an example of a planar configuration of an imaging device according to a first embodiment of the present disclosure. FIG. 6 is a drawing for explaining an example of the configuration of an imaging device according to a first embodiment of the present disclosure. FIG. 7 is a drawing showing an example of an energy level in an imaging device according to a first embodiment of the present disclosure. FIG. 8a is a drawing for explaining an example of a method for manufacturing an imaging device according to a first embodiment of the present disclosure. FIG. 8b is a drawing for explaining an example of a method for manufacturing an imaging device according to a first embodiment of the present disclosure. FIG. 8c is a drawing for explaining an example of a method for manufacturing an imaging device according to a first embodiment of the present disclosure. FIG. 8d is a drawing for explaining an example of a method for manufacturing an imaging device according to a first embodiment of the present disclosure. FIG. 9 is a drawing for explaining another configuration example of an imaging device according to the first embodiment of the present disclosure. FIG. 10 is a drawing showing an example of an energy level in an imaging device according to a first embodiment of the present disclosure. FIG. 11 is a timing chart showing an example of operation of an imaging device according to a first embodiment of the present disclosure. FIG. 12 is a drawing for explaining an example of a cross-sectional configuration of an imaging device according to Variant Example 1 of the present disclosure. FIG. 13 is a drawing for explaining an example of a planar configuration of an imaging device according to Variant Example 1 of the present disclosure. FIG. 14 is a drawing for explaining another configuration example of an imaging device according to Variant Example 1 of the present disclosure. FIG. 15 is a drawing for explaining another configuration example of an imaging device according to Variant Example 1 of the present disclosure. FIG. 16 is a drawing for explaining an example of a cross-sectional configuration of an imaging device according to Variant Example 2 of the present disclosure. FIG. 17 is a drawing showing an example of an energy level in an imaging device according to Variant Example 2 of the present disclosure. FIG. 18 is a drawing for explaining an example of a cross-sectional configuration of an imaging device according to Variant Example 3 of the present disclosure. FIG. 19 is a drawing showing an example of an energy level in an imaging device according to Variant Example 3 of the present disclosure. FIG. 20 is a drawing for explaining an example of the configuration of an imaging device according to Variant Example 4 of the present disclosure. FIG. 21 is a drawing for explaining an example of the configuration of an imaging device according to Variant Example 5 of the present disclosure. FIG. 22 is a drawing for explaining an example of the configuration of an imaging device according to Variant Example 6 of the present disclosure. FIG. 23a is a drawing for explaining an example of the configuration of an imaging device according to Variant Example 6 of the present disclosure. FIG. 23b is a drawing for explaining an example of the configuration of an imaging device according to Variant Example 6 of the present disclosure. FIG. 24 is a drawing for explaining an example of the configuration of an imaging device according to a second embodiment of the present disclosure. FIG. 25 is a drawing showing an example of an energy level in an imaging device according to a second embodiment of the present disclosure. FIG. 26 is a drawing for explaining another configuration example of an imaging device according to a second embodiment of the present disclosure. FIG. 27 is a drawing showing an example of an energy level in an imaging device according to a second embodiment of the present disclosure. FIG. 28a is a drawing for explaining an example of a cross-sectional configuration of an imaging device according to Variant Example 7 of the present disclosure. FIG. 28b is a drawing for explaining an example of a cross-sectional configuration of an imaging device according to Variant Example 7 of the present disclosure. FIG. 29 is a drawing for explaining an example of a cross-sectional configuration of an imaging device according to Variant Example 8 of the present disclosure. FIG. 30 is a drawing showing an example of an energy level in an imaging device according to Variant Example 8 of the present disclosure. Figure 31 is a block diagram showing an example of the configuration of an electronic device. FIG. 32a schematically shows an example of the overall configuration of a light detection system. FIG. 32b schematically shows an example of the overall configuration of a light detection system. FIG. 33 is a block diagram showing an example of the schematic configuration of a vehicle control system. FIG. 34 is an explanatory diagram showing an example of the installation locations of the external information detection unit and the imaging unit. Figure 35 is a diagram showing an example of the schematic configuration of an endoscopic surgical system. FIG. 36 is a block diagram showing an example of the functional configuration of a camera head and a CCU. Specific details for implementing the invention

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In addition, the description will be carried out in the following order.

[0010] 1. First embodiment

[0011] 2. Second embodiment

[0012] 3. Application Examples

[0013] 4. Application Examples

[0014] <1. First Embodiment>

[0015] FIG. 1 is a block diagram showing an example of a schematic configuration of an imaging device, which is an example of a light detection device according to a first embodiment of the present disclosure. FIG. 2 is a diagram showing an example of a pixel section of an imaging device according to a first embodiment. A light detection device is a device capable of detecting incident light. An imaging device (1), which is an example of a light detection device, has a plurality of pixels P having a photoelectric conversion section (photoelectric conversion element) and is configured to generate a signal by photoelectrically converting incident light. The imaging device (1) can generate a signal by receiving light that has passed through an optical system (not shown), for example, including an optical lens.

[0016] The imaging device (1) is configured, for example, using a semiconductor substrate provided with a plurality of pixels P. Each pixel P of the imaging device (1) includes, for example, a photodiode (PD) as a photoelectric conversion unit and is configured to convert light into photoelectric. The imaging device (1) has an area (pixel unit (100)) in which a plurality of pixels P are arranged in a matrix in two dimensions, as shown in the example in FIG. 2, as an imaging area. The pixel unit (100) can also be described as a pixel array in which a plurality of pixels P are arranged.

[0017] The imaging device (1) introduces incident light (image light) from a subject to be measured through an optical system including an optical lens. The imaging device (1) captures an image of the subject formed by the optical lens. The imaging device (1) can generate a pixel signal by photoelectrically converting the received light (e.g., visible light, infrared light, etc.). The imaging device (1), which is a light detection device, is a device capable of generating a signal by receiving incident light, and can also be called a light receiving device.

[0018] The imaging device (1) (light detection device) can be configured as an image sensor, for example. The imaging device (1) is, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The imaging device (1) may have a structure (stacked structure) configured by stacking a plurality of semiconductor layers. The imaging device (1) can be used in various electronic devices such as digital still cameras, video cameras, and mobile phones.

[0019] In addition, as shown in FIG. 2, the direction of incidence of light from the subject is the Z-axis direction, the left-right direction of the ground perpendicular to the Z-axis direction is the X-axis direction, and the up-down direction of the ground perpendicular to the Z-axis direction and the X-axis direction is the Y-axis direction. In subsequent drawings, directions may also be indicated based on the direction of the arrow in FIG. 2.

[0020] The imaging device (1) has, for example, a vertical driving circuit (111), a signal processing circuit (112), a horizontal driving circuit (113), an output circuit (114), a control circuit (115), and an input / output terminal (116), etc., in a peripheral area of ​​a pixel section (100) (pixel array), as shown in FIG. 1. In addition, the imaging device (1) is provided with, for example, a plurality of control lines Lread and a plurality of signal lines VSL.

[0021] A control line Lread is a signal line capable of transmitting a signal to control a pixel P, and is connected to a vertical driving circuit (111) and a pixel P of a pixel unit (100). In the example shown in FIG. 1, a plurality of control lines Lread are wired to each pixel row in the pixel unit (100), which is composed of a plurality of pixels P arranged side by side in a horizontal direction (row direction). The control line Lread is configured to transmit a control signal for reading a signal from a pixel P.

[0022] In each pixel row of the imaging device (1), a plurality of control line Lreads are included, for example, a wire that transmits a signal to control a transmission transistor, a wire that transmits a signal to control a selection transistor, a wire that transmits a signal to control a reset transistor, etc. The control line Lread can also be called a driving line (pixel driving line) that transmits a signal to drive pixel P.

[0023] The signal line VSL is a signal line capable of transmitting a signal from a pixel P and is connected to the pixel P of the pixel unit (100) and the signal processing circuit (112). In the pixel unit (100), for example, one or more signal lines VSL are wired for each pixel column composed of multiple pixels P arranged side by side in a vertical direction (column direction).

[0024] The signal line VSL is a vertical signal line and is configured to transmit a signal output from pixel P. In the imaging device (1), a plurality of signal lines VSL (e.g., three signal lines VSL1 to VSL3) may be provided for one pixel column. The imaging device (1) may have a plurality of signal lines VSL for each pixel column.

[0025] The vertical driving circuit (111) is configured to drive each pixel P of the pixel unit (100). The vertical driving circuit (111) is composed of a plurality of circuits including, for example, a buffer, a shift register, an address decoder, etc. The vertical driving circuit (111) generates a signal to drive the pixel P and outputs it to each pixel P of the pixel unit (100) through a control line Lread. The vertical driving circuit (111) is controlled by the control circuit (115) to control the pixel P of the pixel unit (100).

[0026] The vertical driving circuit (111) generates, for example, a signal to control a select transistor, a signal to control a reset transistor, etc., and supplies them to each pixel P by the control line Lread. The vertical driving circuit (111) can perform control to read a pixel signal from each pixel P. The vertical driving circuit (111) can also be described as a pixel control unit configured to control each pixel P.

[0027] The signal processing circuit (112) is configured to enable signal processing of an input pixel. The signal processing circuit (112) includes, for example, a load circuit, an AD (Analog Digital) conversion circuit, a horizontal selection switch, etc. The load circuit is configured, for example, by a current source capable of supplying current to the amplification transistor of pixel P. The load circuit forms a source follower circuit together with, for example, the amplification transistor of pixel P.

[0028] The signal processing circuit (112) may have an amplification circuit configured to amplify a signal read from pixel P through a signal line VSL. A load circuit, an amplification circuit, and an AD conversion circuit, etc., are provided, for example, for each of a plurality of signal lines VSL. A load circuit, an amplification circuit, and an AD conversion circuit, etc., may be provided for each pixel column of the pixel section (100).

[0029] The signal output from each pixel P selected and scanned by the vertical driving circuit (111) is input to the signal processing circuit (112) through the signal line VSL. The signal processing circuit (112) performs signal processing such as AD conversion and CDS (Correlated Double Sampling) of the signal of pixel P.

[0030] The horizontal driving circuit (113) is configured, for example, by a buffer, a shift register, an address decoder, etc. The horizontal driving circuit (113) is configured to drive the horizontal selection switch of the signal processing circuit (112). The horizontal driving circuit (113) drives each horizontal selection switch of the signal processing circuit (112) sequentially while scanning. The signal of each pixel P transmitted through each of the signal lines VSL is processed by the signal processing circuit (112), and is output sequentially to the horizontal signal line (121) by the selection scanning by the horizontal driving circuit (113).

[0031] The output circuit (114) is configured to perform signal processing on an input signal and output a signal. The output circuit (114) performs signal processing on a pixel signal that is sequentially input from the signal processing circuit (112) via a horizontal signal line (121) and outputs the pixel signal after processing. The output circuit (114) can perform, for example, buffering, black level adjustment, thermal fluctuation correction, and various digital signal processing.

[0032] The control circuit (115) is configured to control each part of the imaging device (1). The control circuit (115) receives data such as a clock and an operation mode commanded from the outside, and can also output data such as internal information of the imaging device (1). The control circuit (115) has, for example, a timing generator configured to generate various timing signals.

[0033] The control circuit (115) controls the driving of peripheral circuits, such as the vertical driving circuit (111), signal processing circuit (112), and horizontal driving circuit (113), based on various timing signals (pulse signals, clock signals, etc.) generated by the timing generator. The input / output terminal (116) performs the exchange of signals with the outside.

[0034] In addition, the vertical driving circuit (111), signal processing circuit (112), horizontal driving circuit (113), horizontal signal line (121), output circuit (114), control circuit (115), etc. may be provided on a single semiconductor substrate or divided among multiple semiconductor substrates. The imaging device (1) may have a structure (stacked structure) formed by stacking multiple substrates.

[0035] FIG. 3 is a drawing for explaining an example of a cross-sectional configuration of an imaging device according to a first embodiment. FIG. 4 is also a drawing for explaining an example of a circuit configuration of a pixel of an imaging device according to a first embodiment. The imaging device (1) has, for example, a light receiving unit (10) and a light receiving unit (20), as shown in the example in FIG. 3.

[0036] A light receiving unit (10) is provided in layer (101) among a plurality of stacked layers. Additionally, a light receiving unit (20) is provided in layer (102). Layer (102) having the light receiving unit (20) is located above layer (101) having the light receiving unit (10). The imaging device (1) has a configuration in which layer (101) having the light receiving unit (10) and layer (102) having the light receiving unit (20) are stacked in the Z-axis direction.

[0037] A pixel P of an imaging device (1) has a plurality of stacked photoelectric conversion units (photoelectric conversion elements). The photoelectric conversion units are configured to receive light and generate a signal. In the example shown in FIGS. 3 and 4, the pixel P has a photoelectric conversion unit (11a), a photoelectric conversion unit (11b), and a photoelectric conversion unit (11c). The pixel P has a structure in which the photoelectric conversion unit (11a), the photoelectric conversion unit (11b), and the photoelectric conversion unit (11c) are stacked.

[0038] The photoelectric conversion unit (11a) and the photoelectric conversion unit (11b) are configured, for example, by a photodiode (PD). Additionally, the photoelectric conversion unit (11c) has a photoelectric conversion film (22). The photoelectric conversion unit (11a), the photoelectric conversion unit (11b), and the photoelectric conversion unit (11c) are each configured to generate an electric charge by photoelectric conversion. The imaging device (1) has a light receiving unit (10) including photoelectric conversion units (11a, 11b) and a light receiving unit (20) including a photoelectric conversion unit (11c).

[0039] The light receiving unit (10) is constructed using a semiconductor layer (110). As shown in FIG. 3, the semiconductor layer (110) has opposing surfaces (11S1) and surfaces (11S2). Surface (11S2) of the semiconductor layer (110) is a surface opposite to surface (11S1). The semiconductor layer (110) is constructed by a semiconductor substrate, for example, a Si (silicon) substrate.

[0040] Additionally, the semiconductor layer (110) may be an SOI (Silicon On Insulator) substrate, a SiGe (Silicon Germanium) substrate, a SiC (Silicon Carbide) substrate, etc., or may be formed using other semiconductor materials. The semiconductor layer (110) may be composed of a III-V group compound semiconductor material, etc.

[0041] The surface (11S1) of the semiconductor layer (110) is a light receiving surface (light incident surface). The surface (11S2) of the semiconductor layer (110) is a device forming surface where a device such as a transistor is formed. On the surface (11S2) of the semiconductor layer (110), a gate electrode, a gate insulating film (e.g., a gate oxide film), etc., may be provided.

[0042] In the example shown in FIG. 3, a light receiving part (20) is provided on the side (11S1) of the semiconductor layer (110). A wiring layer (120) is provided on the side (11S2) of the semiconductor layer (110). A lens (81) and a light receiving part (20), etc., are provided on the side where light from the optical system is incident, and a wiring layer (120) is provided on the side opposite to the side where light is incident.

[0043] In the semiconductor layer (110), a plurality of photoelectric conversion units (11a) and photoelectric conversion units (11b) are provided along the planes (11S1) and (11S2) of the semiconductor layer (110). For example, a plurality of photoelectric conversion units (11a) and a plurality of photoelectric conversion units (11b) are formed embedded in the semiconductor layer (110). The photoelectric conversion units (11a) and photoelectric conversion units (11b) are each photodiodes (PDs) and convert incident light into electric charge.

[0044] The semiconductor layer (110) has a well (13) as shown in FIG. 3. The well (13) is, for example, a p-type semiconductor region and is a p-type well (p-well). In the example shown in FIG. 3, the semiconductor layer (110) is provided with a well (13) which is a p-type well region. The well (13) is provided with a semiconductor region (16), a semiconductor region (17), and a semiconductor region (18).

[0045] The semiconductor region (16) and the semiconductor region (17) are, for example, each an n-type semiconductor region and are regions formed using n-type impurities. In the example shown in FIG. 3, the semiconductor region (16) is provided on the side (11S2) of the semiconductor layer (110), and the semiconductor region (17) is provided on the side (11S1) of the semiconductor layer (110).

[0046] The semiconductor region (18) has an impurity concentration higher than, for example, the impurity concentration of the well (13), and p + It becomes a semiconductor region of the shape. In the example shown in FIG. 3, a part of the semiconductor region (18) is provided between the semiconductor region (16) and the semiconductor region (17), and another part of the semiconductor region (18) is provided on the side of the surface (11S2) of the semiconductor layer (110). The photoelectric conversion unit (11a) is configured to include a semiconductor region (16) provided within the well (13).

[0047] The photoelectric conversion unit (11b) is configured to include a semiconductor region (17) provided within the well (13). The photoelectric conversion unit (11b) is formed to be stacked on the photoelectric conversion unit (11a) in the semiconductor layer (110). The photoelectric conversion unit (11b) is provided on the light incident side rather than the photoelectric conversion unit (11a). Each of the photoelectric conversion unit (11a) and the photoelectric conversion unit (11b) performs photoelectric conversion to generate an electric charge according to the amount of light received. The photoelectric conversion units (11a, 11b) of each pixel P can each be referred to as photoelectric conversion regions.

[0048] The photoelectric conversion unit (11a) and the photoelectric conversion unit (11b) may be configured to photoelectrically convert light of different wavelength ranges. The photoelectric conversion unit (11a) and the photoelectric conversion unit (11b) selectively receive and photoelectrically convert light of a specific wavelength range depending on the location and constituent material of the photoelectric conversion unit (11a, 11b) provided in, for example, the semiconductor layer (110).

[0049] The photoelectric conversion unit (11a) and the photoelectric conversion unit (11b) are located at different distances (depths) from the surface (11S1) of the semiconductor layer (110) and generate charges by absorbing light of different wavelengths of different colors depending on the incident depth (penetration depth) of the light. In the example shown in FIG. 3, the photoelectric conversion unit (11a) is positioned below the photoelectric conversion unit (11b) and can generate charges by photoelectrically converting light passing through the photoelectric conversion unit (11b).

[0050] Additionally, a plurality of floating diffusions (floating diffusions FD1, FD2, and FD3 in the example shown in FIG. 3 and 4) are provided in the semiconductor layer (110) for each pixel P or for each of the plurality of pixels P. Floating diffusions FD1 to FD3 are each configured to include, for example, an n-type semiconductor region.

[0051] The wiring layer (120) includes, for example, a conductor film and an insulating film, and has a plurality of wirings and vias (VIAs), etc. The wiring layer (120) is a multilayer wiring layer and includes, for example, two or more layers or three or more layers of wiring. The wiring layer (120) has a configuration in which a plurality of wirings are laminated through an insulating film serving as an interlayer insulating film (interlayer insulating layer).

[0052] The wiring of the wiring layer (120) is formed using a metal material such as aluminum (Al), tungsten (W), or copper (Cu), for example. The wiring of the wiring layer (120) may also be formed using polysilicon (Poly-Si) or other conductive materials. The interlayer insulating film is formed using, for example, silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), etc.

[0053] In the semiconductor layer (110) and wiring layer (120), for example, a plurality of reading circuits (15) (in the example shown in FIG. 4, reading circuits (15a, 15b, 15c)) are provided for each pixel P or for each plurality of pixels P. In addition, the above-described vertical driving circuit (111), signal processing circuit (112), horizontal driving circuit (113), horizontal signal line (121), output circuit (114), control circuit (115), etc., may be provided on a substrate different from the semiconductor layer (110), or on the semiconductor layer (110) and wiring layer (120).

[0054] The lens (81) is a lens that collects light and is an optical component also called an on-chip lens. The lens (81) is composed of, for example, silicon oxide, silicon nitride, silicon oxynitride, etc. Additionally, the lens (81) may be formed using other materials that transmit light.

[0055] A lens (81) (lens portion) is provided above the semiconductor layer (110), for example, for each pixel P or for each plurality of pixels P. Light from a subject to be measured is incident on the lens (81) through an optical system such as an imaging lens. The lens (81) guides the incident light toward the semiconductor layer (110).

[0056] In the imaging device (1), the photoelectric conversion unit (11a), the photoelectric conversion unit (11b), and the photoelectric conversion unit (11c) each convert light incident through the lens (81) into photoelectric. Each of the photoelectric conversion unit (11a), the photoelectric conversion unit (11b), and the photoelectric conversion unit (11c) can absorb the incident light to generate an electric charge.

[0057] On the side (11S2) of the semiconductor layer (110), transistor TR1, transistor TR2, floating diffusion FD1 to FD3, etc. are provided. Transistor TR1 has a gate electrode (45) and is provided for the photoelectric conversion unit (11a). Transistor TR1 is a transfer transistor and is configured to transfer the charge photoelectrically converted by the photoelectric conversion unit (11a) to the floating diffusion FD1.

[0058] A transistor TR2 has a gate electrode (46) and a gate insulating film (47) and is provided for the photoelectric conversion unit (11b). The transistor TR2 is a transfer transistor and is configured to transfer the charge photoelectrically converted by the photoelectric conversion unit (11b) to the floating diffusion FD2. For example, the transistor TR2 has a bell-shaped gate structure. At least a portion of each of the gate electrode (46) and the gate insulating film (47) is provided within the semiconductor layer (110).

[0059] As shown in the example in FIG. 3, at least a portion of each of the gate electrode (46) and the gate insulating film (47) is provided, for example, by digging into the semiconductor layer (110). The transistor TR2 can also be called a vertical transistor. Each portion of the gate electrode (46) and the gate insulating film (47) can be arranged to be embedded in the semiconductor layer (110).

[0060] The gate electrode (46) of transistor TR2 is provided to extend, for example, in the thickness direction of the semiconductor layer (110). The gate electrode (46) and the gate insulating film (47) of transistor TR2 are formed to reach the photoelectric conversion section (11b) in the semiconductor layer (110), for example. In the example shown in FIG. 3, a portion of the gate electrode (46) of transistor TR2 extends from the surface (11S2) of the semiconductor layer (110) toward the interior of the semiconductor layer (110) and is provided up to the region of the photoelectric conversion section (11b).

[0061] The gate electrode (45) of transistor TR1 and the gate electrode (46) of transistor TR2 are each, for example, constructed using polysilicon (Poly-Si). The gate electrode (45) and the gate electrode (46) may be constructed using a metal material or a metal compound. The gate electrode (45) and the gate electrode (46) may each be constructed using, for example, titanium nitride (TiN), tantalum nitride (TaN), tungsten (W), etc.

[0062] The gate insulating film (47) is composed of a single layer made of, for example, silicon oxide (SiO), silicon oxynitride (SiON), hafnium oxide (HfO), or a stacked layer made of two or more of these. The gate insulating film (47) may be formed using a high dielectric constant material having a dielectric constant higher than that of silicon oxide, such as a hafnium-based insulating film.

[0063] The light receiving unit (20) of the imaging device (1) has a plurality of photoelectric conversion units (11c). Each photoelectric conversion unit (11c) of a pixel P includes a photoelectric conversion film (22), an upper electrode (23), and a reading electrode (24), as shown in the example of FIG. 3. Additionally, the photoelectric conversion unit (11c) has a semiconductor layer (25a), a semiconductor layer (25b), and an accumulation electrode (26). Additionally, the light receiving unit (20) of the imaging device (1) may have a protective layer (29), as shown in the example of FIG. 3.

[0064] The photoelectric conversion film (22) generates an electric charge through photoelectric conversion. The photoelectric conversion film (22) can convert incident light into an electric charge according to the amount of light received. The photoelectric conversion film (22) can also be called a photoelectric conversion layer. The photoelectric conversion film (22) (photoelectric conversion layer) is, for example, a photoelectric conversion film made of an organic material.

[0065] In the imaging device (1), for example, a photoelectric conversion film (22) formed by an organic semiconductor material is provided at each pixel P. As the photoelectric conversion film (22), a photoelectric conversion film composed using an inorganic material may be placed. The material of the photoelectric conversion film (22) may be selected, for example, according to the wavelength range of the incident light to be measured.

[0066] The upper electrode (23) is, for example, an electrode common to the photoelectric conversion film (22) of a plurality of pixels P, and is provided on one side of the photoelectric conversion film (22). In each pixel P, a read electrode (24) and an accumulation electrode (26) are provided on the photoelectric conversion film (22). The read electrode (24) and the accumulation electrode (26) are provided on the other side of the photoelectric conversion film (22) for each pixel P or for each plurality of pixels P. The read electrode (24) and the accumulation electrode (26) are electrodes used to control the charge that is photoelectrically converted by the photoelectric conversion film (22).

[0067] In the example shown in FIG. 3, the upper electrode (23) and the reading electrode (24) are positioned between the photoelectric conversion film (22), the protective layer (29), and the semiconductor layer (25a, 25b). The reading electrode (24) is arranged to face the upper electrode (23) with each part of the semiconductor layer (25a, 25b), the protective layer (29), and the photoelectric conversion film (22) in between. The upper electrode (23) is the upper electrode of the photoelectric conversion film (22), and the reading electrode (24) is the lower electrode of the photoelectric conversion film (22).

[0068] The upper electrode (23) is an electrode common to a plurality of pixels P and can also be called a common electrode. The reading electrode (24) can also be called a lower electrode. The upper electrode (23), the reading electrode (24), and the accumulation electrode (26), etc. are electrically connected to a circuit provided in the semiconductor layer (110) and the wiring layer (120), for example, through different wiring, electrodes, etc.

[0069] The reading electrode (24) and the accumulation electrode (26) are provided on the insulating layer (131). The insulating layer (131) is provided on the surface (11S1) of the semiconductor layer (110). The insulating layer (131) is formed using an insulating film, for example, an oxide film, a nitride film, an oxynitride film, etc. The insulating layer (131) may be composed of silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), etc., or may be composed using other materials that transmit light to be measured.

[0070] The protective layer (29) is a protective layer comprising, for example, an inorganic material and is provided between the photoelectric conversion film (22) and the semiconductor layer (25a). In the example shown in FIG. 3, the protective layer (29) is formed between the photoelectric conversion film (22) and the semiconductor layer (25a) and is located on the semiconductor layer (25a). The protective layer (29) may also be called a passivation film (protective film).

[0071] The protective layer (29) is a layer comprising, for example, at least one of Ti (titanium), Si (silicon), Zr (zirconium), Nb (niobium), V (vanadium), Ta (tantalum), Hf (hafnium), Al (aluminum), Sn (tin), Sc (scandium), Y (yttrium), La (lanthanide), Ga (gallium), and Mg (magnesium).

[0072] The semiconductor layer (25a) and the semiconductor layer (25b) are provided between the insulating layer (131), on which the reading electrode (24) and the accumulation electrode (26) are provided, and the photoelectric conversion film (22). In the example shown in FIG. 3, the semiconductor layer (25a) and the semiconductor layer (25b) are located between the insulating layer (131) and the protective layer (29). The semiconductor layer (25a) and the semiconductor layer (25b) are layers used for the accumulation and transmission of charge converted by the photoelectric conversion film (22), and can also be called charge accumulation and transmission layers. The semiconductor layer (25a) and the semiconductor layer (25b) are arranged to face the photoelectric conversion film (22).

[0073] The semiconductor layer (25a) and the semiconductor layer (25b) are, for example, semiconductor layers each comprising an oxide semiconductor. The semiconductor layer (25a) is, for example, provided between the photoelectric conversion film (22) and the semiconductor layer (25b). In the example shown in FIG. 3, the semiconductor layer (25a) is located between the protective layer (29) and the semiconductor layer (25b) and is formed on the semiconductor layer (25b). The semiconductor layer (25a) is, for example, provided in contact with the protective layer (29).

[0074] A semiconductor layer (25b) is formed between an insulating layer (131) on which a reading electrode (24) and an accumulation electrode (26) are provided, and a semiconductor layer (25a). As shown in the example in FIG. 3, the semiconductor layer (25b) is provided between the semiconductor layer (25a) and the accumulation electrode (26), and between the semiconductor layer (25a) and the reading electrode (24). The semiconductor layer (25b) may be provided in contact with the semiconductor layer (25a).

[0075] The semiconductor layer (25a) may be configured to have a high carrier concentration (carrier density). The semiconductor layer (25a) may be configured to have a carrier concentration that is higher (larger) than the carrier concentration of the semiconductor layer (25b), for example. If the carrier concentration in the semiconductor layer (25a) is N1 and the carrier concentration in the semiconductor layer (25b) is N2, the semiconductor layer (25a) and the semiconductor layer (25b) may be formed to satisfy N1 > N2.

[0076] For example, the carrier concentration N1 (carrier density) of the semiconductor layer (25a) is 1×10 18 cm -3 It may be greater than or equal to 1×10 18 cm -3 It may be less than. In the imaging device (1), the semiconductor layer (25a) may have a relatively high carrier concentration. The thickness (film thickness) of the semiconductor layer (25a) may be, for example, 10 nm or less.

[0077] Additionally, the imaging device (1) can be configured such that the difference between the energy level at the bottom of the conduction band and the Fermi level in the semiconductor layer (25a) is relatively small. For example, the difference φ1 between the energy level at the bottom of the conduction band and the Fermi level in the semiconductor layer (25a) is smaller than the difference φ2 between the energy level at the bottom of the conduction band and the Fermi level in the semiconductor layer (25b).

[0078] In the imaging device (1), the semiconductor layer (25a) and the semiconductor layer (25b) may be configured to satisfy φ1 < φ2. For example, the semiconductor layer (25a) and the semiconductor layer (25b) may be formed to satisfy φ2 - φ1 > 0.02 eV. The semiconductor layer (25a) and the semiconductor layer (25b) may be configured such that the difference φ2 between the energy level at the bottom of the conduction band of the semiconductor layer (25b) and the Fermi level is greater than 0.02 eV greater than the difference φ1 between the energy level at the bottom of the conduction band of the semiconductor layer (25a) and the Fermi level.

[0079] The difference between the energy level at the bottom of the conduction band and the vacuum level in the semiconductor layer (25a) may be greater than the difference between the energy level at the bottom of the conduction band and the vacuum level in the semiconductor layer (25b). In the photoelectric conversion unit (11c) of the imaging device (1), the semiconductor layer (25a) and the semiconductor layer (25b) may be provided in contact with each other with band bending.

[0080] The semiconductor layer (25a) and the semiconductor layer (25b) are formed using, for example, an oxide semiconductor material. The semiconductor layer (25a) and the semiconductor layer (25b) are, for example, oxide semiconductor layers each comprising at least one of In (indium), Ga (gallium), Zn (zinc), Ti (titanium), Sn (tin), Si (silicon), Cu (copper), Sb (antimony), and Cd (cadmium).

[0081] The semiconductor layer (25a) and the semiconductor layer (25b) are constructed using IGZO (indium-gallium-zinc oxide) as an example. The semiconductor layer (25a) and the semiconductor layer (25b) may be constructed using the same type of material or different materials. Additionally, each of the semiconductor layers (25a, 25b) may be constructed by stacking multiple films. The material of the semiconductor layer (25a) may be selected, for example, according to the material of the photoelectric conversion film (22), the material of the semiconductor layer (25b), electron affinity, work function, carriers (signal charge), etc.

[0082] As described above, the semiconductor layer (25a) and the semiconductor layer (25b) may each be oxide semiconductor layers containing In (indium). The composition ratio of In in the semiconductor layer (25a) may be greater than the composition ratio of In in the semiconductor layer (25b). By making the composition ratio of In in the semiconductor layer (25a) larger, it becomes possible to increase the carrier concentration N1 of the semiconductor layer (25a).

[0083] In addition, carrier concentration can be measured, for example, by diffusion resistance measurement, scanning capacitance microscopy, etc. Also, energy levels and work functions can be measured and analyzed by XPS (X-ray photoelectron spectroscopy), UPS (ultraviolet photoelectron spectroscopy), Kelvin probe method, etc.

[0084] The reading electrode (24) is electrically connected to the semiconductor layers (25a, 25b). The reading electrode (24) is provided to be in contact with, for example, the semiconductor layer (25b). In the example shown in FIG. 3, the reading electrode (24) is in contact with the semiconductor layer (25b) at an opening (85) (hole) provided in the insulating layer (131). The reading electrode (24) is an electrode used to read the charge converted by the photoelectric conversion film (22).

[0085] The accumulation electrode (26) is positioned below the semiconductor layer (25b) through a portion of the insulating layer (131). In the example shown in FIG. 3, the accumulation electrode (26) is positioned to face the upper electrode (23) with the portion of the insulating layer (131), the semiconductor layers (25a, 25b), the protective layer (29), and the photoelectric conversion film (22) in between. The accumulation electrode (26) is an electrode used to control the accumulation of charge converted by the photoelectric conversion film (22).

[0086] In the imaging device (1), depending on the potential of the accumulation electrode (26) of each pixel P, the charge converted by the photoelectric conversion film (22) can be drawn toward the semiconductor layer (25a) and the semiconductor layer (25b). For example, the vertical driving circuit (111) (see FIG. 1) of the imaging device (1) can accumulate the signal charge (e.g., electrons) generated by the photoelectric conversion film (22) in the region facing the accumulation electrode (26) in the semiconductor layer (25b) by controlling the voltage to be supplied to the upper electrode (23) and the accumulation electrode (26) (voltage VOU, voltage VOA in FIG. 4).

[0087] Additionally, by changing the voltage (voltage VOA in FIG. 4) to be applied to the accumulation electrode (26), the charge accumulated by the semiconductor layer (25a) and the semiconductor layer (25b) can be moved to the reading electrode (24). The vertical driving circuit (111) can, for example, adjust the voltage VOA to be input to the accumulation electrode (26) and transfer the charge accumulated through photoelectric conversion to the reading electrode (24).

[0088] The upper electrode (23), reading electrode (24), and accumulation electrode (26) described above are, for example, each transparent electrodes and may be composed of ITO (indium tin oxide), IZO (indium zinc oxide), tin oxide (SnO), zinc oxide (ZnO), etc. The upper electrode (23), reading electrode (24), and accumulation electrode (26) may be composed of other metal oxides or may be composed using other transparent conductive materials.

[0089] The upper electrode (23), the reading electrode (24), and the accumulation electrode (26) may be formed using a tin oxide-based material such as tin oxide doped with antimony (Sb) (ATO) or tin oxide doped with fluorine (F) (FTO). The upper electrode (23), the reading electrode (24), and the accumulation electrode (26) may be formed using a zinc oxide-based material.

[0090] The upper electrode (23), the reading electrode (24), and the accumulation electrode (26) may be composed of, for example, aluminum zinc oxide (AZO), gallium zinc oxide (GZO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), etc. Additionally, the upper electrode (23), the reading electrode (24), and the accumulation electrode (26) may be formed using CuI, InSbO4, ZnMgO, CuInO2, MgIN2O4, CdO, ZnSnO3, TiO2, spinel-type oxide, oxide having a YbFe2O4 structure, etc.

[0091] The upper electrode (23), reading electrode (24), or accumulation electrode (26) may be composed of, for example, alkali metals (lithium (Li), sodium (Na), potassium (K), etc.), alkaline earth metals (magnesium (Mg), calcium (Ca), etc.) when transparency is not required. Additionally, the upper electrode (23), reading electrode (24), or accumulation electrode (26) may be formed using metal materials such as platinum (Pt), gold (Au), palladium (Pd), chromium (Cr), nickel (Ni), aluminum (Al), silver (Ag), tantalum (Ta), tungsten (W), copper (Cu), titanium (Ti), indium (In), tin (Sn), iron (Fe), cobalt (Co), molybdenum (Mo).

[0092] The electrodes provided for the photoelectric conversion unit (11c), such as the upper electrode (23), reading electrode (24), and accumulation electrode (26), may be constructed using conductive materials such as polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and graphene. Additionally, the upper electrode (23), reading electrode (24), accumulation electrode (26), etc., may be formed using organic materials (conductive polymers) such as poly(3,4-ethylenedioxythiophene) / polystyrenesulfonic acid [PEDOT / PSS].

[0093] The photoelectric conversion film (22) may separate charges by absorbing, for example, 60% or more of light of a predetermined wavelength included in the visible light region and near-infrared region. The photoelectric conversion film (22) absorbs, for example, some or all wavelengths of light in the visible light region and near-infrared light region from 400 nm to less than 1300 nm. The photoelectric conversion film (22) is composed of two or more types of organic materials that function as, for example, a p-type semiconductor or an n-type semiconductor, and has a junction surface (p / n junction surface) between the p-type semiconductor and the n-type semiconductor. In addition, the photoelectric conversion film (22) may have a stacked structure of a layer made of a p-type semiconductor (p-type semiconductor layer) and a layer made of an n-type semiconductor (n-type semiconductor layer) (p-type semiconductor layer / n-type semiconductor layer), a stacked structure of a p-type semiconductor layer and a mixed layer of a p-type semiconductor and an n-type semiconductor (bulk hetero layer) (p-type semiconductor layer / bulk hetero layer), or a stacked structure of an n-type semiconductor layer and a bulk hetero layer (n-type semiconductor layer / bulk hetero layer). Furthermore, the photoelectric conversion film (22) may be formed only of a mixed layer of a p-type semiconductor and an n-type semiconductor (bulk hetero layer).

[0094] For example, the p-type semiconductor is a hole transport material that functions as a relative electron donor, and the n-type semiconductor is an electron transport material that functions as a relative electron acceptor. For example, the photoelectric conversion film (22) provides a field in which excitons (electron-hole pairs) generated when light is absorbed are separated into electrons and holes, and specifically, the electron-hole pairs are separated into electrons and holes at the interface (p / n junction) between the electron donor and the electron acceptor.

[0095] As p-type semiconductors, for example, naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, perylene derivatives, tetracene derivatives, pentacene derivatives, quinacridone derivatives, thiophene derivatives, thienothiophene derivatives, benzothiophene derivatives, benzothienobenzothiophene (BTBT) derivatives, dinaphthothienothiophene (DNTT) derivatives, dianthracenothienothiophene (DATT) derivatives, benzobisbenzothiophene (BBBT) derivatives, thienobisbenzothiophene (TBBT) derivatives, dibenzothienobisbenzothiophene (DBTBT) derivatives, dithienobenzodithiophene (DTBDT) derivatives, dibenzothienodithiophene (DBTDT) derivatives, benzodithiophene (BDT) derivatives, naphthodithiophene (NDT) derivatives, anthracenodithiophene (ADT) derivatives, Examples of thienoacene-based materials include tetracenodithiophene (TDT) derivatives and pentacenodithiophene (PDT) derivatives. In addition, examples of p-type semiconductors include triphenylamine derivatives, carbazole derivatives, picene derivatives, chrysene derivatives, for example, fluoranthene derivatives, phthalocyanine derivatives, subphthalocyanine derivatives, subporpyrazine derivatives, metal complexes having heterocyclic compounds as ligands, polythiophene derivatives, polybenzothiadiazole derivatives, and polyfluorene derivatives.

[0096] As an n-type semiconductor, for example, fullerene C 60 , Fullerene C 70 , Fullerene C 74Examples include fullerenes and their derivatives, such as higher-order fullerenes or enclosed fullerenes. Examples of substituents included in fullerene derivatives include, for instance, a halogen atom, a straight-chain or branched or cyclic alkyl group or a phenyl group, a group having a straight-chain or condensed aromatic compound, a group having a halide, a partial fluoroalkyl group, a perfluoroalkyl group, a silylalkyl group, a silyl alkoxy group, an arylsilyl group, an arylsulfanyl group, an alkylsulfanyl group, an arylsulfonyl group, an alkylsulfonyl group, an arylsulfide group, an alkylsulfide group, an amino group, an alkylamino group, an arylamino group, a hydroxyl group, an alkoxy group, an acylamino group, an acyloxy group, a carbonyl group, a carboxyl group, a carboxyl carboxyl group, a carboxyl carbamide group, a carboalkoxy group, an acyl group, a sulfonyl group, a cyano group, a nitro group, a group having a chalcogenide, a phosphine group, a phosphon group, and derivatives thereof. Specific fullerene derivatives include, for example, fullerene fluorides, PCBM fullerene compounds, and fullerene polymers. In addition, as n-type semiconductors, organic semiconductors having higher HOMO and LUMO levels than p-type semiconductors, or inorganic metal oxides having light transmittance can be cited.

[0097] Examples of n-type organic semiconductors include heterocyclic compounds containing nitrogen atoms, oxygen atoms, or sulfur atoms. Specifically, examples include organic molecules having pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, isoquinoline derivatives, acridine derivatives, phenazine derivatives, phenanthroline derivatives, tetrazole derivatives, pyrazol derivatives, imidazole derivatives, thiazole derivatives, oxazole derivatives, imidazole derivatives, benzimidazole derivatives, benzotriazole derivatives, benzoxazole derivatives, carbazole derivatives, benzofuran derivatives, dibenzofuran derivatives, subporpyrazine derivatives, polyphenylenevinylene derivatives, polybenzothiadiazole derivatives, polyfluorene derivatives, etc., in part of the molecular backbone, organometallic complexes, subphthalocyanine derivatives, quinacridone derivatives, cyanine derivatives, and melocyanine derivatives.

[0098] The photoelectric conversion film (22) may be composed of, in addition to the p-type semiconductor and n-type semiconductor, an organic material, so-called dye material, that absorbs light of a predetermined wavelength range while transmitting light of another wavelength range. When the photoelectric conversion film (22) is formed using three types of organic materials, such as the p-type semiconductor, the n-type semiconductor, and the dye material, the p-type semiconductor and the n-type semiconductor may be materials that have light transmittance in the visible light region. Accordingly, in the photoelectric conversion film (22), light of the wavelength range absorbed by the dye material is selectively photoelectrically converted.

[0099] As shown in FIG. 3, the imaging device (1) has a through electrode (50). The through electrode (50) is a connecting electrode (connecting part) and connects circuits (elements) provided in different layers. The through electrode (50) is provided in the layer (101) to penetrate the semiconductor layer (110), for example. The through electrode (50) is a structure provided within the semiconductor layer (110) to penetrate the semiconductor layer (110).

[0100] In the imaging device (1), a through electrode (50) is provided for each pixel P or for each plurality of pixels P. For example, the through electrode (50) is formed to reach the surface (11S2) of the semiconductor layer (110) from below the photoelectric conversion unit (11c). In the example shown in FIG. 3, the through electrode (50) is formed to extend in the Z-axis direction and reach into the wiring layer (120).

[0101] In the imaging device (1), the reading electrode (24) of the photoelectric conversion unit (11c) and the circuit provided on the side (11S2) of the semiconductor layer (110) are electrically connected by the through electrode (50). The reading electrode (24) of the photoelectric conversion unit (11c) is electrically connected to the reading circuit (15c) (see FIG. 4) through the through electrode (50).

[0102] The charge accumulated by photoelectric conversion by the photoelectric conversion unit (11c) is transferred by the reading electrode (24) to the floating diffusion FD3 of the reading circuit (15c) through the penetrating electrode (50). The floating diffusion FD3 accumulates the transferred charge.

[0103] The penetrating electrode (50) is composed of, for example, tungsten (W), aluminum (Al), copper (Cu), silver (Ag), etc. The penetrating electrode (50) may be formed using cobalt (Co), molybdenum (Mo), ruthenium (Ru), etc. The penetrating electrode (50) may be composed of other metal materials.

[0104] The imaging device (1) may have at least one of a fixed charge film (55) and a reflection suppression film (56) on the side (11S1) of the semiconductor layer (110). Each portion of the fixed charge film (55) and the reflection suppression film (56) is provided along the side of the through electrode (50), for example, as shown in FIG. 3. The fixed charge film (55) and the reflection suppression film (56) are composed of a metal compound (metal oxide, metal nitride, etc.), for example.

[0105] The fixed charge film (55) is a film having a fixed charge and can be formed using a high dielectric material. The fixed charge film (55) is composed of metal oxides such as hafnium oxide, aluminum oxide, tantalum oxide, titanium oxide, and zirconium oxide, as an example. The fixed charge film (55) is, for example, a film having a negative fixed charge.

[0106] In the imaging device (1), the generation of dark current at the interface of the semiconductor layer (110) is suppressed by providing a fixed charge film (55). Additionally, the fixed charge film (55) may be composed of other metal oxide films, or may be composed using a metal nitride film or a metal oxynitride film. As the fixed charge film (55), a film having a positive fixed charge may be provided.

[0107] The reflection suppression film (56) is composed of, for example, a metal oxide such as hafnium oxide or tantalum oxide. The reflection suppression film (56) is provided on the surface (11S1) side of the semiconductor layer (110) to reduce (suppress) reflection. The reflection suppression film (56) (anti-reflection film) is provided to be laminated with, for example, a fixed charge film (55). In addition, the reflection suppression film (56) may be composed using insulating materials such as silicon nitride (SiN), silicon oxide (SiO), silicon oxynitride (SiON), TEOS, or aluminum oxide (AlO), or may be composed using other materials.

[0108] In the imaging device (1), a reading circuit configured to output a signal based on a charge converted by a photoelectric conversion unit (11a), a signal based on a charge converted by a photoelectric conversion unit (11b), and a signal based on a charge converted by a photoelectric conversion unit (11c) is provided. The imaging device (1) has a plurality of reading circuits (15) each including, for example, an amplification transistor, a selection transistor, a reset transistor, etc.

[0109] For example, a plurality of reading circuits (15) (in FIG. 4, reading circuit (15a), reading circuit (15b), reading circuit (15c)) are provided for each pixel P or for each of the plurality of pixels P. Additionally, the imaging device (1) may have a configuration in which a plurality of pixels P share a reading circuit (15).

[0110] As shown in FIG. 4, the pixel P of the imaging device (1) has the above-described photoelectric conversion unit (11a), a transmission transistor TR1, and a reading circuit (15a). Additionally, the pixel P has a photoelectric conversion unit (11b), a transmission transistor TR2, a reading circuit (15b), a photoelectric conversion unit (11c), and a reading circuit (15c). Each of the reading circuits (15a, 15b, 15c) is configured to output a signal based on the photoelectrically converted charge.

[0111] The read circuit (15a) has, for example, a floating diffusion FD1, an amplification transistor AMP1, a selection transistor SEL1, and a reset transistor RST1. The read circuit (15a) is configured to read a signal (a first pixel signal) based on the charge accumulated in the floating diffusion FD1 to the signal line VSL1. Additionally, the read circuit (15a) may include a transfer transistor TR1.

[0112] The transfer transistor TR1, amplifier transistor AMP1, select transistor SEL1, and reset transistor RST1 are each MOS transistors (MOSFETs) having gate, source, and drain terminals. In the example shown in FIG. 4, the transfer transistor TR1, amplifier transistor AMP1, select transistor SEL1, and reset transistor RST1 are each composed of NMOS transistors. Additionally, the transistor of pixel P may be composed of PMOS transistors.

[0113] The transfer transistor TR1 is configured to transmit the charge converted by the photoelectric conversion unit (11a). The transfer transistor TR1 is controlled by the signal STR1 to electrically connect or disconnect the photoelectric conversion unit (11a) and the floating diffusion FD1. The transfer transistor TR1 can transmit the charge accumulated by photoelectric conversion by the photoelectric conversion unit (11a) to the floating diffusion FD1.

[0114] Floating diffusion FD1 is an accumulation unit and is configured to accumulate transferred charges. Floating diffusion FD1 can accumulate charges converted by photoelectric conversion unit (11a). Floating diffusion FD1 can also be described as a holding unit capable of holding transferred charges. Floating diffusion FD1 accumulates transferred charges and converts them into a voltage according to the capacity of Floating Diffusion FD1.

[0115] The amplifier transistor AMP1 is configured to generate and output a signal based on the charge accumulated in the floating diffusion FD1. As shown in FIG. 4, the gate of the amplifier transistor AMP1 is electrically connected to the floating diffusion FD1, and the voltage converted by the floating diffusion FD1 is input.

[0116] The drain of the amplifier transistor AMP1 is connected to a power line to which the power supply voltage VDD is supplied. The source of the amplifier transistor AMP1 is connected to the signal line VSL1 through the select transistor SEL1. The amplifier transistor AMP1 can generate a signal based on the charge accumulated in the floating diffusion FD1, that is, a signal based on the voltage of the floating diffusion FD1, and output it to the signal line VSL1.

[0117] The select transistor SEL1 is configured to control the output of the pixel signal. The select transistor SEL1 is electrically connected in series with the amplifier transistor AMP1, for example, as shown in FIG. 4. The select transistor SEL1 is configured to be controlled by the signal SSEL1 to output a signal from the amplifier transistor AMP1 to the signal line VSL1. The select transistor SEL1 can control the output timing of the pixel signal.

[0118] The select transistor SEL1 is configured to output a signal (first pixel signal) based on the charge converted by the photoelectric conversion unit (11a). The select transistor SEL1 can output the first pixel signal of pixel P to the signal line VSL1. Additionally, the select transistor SEL1 may be electrically connected between the power line to which the power supply voltage VDD is applied and the amplifier transistor AMP1. Additionally, the select transistor SEL1 may be omitted if necessary.

[0119] The reset transistor RST1 is configured to reset the voltage of the floating diffusion FD1. In the example shown in FIG. 4, the reset transistor RST1 is electrically connected to a power line to which a power supply voltage VDD is applied, and is configured to perform a charge reset. The reset transistor RST1 is controlled by the signal SRST1 to reset the charge accumulated in the floating diffusion FD1 and to reset the voltage of the floating diffusion FD1.

[0120] The reset transistor RST1 can electrically connect the power line and the floating diffusion FD1 to discharge the charge accumulated in the floating diffusion FD1. Additionally, the reset transistor RST1 can discharge the charge accumulated in the photoelectric conversion unit (11a) through the transmission transistor TR1.

[0121] The vertical driving circuit (111) (see FIG. 1) of the imaging device (1) supplies a control signal to the gates of the transmission transistor TR1, selection transistor SEL1, reset transistor RST1, etc. of each pixel P through the control line Lread described above, thereby turning the transistors on (conducting state) or off (non-conducting state).

[0122] A plurality of control lines Lread for each pixel row of the imaging device (1) include, for example, a wire that transmits a signal STR1 that controls a transmission transistor TR1, a wire that transmits a signal SSEL1 that controls a selection transistor SEL1, a wire that transmits a signal SRST1 that controls a reset transistor RST1, etc.

[0123] The transmission transistor TR1, selection transistor SEL1, reset transistor RST1, etc. are turned on / off by the vertical driving circuit (111). The vertical driving circuit (111) controls the reading circuit (15a) of each pixel P to output a first pixel signal based on the charge generated by the photoelectric conversion unit (11a) from each pixel P to the signal line VSL1. The vertical driving circuit (111) can perform control to read the first pixel signal of each pixel P to the signal line VSL1.

[0124] The reading circuit (15a) may be configured to change the conversion efficiency (gain) when converting charge into voltage. For example, the reading circuit (15a) may have a switching transistor used to set the conversion efficiency. The switching transistor is provided, for example, between a floating diffusion FD1 and a reset transistor RST1.

[0125] In addition, the switching transistor may be electrically connected in series with the reset transistor RST1, or electrically connected in parallel with the reset transistor RST1. For example, the switching transistor may be configured to electrically connect a floating diffusion FD1 and a capacitive element.

[0126] In the reading circuit (15a), the switching transistor is turned on, so that the capacitance added to the floating diffusion FD1 of pixel P increases, and the conversion efficiency is switched. The switching transistor can change the conversion efficiency by switching the capacitance connected to the gate of the amplification transistor AMP1.

[0127] The reading circuit (15b) has a circuit configuration similar to, for example, the reading circuit (15a). The floating diffusion FD2 of the reading circuit (15b) corresponds to the floating diffusion FD1 of the reading circuit (15a). The transfer transistor TR2 can transfer the charge converted by photoelectric conversion unit (11b) to the floating diffusion FD2. The floating diffusion FD2 can accumulate the charge converted by photoelectric conversion unit (11b). Additionally, the reading circuit (15b) may include the transfer transistor TR2.

[0128] The amplification transistor AMP2 in the reading circuit (15b) corresponds to the amplification transistor AMP1 of the reading circuit (15a). The selection transistor SEL2 corresponds to the selection transistor SEL1. The reset transistor RST2 corresponds to the reset transistor RST1. The reading circuit (15b) can generate and output a signal based on the charge accumulated in the floating diffusion FD2, that is, a signal based on the charge converted by the photoelectric conversion unit (11b) (second pixel signal).

[0129] The transmission transistor TR2, selection transistor SEL2, reset transistor RST2, etc. are turned on / off by the vertical driving circuit (111). The vertical driving circuit (111) outputs a second pixel signal based on the charge generated by the photoelectric conversion unit (11b) from each pixel P to the signal line VSL2 by controlling the reading circuit (15b) of each pixel P. The vertical driving circuit (111) can perform control to read the second pixel signal of each pixel P to the signal line VSL2.

[0130] The read circuit (15c) has a circuit configuration similar to, for example, the read circuit (15a). The floating diffusion FD3 of the read circuit (15c) corresponds to the floating diffusion FD1 of the read circuit (15a). The amplification transistor AMP3 in the read circuit (15c) corresponds to the amplification transistor AMP1 of the read circuit (15a).

[0131] Additionally, the select transistor SEL3 corresponds to the select transistor SEL1. The reset transistor RST3 corresponds to the reset transistor RST1. The read circuit (15c) can generate and output a signal based on the charge accumulated in the floating diffusion FD3, that is, a signal based on the charge converted by the photoelectric converter (11c) (third pixel signal).

[0132] The photoelectric conversion unit (11c) is electrically connected to the reading circuit (15c) through the above-described through electrode (50). The reading electrode (24) of the photoelectric conversion unit (11c) is connected to the floating diffusion FD3 through the through electrode (50). The charge converted by the photoelectric conversion unit (11c) can be transmitted to the floating diffusion FD3 from the photoelectric conversion unit (11c) through the through electrode (50).

[0133] Select transistor SEL3, reset transistor RST3, etc. are turned on / off controlled by the vertical driving circuit (111). The vertical driving circuit (111) controls the accumulation electrode (26) and reading circuit (15c) of each pixel P, etc., to output a third pixel signal based on the charge generated by the photoelectric conversion unit (11c) from each pixel P to the signal line VSL3. The vertical driving circuit (111) can perform control to read the third pixel signal of each pixel P to the signal line VSL3.

[0134] In the example shown in FIG. 3, light from a subject to be measured is incident on the photoelectric conversion unit (11c), photoelectric conversion unit (11b), and photoelectric conversion unit (11a) of pixel P through a lens (81). The photoelectric conversion unit (11c) can generate an electric charge by photoelectrically converting the light incident through the lens (81). Light that has passed through the photoelectric conversion unit (11c), for example, is incident on the photoelectric conversion unit (11b) of pixel P. In the example shown in FIG. 3, light that has passed through the lens (81) and the photoelectric conversion unit (11c) is incident on the photoelectric conversion unit (11b).

[0135] The photoelectric conversion unit (11b) can generate an electric charge by photoelectrically converting light passing through the photoelectric conversion unit (11c). Light passing through, for example, the photoelectric conversion unit (11b) is incident on the photoelectric conversion unit (11a) of pixel P. In the example shown in FIG. 3, light passing through the lens (81), the photoelectric conversion unit (11c), and the photoelectric conversion unit (11b) is incident on the photoelectric conversion unit (11a). The photoelectric conversion unit (11a) can generate an electric charge by photoelectrically converting light passing through the photoelectric conversion unit (11b).

[0136] The imaging device (1) can obtain a first pixel signal based on a charge converted by a photoelectric conversion unit (11a), a second pixel signal based on a charge converted by a photoelectric conversion unit (11b), and a third pixel signal based on a charge converted by a photoelectric conversion unit (11c). Additionally, each of the photoelectric conversion unit (11a), the photoelectric conversion unit (11b), and the photoelectric conversion unit (11c) may be configured to receive visible light and convert it photoelectrically, or may be configured to receive infrared light (e.g., near-infrared light) and convert it photoelectrically.

[0137] For example, the photoelectric conversion unit (11a), the photoelectric conversion unit (11b), and the photoelectric conversion unit (11c) may be configured to generate an electric charge by photoelectrically converting visible light of different wavelength ranges. Additionally, for example, the photoelectric conversion unit (11a) or the photoelectric conversion unit (11b) may be configured to generate an electric charge by photoelectrically converting infrared light. By using the first pixel signal, the second pixel signal, and the third pixel signal of each pixel P, it becomes possible to generate a visible image (e.g., an RGB image), an infrared image (IR image), etc.

[0138] For example, the photoelectric conversion unit (11c) of pixel P receives light from the subject being measured, primarily in the green (G) wavelength range, and converts it into photoelectric. The photoelectric conversion unit (11b) receives light primarily in the blue (B) wavelength range and converts it into photoelectric. Additionally, the photoelectric conversion unit (11a) receives light primarily in the red (R) wavelength range and converts it into photoelectric.

[0139] Each pixel P of the imaging device (1) can generate a pixel signal of the R component, a pixel signal of the G component, and a pixel signal of the B component. The imaging device (1) can obtain RGB pixel signals. In addition, the wavelength range indicating sensitivity in each of the photoelectric conversion unit (11a), photoelectric conversion unit (11b), and photoelectric conversion unit (11c) can be arbitrarily set.

[0140] FIG. 5 is a drawing for explaining an example of a planar configuration of an imaging device according to a first embodiment. The imaging device (1) may have a configuration in which any number (e.g., 4) of pixels P arranged side by side in a row direction (horizontal direction) or a column direction (vertical direction) share a reading electrode (24) and a reading circuit (15), etc.

[0141] FIG. 5 illustrates an example in which each of the photoelectric conversion units (11c) of four adjacent pixels P shares a single read electrode (24). In the example shown in FIG. 5, the imaging device (1) has a configuration in which the photoelectric conversion units (11c) of four pixels P, which form a 2×2 pixel, share a read electrode (24) and a read circuit (15c).

[0142] A read electrode (24) is provided for four adjacent photoelectric conversion units (11c). For example, at least a portion of the read electrode (24) is provided at the boundary of four pixels P. In the example shown in FIG. 5, the read electrode (24) is placed in the central region of four pixels P. An accumulation electrode (26) is provided, for example, for each photoelectric conversion unit (11c).

[0143] Additionally, the imaging device (1) may have a shield electrode (27), as shown in the example in FIG. 5. The shield electrode (27) is provided around the accumulation electrode (26) in the insulating layer (131) (see FIG. 6 described later). The shield electrode (27) is provided for each pixel P or for each plurality of pixels P on the photoelectric conversion film (22). A predetermined potential (voltage) is supplied to the shield electrode (27), for example, through wiring and electrodes.

[0144] The shield electrode (27) is electrically connected to a wiring to which a constant voltage is applied, for example, to create a potential barrier in the semiconductor layer (25b). By providing the shield electrode (27), the leakage of the charge converted by the photoelectric conversion unit (11c) of pixel P to surrounding pixels P is suppressed.

[0145] The shield electrode (27) is, for example, a transparent electrode and is composed of a material that transmits light converted by a photoelectric conversion unit. The shield electrode (27) is composed using, for example, ITO, IZO, etc. The shield electrode (27) may be formed using other tin oxide-based materials, zinc oxide-based materials, etc., or may be composed using other transparent conductive materials. The shield electrode (27) may be composed using a material of the same type as, for example, the reading electrode (24) and the accumulation electrode (26).

[0146] FIG. 6 is a drawing for explaining an example of the configuration of an imaging device according to the first embodiment. FIG. 7 is a drawing showing an example of energy levels in an imaging device according to the first embodiment. FIG. 7 shows the energy levels of an upper electrode (23), a photoelectric conversion film (22), a protective layer (29), a semiconductor layer (25a), a semiconductor layer (25b), and an accumulation electrode (26).

[0147] In the imaging device (1) according to the present embodiment, as shown in FIGS. 3 and FIGS. 6, a semiconductor layer (25a) is provided. The semiconductor layer (25a) has a carrier concentration higher than that of the semiconductor layer (25b), for example, as described above. By doing so, the interface level of the photoelectric conversion film (22) can be filled with charge (electrons), and thus it is possible to suppress noise caused by the interface level of the photoelectric conversion film (22) from being mixed into the pixel signal.

[0148] In the imaging device (1), electrons can be filled at the interface level between the protective layer (29) and the semiconductor layer (25a) by means of a semiconductor layer (25a) having a high carrier concentration, schematically represented by the “X” mark in FIG. 7. By doing so, signal charges (electrons) converted by photoelectric conversion film (22) can be prevented from being trapped at the interface level between the protective layer (29) and the semiconductor layer (25a).

[0149] In the imaging device (1), by providing a semiconductor layer (25a), noise caused by an interface level, for example, noise components caused by electrons emitted with delay from the interface level, can be reduced. This allows for suppressing the degradation of the quality of the pixel signal (the third pixel signal described above), thereby enabling suppression of the degradation of the image quality of the image generated using the pixel signal.

[0150] Additionally, the imaging device (1) can be configured such that the difference φ1 between the energy level at the bottom of the conduction band and the Fermi level in the semiconductor layer (25a) is smaller than the difference φ2 between the energy level at the bottom of the conduction band and the Fermi level in the semiconductor layer (25b). Because of this, electrons can be moved to the defect levels at the interface between the protection layer (29) and the semiconductor layer (25a) by the semiconductor layer (25a) and the semiconductor layer (25b), thereby reducing the interface levels that are not filled with electrons (i.e., empty interface defects). This makes it possible to effectively suppress noise mixed into the pixel signal.

[0151] The difference between the energy level at the bottom of the conduction band and the vacuum level in the protective layer (29) may be smaller than the difference between the energy level at the bottom of the conduction band and the vacuum level in the semiconductor layer (25a). Additionally, the thickness (film thickness) of the protective layer (29) may be, for example, 5 nm or less. This prevents the formation of an unnecessary potential barrier between the protective layer (29) and the semiconductor layer (25a). It also makes it possible to prevent the reduction of the charge transfer efficiency generated by the photoelectric conversion film (22).

[0152] FIGS. 8a to 8d are drawings for explaining an example of a method for manufacturing an imaging device according to a first embodiment. First, a reading electrode (24), an accumulation electrode (26), a shield electrode (27), etc. are sequentially formed on a semiconductor layer (110) on which a photoelectric conversion unit (11a) and a photoelectric conversion unit (11b), etc. are formed.

[0153] Then, as shown in FIG. 8a, a semiconductor layer (25b) is formed on the insulating layer (131) by sputtering or ALD (Atomic Vapor Deposition). For example, an IGZO film is formed as the semiconductor layer (25b). Additionally, after the formation of the semiconductor layer (25b), an annealing treatment (e.g., 100°C to 600°C) may be performed.

[0154] Next, as shown in FIG. 8b, an Al film (90) (aluminum film) is formed on the semiconductor layer (25b) by sputtering. For example, the thickness of the Al film (90) is about 5 nm. Then, by performing an annealing treatment (e.g., 300°C to 400°C), a semiconductor layer (25a) and a protective layer (29) composed of Al2O3 are formed as shown in FIG. 8c.

[0155] By forming an Al film (90) on a semiconductor layer (25b) made of an IGZO film and performing an annealing treatment, a semiconductor layer (25a) having a high carrier concentration and a protective layer (29) can be formed. By providing a protective layer (29) made of Al2O3 on the semiconductor layer (25a), the sealing performance of the semiconductor layer (25a) can be improved. In addition, a reduction in interfacial defects can be expected.

[0156] As shown in FIG. 8d, the protective layer (29) may be removed by etching as needed. After forming the semiconductor layer (25a), the photoelectric conversion film (22), upper electrode (23), etc. are formed. By the above manufacturing method, the imaging device (1) shown in FIG. 3, etc. can be manufactured.

[0157] In the imaging device (1), the constituent elements of the semiconductor layer (25a) may be different from the constituent elements of the semiconductor layer (25b). For example, the semiconductor layer (25a) may contain an element different from the constituent elements of the semiconductor layer (25b) (e.g., aluminum in the example described above using FIGS. 8a to 8c).

[0158] The semiconductor layer (25a) may be configured to include cations constituting the protective layer (29). For example, when the protective layer (29) is composed of Al2O3, the semiconductor layer (25a) may be configured to include aluminum that penetrates from the Al film (90) during annealing as a cation.

[0159] In addition, the manufacturing method described above is merely an example, and other manufacturing methods may be adopted. Also, the configuration of the imaging device (1) is not limited to the example described above. Instead of the Al film (90), Ga (gallium), In (indium), Sc (scandium), Y (yttrium), etc. may be deposited on the semiconductor layer (25b), and the semiconductor layer (25a) may be formed by annealing.

[0160] Additionally, the semiconductor layer (25a) may be formed by the ALD method. As an example, a stacked film of ZnO and Al2O3 may be formed as the semiconductor layer (25a) by ALD. The semiconductor layer (25a) and the semiconductor layer (25b) may be composed of Si-doped Ga2O3, Al-doped ZnO, Ga-doped ZnO, etc.

[0161] FIG. 9 is a drawing for explaining another configuration example of an imaging device according to the first embodiment. The imaging device (1) may not have a protective layer (29) as shown in the example in FIG. 9. Also, FIG. 10 is a drawing showing an example of energy levels in an imaging device. FIG. 10 shows the energy levels of the upper electrode (23), the photoelectric conversion film (22), the semiconductor layer (25a), the semiconductor layer (25b), and the storage electrode (26), respectively. The semiconductor layer (25a) is provided, for example, in contact with the photoelectric conversion film (22).

[0162] In the imaging device (1), a semiconductor layer (25a) having a high carrier concentration is provided, thereby allowing electrons to fill the interface level between the photoelectric conversion film (22) and the semiconductor layer (25a), schematically represented by the "X" mark in FIG. 10. By doing so, signal charges (electrons) converted by photoelectric conversion film (22) can be suppressed from being trapped in the interface level between the photoelectric conversion film (22) and the semiconductor layer (25a). Because of this, it is possible to suppress noise caused by the interface level from being mixed into the pixel signal.

[0163] Additionally, the difference φ1 between the energy level at the bottom of the conduction band and the Fermi level in the semiconductor layer (25a) may be smaller than the difference φ2 between the energy level at the bottom of the conduction band and the Fermi level in the semiconductor layer (25b). By the semiconductor layer (25a) and the semiconductor layer (25b), electrons can be moved to the interface level between the photoelectric conversion film (22) and the semiconductor layer (25a), thereby reducing the interface level that is not filled with electrons (empty interface defects). This makes it possible to effectively suppress noise mixed into the pixel signal. It makes it possible to suppress the degradation of image quality.

[0164] FIG. 11 is a timing chart showing an example of operation of an imaging device according to a first embodiment. The timing chart shown in FIG. 11 schematically illustrates the voltage of the accumulation electrode (26) of pixel P, the voltage of the floating diffusion FD3 (referred to as voltage VFD), and the voltage of the signal SRST3 supplied to the reset transistor RST3, with the horizontal axis as the time.

[0165] In the imaging device (1), during the period from time t0 to time t2 shown in FIG. 11, a potential V1 is applied to the reading electrode (24) and a potential V2 is applied to the accumulation electrode (26) by the vertical driving circuit (111). Here, potentials V1 and V2 are set such that V2 > V1. Accordingly, the charge (signal charge; electron) generated by photoelectric conversion is attracted to the accumulation electrode (26) and accumulated in the region of the semiconductor layer (25b) opposite the accumulation electrode (26) (accumulation period).

[0166] At time t1, the vertical driving circuit (111) changes the voltage of signal SRST3 from a low level to a high level. As a result, in pixel P, the reset transistor RST3 is turned on, and the voltage of the floating diffusion FD3 is reset (reset period).

[0167] At time t2, potential V3 is applied to the reading electrode (24) and potential V4 is applied to the accumulation electrode (26) by the vertical driving circuit (111). Here, potentials V3 and V4 are set such that V3 > V4. As a result, the charge accumulated in the area corresponding to the accumulation electrode (26) is read from the reading electrode (24) as floating diffusion FD3 (transmission period).

[0168] After the reading operation is completed, a potential V1 is applied to the reading electrode (24) and a potential V2 is applied to the accumulation electrode (26) by the vertical driving circuit (111). As a result, the charge generated by photoelectric conversion is attracted to the accumulation electrode (26) and accumulated in the region of the semiconductor layer (25b) opposite the accumulation electrode (26) (accumulation period).

[0169] In the imaging device (1), for example, among the light transmitted through the photoelectric conversion unit (11c), blue light (B) is absorbed in the photoelectric conversion unit (11b) and red light (R) is absorbed in the photoelectric conversion unit (11a), respectively, and converted into photoelectric light. In the photoelectric conversion unit (11b), electrons corresponding to the incident blue light (B) are accumulated in the photoelectric conversion unit (11b), and the accumulated electrons are transmitted to the floating diffusion FD2 by the transmission transistor TR2. Also, in the photoelectric conversion unit (11a), electrons corresponding to the incident red light (R) are accumulated in the photoelectric conversion unit (11a), and the accumulated electrons are transmitted to the floating diffusion FD1 by the transmission transistor TR1.

[0170] [Mechanism of Action / Effect]

[0171] The light detection device according to the present embodiment comprises a first electrode (e.g., upper electrode (23)), a second electrode (e.g., accumulation electrode (26)) arranged to face the first electrode, a photoelectric conversion film (photoelectric conversion film (22)) arranged between the first electrode and the second electrode, a first semiconductor layer (semiconductor layer (25a)) arranged between the photoelectric conversion film and the second electrode, and a second semiconductor layer (semiconductor layer (25b)) arranged between the first semiconductor layer and the second electrode. The difference between the energy level at the bottom of the conduction band and the Fermi level in the first semiconductor layer is smaller than the difference between the energy level at the bottom of the conduction band and the Fermi level in the second semiconductor layer.

[0172] In the light detection device (imaging device (1)) according to the present embodiment, the difference between the energy level at the bottom of the conduction band in the semiconductor layer (25a) and the Fermi level is smaller than the difference between the energy level at the bottom of the conduction band in the semiconductor layer (25b) and the Fermi level. Because of this, noise caused by the interface level can be suppressed, and the degradation of the pixel signal quality can be suppressed. It becomes possible to realize a light detection device capable of suppressing the degradation of signal quality.

[0173] The light detection device according to the present embodiment comprises a first electrode (e.g., upper electrode (23)), a second electrode (e.g., accumulation electrode (26)) arranged to face the first electrode, a photoelectric conversion film (photoelectric conversion film (22)) arranged between the first electrode and the second electrode, a first semiconductor layer (semiconductor layer (25a)) arranged between the photoelectric conversion film and the second electrode, and a second semiconductor layer (semiconductor layer (25b)) arranged between the first semiconductor layer and the second electrode. The carrier concentration in the first semiconductor layer is higher than the carrier concentration in the second semiconductor layer.

[0174] In the light detection device (imaging device (1)) according to the present embodiment, a semiconductor layer (25a) is provided. The carrier concentration in the semiconductor layer (25a) is higher than the carrier concentration in the semiconductor layer (25b). Because of this, noise caused by the interface level can be suppressed. It becomes possible to realize a light detection device capable of suppressing the degradation of signal quality.

[0175] Next, variations of the present disclosure will be described. Hereinafter, components identical to those in the above embodiments are denoted by the same reference numerals, and descriptions are appropriately omitted.

[0176] (Variation Example 1)

[0177] FIG. 12 is a drawing for explaining an example of a cross-sectional configuration of an imaging device according to Variant Example 1 of the present disclosure. FIG. 13 is a drawing for explaining an example of a planar configuration of an imaging device. As shown in the examples in FIG. 12 and FIG. 13, a semiconductor layer (25a) may be provided in a region portion facing the accumulation electrode (26). As shown in the example in FIG. 13, the semiconductor layer (25a) is provided to overlap the accumulation electrode (26) when viewed in a planar manner.

[0178] FIG. 14 is a drawing for explaining another configuration example of an imaging device according to Variant Example 1. In the imaging device (1), a semiconductor layer (25c) different from the semiconductor layer (25b) may be provided in a peripheral region of the semiconductor layer (25a). The semiconductor layer (25c) is provided adjacent to the semiconductor layer (25a), for example, as shown in FIG. 14. The semiconductor layer (25a) and the semiconductor layer (25c) may be selectively formed, for example, by ion implantation, plasma doping, solid-state diffusion, etc.

[0179] In the example shown in FIG. 14, the semiconductor layer (25c) is formed in a region portion facing the reading electrode (24) and a region portion facing the shield electrode (27), respectively. The semiconductor layer (25a) has a carrier concentration higher than, for example, the carrier concentration of the semiconductor layer (25c). Additionally, the difference between the energy level at the bottom of the conduction band and the Fermi level in the semiconductor layer (25a) may be smaller than the difference between the energy level at the bottom of the conduction band and the Fermi level in the semiconductor layer (25c).

[0180] FIG. 15 is a drawing for explaining another configuration example of an imaging device according to Variant Example 1. Each pixel P of the imaging device (1) may have a control electrode (28) as shown in FIG. 15. The vertical driving circuit (111) of the imaging device (1) can adjust the potential in the photoelectric conversion unit (11c) by, for example, controlling the voltage supplied to the control electrode (28). In the imaging device (1), it becomes possible to efficiently perform the accumulation and transmission of electric charge by the accumulation electrode (26) and the reading electrode (24).

[0181] (Variation Example 2)

[0182] FIG. 16 is a drawing for explaining an example of a cross-sectional configuration of an imaging device according to Variant Example 2. FIG. 17 is also a drawing showing an example of an energy level in an imaging device. The semiconductor layer (25a) and the semiconductor layer (25b) may be composed of different materials. As shown in the example in FIG. 17, the energy level at the bottom of the conduction band in the semiconductor layer (25a) may be deeper (smaller) than the energy level at the bottom of the conduction band in the semiconductor layer (25b).

[0183] In the case of this modified example, the interface level can be filled with electrons by means of the semiconductor layer (25a) and the semiconductor layer (25b), thereby suppressing noise caused by the interface level from being mixed into the pixel signal. By reducing the noise component mixed into the pixel signal, it is possible to prevent the deterioration of the image quality.

[0184] (Variation Example 3)

[0185] FIG. 18 is a drawing for explaining an example of a cross-sectional configuration of an imaging device according to Variant Example 3. FIG. 19 is also a drawing showing an example of an energy level in an imaging device. The protective layer (29) may be configured as a thin tunnel layer, as shown in the example schematically illustrated in FIG. 18 and FIG. 19. The thickness (film thickness) of the protective layer (29) may be, for example, 5 nm or less. In the case of this variant example, the same effect as that of the above-described embodiment can be obtained.

[0186] (Variation Example 4)

[0187] FIG. 20 is a drawing for explaining an example of the configuration of an imaging device according to Variant Example 4. The semiconductor layer (25a) and the semiconductor layer (25b) may each be an oxide semiconductor layer containing Zn (zinc). If the composition ratio of Zn is small (low), there is a tendency for many Zn vacancies that capture electrons to occur, as schematically shown in FIG. 20.

[0188] Therefore, in the imaging device (1), the composition ratio of Zn in the semiconductor layer (25a) may be greater than the composition ratio of Zn in the semiconductor layer (25b). By making the composition ratio of Zn in the semiconductor layer (25a) larger, the carrier concentration of the semiconductor layer (25a) can be increased. Since the increase in carrier concentration is not due to defects, it is possible to improve the reliability of the device.

[0189] In the light detection device according to the present modification example, the first semiconductor layer and the second semiconductor layer (semiconductor layer (25a), semiconductor layer (25b)) are each oxide semiconductor layers containing Zn. The composition ratio of Zn in the first semiconductor layer is greater than the composition ratio of Zn in the second semiconductor layer. As a result, noise caused by interface levels can be suppressed, thereby enabling suppression of pixel signal quality degradation. In addition, it is possible to improve the reliability of the device.

[0190] (Variation Example 5)

[0191] FIG. 21 is a drawing for explaining an example of the configuration of an imaging device according to Variant Example 5. As schematically shown in FIG. 21, if the bandgap of the semiconductor layer is large, there is a risk that many defect levels (e.g., interface levels of the photoelectric conversion film (22) or the protective layer (29)) will not be filled with electrons. Therefore, the semiconductor layer (25a) may be configured to have a relatively small bandgap.

[0192] The band gap of the semiconductor layer (25a) may be smaller than, for example, the band gap of the semiconductor layer (25b). The semiconductor layer (25a) may be composed of a material having a band gap smaller than the band gap of the semiconductor layer (25b). By configuring the imaging device (1) in this way, the carrier concentration in the semiconductor layer (25a) can be increased, making it possible to fill the defect level with electrons as schematically shown in FIG. 21.

[0193] In the imaging device (1), the energy level of the lower conduction band in the photoelectric conversion film (22) may be greater than the energy level of the lower conduction band in the semiconductor layer (25a). Additionally, the energy level of the lower conduction band in the semiconductor layer (25a) may be greater than the energy level of the lower conduction band in the semiconductor layer (25b). In the case of the imaging device (1) according to this modified example, the same effect as the above-described embodiment can be obtained.

[0194] In addition, the energy level of the upper valence band in the protective layer (29) of the imaging device (1) may be greater than the energy level of the upper valence band in the semiconductor layer (25a). In this case, it becomes possible to reduce the defect level that is not filled with electrons. This allows for suppressing noise mixed into the pixel signal, thereby suppressing image quality degradation.

[0195] In the light detection device according to the present modification example, the band gap in the first semiconductor layer (semiconductor layer (25a)) is smaller than the band gap in the second semiconductor layer (semiconductor layer (25b)). Because of this, the occurrence of noise caused by the interface level can be suppressed. It becomes possible to realize a light detection device capable of suppressing the degradation of signal quality.

[0196] (Variation Example 6)

[0197] In the above-described embodiments and variations, an example of the configuration of the imaging device (1) has been described, but this is merely an example, and the configuration of the imaging device (1) is not limited to the above-described example. FIG. 22 is a drawing for explaining an example of the configuration of the imaging device according to Variant Example 6. The imaging device (1) according to the present variation has a structure in which a photoelectric conversion unit (11a), a photoelectric conversion unit (11b), and a photoelectric conversion unit (11c) are stacked, as shown in FIG. 22. From the side where light is incident, the photoelectric conversion unit (11c), the photoelectric conversion unit (11b), and the photoelectric conversion unit (11a) are provided.

[0198] The photoelectric conversion unit (11b) includes, for example, the photoelectric conversion film (22) described above, an upper electrode (23), a reading electrode (24), a semiconductor layer (25a), a semiconductor layer (25b), and an accumulation electrode (26). Additionally, the photoelectric conversion unit (11c) is provided to be stacked on the photoelectric conversion unit (11b). The photoelectric conversion unit (11c) may have the same configuration as the photoelectric conversion unit (11b).

[0199] The photoelectric conversion unit (11c) includes, for example, a photoelectric conversion film (32), an upper electrode (33), a reading electrode (34), a semiconductor layer (35a), a semiconductor layer (35b), and a storage electrode (36). The photoelectric conversion film (32), the upper electrode (33), and the reading electrode (34) of the photoelectric conversion unit (11c) correspond to the photoelectric conversion film (22), the upper electrode (23), and the reading electrode (24) of the photoelectric conversion unit (11b), respectively. The semiconductor layer (35a), the semiconductor layer (35b), and the storage electrode (36) of the photoelectric conversion unit (11c) correspond to the semiconductor layer (25a), the semiconductor layer (25b), and the storage electrode (26) of the photoelectric conversion unit (11b), respectively.

[0200] The photoelectric conversion unit (11a), the photoelectric conversion unit (11b), and the photoelectric conversion unit (11c) are configured to selectively detect light of different wavelength ranges, for example, and perform photoelectric conversion. As an example, the photoelectric conversion unit (11b) acquires a pixel signal of the green (G) color component. The photoelectric conversion unit (11c) acquires a pixel signal of the blue (B) color component. Additionally, the photoelectric conversion unit (11a) acquires a pixel signal of the red (R) color component. By doing so, the imaging device (1) can acquire multiple types of color signals in a single pixel.

[0201] FIG. 23a is a drawing for explaining another configuration example of an imaging device according to Variant Example 6. As shown in FIG. 23a, the imaging device (1) may have a stacked structure of a photoelectric conversion unit (11a) and a photoelectric conversion unit (11c). Additionally, the imaging device (1) may be provided with a filter (57). The filter (57) is configured to selectively transmit light of a specific wavelength range among the incident light.

[0202] A filter (57) is provided, for example, between a lens (81) and a photoelectric converter (11c). The filter (57) is an RGB color filter, a filter that transmits infrared light, etc. The filter (57) is provided, for example, above the photoelectric converter (11c) for each pixel P or for each of a plurality of pixels P (i.e., for a predetermined number of pixels P).

[0203] In a plurality of pixels P provided in a pixel section (100) (see FIG. 1 and FIG. 2) of an imaging device (1), for example, a pixel Pr (R pixel) provided with a filter (57) that transmits red (R) light, a pixel Pg (G pixel) provided with a filter (57) that transmits green (G) light, and a pixel Pb (B pixel) provided with a filter (57) that transmits blue (B) light are included. In the pixel section (100), a plurality of pixels Pr, a plurality of pixels Pg, and a plurality of pixels Pb are repeatedly arranged. Pixels Pr, Pg, and Pb are arranged according to a Bayer array, for example.

[0204] Pixel Pr, pixel Pg, and pixel Pb of the pixel unit (100) can each generate a pixel signal of the R component, a pixel signal of the G component, and a pixel signal of the B component. The imaging device (1) can obtain RGB pixel signals. Additionally, a filter (57) may be placed between the photoelectric conversion unit (11b) and the photoelectric conversion unit (11a).

[0205] In the imaging device (1), for example, among the light that passes through the filter (57), the light in the visible light region (red light (R), green light (G), and blue light (B)) is absorbed and converted by the photoelectric conversion unit (11c) of each pixel P. The photoelectric conversion unit (11a) of each pixel P may be configured to convert infrared light (IR) that passes through the photoelectric conversion unit (11c). This makes it possible to generate both visible light images and infrared light images.

[0206] FIG. 23b is a drawing for explaining another configuration example of an imaging device according to Variant Example 6. As shown in the example in FIG. 23b, a filter (57) may be provided between the photoelectric converter (11c) and the photoelectric converter (11a) (or photoelectric converter (11b)). In the imaging device (1), for example, a filter (57) (filter (57R)) that selectively transmits at least red light (R) and a filter (57) (filter (57B)) that selectively transmits at least blue light (B) may be provided.

[0207] The photoelectric conversion unit (11c) is configured to selectively absorb light having a wavelength corresponding to, for example, green light (G). In the photoelectric conversion unit (11a), light having a wavelength corresponding to red light (R) is selectively absorbed, and in the photoelectric conversion unit (11b), light having a wavelength corresponding to blue light (B) is selectively absorbed. By doing so, it becomes possible to acquire a signal corresponding to red light (R), green light (G), or blue light (B). The area of ​​each RGB photoelectric conversion unit can be expanded compared to the case of a general Bayer array, thereby making it possible to improve the S / N ratio.

[0208] <2. Second Embodiment>

[0209] Next, a second embodiment of the present disclosure will be described. Hereinafter, components identical to those in the above-described embodiment are denoted by the same reference numerals, and descriptions are appropriately omitted.

[0210] FIG. 24 is a drawing for explaining an example of the configuration of an imaging device according to a second embodiment of the present disclosure. FIG. 25 is also a drawing showing an example of an energy level in an imaging device. The semiconductor layer (25a) of the imaging device (1) is configured to have a high carrier concentration (carrier density). The semiconductor layer (25a) is configured to have a carrier concentration that is higher (larger) than, for example, the carrier concentration of the semiconductor layer (25b).

[0211] Additionally, the imaging device (1) may be configured such that the difference between the energy level at the bottom of the conduction band and the vacuum level on the side of the semiconductor layer (25a) in the photoelectric conversion film (22) is greater than the difference between the energy level at the bottom of the conduction band and the vacuum level on the side of the semiconductor layer (25a) in the photoelectric conversion film (22). In the example shown in FIG. 25, the difference between the energy level E1 at the bottom of the conduction band and the vacuum level on the side of the semiconductor layer (25a) in the photoelectric conversion film (22) is greater than the difference between the energy level E2 at the bottom of the conduction band and the vacuum level on the side of the photoelectric conversion film (22) in the semiconductor layer (25a).

[0212] In the imaging device (1), for example, as shown in FIG. 25, the photoelectric conversion film (22) and the semiconductor layer (25a) are arranged in contact with each other with band bending. By configuring the imaging device (1) in this way, the tunnel distance between, for example, the photoelectric conversion film (22) and the semiconductor layer (25a) can be reduced, thereby making it possible to suppress the deterioration of the transmission efficiency of signal charges (e.g., electrons).

[0213] In the imaging device (1) according to the present embodiment, the band bending in the semiconductor layer (25a) can be strengthened (i.e., changed abruptly). Because of this, it is possible to suppress the inhibition of electron transport and to suppress the reduction of light utilization efficiency. In addition, it is possible to suppress the occurrence of noise caused by the interface level.

[0214] FIG. 26 is a drawing for explaining another configuration example of an imaging device according to a second embodiment. The imaging device (1) may have a protective layer (29), as shown in the example in FIG. 26. Also, FIG. 27 is a drawing showing an example of energy levels in an imaging device. FIG. 27 shows the energy levels of the upper electrode (23), the photoelectric conversion film (22), the protective layer (29), the semiconductor layer (25a), the semiconductor layer (25b), and the storage electrode (26), respectively.

[0215] The protective layer (29) is a protective layer comprising, for example, an inorganic material and is provided between the photoelectric conversion film (22) and the semiconductor layer (25a). In the example shown in FIG. 26, the protective layer (29) is formed between the photoelectric conversion film (22) and the semiconductor layer (25a) and is located on the semiconductor layer (25a).

[0216] In the imaging device (1), the difference between the energy level at the bottom of the conduction band and the vacuum level on the side of the semiconductor layer (25a) in the protective layer (29) may be greater than the difference between the energy level at the bottom of the conduction band and the vacuum level on the side of the protective layer (29) in the semiconductor layer (25a). By reducing the tunnel distance between the protective layer (29) and the semiconductor layer (25a), it is possible to suppress the decrease in the charge transport efficiency generated by the photoelectric conversion film (22).

[0217] [Mechanism of Action / Effect]

[0218] In the light detection device (imaging device (1)) according to the present embodiment, the difference between the energy level at the bottom of the conduction band and the vacuum level on the side of the first semiconductor layer (semiconductor layer (25a)) in the photoelectric conversion film (photoelectric conversion film (22)) is greater than the difference between the energy level at the bottom of the conduction band and the vacuum level on the side of the photoelectric conversion film in the first semiconductor layer.

[0219] In the light detection device (imaging device (1)) according to the present embodiment, the reduction in charge transport efficiency can be suppressed by providing a semiconductor layer (25a). Therefore, it is possible to realize a light detection device capable of suppressing the reduction in signal quality.

[0220] Next, variations of the present disclosure will be described. Hereinafter, components identical to those in the above embodiments are denoted by the same reference numerals, and descriptions are appropriately omitted.

[0221] (Variation Example 7)

[0222] FIGS. 28a and FIG. 28b are drawings for explaining an example of a cross-sectional configuration of an imaging device according to Variant Example 7 of the present disclosure. As shown in FIG. 28a or FIG. 28b, a semiconductor layer (25a) may be provided in a region portion facing the accumulation electrode (26). In addition, in the imaging device (1), a semiconductor layer (25c) may be provided in a region surrounding the semiconductor layer (25a). In addition, the imaging device (1) may have a control electrode (28) as shown in FIG. 25b.

[0223] (Variation Example 8)

[0224] FIG. 29 is a drawing for explaining an example of a cross-sectional configuration of an imaging device according to Variant Example 8. The imaging device (1) may have a plurality of protective layers (29) (in FIG. 29, protective layers (29a), protective layers (29b)). FIG. 30 is a drawing showing an example of energy levels in an imaging device. FIG. 30 shows the energy levels of an upper electrode (23), a photoelectric conversion film (22), a protective layer (29a), a protective layer (29b), a semiconductor layer (25a), a semiconductor layer (25b), and an accumulation electrode (26), respectively.

[0225] Each of the protective layer (29a) and the protective layer (29b) is a protective layer comprising, for example, an inorganic material and is provided between the photoelectric conversion film (22) and the semiconductor layer (25a). The protective layer (29a) and the protective layer (29b) are each composed of, for example, at least one of Ti, Si, Zr, Nb, V, Ta, Hf, Al, Sn, Sc, Y, La, Ga, and Mg.

[0226] In the example shown in FIG. 29, the protective layer (29a) is formed between the photoelectric conversion film (22) and the protective layer (29b) and is located on the protective layer (29b). The protective layer (29b) is formed between the protective layer (29a) and the semiconductor layer (25a) and is located on the semiconductor layer (25a). The protective layer (29a) and the protective layer (29b) may be arranged to be stacked on top of each other. Additionally, the protective layer (29a) and the protective layer (29b) may be constructed using the same type of material or different materials.

[0227] In the imaging device (1), the difference between the energy level at the bottom of the conduction band of the protective layer (29b) and the vacuum level may be smaller than the difference between the energy level at the bottom of the conduction band of the semiconductor layer (25a) and the vacuum level. The protective layer (29b) may be configured, for example, as a tunnel layer. The thickness of the protective layer (29b) may be 5 nm or less. In the case of this modified example, the same effect as in the above-described embodiment can be obtained.

[0228] <3. Application Examples>

[0229] (Application Example 1)

[0230] The light detection device (imaging device (1)) described above can be applied to various electronic devices, such as an imaging system such as a digital still camera or a digital video camera, a mobile phone equipped with an imaging function, or other devices equipped with an imaging function.

[0231] Figure 31 is a block diagram showing an example of the configuration of an electronic device.

[0232] As shown in FIG. 31, the electronic device (1001) is equipped with an optical system (1002), a light detection device (1003), and a Digital Signal Processor (DSP) (1004), and is configured such that the DSP (1004), a display device (1005), an operating system (1006), a memory (1008), a recording device (1009), and a power system (1010) are connected via a bus (1007), and is capable of capturing still images and moving images.

[0233] The optical system (1002) is configured with one or more lenses and guides incident light from a subject to a light detection device (1003) to form an image on the light receiving surface (sensor part) of the light detection device (1003).

[0234] As the light detection device (1003), the light detection device (imaging device (1)) described above may be applied. In the light detection device (1003), electrons are accumulated for a certain period of time according to the image formed on the light receiving surface through the optical system (1002). Then, a signal corresponding to the electrons accumulated in the light detection device (1003) is supplied to the DSP (1004).

[0235] The DSP (1004) performs various signal processing on the signal from the light detection device (1003) to acquire an image, and temporarily stores the image data in the memory (1008). The image data stored in the memory (1008) is recorded in the recording device (1009) or supplied to the display device (1005) to display the image. Additionally, the control system (1006) receives various operations by the user and supplies operation signals to each block of the electronic device (1001). The power system (1010) supplies the power required to drive each block of the electronic device (1001).

[0236] (Application Example 2)

[0237] FIG. 32a schematically illustrates an example of the overall configuration of a light detection system (2000) equipped with a light detection device (imaging device (1)). FIG. 32b schematically illustrates an example of the circuit configuration of a light detection system (2000). The light detection system (2000) is equipped with a light-emitting device (2001) as a light source unit that emits light L2, and a light detection device (2002) as a light-receiving unit having a photoelectric conversion element.

[0238] As the light detection device (2002), the light detection device (imaging device (1)) described above may be used. The light detection system (2000) may also be equipped with a system control unit (2003), a light source driving unit (2004), a sensor control unit (2005), a light source side optical system (2006), and a camera side optical system (2007).

[0239] The light detection device (2002) can detect light L1 and light L2. Light L1 is light reflected from the subject (2100) (measurement target) from ambient light from the outside (see FIG. 32a). Light L2 is light reflected by the subject (2100) among the light emitted from the light-emitting device (2001). Light L1 is, for example, visible light, and light L2 is, for example, infrared light.

[0240] Light L1 can be detected in the photoelectric conversion unit of the light detection device (2002), and light L2 can be detected in the photoelectric conversion unit of the light detection device (2002). Image information of the subject (2100) can be obtained from light L1, and distance information between the subject (2100) and the light detection system (2000) can be obtained from light L2.

[0241] The light detection system (2000) can be mounted on an electronic device such as a smartphone or a mobile vehicle such as a car. The light-emitting device (2001) can be configured using, for example, a semiconductor laser, a surface-emitting semiconductor laser, or a vertical resonator-type surface-emitting laser (VCSEL).

[0242] As a detection method by a light detection device (2002) for light L2 emitted from a light-emitting device (2001), for example, an iTOF method may be adopted, but is not limited thereto. In the iTOF method, the photoelectric converter may measure the distance to the subject (2100) for example by the Time-of-Flight (TOF).

[0243] As a detection method using a light detection device (2002) for light L2 emitted from a light-emitting device (2001), for example, a structured light method or a stereo vision method may be adopted. For example, in the structured light method, light of a predetermined pattern is projected onto a subject (2100), and the distance between the light detection system (2000) and the subject (2100) can be measured by analyzing the deformation state of the pattern.

[0244] In addition, in the stereo vision method, for example, by using two or more cameras to acquire two or more images of the subject (2100) viewed from two or more different viewpoints, the distance between the light detection system (2000) and the subject can be measured. In addition, the light emitting device (2001) and the light detection device (2002) can be synchronously controlled by the system control unit (2003).

[0245] <4. Application Examples>

[0246] (Application example for moving objects)

[0247] The technology of the present disclosure (the technology) can be applied to various products. For example, the technology of the present disclosure may be realized as a device mounted on any type of mobile body, such as an automobile, an electric vehicle, a hybrid electric vehicle, an automatic two-wheeled vehicle, a bicycle, a personal mobility device, an airplane, a drone, a ship, or a robot.

[0248] FIG. 33 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a moving object control system to which the technology of the present disclosure may be applied.

[0249] The vehicle control system (12000) is equipped with a plurality of electronic control units connected via a communication network (12001). In the example shown in FIG. 33, the vehicle control system (12000) is equipped with a drive system control unit (12010), a body system control unit (12020), an external information detection unit (12030), an internal information detection unit (12040), and an integrated control unit (12050). Additionally, as a functional configuration of the integrated control unit (12050), a microcomputer (12051), a voice-image output unit (12052), and a vehicle-mounted network interface (12053) are shown.

[0250] The drivetrain control unit (12010) controls the operation of devices related to the vehicle's drivetrain according to various programs. For example, the drivetrain control unit (12010) functions as a control device for a driving force generating device for generating the driving force of a vehicle, such as an internal combustion engine or a driving motor, a driving force transmission mechanism for transmitting the driving force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating the braking force of the vehicle.

[0251] The body control unit (12020) controls the operation of various devices equipped on the vehicle body according to various programs. For example, the body control unit (12020) functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlights, taillights, brake lights, turn signals, or fog lamps. In this case, radio waves transmitted from a portable device that replaces a key or signals from various switches may be input to the body control unit (12020). The body control unit (12020) receives the input of these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0252] The external information detection unit (12030) detects external information of a vehicle equipped with a vehicle control system (12000). For example, an imaging unit (12031) is connected to the external information detection unit (12030). The external information detection unit (12030) captures an image of the outside of the vehicle with the imaging unit (12031) and receives the captured image. Based on the received image, the external information detection unit (12030) may perform object detection processing, such as people, vehicles, obstacles, signs, or text on the road surface, or distance detection processing.

[0253] The imaging unit (12031) is a light sensor that receives light and outputs an electrical signal according to the amount of light received. The imaging unit (12031) may output the electrical signal as an image or as distance measurement information. In addition, the light received by the imaging unit (12031) may be visible light or non-visible light such as infrared light.

[0254] The in-vehicle information detection unit (12040) detects information inside the vehicle. The in-vehicle information detection unit (12040) is connected to, for example, a driver state detection unit (12041) that detects the driver's state. The driver state detection unit (12041) includes, for example, a camera that captures the driver, and the in-vehicle information detection unit (12040) may calculate the driver's fatigue level or concentration level based on the detection information input from the driver state detection unit (12041), or determine whether the driver is dozing off.

[0255] The microcomputer (12051) can calculate a control target value for a driving force generating device, a steering mechanism, or a braking device based on information inside and outside the vehicle obtained by an external information detection unit (12030) or an internal information detection unit (12040), and output a control command to the drive system control unit (12010). For example, the microcomputer (12051) can perform cooperative control aimed at realizing functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or shock mitigation, following driving based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

[0256] Additionally, the microcomputer (12051) can perform cooperative control for the purpose of autonomous driving without driver operation by controlling a driving force generating device, a steering mechanism, or a braking device based on information about the vehicle's surroundings obtained by an external information detection unit (12030) or an internal information detection unit (12040).

[0257] Additionally, the microcomputer (12051) can output a control command to the body system control unit (12020) based on information from outside the vehicle obtained by the outside information detection unit (12030). For example, the microcomputer (12051) can perform cooperative control aimed at achieving illumination, such as switching the high beam to the low beam, by controlling the headlamps according to the position of the preceding vehicle or the opposing vehicle detected by the outside information detection unit (12030).

[0258] The voice-image output unit (12052) transmits at least one of a voice and an image output signal to an output device capable of notifying information visually or audibly to the occupants of the vehicle or outside the vehicle. In the example of FIG. 33, an audio speaker (12061), a display unit (12062), and an instrument panel (12063) are exemplified as output devices. The display unit (12062) may include, for example, at least one of an onboard display and a head-up display.

[0259] FIG. 34 is a drawing showing an example of the installation location of the imaging unit (12031).

[0260] In FIG. 34, as an imaging unit (12031), it has imaging units (12101, 12102, 12103, 12104, 12105).

[0261] The imaging units (12101, 12102, 12103, 12104, 12105) are provided at locations such as the front nose, side mirrors, rear bumpers, back doors, and the upper part of the front glass inside the vehicle (12100). The imaging unit (12101) provided on the front nose and the imaging unit (12105) provided on the upper part of the front glass inside the vehicle mainly acquire images of the front of the vehicle (12100). The imaging units (12102, 12103) provided on the side mirrors mainly acquire images of the side of the vehicle (12100). The imaging unit (12104) provided on the rear bumper or back door mainly acquires images of the rear of the vehicle (12100). The imaging unit (12105) provided on the upper part of the front glass inside the vehicle is mainly used for detecting preceding vehicles, or pedestrians, obstacles, signals, traffic signs, or lanes.

[0262] Additionally, FIG. 34 illustrates an example of the shooting range of the imaging units (12101 to 12104). The imaging range (12111) represents the imaging range of the imaging unit (12101) provided on the front nose, the imaging ranges (12112, 12113) represent the imaging ranges of the imaging units (12102, 12103) provided on the side mirrors, respectively, and the imaging range (12114) represents the imaging range of the imaging unit (12104) provided on the rear bumper or back door. For example, by superimposing image data captured by the imaging units (12101 to 12104), an overhead view image of the vehicle (12100) viewed from above is obtained.

[0263] At least one of the imaging units (12101 to 12104) may have a function for acquiring distance information. For example, at least one of the imaging units (12101 to 12104) may be a stereo camera composed of a plurality of imaging elements, or an imaging element having a pixel for phase difference detection.

[0264] For example, the microcomputer (12051) can determine the distance to each object within the imaging range (12111 to 12114) and the temporal change of this distance (relative speed with respect to the vehicle (12100)) based on distance information obtained from the imaging unit (12101 to 12104), and can extract as a leading vehicle the closest object on the vehicle (12100) and the object traveling at a predetermined speed (e.g., 0 km / h or higher) in approximately the same direction as the vehicle (12100). In addition, the microcomputer (12051) can set the distance between vehicles to be secured in advance immediately before the leading vehicle and perform automatic brake control (including follow-up stop control) or automatic acceleration control (including follow-up start control). In this way, cooperative control can be performed for the purpose of autonomous driving, such as driving autonomously without following the driver's operation.

[0265] For example, the microcomputer (12051) can classify and extract object data regarding objects based on distance information obtained from the imaging unit (12101 to 12104), such as two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other objects, and use this for automatic avoidance of obstacles. For example, the microcomputer (12051) identifies obstacles around the vehicle (12100) as obstacles that are visible to the driver of the vehicle (12100) and obstacles that are difficult to see. Then, the microcomputer (12051) determines a collision risk indicating the risk of collision with each obstacle, and when the collision risk is greater than a set value and there is a possibility of a collision, it can provide driving support for collision avoidance by outputting an alarm to the driver through the audio speaker (12061) or display unit (12062), or by performing forced deceleration or evasive steering through the drive system control unit (12010).

[0266] At least one of the imaging units (12101 to 12104) may be an infrared camera that detects infrared rays. For example, a microcomputer (12051) can recognize a pedestrian by determining whether a pedestrian exists in the image captured by the imaging units (12101 to 12104). This recognition of a pedestrian is performed by a procedure of extracting feature points in the image captured by the imaging units (12101 to 12104), for example, as an infrared camera, and a procedure of determining whether it is a pedestrian by performing pattern matching processing on a series of feature points representing the outline of an object. When the microcomputer (12051) determines that a pedestrian exists in the image captured by the imaging units (12101 to 12104) and recognizes the pedestrian, the voice image output unit (12052) controls the display unit (12062) to superimpose a rectangular outline for emphasis on the recognized pedestrian. Additionally, the voice-image output unit (12052) may control the display unit (12062) to display an icon representing a pedestrian, etc., at a desired location.

[0267] The above describes an example of a mobile object control system to which the technology of the present disclosure may be applied. The technology of the present disclosure may be applied to, for example, the imaging unit (12031) among the configurations described above. Specifically, for example, an imaging device (1) may be applied to the imaging unit (12031). By applying the technology of the present disclosure to the imaging unit (12031), it becomes possible to obtain a high-precision captured image. In the mobile object control system, it becomes possible to perform high-precision control using the captured image.

[0268] (Application example for endoscopic surgical systems)

[0269] The technology of the present disclosure (the technology) can be applied to various products. For example, the technology of the present disclosure may be applied to endoscopic surgical systems.

[0270] FIG. 35 is a drawing showing an example of a schematic configuration of an endoscopic surgical system to which the technology of the present disclosure (the technology) can be applied.

[0271] In FIG. 35, a surgeon (doctor) (11131) is shown performing surgery on a patient (11132) on a patient bed (11133) using an endoscopic surgery system (11000). As shown, the endoscopic surgery system (11000) is composed of an endoscope (11100), other surgical tools (11110) such as a retractable tube (11111) or an energy treatment device (11112), a support arm device (11120) that supports the endoscope (11100), and a cart (11200) equipped with various devices for endoscopic surgery.

[0272] The endoscope (11100) is composed of a tube (11101) into which a predetermined length of area from the tip is inserted into the body cavity of a patient (11132), and a camera head (11102) connected to the base of the tube (11101). In the illustrated example, the endoscope (11100) is configured as a so-called rigid endoscope having a rigid tube (11101), but the endoscope (11100) may be configured as a so-called flexible endoscope having a flexible tube.

[0273] An opening into which an objective lens is fitted is provided at the tip of the tube (11101). A light source device (11203) is connected to the endoscope (11100), and light generated by the light source device (11203) is guided to the tip of the tube by a light guide that extends inside the tube (11101), and is directed toward an object of observation inside the body cavity of a patient (11132) through the objective lens. Additionally, the endoscope (11100) may be a direct-viewing endoscope, a strabismus endoscope, or a lateral-viewing endoscope.

[0274] An optical system and an image element are provided inside the camera head (11102), and reflected light (observation light) from the object to be observed is collected by the optical system and directed to the image element. The observation light is converted by photoelectricity by the image element, and an electrical signal corresponding to the observation light, that is, an image signal corresponding to the observation image, is generated. The image signal is transmitted as RAW data to the camera control unit (CCU: Camera Control Unit) (11201).

[0275] The CCU (11201) is composed of a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), and comprehensively controls the operation of the endoscope (11100) and the display device (11202). Additionally, the CCU (11201) receives an image signal from the camera head (11102) and performs various image processing on the image signal to display an image based on the image signal, such as developing processing (demosaic processing).

[0276] The display device (11202) displays an image based on an image signal for which image processing has been performed by the CCU (11201) under control from the CCU (11201).

[0277] The light source device (11203) is composed of a light source such as an LED (Light Emitting Diode) and supplies illumination light to the endoscope (11100) when photographing the surgical site, etc.

[0278] The input device (11204) is an input interface for the endoscopic surgery system (11000). Through the input device (11204), the user can input various information or instructions to the endoscopic surgery system (11000). For example, the user inputs instructions such as changing the imaging conditions (type of illumination light, magnification, focal length, etc.) by the endoscope (11100).

[0279] The treatment device control device (11205) controls the operation of the energy treatment device (11112) for tissue cauterization, incision, or sealing of blood vessels. The inflating device (11206) sends gas into the body cavity through the inflating tube (11111) to inflate the body cavity of the patient (11132) for the purpose of securing a field of view by the endoscope (11100) and securing a workspace for the operator. The recorder (11207) is a device capable of recording various information regarding the surgery. The printer (11208) is a device capable of printing various information regarding the surgery in various formats such as text, images, or graphs.

[0280] Additionally, the light source device (11203) that supplies illumination light to the endoscope (11100) when photographing the surgical site may be composed of, for example, a white light source composed of an LED, a laser light source, or a combination thereof. When the white light source is composed of a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, so the white balance of the captured image can be adjusted in the light source device (11203). In addition, in this case, it is also possible to capture images corresponding to each RGB in time division by irradiating laser light from each of the RGB laser light sources onto the object of observation in time division and controlling the driving of the imaging element of the camera head (11102) in synchronization with the irradiation timing. According to the method, a color image can be obtained without providing a color filter in the imaging element.

[0281] Additionally, the light source device (11203) may be controlled to change the intensity of the light to be output at predetermined intervals. By controlling the driving of the imaging element of the camera head (11102) in synchronization with the timing of the change in the intensity of the light, images are acquired in time division, and by synthesizing the images, a high dynamic range image without so-called black blurring and whiteout can be generated.

[0282] Additionally, the light source device (11203) may be configured to supply light of a predetermined wavelength band corresponding to special light observation. In special light observation, so-called Narrow Band Imaging is performed, which involves irradiating a narrow band of light compared to the irradiation light (i.e., white light) used in normal observation, thereby capturing a predetermined tissue, such as a blood vessel on the surface of a mucous membrane, with high contrast by utilizing the wavelength dependence of light absorption in body tissue, for example. Alternatively, in special light observation, fluorescence observation may be performed, in which an image is obtained by irradiating an excitation light to obtain a fluorescence. In fluorescence observation, irradiating an excitation light to body tissue to observe fluorescence from said body tissue (autofluorescence observation), or locally injecting a reagent such as indocyanine green (ICG) into said body tissue and simultaneously irradiating the said body tissue with excitation light corresponding to the fluorescence wavelength of said reagent to obtain a fluorescence image, etc. The light source device (11203) may be configured to supply narrowband light and / or excitation light corresponding to such special light observation.

[0283] FIG. 36 is a block diagram showing an example of the functional configuration of the camera head (11102) and CCU (11201) shown in FIG. 35.

[0284] The camera head (11102) has a lens unit (11401), an imaging unit (11402), a driving unit (11403), a communication unit (11404), and a camera head control unit (11405). The CCU (11201) has a communication unit (11411), an image processing unit (11412), and a control unit (11413). The camera head (11102) and the CCU (11201) are connected to communicate with each other by a transmission cable (11400).

[0285] The lens unit (11401) is an optical system provided at the connection point with the lens barrel (11101). Observation light introduced from the tip of the lens barrel (11101) is guided to the camera head (11102) and incident on the lens unit (11401). The lens unit (11401) is composed of a combination of multiple lenses, including a zoom lens and a focus lens.

[0286] The imaging unit (11402) is composed of imaging elements. The imaging elements constituting the imaging unit (11402) may be one (so-called single-plate type) or multiple (so-called multi-plate type). When the imaging unit (11402) is configured as a multi-plate type, for example, image signals corresponding to each RGB may be generated by each imaging element, and a color image may be obtained by combining them. Alternatively, the imaging unit (11402) may be configured to have a pair of imaging elements to acquire image signals for the right eye and the left eye, respectively, corresponding to a 3D (Dimensional) display. By performing a 3D display, the operator (11131) can more accurately determine the depth of the biological tissue in the surgical site. In addition, if the imaging unit (11402) is configured as a multi-plate type, a plurality of lens units (11401) may also be provided in correspondence with each imaging element.

[0287] Additionally, the imaging unit (11402) does not necessarily have to be provided in the camera head (11102). For example, the imaging unit (11402) may be provided inside the lens barrel (11101), immediately behind the objective lens.

[0288] The driving unit (11403) is configured by an actuator and moves the zoom lens and focus lens of the lens unit (11401) by a predetermined distance along the optical axis under control from the camera head control unit (11405). By doing so, the magnification and focus of the image captured by the imaging unit (11402) can be appropriately adjusted.

[0289] The communication unit (11404) is configured by a communication device for transmitting and receiving various information between the CCU (11201) and the CCU (11201). The communication unit (11404) transmits an image signal obtained from the imaging unit (11402) as RAW data to the CCU (11201) through a transmission cable (11400).

[0290] Additionally, the communication unit (11404) receives a control signal from the CCU (11201) to control the driving of the camera head (11102) and supplies it to the camera head control unit (11405). The control signal includes information regarding imaging conditions, such as information specifying the frame rate of the captured image, information specifying the exposure value during imaging, and / or information specifying the magnification and focus of the captured image.

[0291] In addition, the aforementioned imaging conditions, such as frame rate, exposure value, magnification, and focus, may be appropriately specified by the user or may be automatically set by the control unit (11413) of the CCU (11201) based on the acquired image signal. In the latter case, so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function are equipped in the endoscope (11100).

[0292] The camera head control unit (11405) controls the driving of the camera head (11102) based on a control signal from the CCU (11201) received through the communication unit (11404).

[0293] The communication unit (11411) is configured by a communication device for transmitting and receiving various information with the camera head (11102). The communication unit (11411) receives an image signal transmitted from the camera head (11102) through a transmission cable (11400).

[0294] Additionally, the communication unit (11411) transmits a control signal to the camera head (11102) to control the driving of the camera head (11102). The image signal or the control signal may be transmitted via electrical communication or optical communication, etc.

[0295] The image processing unit (11412) performs various image processing on the image signal, which is RAW data transmitted from the camera head (11102).

[0296] The control unit (11413) performs various controls regarding the imaging of a surgical site, etc. by the endoscope (11100) and the display of the image obtained by imaging of the surgical site, etc. For example, the control unit (11413) generates a control signal to control the driving of the camera head (11102).

[0297] Additionally, the control unit (11413) displays an image of a surgical site, etc., on a display device (11202) based on an image signal in which image processing has been performed by the image processing unit (11412). At this time, the control unit (11413) may recognize various objects within the image using various image recognition technologies. For example, the control unit (11413) may recognize surgical tools such as forceps, specific biological parts, bleeding, mist when using an energy treatment device (11112), etc., by detecting the shape or color of the edges of objects included in the image. When displaying the image on the display device (11202), the control unit (11413) may use the recognition results to superimpose various surgical support information onto the image of the surgical site. By displaying surgical support information in an overlapping manner and presenting it to the operator (11131), it is possible to reduce the burden on the operator (11131) or to ensure that the operator (11131) proceeds with the surgery.

[0298] The transmission cable (11400) connecting the camera head (11102) and the CCU (11201) is an electric signal cable corresponding to the communication of electric signals, an optical fiber corresponding to optical communication, or a composite cable thereof.

[0299] In the example illustrated here, communication was performed via a wired connection using a transmission cable (11400), but communication between the camera head (11102) and the CCU (11201) may be performed wirelessly.

[0300] The above describes an example of an endoscopic surgical system to which the technology of the present disclosure may be applied. The technology of the present disclosure may be appropriately applied to, for example, an imaging unit (11402) provided in the camera head (11102) of the endoscope (11100) among the configurations described above. By applying the technology of the present disclosure to the imaging unit (11402), it becomes possible to provide a high-precision endoscope (11100).

[0301] Although the present disclosure has been described above with reference to embodiments, variations, applications, and applications, the present technology is not limited to the above embodiments, and various modifications are possible. For example, the above-described variations were explained as variations of the above embodiments, but the configurations of each variation can be appropriately combined.

[0302] In the above embodiments, etc., an imaging device was described as an example, but the light detection device of the present disclosure only needs to receive incident light and convert the light into an electric charge, for example. The output signal may be a signal of image information or a signal of distance information. The light detection device (imaging device) can be applied to an image sensor, a distance sensor, etc. Furthermore, the present disclosure is not limited to a back-illuminated image sensor and can also be applied to a surface-illuminated image sensor.

[0303] The light detection device according to the present disclosure may also be applied as a distance measuring sensor capable of Time Of Flight (TOF) distance measurement. The light detection device (imaging device) may also be applied as a sensor capable of detecting events, for example, as an event-driven sensor (referred to as an Event Vision Sensor (EVS), Event Driven Sensor (EDS), Dynamic Vision Sensor (DVS), etc.).

[0304] A photodetector device of one embodiment of the present disclosure comprises a first electrode, a second electrode provided to face the first electrode, a photoelectric conversion film provided between the first electrode and the second electrode, a first semiconductor layer provided between the photoelectric conversion film and the second electrode, and a second semiconductor layer provided between the first semiconductor layer and the second electrode. The difference between the energy level at the bottom of the conduction band and the Fermi level in the first semiconductor layer is smaller than the difference between the energy level at the bottom of the conduction band and the Fermi level in the second semiconductor layer. Accordingly, it is possible to realize a photodetector device capable of suppressing the degradation of signal quality.

[0305] A photodetector device of one embodiment of the present disclosure comprises a first electrode, a second electrode provided to face the first electrode, a photoelectric conversion film provided between the first electrode and the second electrode, a first semiconductor layer provided between the photoelectric conversion film and the second electrode, and a second semiconductor layer provided between the first semiconductor layer and the second electrode. The carrier concentration in the first semiconductor layer is higher than the carrier concentration in the second semiconductor layer. Accordingly, it is possible to realize a photodetector device capable of suppressing the degradation of signal quality.

[0306] Furthermore, the effects described in this specification are merely examples and are not limited thereto; other effects may also exist. Additionally, the present disclosure may adopt the following configurations.

[0307] (1)

[0308] The first electrode and,

[0309] A second electrode provided to face the first electrode, and

[0310] A photoelectric conversion film provided between the first electrode and the second electrode, and

[0311] A first semiconductor layer provided between the photoelectric conversion film and the second electrode, and

[0312] A second semiconductor layer provided between the first semiconductor layer and the second electrode

[0313] Equipped,

[0314] The difference between the energy level at the bottom of the conduction band and the Fermi level in the first semiconductor layer is smaller than the difference between the energy level at the bottom of the conduction band and the Fermi level in the second semiconductor layer.

[0315] Light detection device.

[0316] (2)

[0317] The first semiconductor layer is a semiconductor layer including an oxide semiconductor,

[0318] The light detection device described in (1) above.

[0319] (3)

[0320] The second semiconductor layer is a semiconductor layer comprising an oxide semiconductor,

[0321] The light detection device described in (1) or (2) above.

[0322] (4)

[0323] The first semiconductor layer and the second semiconductor layer are each oxide semiconductor layers comprising at least one of In, Ga, Zn, Ti, Sn, Si, Cu, Sb, and Cd.

[0324] A light detection device described in any one of (1) to (3) above.

[0325] (5)

[0326] The first semiconductor layer and the second semiconductor layer are each oxide semiconductor layers containing In,

[0327] The composition ratio of In in the first semiconductor layer is greater than the composition ratio of In in the second semiconductor layer.

[0328] A light detection device described in any one of (1) to (4) above.

[0329] (6)

[0330] The first semiconductor layer and the second semiconductor layer are each oxide semiconductor layers containing Zn, and

[0331] The composition ratio of Zn in the first semiconductor layer is greater than the composition ratio of Zn in the second semiconductor layer.

[0332] A light detection device described in any one of (1) to (5) above.

[0333] (7)

[0334] The first semiconductor layer and the second semiconductor layer are each semiconductor layers comprising an oxide semiconductor, and

[0335] The constituent elements of the first semiconductor layer and the constituent elements of the second semiconductor layer are different from each other.

[0336] A light detection device described in any one of (1) to (6) above.

[0337] (8)

[0338] The first semiconductor layer comprises an element different from the constituent element of the second semiconductor layer.

[0339] A light detection device described in any one of (1) to (7) above.

[0340] (9)

[0341] The difference between the energy level at the bottom of the conduction band and the Fermi level in the second semiconductor layer is at least 0.02 eV greater than the difference between the energy level at the bottom of the conduction band and the Fermi level in the first semiconductor layer.

[0342] A light detection device described in any one of (1) to (8) above.

[0343] (10)

[0344] The difference between the energy level at the bottom of the conduction band and the vacuum level in the first semiconductor layer is greater than the difference between the energy level at the bottom of the conduction band and the vacuum level in the second semiconductor layer.

[0345] A light detection device described in any one of (1) to (9) above.

[0346] (11)

[0347] A protective layer comprising an inorganic material, provided between the photoelectric conversion film and the first semiconductor layer.

[0348] A light detection device described in any one of (1) to (10) above.

[0349] (12)

[0350] The above protective layer is a layer comprising at least one of Ti, Si, Zr, Nb, V, Ta, Hf, Al, Sn, Sc, Y, La, Ga, and Mg,

[0351] The light detection device described in (11) above.

[0352] (13)

[0353] The difference between the energy level at the bottom of the conduction band of the protective layer and the vacuum level is smaller than the difference between the energy level at the bottom of the conduction band of the first semiconductor layer and the vacuum level.

[0354] The light detection device described in (11) or (12) above.

[0355] (14)

[0356] The thickness of the above protective layer is 5 nm or less,

[0357] A light detection device described in any one of (11) to (13) above.

[0358] (15)

[0359] The first semiconductor layer comprises cations constituting the protective layer,

[0360] A light detection device described in any one of (11) to (14) above.

[0361] (16)

[0362] The difference between the energy level at the bottom of the conduction band and the vacuum level on the side of the first semiconductor layer in the above photoelectric conversion film is greater than the difference between the energy level at the bottom of the conduction band and the vacuum level on the side of the first semiconductor layer.

[0363] A light detection device described in any one of (1) to (15) above.

[0364] (17)

[0365] A first protective layer comprising an inorganic material is further provided between the photoelectric conversion film and the first semiconductor layer.

[0366] The difference between the energy level at the bottom of the conduction band and the vacuum level on the side of the first semiconductor layer in the first protective layer is greater than the difference between the energy level at the bottom of the conduction band and the vacuum level on the side of the first protective layer in the first semiconductor layer.

[0367] A light detection device described in any one of (1) to (16) above.

[0368] (18)

[0369] A second protective layer comprising an inorganic material is further provided between the first protective layer and the first semiconductor layer.

[0370] The difference between the energy level at the bottom of the conduction band of the second protective layer and the vacuum level is smaller than the difference between the energy level at the bottom of the conduction band of the first semiconductor layer and the vacuum level.

[0371] The light detection device described in (17) above.

[0372] (19)

[0373] The thickness of the second protective layer is 5 nm or less.

[0374] The light detection device described in (18) above.

[0375] (20)

[0376] The first protective layer and the second protective layer are each layers comprising at least one of Ti, Si, Zr, Nb, V, Ta, Hf, Al, Sn, Sc, Y, La, Ga, and Mg.

[0377] The light detection device described in (18) or (19) above.

[0378] (21)

[0379] The thickness of the first semiconductor layer is 10 nm or less.

[0380] A light detection device described in any one of (1) to (20) above.

[0381] (22)

[0382] A third electrode is further provided around the second electrode in a direction orthogonal to the thickness direction of the second semiconductor layer, and

[0383] The first semiconductor layer is arranged to overlap the second electrode among the second electrode and the third electrode when viewed in a planar view.

[0384] A light detection device described in any one of (1) to (21) above.

[0385] (23)

[0386] The band gap in the first semiconductor layer is smaller than the band gap in the second semiconductor layer.

[0387] A light detection device described in any one of (1) to (22) above.

[0388] (24)

[0389] The energy level at the bottom of the conduction band in the above photoelectric conversion film is greater than the energy level at the bottom of the conduction band in the above first semiconductor layer, and

[0390] The energy level at the bottom of the conduction band in the first semiconductor layer is greater than the energy level at the bottom of the conduction band in the second semiconductor layer.

[0391] The light detection device described in (23) above.

[0392] (25)

[0393] A protective layer comprising an inorganic material is further provided between the photoelectric conversion film and the first semiconductor layer.

[0394] The energy level at the upper end of the valence band in the above protective layer is greater than the energy level at the upper end of the valence band in the above first semiconductor layer.

[0395] The light detection device described in (23) or (24) above.

[0396] (26)

[0397] Optical system and,

[0398] A light detection device that receives light transmitted through the above optical system

[0399] Equipped,

[0400] The above light detection device is,

[0401] The first electrode and,

[0402] A second electrode provided to face the first electrode, and

[0403] A photoelectric conversion film provided between the first electrode and the second electrode, and

[0404] A first semiconductor layer provided between the photoelectric conversion film and the second electrode, and

[0405] A second semiconductor layer provided between the first semiconductor layer and the second electrode

[0406] Have,

[0407] The difference between the energy level at the bottom of the conduction band and the Fermi level in the first semiconductor layer is smaller than the difference between the energy level at the bottom of the conduction band and the Fermi level in the second semiconductor layer.

[0408] Electronic devices.

[0409] (27)

[0410] The first electrode and,

[0411] A second electrode provided to face the first electrode, and

[0412] A photoelectric conversion film provided between the first electrode and the second electrode, and

[0413] A first semiconductor layer provided between the photoelectric conversion film and the second electrode, and

[0414] A second semiconductor layer provided between the first semiconductor layer and the second electrode

[0415] Equipped,

[0416] The carrier concentration in the first semiconductor layer is higher than the carrier concentration in the second semiconductor layer.

[0417] Light detection device.

[0418] (28)

[0419] The first semiconductor layer is a semiconductor layer including an oxide semiconductor,

[0420] The light detection device described in (27) above.

[0421] (29)

[0422] The second semiconductor layer is a semiconductor layer comprising an oxide semiconductor,

[0423] The light detection device described in (27) or (28) above.

[0424] (30)

[0425] The carrier concentration of the first semiconductor layer is 1×10 18 cm -3 Lee Sang-in,

[0426] A light detection device described in any one of (27) to (29) above.

[0427] (31)

[0428] The carrier concentration of the second semiconductor layer is 1×10 18 cm -3 Less than,

[0429] A light detection device described in any one of (27) to (30) above.

[0430] (32)

[0431] The first semiconductor layer and the second semiconductor layer are each oxide semiconductor layers comprising at least one of In, Ga, Zn, Ti, Sn, Si, Cu, Sb, and Cd.

[0432] A light detection device described in any one of (27) to (31) above.

[0433] (33)

[0434] The first semiconductor layer and the second semiconductor layer are each oxide semiconductor layers containing In,

[0435] The composition ratio of In in the first semiconductor layer is greater than the composition ratio of In in the second semiconductor layer.

[0436] A light detection device described in any one of (27) to (32) above.

[0437] (34)

[0438] The first semiconductor layer and the second semiconductor layer are each oxide semiconductor layers containing Zn, and

[0439] The composition ratio of Zn in the first semiconductor layer is greater than the composition ratio of Zn in the second semiconductor layer.

[0440] A light detection device described in any one of (27) to (33) above.

[0441] (35)

[0442] The first semiconductor layer and the second semiconductor layer are each semiconductor layers comprising an oxide semiconductor, and

[0443] The constituent elements of the first semiconductor layer and the constituent elements of the second semiconductor layer are different from each other.

[0444] A light detection device described in any one of (27) to (34) above.

[0445] (36)

[0446] The first semiconductor layer comprises an element different from the constituent element of the second semiconductor layer.

[0447] A light detection device described in any one of (27) to (35) above.

[0448] (37)

[0449] A protective layer comprising an inorganic material, provided between the photoelectric conversion film and the first semiconductor layer.

[0450] A light detection device described in any one of (27) to (36) above.

[0451] (38)

[0452] The above protective layer is a layer comprising at least one of Ti, Si, Zr, Nb, V, Ta, Hf, Al, Sn, Sc, Y, La, Ga, and Mg,

[0453] The light detection device described in (37) above.

[0454] (39)

[0455] The difference between the energy level at the bottom of the conduction band of the protective layer and the vacuum level is smaller than the difference between the energy level at the bottom of the conduction band of the first semiconductor layer and the vacuum level.

[0456] The light detection device described in (37) or (38) above.

[0457] (40)

[0458] The thickness of the above protective layer is 5 nm or less,

[0459] A light detection device described in any one of (37) to (39) above.

[0460] (41)

[0461] The first semiconductor layer comprises cations constituting the protective layer,

[0462] A light detection device described in any one of (37) to (40) above.

[0463] (42)

[0464] The difference between the energy level at the bottom of the conduction band and the vacuum level on the side of the first semiconductor layer in the above photoelectric conversion film is greater than the difference between the energy level at the bottom of the conduction band and the vacuum level on the side of the first semiconductor layer.

[0465] A light detection device described in any one of (27) to (41) above.

[0466] (43)

[0467] A first protective layer comprising an inorganic material is further provided between the photoelectric conversion film and the first semiconductor layer.

[0468] The difference between the energy level at the bottom of the conduction band and the vacuum level on the side of the first semiconductor layer in the first protective layer is greater than the difference between the energy level at the bottom of the conduction band and the vacuum level on the side of the first protective layer in the first semiconductor layer.

[0469] A light detection device described in any one of (27) to (42) above.

[0470] (44)

[0471] A second protective layer comprising an inorganic material is further provided between the first protective layer and the first semiconductor layer.

[0472] The difference between the energy level at the bottom of the conduction band of the second protective layer and the vacuum level is smaller than the difference between the energy level at the bottom of the conduction band of the first semiconductor layer and the vacuum level.

[0473] The light detection device described in (43) above.

[0474] (45)

[0475] The thickness of the second protective layer is 5 nm or less.

[0476] The light detection device described in (44) above.

[0477] (46)

[0478] The first protective layer and the second protective layer are each layers comprising at least one of Ti, Si, Zr, Nb, V, Ta, Hf, Al, Sn, Sc, Y, La, Ga, and Mg.

[0479] The light detection device described in (44) or (45) above.

[0480] (47)

[0481] The thickness of the first semiconductor layer is 10 nm or less.

[0482] A light detection device described in any one of (27) to (46) above.

[0483] (48)

[0484] A third electrode is further provided around the second electrode in a direction orthogonal to the thickness direction of the second semiconductor layer, and

[0485] The first semiconductor layer is arranged to overlap the second electrode among the second electrode and the third electrode when viewed in a planar view.

[0486] A light detection device described in any one of (27) to (47) above.

[0487] (49)

[0488] The band gap in the first semiconductor layer is smaller than the band gap in the second semiconductor layer.

[0489] A light detection device described in any one of (27) to (48) above.

[0490] (50)

[0491] The energy level at the bottom of the conduction band in the above photoelectric conversion film is greater than the energy level at the bottom of the conduction band in the above first semiconductor layer, and

[0492] The energy level at the bottom of the conduction band in the first semiconductor layer is greater than the energy level at the bottom of the conduction band in the second semiconductor layer.

[0493] The light detection device described in (49) above.

[0494] (51)

[0495] A protective layer comprising an inorganic material is further provided between the photoelectric conversion film and the first semiconductor layer.

[0496] The energy level at the upper end of the valence band in the above protective layer is greater than the energy level at the upper end of the valence band in the above first semiconductor layer.

[0497] The light detection device described in (49) or (50) above.

[0498] (52)

[0499] Optical system and,

[0500] A light detection device that receives light transmitted through the above optical system

[0501] Equipped,

[0502] The above light detection device is,

[0503] The first electrode and,

[0504] A second electrode provided to face the first electrode, and

[0505] A photoelectric conversion film provided between the first electrode and the second electrode, and

[0506] A first semiconductor layer provided between the photoelectric conversion film and the second electrode, and

[0507] A second semiconductor layer provided between the first semiconductor layer and the second electrode

[0508] Have,

[0509] The carrier concentration in the first semiconductor layer is higher than the carrier concentration in the second semiconductor layer.

[0510] Electronic devices.

[0511] This application claims priority based on Japanese Patent Application No. 2023-210156 filed with the Japan Patent Office on December 13, 2023, and incorporates all contents of this application by reference.

[0512] A person skilled in the art may make various modifications, combinations, sub-combinations, and changes depending on design requirements or other factors, but it is understood that these are included within the scope of the appended claims or their equivalents.

Claims

Claim 1 A light detection device comprising a first electrode, a second electrode arranged opposite to the first electrode, a photoelectric conversion film arranged between the first electrode and the second electrode, a first semiconductor layer arranged between the photoelectric conversion film and the second electrode, and a second semiconductor layer arranged between the first semiconductor layer and the second electrode, wherein the difference between the energy level at the bottom of the conduction band and the Fermi level in the first semiconductor layer is smaller than the difference between the energy level at the bottom of the conduction band and the Fermi level in the second semiconductor layer. Claim 2 A light detection device according to claim 1, wherein the first semiconductor layer is a semiconductor layer comprising an oxide semiconductor. Claim 3 In paragraph 2, the second semiconductor layer is a semiconductor layer comprising an oxide semiconductor, in a light detection device. Claim 4 A photodetector according to claim 1, wherein the first semiconductor layer and the second semiconductor layer are each oxide semiconductor layers comprising at least one of In, Ga, Zn, Ti, Sn, Si, Cu, Sb, and Cd. Claim 5 A light detection device according to claim 1, wherein the first semiconductor layer and the second semiconductor layer are each oxide semiconductor layers containing In, and the composition ratio of In in the first semiconductor layer is greater than the composition ratio of In in the second semiconductor layer. Claim 6 A light detection device according to claim 1, wherein the first semiconductor layer and the second semiconductor layer are each oxide semiconductor layers containing Zn, and the composition ratio of Zn in the first semiconductor layer is greater than the composition ratio of Zn in the second semiconductor layer. Claim 7 A light detection device according to claim 1, wherein the first semiconductor layer and the second semiconductor layer are each semiconductor layers comprising an oxide semiconductor, and the constituent elements of the first semiconductor layer and the constituent elements of the second semiconductor layer are different. Claim 8 A light detection device according to claim 1, wherein the first semiconductor layer comprises an element different from the constituent element of the second semiconductor layer. Claim 9 A photodetector according to claim 1, wherein the difference between the energy level at the bottom of the conduction band and the Fermi level in the second semiconductor layer is at least 0.02 eV greater than the difference between the energy level at the bottom of the conduction band and the Fermi level in the first semiconductor layer. Claim 10 A light detection device according to claim 1, wherein the difference between the energy level at the bottom of the conduction band and the vacuum level in the first semiconductor layer is greater than the difference between the energy level at the bottom of the conduction band and the vacuum level in the second semiconductor layer. Claim 11 A light detection device according to claim 1, further comprising a protective layer including an inorganic material provided between the photoelectric conversion film and the first semiconductor layer. Claim 12 A light detection device according to claim 11, wherein the protective layer is a layer comprising at least one of Ti, Si, Zr, Nb, V, Ta, Hf, Al, Sn, Sc, Y, La, Ga, and Mg. Claim 13 A photodetector according to claim 11, wherein the difference between the energy level at the bottom of the conduction band of the protective layer and the vacuum level is smaller than the difference between the energy level at the bottom of the conduction band of the first semiconductor layer and the vacuum level. Claim 14 A light detection device according to claim 11, wherein the thickness of the protective layer is 5 nm or less. Claim 15 In claim 11, the first semiconductor layer comprises a cation constituting the protective layer, in a light detection device. Claim 16 A photodetector according to claim 1, wherein the difference between the energy level at the bottom of the conduction band on the side of the first semiconductor layer in the photoelectric conversion film and the vacuum level is greater than the difference between the energy level at the bottom of the conduction band on the side of the first semiconductor layer and the vacuum level. Claim 17 A photodetector according to claim 1, further comprising a first protective layer including an inorganic material provided between the photoelectric conversion film and the first semiconductor layer, wherein the difference between the energy level at the bottom of the conduction band on the side of the first semiconductor layer in the first protective layer and the vacuum level is greater than the difference between the energy level at the bottom of the conduction band on the side of the first protective layer in the first semiconductor layer and the vacuum level. Claim 18 A light detection device according to claim 17, further comprising a second protective layer containing an inorganic material provided between the first protective layer and the first semiconductor layer, wherein the difference between the energy level at the bottom of the conduction band of the second protective layer and the vacuum level is smaller than the difference between the energy level at the bottom of the conduction band of the first semiconductor layer and the vacuum level. Claim 19 A light detection device according to claim 18, wherein the thickness of the second protective layer is 5 nm or less. Claim 20 A light detection device according to claim 18, wherein the first protective layer and the second protective layer are each layers comprising at least one of Ti, Si, Zr, Nb, V, Ta, Hf, Al, Sn, Sc, Y, La, Ga, and Mg. Claim 21 A light detection device according to claim 1, wherein the thickness of the first semiconductor layer is 10 nm or less. Claim 22 A light detection device according to claim 1, further comprising a third electrode provided around the second electrode in a direction orthogonal to the thickness direction of the second semiconductor layer, wherein the first semiconductor layer is provided to overlap the second electrode among the second electrode and the third electrode when viewed in a planar view. Claim 23 A light detection device according to claim 1, wherein the band gap in the first semiconductor layer is smaller than the band gap in the second semiconductor layer. Claim 24 A photodetector according to claim 23, wherein the energy level of the lower conduction band in the photoelectric conversion film is greater than the energy level of the lower conduction band in the first semiconductor layer, and the energy level of the lower conduction band in the first semiconductor layer is greater than the energy level of the lower conduction band in the second semiconductor layer. Claim 25 A photodetector according to claim 23, further comprising a protective layer containing an inorganic material provided between the photoelectric conversion film and the first semiconductor layer, wherein the energy level of the upper valence band in the protective layer is greater than the energy level of the upper valence band in the first semiconductor layer. Claim 26 An electronic device comprising an optical system and a light detection device for receiving light transmitted through the optical system, wherein the light detection device comprises a first electrode, a second electrode arranged opposite to the first electrode, a photoelectric conversion film arranged between the first electrode and the second electrode, a first semiconductor layer arranged between the photoelectric conversion film and the second electrode, and a second semiconductor layer arranged between the first semiconductor layer and the second electrode, wherein the difference between the energy level at the bottom of the conduction band and the Fermi level in the first semiconductor layer is smaller than the difference between the energy level at the bottom of the conduction band and the Fermi level in the second semiconductor layer.

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