Light detection device and electronic equipment

Abstract

A light detection device according to one embodiment of the present disclosure comprises: a semiconductor substrate having a first surface and a second surface that face each other; a first photoelectric conversion unit that is disposed on the first surface side and converts light into an electric charge; first through wiring that passes between the first surface and second surface of the semiconductor substrate and transfers the electric charge; a first well region that is provided so as to span the entire surface of the semiconductor substrate and is of a first conductivity type; a second well region that is provided so as to surround the first through wiring and is of the first conductivity type; and a third well region that is provided between the first well region and the second well region, electrically separates the first well region and the second well region, and is of a second conductivity type different from the first conductivity type.

Description

Photodetector and electronic equipment

[0001] This disclosure relates to an optical detection device and an electronic device equipped therewith.

[0002] For example, Patent Document 1 discloses a solid-state image sensor in which a photoelectric conversion element is formed on one of the front and back surfaces of a semiconductor substrate, and a through-electrode is provided that penetrates the semiconductor substrate for transferring the charge converted by the photoelectric conversion of the photoelectric conversion element to the other of the front and back surfaces of the semiconductor substrate.

[0003] Japanese Patent Publication No. 2020-174188

[0004] By the way, there is a demand for improved image quality in light detection devices, which are also used as imaging devices.

[0005] It is desirable to provide light detection devices and electronic equipment capable of improving image quality.

[0006] An optical detection device according to one embodiment of the present disclosure comprises a semiconductor substrate having opposing first and second surfaces, a first photoelectric conversion unit disposed on the first surface side and converting light into electric charge, a first through-wiring that penetrates between the first and second surfaces of the semiconductor substrate and transfers electric charge, a first well region having a first conductivity type provided over the entire surface of the semiconductor substrate, a second well region having a first conductivity type provided around the first through-wiring, and a third well region having a second conductivity type different from the first conductivity type, provided between the first and second well regions and electrically separating the first and second well regions.

[0007] An electronic device according to one embodiment of the present disclosure is equipped with the optical detection device according to the present disclosure described above.

[0008] In one embodiment of the present disclosure, a photodetector and an electronic device have a first through-wiring that penetrates a semiconductor substrate having opposing first and second surfaces and transfers the charge generated by photoelectric conversion in a first photoelectric conversion unit provided on the first surface side to the second surface side of the semiconductor substrate. The semiconductor substrate has a first well region having a first conductivity type provided over its entire surface, a second well region having a first conductivity type provided around the first through-wiring, and a third well region having a second conductivity type different from the first conductivity type, provided between the first and second well regions and electrically separating the first and second well regions. This shields the dark current generated between the first through-wiring and the semiconductor substrate.

[0009] Figure 1 is a schematic cross-sectional view showing an example of the configuration of a photodetector according to an embodiment of the present disclosure. Figure 2 is a block diagram showing the overall configuration of the photodetector shown in Figure 1. Figure 3 is an equivalent circuit diagram of a unit pixel constituting the photodetector shown in Figure 2. Figure 4 is a schematic diagram showing the arrangement of the lower electrode of a unit pixel constituting the photodetector shown in Figure 2 and the transistors constituting the control unit. Figure 5 is a diagram illustrating the configuration around the through-wiring of the photodetector shown in Figure 1. Figure 6 is a schematic plan view corresponding to Sec1 shown in Figure 5. Figure 7 is a schematic plan view showing an example of the configuration in the pixel array section of the photodetector shown in Figure 1. Figure 8 is a cross-sectional view for explaining the manufacturing method of the photodetector shown in Figure 1. Figure 9 is a cross-sectional view showing the process following Figure 8. Figure 10 is a cross-sectional view showing the process following Figure 9. Figure 11 is a cross-sectional view showing the process following Figure 10. Figure 12 is a cross-sectional view showing the process following Figure 11. Figure 13 is a cross-sectional view showing the process following Figure 12. Figure 14 is a timing diagram showing an example of operation of the photodetector shown in Figure 1. Figure 15 is a schematic cross-sectional diagram showing the schematic configuration of an imaging device as Comparative Example 1 of the present disclosure. Figure 16 is a schematic cross-sectional diagram showing the schematic configuration of an imaging device as Comparative Example 2 of the present disclosure. Figure 17 is a schematic cross-sectional diagram showing an example of the schematic configuration of a photodetector according to Modification 1 of the present disclosure. Figure 18 is a schematic cross-sectional diagram showing another example of the schematic configuration of a photodetector according to Modification 1 of the present disclosure. Figure 19 is a schematic plan view showing an example of the configuration of the pixel array section of a photodetector according to Modification 2 of the present disclosure. Figure 20 is a schematic plan view showing an example of the configuration of the pixel array section of a photodetector according to Modification 3 of the present disclosure. Figure 21A is a schematic cross-sectional diagram showing an example of the configuration of a photodetector according to Another Modification 1 of the present disclosure. Figure 21B is a schematic plan view showing an example of the pixel configuration of a photodetector having the photodetector shown in Figure 21A. Figure 22A is a schematic cross-sectional diagram showing another example of the configuration of a photodetector according to Another Modification 2 of the present disclosure. Figure 22B is a schematic plan view showing an example of the pixel configuration of a photodetector having the photodetector shown in Figure 22A. Figure 23 is a schematic cross-sectional view showing another example of the configuration of a photodetector according to modification 3 of the present disclosure. Figure 24 schematically shows another example of the configuration of a photodetector according to modification 4 of the present disclosure.Figure 25A is a schematic cross-sectional view showing another example of the configuration of a photodetector according to another modification 5 of the present disclosure. Figure 25B is a schematic plan view showing an example of the pixel configuration of a photodetector having the photodetector shown in Figure 25A. Figure 26A is a schematic cross-sectional view showing another example of the configuration of a photodetector according to another modification 6 of the present disclosure. Figure 26B is a schematic plan view showing an example of the pixel configuration of a photodetector having the photodetector shown in Figure 26A. Figure 27 is a schematic cross-sectional view showing another example of the configuration of a photodetector according to another modification 7 of the present disclosure. Figure 28 is a block diagram showing an example of the configuration of an electronic device using the photodetector shown in Figure 1, etc. Figure 29A is a schematic diagram showing an example of the overall configuration of a photodetector system using the photodetector shown in Figure 2. Figure 29B is a diagram showing an example of the circuit configuration of the photodetector system shown in Figure 29A. Figure 30 is a diagram showing an example of the schematic configuration of an endoscopic surgical system. Figure 31 is a block diagram showing an example of the functional configuration of a camera head and a CCU. Figure 32 is a block diagram showing an example of the schematic configuration of a vehicle control system. Figure 33 is an explanatory diagram showing an example of the installation location of the external information detection unit and the imaging unit.

[0010] The embodiments of this disclosure will be described in detail below with reference to the drawings. The following description is one specific example of this disclosure, and this disclosure is not limited to the following embodiments. Furthermore, this disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc. of each component shown in each figure. The order of description is as follows: 1. Embodiment (An example of an electrically isolated photodetector in which an n-well region is provided around the through-wiring, and a p-well region provided over the entire surface of the semiconductor substrate is separated into a region surrounding the through-wiring inside the n-well region and a region outside the n-well region) 2. Modifications 2-1. Modification 1 (Another example of the configuration of the photodetector) 2-2. Modification 2 (Another example of the configuration of the photodetector) 2-3. Modification 3 (Another example of the configuration of the photodetector) 3. Other Modifications 3-1. Other Modification 1 (Another example of the configuration of the photodetector) 3-2. Other Modification 2 (Another example of the configuration of the photodetector) 3-3. Other Modification 3 (Another example of the configuration of the photodetector) 3-4. Other variations 4-7 (other examples of the configuration of the photodetector) 4. Application examples 5. Application examples

[0011] <1. Embodiment> Figure 1 schematically shows an example of a cross-sectional configuration of a photodetector (photodetector 1) according to one embodiment of the present disclosure. The photodetector 1 is an imaging device such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor used in electronic devices such as digital still cameras and video cameras. Figure 1 shows the configuration of a single pixel (unit pixel P) that is repeatedly arranged in a two-dimensional array in the pixel array section 100A (see Figure 2) of the photodetector 1.

[0012] The photodetector 1 of this embodiment includes a semiconductor substrate 30 having opposing first surfaces 30A and second surfaces 30B, a photoelectric conversion unit 10 disposed on the first surface 30A side of the semiconductor substrate 30, and through-wiring 34 penetrating between the first surface 30A and the second surface 30B of the semiconductor substrate 30. The semiconductor substrate 30 has a p-well region 31A provided over its entire surface, a p-well region 31B provided around the through-wiring 34, and an n-well region 31C that electrically separates the p-well region 31A and the p-well region 31B.

[0013] Here, the semiconductor substrate 30 corresponds to a specific example of the "semiconductor substrate" in one embodiment of the present disclosure. The through-wiring 34 corresponds to a specific example of the "first through-wiring" in one embodiment of the present disclosure. The p-well region 31A corresponds to a specific example of the "first well region" in one embodiment of the present disclosure. The p-well region 31B corresponds to a specific example of the "second well region" in one embodiment of the present disclosure. The n-well region 31C corresponds to a specific example of the "third well region" in one embodiment of the present disclosure.

[0014] [Overall Configuration of the Photodetection Device] FIG. 2 shows an example of the overall configuration of the photodetection device 1.

[0015] The photodetection device 1 is, for example, a CMOS image sensor, which takes in incident light (image light) from a subject through an optical lens system (not shown) and converts the amount of incident light imaged on the imaging surface into an electrical signal in pixel units and outputs it as a pixel signal. The photodetection device 1 has a pixel array unit 100A as an imaging area on the semiconductor substrate 30, and in the peripheral area of this pixel array unit 100A, for example, a vertical drive circuit 111, a column signal processing circuit 112, a horizontal drive circuit 113, an output circuit 114, a control circuit 115, and input / output terminals 116.

[0016] The pixel array unit 100A has, for example, a plurality of unit pixels P two-dimensionally arranged in a matrix. Pixel drive lines Lread (specifically, row selection lines and reset control lines) are wired for each pixel row in this unit pixel P, and vertical signal lines Lsig are wired for each pixel column. The pixel drive line Lread transmits a drive signal for signal readout from the pixel. One end of the pixel drive line Lread is connected to the output end corresponding to each row of the vertical drive circuit 111.

[0017] The vertical drive circuit 111 is a pixel drive unit composed of a shift register, an address decoder, etc., which drives each unit pixel P of the pixel array section 100A, for example, in row units. The signals output from each unit pixel P of the pixel row selected and scanned by the vertical drive circuit 111 are supplied to the column signal processing circuit 112 through each of the vertical signal lines Lsig. The column signal processing circuit 112 is composed of amplifiers, horizontal selection switches, etc., provided for each vertical signal line Lsig.

[0018] The horizontal drive circuit 113 is composed of a shift register, an address decoder, etc., and sequentially drives each horizontal selection switch of the column signal processing circuit 112 while scanning it. Through this selection scanning by the horizontal drive circuit 113, the signals of each pixel transmitted through each of the vertical signal lines Lsig are sequentially output to the horizontal signal line 121 and transmitted to the outside of the semiconductor substrate 30 through the horizontal signal line 121.

[0019] The output circuit 114 processes the signals sequentially supplied from each of the column signal processing circuits 112 via the horizontal signal line 121 and outputs them. The output circuit 114 may, for example, only perform buffering, or it may perform black level adjustment, column variation correction, and various digital signal processing.

[0020] The circuit portion consisting of the vertical drive circuit 111, column signal processing circuit 112, horizontal drive circuit 113, horizontal signal line 121, and output circuit 114 may be formed directly on the semiconductor substrate 30, or it may be arranged on an external control IC. Alternatively, these circuit portions may be formed on other substrates connected by cables or the like.

[0021] The control circuit 115 receives a clock signal and data commanding the operating mode from outside the semiconductor substrate 30, and outputs data such as internal information of the photodetector 1. The control circuit 115 also has a timing generator that generates various timing signals, and controls the drive of peripheral circuits such as the vertical drive circuit 111, the column signal processing circuit 112, and the horizontal drive circuit 113 based on the various timing signals generated by the timing generator.

[0022] The input / output terminal 116 is used for exchanging signals with the outside.

[0023] [Circuit Configuration of Unit Pixel] Figure 3 is an equivalent circuit diagram of the photodetector 1 shown in Figure 1. Figure 4 schematically shows the arrangement of transistors constituting the lower electrode 11 and control unit of the photodetector 1 shown in Figure 1. The photodetector 1 has one photoelectric conversion unit 10 and two photoelectric conversion regions 32B and 32R, each with different detection wavelengths. Readout circuits that output pixel signals based on the output charge are connected to the one photoelectric conversion unit 10 and the two photoelectric conversion regions 32B and 32R, respectively, and the readout circuits are provided on the second surface 30B side of the semiconductor substrate 30.

[0024] The reset transistor RST1 is for resetting the charge transferred from the photoelectric conversion unit 10 to the floating diffusion FD1, and is composed of, for example, a MOS transistor. Specifically, the reset transistor RST1 consists of a reset gate Grst, a channel formation region 36A, and source / drain regions 36B and 36C. The reset gate Grst is connected to the reset line RSTL1, and one of the source / drain regions 36B of the reset transistor RST1 also serves as the floating diffusion FD1. The other source / drain region 36C of the reset transistor RST1 is connected to the power line VDD.

[0025] The amplifier transistor AMP1 is a modulation element that modulates the amount of charge generated in the photoelectric conversion unit 10 into a voltage, and is composed of, for example, a MOS transistor. Specifically, the amplifier transistor AMP consists of a gate Gamp, a channel formation region 35A, and source / drain regions 35B and 35C. The gate Gamp is connected to the read electrode 11A and one of the source / drain regions 36B (floating diffusion FD1) of the reset transistor RST1 via a lower first contact 45, a connection portion 41A, a lower second contact 46, and through wiring 34, etc. Furthermore, one of the source / drain regions 35B shares a region with the other source / drain region 36C that constitutes the reset transistor RST1 and is connected to the power line VDD.

[0026] The selection transistor SEL1 consists of a gate Gsel, a channel formation region 34A, and source / drain regions 34B and 34C. The gate Gsel is connected to the selection line SELL1. One source / drain region 34B shares a region with the other source / drain region 35C that constitutes the amplifier transistor AMP, and the other source / drain region 34C is connected to the signal line (data output line) VSL1.

[0027] The transfer transistor TR2 is for transferring the blue signal charge generated and accumulated in the photoelectric conversion region 32B to the floating diffusion FD2. Since the photoelectric conversion region 32B is formed deep from the second surface 30B of the semiconductor substrate 30, it is preferable that the transfer transistor TR2 in the photoelectric conversion region 32B is a vertical transistor. The transfer transistor TR2 is connected to the transfer gate line TGL2. A floating diffusion FD2 is provided in the region 37C near the gate Gtrs2 of the transfer transistor TR2. The charge accumulated in the photoelectric conversion region 32B is read out to the floating diffusion FD2 via a transfer channel formed along the gate Gtrs2.

[0028] The transfer transistor TR3 is for transferring the signal charge corresponding to the red color, which is generated and accumulated in the photoelectric conversion region 32R, to the floating diffusion FD3, and is composed of, for example, a MOS transistor. The transfer transistor TR3 is connected to the transfer gate line TGL3. A floating diffusion FD3 is provided in the region 38C near the gate Gtrs3 of the transfer transistor TR3. The charge accumulated in the photoelectric conversion region 32R is read out to the floating diffusion FD3 via a transfer channel formed along the gate Gtrs3.

[0029] On the second surface 30B side of the semiconductor substrate 30, a reset transistor RST2, an amplifier transistor AMP2, and a selection transistor SEL2 are provided, which constitute the control unit of the photoelectric conversion region 32B. Furthermore, a reset transistor RST3, an amplifier transistor AMP3, and a selection transistor SEL3 are provided, which constitute the control unit of the photoelectric conversion region 32R.

[0030] The reset transistor RST2 consists of a gate, a channel formation region, and a source / drain region. The gate of the reset transistor RST2 is connected to the reset line RSTL2, and one of the source / drain regions of the reset transistor RST2 is connected to the power line VDD. The other source / drain region of the reset transistor RST2 also serves as the floating diffusion FD2.

[0031] The amplifier transistor AMP2 consists of a gate, a channel formation region, and a source / drain region. The gate is connected to the other source / drain region (floating diffusion FD2) of the reset transistor RST2. One source / drain region of the amplifier transistor AMP2 shares a region with the other source / drain region of the reset transistor RST2 and is connected to the power line VDD.

[0032] The selection transistor SEL2 consists of a gate, a channel formation region, and a source / drain region. The gate is connected to the selection line SELL2. One source / drain region of the selection transistor SEL2 shares a region with the other source / drain region of the amplifier transistor AMP2. The other source / drain region of the selection transistor SEL2 is connected to the signal line (data output line) VSL2.

[0033] The reset transistor RST3 consists of a gate, a channel formation region, and a source / drain region. The gate of the reset transistor RST3 is connected to the reset line RSTL3, and one of the source / drain regions constituting the reset transistor RST3 is connected to the power line VDD. The other source / drain region constituting the reset transistor RST3 also serves as the floating diffusion FD3.

[0034] The amplifier transistor AMP3 consists of a gate, a channel formation region, and a source / drain region. The gate is connected to the other source / drain region (floating diffusion FD3) that constitutes the reset transistor RST3. One source / drain region of the amplifier transistor AMP3 shares a region with the other source / drain region of the reset transistor RST3 and is connected to the power line VDD.

[0035] The selection transistor SEL3 consists of a gate, a channel formation region, and a source / drain region. The gate is connected to the selection line SELL3. One source / drain region of the selection transistor SEL3 shares a region with the other source / drain region of the amplifier transistor AMP3. The other source / drain region of the selection transistor SEL3 is connected to the signal line (data output line) VSL3.

[0036] The reset lines RSTL1, RSTL2, RSTL3, the selection lines SELL1, SELL2, SELL3, and the transfer gate lines TGL2, TGL3 are each connected to the vertical drive circuits that constitute the drive circuit. The signal lines (data output lines) VSL1, VSL2, VSL3 are connected to the column signal processing circuit 112 that constitutes the drive circuit.

[0037] [Cross-sectional configuration of the photodetector] The photodetector 1 is a so-called vertical spectral imaging device in which, for example, one photoelectric conversion unit 10 and two photoelectric conversion regions 32B and 32R are stacked in the vertical direction. The photoelectric conversion unit 10 is provided on the back side (first surface 30A) of the semiconductor substrate 30. The photoelectric conversion regions 32B and 32R are embedded and formed within the semiconductor substrate 30 and are stacked in the thickness direction of the semiconductor substrate 30.

[0038] The photoelectric conversion unit 10 and the photoelectric conversion regions 32B and 32R selectively detect light in different wavelength ranges and perform photoelectric conversion. For example, the photoelectric conversion unit 10 acquires a green (G) color signal. The photoelectric conversion regions 32B and 32R acquire blue (B) and red (R) color signals, respectively, due to differences in absorption coefficients. As a result, the light detection device 1 can acquire multiple types of color signals in a single pixel without using a color filter.

[0039] In this embodiment, we will describe the case where the electron is read out as the signal charge from the electron-hole pair (exciton) generated by photoelectric conversion (when the n-type semiconductor region is used as the photoelectric conversion layer). In the figure, the "+" (plus) sign attached to "p" and "n" indicates a high concentration of p-type or n-type impurities.

[0040] The semiconductor substrate 30 is made of, for example, an n-type silicon (Si) substrate. The surface (second surface 30B) of the semiconductor substrate 30 is provided with, for example, a floating diffusion FD1 (region 36B within the semiconductor substrate 30), FD2 (region 37C within the semiconductor substrate 30), FD3 (region 38C within the semiconductor substrate 30), transfer transistors Tr2 and Tr3, an amplifier transistor (modulation element) AMP, a reset transistor RST, and a selection transistor SEL. The second surface 30B of the semiconductor substrate 30 is further provided with a multilayer wiring layer 40 via a gate insulating layer 33. The multilayer wiring layer 40 has a configuration in which, for example, wiring layers 41, 42, and 43 are stacked within an insulating layer 44. The peripheral part of the semiconductor substrate 30, that is, around the pixel array section 100A, is provided with the vertical drive circuit 111, column signal processing circuit 112, horizontal drive circuit 113, output circuit 114, control circuit 115, and input / output terminals 116, etc.

[0041] Between the back surface (first surface 30A) of the semiconductor substrate 30 and the photoelectric conversion unit 10, for example, a fixed charge layer (fixed charge layer 21) and an interlayer insulating layer 22 are laminated in this order from the first surface 30A side of the semiconductor substrate 30. A through-wiring 34 is provided between the first surface 30A and the second surface 30B of the semiconductor substrate 30. The semiconductor substrate 30 further has a p-well region 31A provided over its entire surface, a p-well region 31B provided around the through-wiring 34, and an n-well region 31C that electrically separates the p-well region 31A and the p-well region 31B. Details of the through-wiring 34 and the p-well regions 31A, 31B, and n-well region 31C around it will be described later.

[0042] Above the photoelectric conversion unit 10, optical components such as an on-chip lens 52 are arranged with a protective layer 51 in between. Within the protective layer 51, for example, wiring 53 is provided to electrically connect the upper electrode 15 and the peripheral circuit section around the pixel array section 100A.

[0043] In the drawing, the first surface 30A of the semiconductor substrate 30 is shown as the light incident side S1, and the second surface 30B is shown as the wiring layer side S2.

[0044] In the photodetector 1, light incident on the photoelectric conversion unit 10 from the light incident side S1 is absorbed by the photoelectric conversion layer 14. The excitons generated by this process move to the interface between the electron donor and electron acceptor constituting the photoelectric conversion layer 14, where they undergo exciton separation, i.e., dissociation into electrons and holes. The charges (electrons and holes) generated here are transported to different electrodes by diffusion due to the carrier concentration difference and by the internal electric field due to the difference in work functions between the anode (e.g., upper electrode 15) and cathode (e.g., lower electrode 11), and are detected as a photocurrent. Furthermore, the transport direction of electrons and holes can also be controlled by applying a potential between the lower electrode 11 and the upper electrode 15.

[0045] The following provides a detailed explanation of the composition and materials of each part.

[0046] The photoelectric conversion unit 10 is an organic photoelectric conversion element that absorbs, for example, green light, corresponding to a part or all of a selective wavelength range (for example, 450 nm to 650 nm), and generates excitons. The photoelectric conversion unit 10 is constructed by stacking a lower electrode 11, an insulating layer 12, an oxide semiconductor layer 13, a photoelectric conversion layer 14, and an upper electrode 15 in order from the semiconductor substrate 30 side. The photoelectric conversion layer 14 is composed of, for example, a p-type semiconductor and an n-type semiconductor, and has a bulk heterojunction structure within the layer. The bulk heterojunction structure is a p / n junction surface formed by the mixing of p-type semiconductors and n-type semiconductors.

[0047] The lower electrode 11 includes, for example, a read electrode 11A and a storage electrode 11B arranged in parallel on the interlayer insulating layer 22.

[0048] The readout electrode 11A is for transferring, for example, electrons as signal charges from the charge generated in the photoelectric conversion layer 14 to the floating diffusion FD1. The readout electrode 11A is connected to the floating diffusion FD1 via, for example, an upper second contact 26A, a pad portion 25A, an upper first contact 24, a pad portion 23, a through-wiring 34, a connection portion 41A, and a lower second contact 46.

[0049] The storage electrode 11B is for storing, as signal charges, for example, electrons among the charges generated in the photoelectric conversion layer 14. The storage electrode 11B is provided in a region covering the light-receiving surfaces of the photoelectric conversion regions 32B and 32R formed in the semiconductor substrate 30, facing the light-receiving surfaces for each unit pixel P. The storage electrode 11B is preferably larger than the readout electrode 11A. Thereby, a large amount of charges can be stored. As shown in FIG. 3, a voltage application unit 48 is connected to the storage electrode 11B via wirings such as an upper third contact 26B and a pad portion 25B, for example.

[0050] The lower electrode 11 is formed of, for example, a conductive film having light-transmittance. The lower electrode 11 preferably has a work function of, for example, 4.0 eV or more and 5.5 eV or less. As a constituent material of such a lower electrode 11, for example, In to which tin (Sn) is added as a dopant ２ O ３ indium tin oxide (ITO) is mentioned. The ITO film may have high crystallinity or low crystallinity (close to amorphous). As a constituent material of the lower electrode 11, in addition to the above, tin oxide (SnO ２ )-based materials, for example, ATO to which antimony (Sb) is added as a dopant, and FTO to which fluorine (F) is added as a dopant are mentioned. Further, zinc oxide (ZnO) or a zinc oxide-based material obtained by adding a dopant may be used. Examples of ZnO-based materials include aluminum zinc oxide (AZO) to which aluminum (Al) is added as a dopant, gallium zinc oxide (GZO) to which gallium (Ga) is added, boron zinc oxide to which boron (B) is added, and indium zinc oxide (IZO) to which indium (In) is added. Furthermore, zinc oxide to which indium and gallium are added as dopants (IGZO, In-GaZnO ４ ) may be used. As a constituent material of the lower electrode 11, CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３ or TiO ２You may also use spinel-type oxides or YbFe ２ O ４ Oxides having a specific structure may also be used.

[0051] When light transmission is not required for the lower electrode 11 (for example, when light is incident from the upper electrode 15 side and there are no photoelectric conversion regions 32R, 32B below the storage electrode 11B), a single metal or alloy having a small work function (for example, φ = 3.5 eV to 4.5 eV) can be used. Specifically, examples include alkali metals (e.g., lithium (Li), sodium (Na), and potassium (K), etc.) and their fluorides or oxides, and alkaline earth metals (e.g., magnesium (Mg), calcium (Ca), etc.) and their fluorides or oxides. Other examples include aluminum (Al), Al-Si-Cu alloys, zinc (Zn), tin (Sn), thallium (Tl), Na-K alloys, Al-Li alloys, Mg-Ag alloys, rare earth metals such as In and ytterbium (Yb), or alloys thereof.

[0052] Examples of materials constituting the lower electrode 11 include metals 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), and molybdenum (Mo), or alloys containing these metal elements, or conductive particles made from these metals, conductive particles of alloys containing these metals, conductive materials such as polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and graphene. In addition, examples of materials constituting the lower electrode 11 include organic materials (conductive polymers) such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid [PEDOT / PSS]. Alternatively, the above materials may be mixed with a binder (polymer) to form a paste or ink, which can then be cured and used as an electrode.

[0053] The lower electrode 11 can be formed as a single layer or a multilayer film made of the above material. The thickness of the lower electrode 11 in the stacking direction (hereinafter simply referred to as thickness) is, for example, 20 nm to 200 nm, and preferably 30 nm to 150 nm.

[0054] The insulating layer 12 is for electrically separating the storage electrode 11B from the oxide semiconductor layer 13. The insulating layer 12 is provided on, for example, an interlayer insulating layer 22 so as to cover the lower electrode 11. An opening 12H is provided in the insulating layer 12 on the read electrode 11A of the lower electrode 11, and the read electrode 11A and the oxide semiconductor layer 13 are electrically connected through this opening 12H. The insulating layer 12 is made of, for example, silicon oxide (SiO ｘ ), silicon nitride (SiN ｘ It is composed of a single layer film made of one of the following: ) and silicon oxynitride (SiON), or a multilayer film made of two or more of these materials. The thickness of the insulating layer 12 is, for example, 20 nm to 500 nm.

[0055] The oxide semiconductor layer 13 is for accumulating the charge generated in the photoelectric conversion layer 14. The oxide semiconductor layer 13 can be formed using an oxide semiconductor containing at least one element from among indium (In), gallium (Ga), zinc (Zn), aluminum (Al), and tin (Sn). In this embodiment, electrons from the charge generated in the photoelectric conversion layer 14 are used as signal charges. For this reason, the oxide semiconductor layer 13 can be formed using an n-type oxide semiconductor material. Specifically, the constituent materials of the oxide semiconductor layer 13 include IGZO (In-Ga-Zn-O based oxide semiconductor), gallium oxide (Ga ２ O ３ Examples include Zn-Sn-O oxide semiconductors, IZO (In-Zn-O oxide semiconductors), ITO, indium gallium aluminum oxide (InGaAlO), and indium gallium silicon oxide (InGaSiO). The thickness of the oxide semiconductor layer 13 is, for example, 10 nm to 300 nm.

[0056] The photoelectric conversion layer 14 converts light energy into electrical energy. The photoelectric conversion layer 14 is composed of, for example, two or more organic materials (p-type semiconductor material or n-type semiconductor material) that each function as either a p-type semiconductor or an n-type semiconductor. The photoelectric conversion layer 14 has a junction surface (p / n junction surface) between the p-type semiconductor material and the n-type semiconductor material within the layer. The p-type semiconductor functions relatively as an electron donor, and the n-type semiconductor functions relatively as an electron acceptor. The photoelectric conversion layer 14 provides a field where excitons generated when light is absorbed are separated into electrons and holes. Specifically, the excitons are separated into electrons and holes at the interface (p / n junction surface) between the electron donor and the electron acceptor.

[0057] The photoelectric conversion layer 14 may also include, in addition to the p-type semiconductor material and the n-type semiconductor material, an organic material, so-called dye material, that photoelectrically converts light in a predetermined wavelength range while transmitting light in other wavelength ranges. When the photoelectric conversion layer 14 is formed using three types of organic materials—a p-type semiconductor material, an n-type semiconductor material, and a dye material—it is preferable that the p-type semiconductor material and the n-type semiconductor material are light-transmitting materials in the visible region (for example, 450 nm to 800 nm). The thickness of the photoelectric conversion layer 14 is, for example, 50 nm to 500 nm.

[0058] Examples of organic materials constituting the photoelectric conversion layer 14 include quinacridone derivatives, naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, and fluorantene derivatives. The photoelectric conversion layer 14 is composed of a combination of two or more of the above organic materials. Depending on the combination, the above organic materials function as a p-type semiconductor or an n-type semiconductor.

[0059] The organic material constituting the photoelectric conversion layer 14 is not particularly limited. Examples of organic materials that can be used to constitute the photoelectric conversion layer 14 include polymers or derivatives thereof such as phenylenevinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, and diacetylene. As organic materials constituting the photoelectric conversion layer 14, metal complex dyes, cyanine dyes, merocyanine dyes, phenylxanthene dyes, triphenylmethane dyes, rhodacyanine dyes, xanthene dyes, macrocyclic azaanurene dyes, azulene dyes, naphthoquinone dyes, anthraquinone dyes, chain compounds formed by the condensation of condensed polycyclic aromatic, aromatic ring, or heterocyclic compounds such as pyrene, quinoline having a squarylium group and a croconicmethine group as a bonding chain, benzothiazole, benzoxazole, and other two nitrogen-containing heterocyclics or cyanine-like dyes linked by a squarylium group and a croconicmethine group can be used. Examples of metal complex dyes include dithiol metal complex dyes, metal phthalocyanine dyes, metal porphyrin dyes, and ruthenium complex dyes. Of these, ruthenium complex dyes are particularly preferred, but the invention is not limited to these. The photoelectric conversion layer 14 may be made up of materials other than organic materials, such as quantum dots.

[0060] The upper electrode 15, like the lower electrode 11, is composed of, for example, a light-transmitting conductive film. The constituent material of the upper electrode 15 is, for example, In, which has Sn added as a dopant. ２ O ３ ITO is one example. The crystallinity of the ITO film may be high or low (close to amorphous). In addition to the above, SnO with dopant added can also be used as a constituent material for the upper electrode 15. ２Examples of ZnO-based materials include ATO with Sb added as a dopant, and FTO with fluorine added as a dopant. Alternatively, zinc oxide-based materials with ZnO or dopants added may be used. Examples of ZnO-based materials include AZO with Al added as a dopant, GZO with Ga added, zinc boro oxide with B added, and IZO with In added. Furthermore, IGZO (In-GaZnO4) may be used with indium and gallium added as dopants. The constituent materials of the lower electrode 11 include CuI and InSbO. ４ , ZnMgO, CuInO ２ MgIN ２ O ４ , CdO, ZnSnO ３ or TiO ２ You may also use spinel-type oxides or YbFe ２ O ４ Oxides having a specific structure may also be used.

[0061] Furthermore, if light transmittance is not required for the upper electrode 15, a single metal or alloy with a large work function (e.g., φ = 4.5 eV to 5.5 eV) can be used. Specifically, examples include Au, Ag, Cr, Ni, Pd, Pt, Fe, iridium (Ir), germanium (Ge), osmium (Os), rhenium (Re), tellurium (Te), and their alloys.

[0062] Furthermore, the materials constituting the upper electrode 15 include metals such as Pt, Au, Pd, Cr, Ni, Al, Ag, Ta, W, Cu, Ti, In, Sn, Fe, Co, and Mo, or alloys containing these metal elements, or conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, graphene, and other conductive materials. In addition, organic materials (conductive polymers) such as PEDOT / PSS can be used as materials constituting the upper electrode 15. Alternatively, the above materials may be mixed with a binder (polymer) to form a paste or ink, which may then be cured and used as an electrode.

[0063] The upper electrode 15 can be formed as a single layer or a multilayer film made of the above material. The thickness of the upper electrode 15 is, for example, 20 nm to 200 nm, preferably 30 nm to 150 nm.

[0064] The photoelectric conversion unit 10 may have other layers between the lower electrode 11 and the photoelectric conversion layer 14, and between the photoelectric conversion layer 14 and the upper electrode 15. For example, a hole blocking layer may be provided between the lower electrode 11 and the photoelectric conversion layer 14. The hole blocking layer prevents the movement of holes from the lower electrode 11 to the photoelectric conversion layer 14 and efficiently transports electrons from the charge generated in the photoelectric conversion layer 14 to the lower electrode 11. An electron blocking layer or a work function adjustment layer may be provided between the photoelectric conversion layer 14 and the upper electrode 15. The electron blocking layer prevents the movement of electrons from the upper electrode 15 to the photoelectric conversion layer 14 and efficiently transports holes from the charge generated in the photoelectric conversion layer 14 to the upper electrode 15. The work function adjustment layer has an electron affinity or work function greater than the work function of the upper electrode 15 and improves the electrical junction between the photoelectric conversion layer 14 and the upper electrode 15.

[0065] Furthermore, the photoelectric conversion layer 14 may be, for example, a PIN bulk heterostructure in which a p-type blocking layer, a layer containing a p-type semiconductor and an n-type semiconductor (i-layer), and an n-type blocking layer are stacked. In addition, although Figure 1 shows an example in which the insulating layer 12, oxide semiconductor layer 13, photoelectric conversion layer 14, and upper electrode 15 are formed separately for each unit pixel P, the oxide semiconductor layer 13, photoelectric conversion layer 14, and upper electrode 15 may be formed continuously over the entire surface of the pixel array portion 100A, for example.

[0066] The fixed charge layer 21 is intended to reduce the interface state with the semiconductor substrate 30 and to suppress the generation of dark current from the interface with the semiconductor substrate 30. The fixed charge layer 21 may be a film having a positive fixed charge or a film having a negative fixed charge. It is preferable to form the fixed charge layer 21 using a semiconductor material or conductive material with a band gap wider than that of the semiconductor substrate 30 as the constituent material. This makes it possible to suppress the generation of dark current at the interface with the semiconductor substrate 30. Examples of constituent materials for the fixed charge layer 21 include hafnium oxide (HfO ｘ ), aluminum oxide (AlO ｘ ), zirconium oxide (ZrO ｘ ), tantalum oxide (TaO ｘ ), titanium oxide (TiO ｘ ), lanthanum oxide (LaO ｘ ), praseodymium oxide (ProO ｘ ), cerium oxide (CeO ｘ ), neodymium oxide (NdO ｘ ), promethium oxide (PmO ｘ ), samarium oxide (SmO ｘ ), Europium oxide (EuO ｘ ), gadolinium oxide (GdO ｘ ), terbium oxide (TbO ｘ ), dysprosium oxide (DyO ｘ ), holmium oxide (HoO ｘ ), thulium oxide (TmO ｘ ), ytterbium oxide (YbO ｘ ), lutetium oxide (LuO ｘ ), yttrium oxide (YO ｘ ), hafnium nitride (HfN ｘ ), aluminum nitride (AlN ｘ ), hafnium oxynitride (HfO ｘ N ｙ ) and aluminum oxynitride (AlO ｘ N ｙ Examples include:

[0067] The interlayer insulating layer 22 is composed of a single layer film made of one of the following materials: silicon oxide, silicon nitride, and silicon oxynitride, or a laminated layer made of two or more of these materials. Pad portions 23, 25A, 25B, an upper first contact 24, an upper second contact 26A, and an upper third contact 26B are provided within the interlayer insulating layer 22.

[0068] The photoelectric conversion regions 32B and 32R are composed of, for example, PIN (Positive Intrinsic Negative) type photodiodes, each having a pn junction in a predetermined region of the semiconductor substrate 30. The photoelectric conversion regions 32B and 32R enable the spectral separation of light in the longitudinal direction by utilizing the fact that the wavelength of light absorbed in the silicon substrate differs depending on the depth of incidence of the light.

[0069] Photoelectric conversion region 32B selectively detects blue light and accumulates a signal charge corresponding to blue light, and is positioned at a depth that allows for efficient photoelectric conversion of blue light. Photoelectric conversion region 32R selectively detects red light and accumulates a signal charge corresponding to red light, and is positioned at a depth that allows for efficient photoelectric conversion of red light. Blue (B) corresponds to a wavelength range of, for example, 400 nm to less than 495 nm, and red (R) corresponds to a wavelength range of, for example, 620 nm to less than 750 nm. Photoelectric conversion regions 32B and 32R only need to be capable of detecting light in some or all of the wavelength ranges within their respective wavelength ranges.

[0070] Specifically, as shown in Figure 1, the photoelectric conversion region 32B and the photoelectric conversion region 32R each have, for example, a p+ region that becomes a hole storage layer and an n region that becomes an electron storage layer (having a p-n-p stacked structure). The n region of the photoelectric conversion region 32B is connected to the transfer transistor Tr2. The p+ region of the photoelectric conversion region 32B is bent along the transfer transistor Tr2 and connected to the p+ region of the photoelectric conversion region 32R.

[0071] The gate insulating layer 33 is, for example, silicon oxide (SiO ｘ ), silicon nitride (SiN ｘIt is composed of a single layer film made of one of the following: ) and silicon oxynitride (SiON), or a multilayer film made of two or more of these.

[0072] The through-wiring 34 is provided between the first surface 30A and the second surface 30B of the semiconductor substrate 30 and functions as a connector between the photoelectric conversion unit 10, the gate Gamp of the amplifier transistor AMP, and the floating diffusion FD1, as well as serving as a transmission path for the charge generated in the photoelectric conversion unit 10. The reset gate Grst of the reset transistor RST is located next to the floating diffusion FD1 (one source / drain region 36B of the reset transistor RST). This makes it possible to reset the charge accumulated in the floating diffusion FD1 by the reset transistor RST.

[0073] The upper end of the through-wiring 34 is connected to the read electrode 11A via, for example, a pad portion 23, an upper first contact 24, a pad portion 25A, and an upper second contact 26A provided within the interlayer insulating layer 22. The lower end of the through-wiring 34 is connected to a connection portion 41A within the wiring layer 41, and the connection portion 41A is connected to the gate Gamp of the amplifier transistor AMP via a lower first contact 45. The connection portion 41A is connected to the floating diffusion FD1 (region 36B) via, for example, a lower second contact 46.

[0074] The through-wiring 34 has, for example, a conductive portion 34X extending between the first surface 30A and the second surface 30B of the semiconductor substrate 30, and an insulating film 34Y covering the side surface of the conductive portion 34X within the semiconductor substrate 30. The insulating film 34Y extends on the fixed charge layer 21 on the first surface 30A side of the semiconductor substrate 30. In other words, the fixed charge layer 21 and the insulating film 34Y are stacked in this order on the first surface 30A side of the semiconductor substrate 30. Examples of materials constituting the conductive portion 34X include polysilicon (Poly-Si), aluminum (Al), tungsten (W), titanium (Ti), cobalt (Co), platinum (Pt), palladium (Pd), copper (Cu), hafnium (Hf), and tantalum (Ta), which contain impurities. Examples of materials constituting the insulating film 34Y include silicon oxide (SiO ｘ ), TEOS, silicon nitride (SiN ｘ Examples include silicon oxynitride (SiON) and others.

[0075] The pad portions 23, 25A, 25B, the upper first contact 24, the upper second contact 26A, the upper third contact 26B, the lower first contact 45, the lower second contact 46, and the wiring 53 can be formed using, for example, silicon material doped with impurities such as PDAS (Phosphorus Doped Amorphous Silicon), or metallic materials such as aluminum (Al), tungsten (W), titanium (Ti), cobalt (Co), hafnium (Hf), and tantalum (Ta).

[0076] Figure 5 schematically shows the configuration of the through-wiring 34 and the semiconductor substrate 30 surrounding it. Figure 6 schematically shows the planar configuration corresponding to Sec1 shown in Figure 5.

[0077] As described above, the semiconductor substrate 30 has a p-well region 31A provided over its entire surface, a p-well region 31B provided around the through-wiring 34, and an n-well region 31C that electrically separates the p-well region 31A and the p-well region 31B. In other words, the semiconductor substrate 30 has, for example, a p-well region provided over its entire surface. The semiconductor substrate 30 is further provided with an annular n-well region 31C provided so as to surround the through-wiring 34 in a plan view, and the p-well region is separated into a p-well region 31A that extends outside the n-well region 31C and a p-well region 31B that surrounds the through-wiring 34 inside the n-well region 31C.

[0078] Contact regions 311, 312, and 313 are provided on the second surface 30B of the p-well region 31A, p-well region 31B, and n-well region 31C, respectively. The contact regions 311, 312, and 313 contain impurities at a higher concentration than the well regions 31A, 31B, and 31C to which they are provided. Voltage application units 49A, 49B, and 49C are connected to each contact region 311, 312, and 313, respectively, so that a predetermined voltage is applied to the p-well region 31A, p-well region 31B, and n-well region 31C via each contact region 311, 312, and 313. For example, a fixed potential (GND) is applied to the p-well region 31A. A voltage is applied to the p-well region 31B such that the voltage difference between the through-wiring 34 and the p-well region 31B is reduced when charge is transferred via the through-wiring 34. This reduces the parasitic capacitance between the through-wiring 34 and the semiconductor substrate 30. For example, a power supply voltage is applied to the n-well region 31C. This allows the dark current generated between the through-wiring 34 and the semiconductor substrate 30 to be discharged.

[0079] Figure 7 schematically shows, for example, an example of the planar configuration of the pixel array section 100A corresponding to Sec1 shown in Figure 5.

[0080] Between the first surface 30A and the second surface 30B of the semiconductor substrate 30, in addition to the through-wiring 34 which is electrically connected to the floating diffusion FD1, there is a through-wiring 39 which is not electrically connected to the floating diffusion FD1. The through-wiring 39 is electrically connected to, for example, the upper electrode 15 of the photoelectric conversion unit 10 and serves as a voltage supply path that applies a predetermined voltage to the upper electrode 15. The through-wiring 39 has, for example, a conductive portion 39A that extends between the first surface 30A and the second surface 30B of the semiconductor substrate 30, and an insulating film 39B that covers the side surface of the conductive portion 39A within the semiconductor substrate 30. The insulating film 39B may be formed continuously with the insulating film 34Y that constitutes the through-wiring 34. Examples of materials constituting the conductive portion 39A include polysilicon (Poly-Si) containing impurities, aluminum (Al), tungsten (W), titanium (Ti), cobalt (Co), platinum (Pt), palladium (Pd), copper (Cu), hafnium (Hf), and tantalum (Ta). Examples of materials constituting the insulating film 39B include silicon oxide (SiO ｘ ), TEOS, silicon nitride (SiN ｘ Examples include silicon oxynitride (SiON) and others.

[0081] In the light detection device 1, the multiple through-wirings 34 and 39 are arranged spaced apart from each other between adjacent unit pixels P, as shown in Figure 7, for example.

[0082] The protective layer 51 protects the upper surface of the upper electrode 15 and flattens the surface of the light incident side S1 of the photoelectric conversion unit 10. The protective layer 51 is made of a light-transmitting material, for example, silicon oxide (SiO ｘ ), silicon nitride (SiN ｘ ), silicon oxynitride (SiON) and aluminum oxide (AlO2) ｘ It is composed of one of the following: ) etc. The thickness of this protective layer 51 is, for example, 100 nm to 30,000 nm.

[0083] The on-chip lens 52 is made of a light-transmitting material, such as silicon oxide, silicon nitride, and silicon oxynitride. An anti-reflective coating may be provided on the surface of the on-chip lens 52.

[0084] [Manufacturing Method for the Photodetector] The photodetector 1 of this embodiment can be manufactured, for example, as follows.

[0085] Figures 8 to 13 show the manufacturing method of the photodetector 1 in order of steps. First, as shown in Figure 8, a p-well region is formed over the entire surface of the semiconductor substrate 30, and n-type photoelectric conversion regions 32B and 32R are formed within this p-well region. A p+ region is formed near the first surface 30A of the semiconductor substrate 30. Furthermore, an n-well region 31C is formed at a predetermined position in the p-well region, separating the p-well region into multiple regions (p-well region 31A and p-well region 31B).

[0086] On the second surface 30B of the semiconductor substrate 30, as shown in Figure 8, an n+ region, for example, which will be a floating diffusion FD1 to FD3, is formed, followed by the formation of a gate insulating layer 33 and a gate wiring layer 47 including the gates of the transfer transistor Tr2, transfer transistor Tr3, selection transistor SEL, amplifier transistor AMP, and reset transistor RST. This forms the transfer transistor Tr2, transfer transistor Tr3, selection transistor SEL, amplifier transistor AMP, and reset transistor RST. Furthermore, a multilayer wiring layer 40 consisting of wiring layers 41 to 43 including a lower first contact 45, a lower second contact 46, and a connection portion 41A, and an insulating layer 44 is formed on the second surface 30B of the semiconductor substrate 30.

[0087] As the base material for the semiconductor substrate 30, for example, an SOI (Silicon on Insulator) substrate is used, which is formed by laminating the semiconductor substrate 30, an embedded oxide film (not shown), and a holding substrate (not shown). The embedded oxide film and the holding substrate are bonded to the first surface 30A of the semiconductor substrate 30, although these are not shown in Figure 8. After ion implantation, an annealing treatment is performed.

[0088] Next, a support substrate (not shown) or another semiconductor substrate is bonded to the multilayer wiring layer 40 provided on the second surface 30B side of the semiconductor substrate 30, and then the substrate is inverted. Subsequently, the semiconductor substrate 30 is separated from the embedded oxide film and holding substrate of the SOI substrate, exposing the first surface 30A of the semiconductor substrate 30. The above steps can be carried out using technologies commonly used in CMOS processes, such as ion implantation and CVD (Chemical Vapor Deposition).

[0089] Next, as shown in Figure 9, the semiconductor substrate 30 is processed from the first surface 30A side by, for example, dry etching to form, for example, an annular opening 34H. As shown in Figure 9, the depth of the opening 34H penetrates from the first surface 30A to the second surface 30B of the semiconductor substrate 30 and reaches, for example, the connection portion 41A.

[0090] Next, a negative fixed charge layer 21 and an insulating film 34Y are sequentially formed on the first surface 30A and the side surface of the opening 34H of the semiconductor substrate 30. The fixed charge layer 21 is formed, for example, using atomic layer deposition (ALD) with HfO ｘ It can be formed by depositing a film. The insulating film 34Y can be formed, for example, by plasma CVD using SiO ｘ It can be formed by fabricating a film. Next, a pad portion 23 is formed at a predetermined position on the insulating film 34Y, in which a barrier metal made of, for example, a multilayer film of titanium and titanium nitride (Ti / TiN film) and a W film are laminated. After that, an interlayer insulating layer 22 is formed on the insulating film 34Y and the pad portion 23, and the surface of the interlayer insulating layer 22 is planarized using the CMP (Chemical Mechanical Polishing) method.

[0091] Next, as shown in Figure 10, an opening 23H is formed on the pad portion 23, and then a conductive material such as Al is embedded in this opening 23H to form the upper first contact 24. Then, as shown in Figure 10, pad portions 25A and 25B are formed in the same manner as the pad portion 23, and then the interlayer insulating layer 22 and the upper second contact 26A and upper third contact 26B are formed in order.

[0092] Next, as shown in Figure 11, a conductive film 11X is deposited on the interlayer insulating layer 22, for example, using a sputtering method, and then patterning is performed using photolithography technology. Specifically, a photoresist PR is formed at a predetermined position on the conductive film 11X, and then the conductive film 11X is processed using dry etching or wet etching. After that, the photoresist PR is removed to form the read electrode 11A and the storage electrode 11B, as shown in Figure 12.

[0093] Next, as shown in Figure 13, the insulating layer 12, oxide semiconductor layer 13, photoelectric conversion layer 14, and upper electrode 15 are deposited in order. For the insulating layer 12, for example, a silicon oxide film is deposited using the ALD method, and then the surface of the insulating layer 12 is planarized using the CMP method. After that, an opening 12H is formed on the readout electrode 11A, for example, using wet etching. The oxide semiconductor layer 13 can be formed, for example, using the sputtering method. The photoelectric conversion layer 14 is formed, for example, using the vacuum deposition method. The upper electrode 15 is formed in the same way as the lower electrode 11, for example, using the sputtering method. After that, a protective layer 51 is deposited so as to cover the upper electrode 15, and then an on-chip lens 52 is placed on the protective layer 51. With the above steps, the photodetector 1 shown in Figure 1 is completed.

[0094] The conductive films, such as the photoelectric conversion layer 14, the lower electrode 11, and the upper electrode 15, can be formed using dry or wet deposition methods. Dry deposition methods include vacuum deposition using resistance heating or high-frequency heating, as well as electron beam (EB) deposition, various sputtering methods (magnetron sputtering, RF-DC coupled bias sputtering, ECR sputtering, opposing target sputtering, high-frequency sputtering), ion plating, laser aeration, molecular beam epitaxy, and laser transfer. Other dry deposition methods include chemical vapor deposition methods such as plasma CVD, thermal CVD, MOCVD, and photoCVD. Wet deposition methods include spin coating, inkjet printing, spray coating, stamping, microcontact printing, flexographic printing, offset printing, gravure printing, and dip printing.

[0095] For patterning, in addition to photolithography, chemical etching such as shadow masks and laser transfer, and physical etching using ultraviolet light or lasers can be used. For planarization, in addition to the CMP method, laser planarization and reflow methods can be used.

[0096] [Signal acquisition operation of the light detection device] In the light detection device 1, when light is incident on the photoelectric conversion unit 10 via the on-chip lens 52, the light passes through the photoelectric conversion unit 10, then the photoelectric conversion regions 32B and 32R in that order, and during this process, green, blue, and red light are photoelectrically converted. The signal acquisition operation for each color will be described below.

[0097] (Acquisition of green signal by photoelectric conversion unit 10) Of the light incident on the light detection device 1, green light (G) is first selectively detected (absorbed) by the photoelectric conversion unit 10 and converted into photoelectric light.

[0098] The photoelectric conversion unit 10 is connected to the gate Gamp of the amplifier transistor AMP and the floating diffusion FD1 via a through-wiring 34. Therefore, electrons from the excitons generated in the photoelectric conversion unit 10 are extracted from the lower electrode 11 side, transferred to the second surface 30B side of the semiconductor substrate 30 via the through-wiring 34, and accumulated in the floating diffusion FD1. At the same time, the amount of charge generated in the photoelectric conversion unit 10 is modulated into a voltage by the amplifier transistor AMP.

[0099] Furthermore, the reset gate Grst of the reset transistor RST is located next to the floating diffusion FD1. As a result, the charge accumulated in the floating diffusion FD1 is reset by the reset transistor RST.

[0100] Since the photoelectric conversion unit 10 is connected not only to the amplifier transistor AMP but also to the floating diffusion FD1 via through wiring 34, the charge accumulated in the floating diffusion FD1 can be easily reset by the reset transistor RST.

[0101] In contrast, if the through-wiring 34 and the floating diffusion FD1 are not connected, it becomes difficult to reset the charge accumulated in the floating diffusion FD1, requiring a large voltage to be applied to pull it out towards the upper electrode 15. This could potentially damage the photoelectric conversion layer 14. Furthermore, a structure that allows for quick resetting would lead to increased noise in the dark, creating a trade-off, making this structure impractical.

[0102] Figure 14 shows an example of operation of the photodetector 1. (A) shows the potential at the storage electrode 11B, (B) shows the potential at the floating diffusion FD1 (readout electrode 11A), and (C) shows the potential at the gate (Gsel) of the reset transistor RST1. In the photodetector 1, the readout electrode 11A and the storage electrode 11B are each individually supplied with voltage.

[0103] In the photodetector 1, during the storage period, a potential V1 is applied to the readout electrode 11A from the drive circuit, and a potential V2 is applied to the storage electrode 11B. Here, the potentials V1 and V2 are set such that V2 > V1. As a result, the charge (signal charge; electrons) generated by photoelectric conversion is attracted to the storage electrode 11B and stored in the region of the oxide semiconductor layer 13 facing the storage electrode 11B (storage period). Incidentally, the potential of the region of the oxide semiconductor layer 13 facing the storage electrode 11B becomes more negative as the photoelectric conversion progresses. Holes are sent from the upper electrode 15 to the drive circuit.

[0104] In the photodetector 1, a reset operation is performed in the later stages of the storage period. Specifically, at timing t1, the scanning unit changes the voltage of the reset signal from a low level to a high level. As a result, the reset transistor RST1 is turned on in the unit pixel P, and consequently, the voltage of the floating diffusion FD1 is set to the power supply voltage, and the voltage of the floating diffusion FD1 is reset (reset period).

[0105] After the reset operation is complete, the charge is read out. Specifically, at timing t2, a potential V3 is applied to the read electrode 11A from the drive circuit, and a potential V4 is applied to the storage electrode 11B. Here, the potentials V3 and V4 are set such that V3 > V4. As a result, the charge that was stored in the region corresponding to the storage electrode 11B is read out from the read electrode 11A to the floating diffusion FD1. That is, the charge stored in the oxide semiconductor layer 13 is read out to the control unit (transfer period).

[0106] After the read operation is complete, the drive circuit again applies a potential V1 to the read electrode 11A and a potential V2 to the storage electrode 11B. As a result, the charge generated by photoelectric conversion is attracted to the storage electrode 11B and stored in the region of the photoelectric conversion layer 14 facing the storage electrode 11B (storage period).

[0107] (Acquisition of blue and red signals by photoelectric conversion regions 32B and 32R) Next, of the light transmitted through the photoelectric conversion unit 10, the blue light (B) is absorbed in the photoelectric conversion region 32B and the red light (R) is absorbed in the photoelectric conversion region 32R, respectively, and converted photoelectrically. In the photoelectric conversion region 32B, electrons corresponding to the incident blue light (B) are accumulated in the n region of the photoelectric conversion region 32B, and the accumulated electrons are transferred to the floating diffusion FD2 by the transfer transistor Tr2. Similarly, in the photoelectric conversion region 32R, electrons corresponding to the incident red light (R) are accumulated in the n region of the photoelectric conversion region 32R, and the accumulated electrons are transferred to the floating diffusion FD3 by the transfer transistor Tr3.

[0108] [Function and Effects] In the photodetector 1 of this embodiment, for example, in a plan view, an annular n-well region 31C is provided on the semiconductor substrate 30 around a through-wiring 34 that penetrates between the first surface 30A and the second surface 30B of the semiconductor substrate 30, and the p-well region provided over the entire surface of the semiconductor substrate 30 is separated into a p-well region 31A that extends outside the n-well region 31C and a p-well region 31B that surrounds the through-wiring 34 inside the n-well region 31C. This reduces parasitic capacitance between the through-wiring 34 and the semiconductor substrate 30. This will be explained below.

[0109] To date, structures have been proposed in which photoelectric conversion regions (such as photodiodes) that convert light of red (R), green (G), and blue (B) wavelengths into photoelectric light are stacked in the vertical direction within the pixel region. Structures have also been proposed in which a photoelectric conversion film or the like is disposed outside the semiconductor substrate. When such a structure is applied to a back-illuminated solid-state image sensor, for example, as shown in the imaging device 210 in Figure 15, through-wiring 2134 is provided that penetrates the semiconductor substrate 2130 to transfer the charge obtained in the photoelectric conversion unit 2110 disposed on the back surface 2130A side of the semiconductor substrate 2130 to the front surface 2130B side of the semiconductor substrate 2130.

[0110] Generally, the central portion of the through-wiring 2134 is formed from a conductor, and an insulating film is formed between the conductor and the semiconductor substrate 2130. The through-wiring 2134 penetrates the semiconductor substrate 2130 and connects to the amplifier transistor and the floating diffusion (FD). In such an imaging device 210, the generation of dark current due to processing damage to the through-wiring 2134 becomes a problem. When the dark signal generated here reaches the FD, the signal-to-noise ratio deteriorates, and the quality of the resulting image signal decreases.

[0111] Dark current generated by processing damage to the through-wiring 2134 can be resolved, for example, by providing a charge discharge section 2231, which is made of, for example, an n-type semiconductor region, around the through-wiring 2234, as shown in the imaging device 220 in Figure 16. In the imaging device 220, the generated dark current can be shielded by the charge discharge section 2231, thus preventing degradation of the signal-to-noise ratio.

[0112] However, in an imaging device 220 in which a charge discharge section 2231, for example, consisting of an n-type semiconductor region, is provided around the through-wiring 2234, the conversion efficiency decreases due to the large parasitic capacitance between the through-wiring 2234 and the semiconductor substrate 2230, resulting in a decrease in the quality of the resulting image signal. To reduce the parasitic capacitance, it is relatively easy to increase the distance between the through-wiring 2234 and the semiconductor substrate 2130, but in that case, the area represented by the through-wiring 2234 increases, and the element area increases.

[0113] In contrast, in this embodiment, as described above, for example, in a plan view, an annular n-well region 31C is provided on the semiconductor substrate 30 around the through-wiring 34 that penetrates between the first surface 30A and the second surface 30B of the semiconductor substrate 30, and the p-well region provided over the entire surface of the semiconductor substrate 30 is separated into a p-well region 31A that extends outside the n-well region 31C and a p-well region 31B that surrounds the through-wiring 34 inside the n-well region 31C. This prevents the dark current generated between the through-wiring 34 and the semiconductor substrate 30 from flowing into the floating diffusion FD1.

[0114] As described above, the light detection device 1 of this embodiment makes it possible to improve image quality without increasing the element area.

[0115] Furthermore, in the photodetector 1 of this embodiment, a voltage is applied to the p-well region 31B that reduces the voltage difference between the through-wiring 34 and the p-well region 31B, thereby reducing the parasitic capacitance between the through-wiring 34 and the semiconductor substrate 30. As a result, a decrease in conversion efficiency can be suppressed, making it possible to further improve image quality.

[0116] Furthermore, in the optical detection device 1 of this embodiment, since the power supply voltage is applied to the n-well region 31C, the dark current generated between the through-wiring 34 and the semiconductor substrate 30 is discharged. Therefore, it is possible to improve the quality of the pixel signal.

[0117] Next, Modifications 1 to 3 and other Modifications 1 to 7 of the present disclosure, as well as application examples and usage examples, will be described. Note that components corresponding to the light detection device 1 of the above embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0118] <2. Modifications> (2-1. Modification 1) Figure 17 schematically shows an example of the configuration of the through-wiring 34 and the surrounding semiconductor substrate 30 of the photodetector (photodetector 1A) according to Modification 1 of the present disclosure. The photodetector 1A is an imaging device such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, similar to the photodetector 1 of the above embodiment.

[0119] In the above embodiment, an example was shown in which a voltage application unit 49B is connected to the p-well region 31B surrounding the through-wiring 34, and a voltage is applied to reduce the voltage difference between the through-wiring 34 and the p-well region 31B when charge is transferred through the through-wiring 34. However, the embodiment is not limited to this. In the modified photodetector 1A, for example, an amplifier transistor AMP1 is provided in the p-well region 31B, and its source region 35B is connected to a contact region 312. Except for this point, the photodetector 1A has substantially the same configuration as the photodetector 1 of the above embodiment.

[0120] As described above, in the modified photodetector 1A, the contact area 312 of the p-well region 31B provided around the through-wiring 34 is electrically connected to the source region 35B of the amplifier transistor AMP1. This reduces the parasitic capacitance between the through-wiring 34E and the semiconductor substrate 30. Therefore, a decrease in conversion efficiency can be suppressed, and thus, as in the above embodiment, it becomes possible to further improve image quality.

[0121] In the above embodiment and Figure 17 of this modification, an example is shown in which the n-well region 31C separating the p-well region 31A and the p-well region 31B extends linearly between the first surface 30A and the second surface 30B of the semiconductor substrate 30, but the invention is not limited to this. The n-well region 31C may be bent within the semiconductor substrate 30, for example, as shown in Figure 18.

[0122] (2-2. Modification 2) Figure 19 schematically shows an example of the planar configuration of the pixel array section 100A in the light detection device (light detection device 1B) according to Modification 2 of the present disclosure.

[0123] Since the through-wiring 39, which does not have an electrical connection with the floating diffusion FD1, does not need to reduce the capacitance between it and the semiconductor substrate 30 like the through-wiring 34, an n-well region 31C may be provided around it without passing through a p-well region 31B, as shown in Figure 19. Furthermore, if there are multiple through-wirings 34 and 39, the n-well regions 31C provided around each of the through-wirings 34 and 39 may be continuous with each other, as shown in Figure 19.

[0124] Thus, in this modified optical detection device 1B, an n-well region 31C is provided around the through-wiring 39, which has no electrical connection to the floating diffusion FD1. This makes it possible to shield against dark current generated by processing damage to the through-wiring 39 while ensuring a sufficient pixel area. Therefore, it is possible to further improve the quality of the pixel signal compared to the above embodiment.

[0125] (2-3. Modification 3) Figure 20 schematically shows an example of the planar configuration of the pixel array section 100A in the optical detection device (optical detection device 1C) according to Modification 3 of the present disclosure.

[0126] In this modified photodetector 1C, a pixel isolation section 54 is provided between adjacent unit pixels P. The pixel isolation section 54 has a configuration in which an insulating film is filled into isolation grooves having an FTI (Full Trench Isolation) structure that extends from one of the first surface 30A and the second surface 30B of the semiconductor substrate 30 toward the other. In this modified photodetector 1C, the isolation grooves are connected to openings (for example, opening 34H) in which through-wirings 34 and 39 are formed, so that the insulating films 34Y and 39B constituting the through-wirings 34 and 39 extend between adjacent unit pixels P.

[0127] Thus, in this modified optical detection device 1C, a pixel separation section 54 is provided that extends between multiple through-wirings 34 and 39. As a result, adjacent unit pixels P are electrically and optically separated, making it possible to suppress crosstalk between adjacent unit pixels P. Therefore, it is possible to further improve image quality compared to the above embodiment.

[0128] <3. Other Modifications> (3-1. Other Modification 1) Figure 21A schematically shows the cross-sectional configuration of the photodetector 2A according to Other Modification 1 of the present disclosure. Figure 21B schematically shows an example of the planar configuration of the photodetector 2A shown in Figure 21A, and Figure 21A shows a cross-section corresponding to the line I-I shown in Figure 21B. The photodetector 2A is, for example, a stacked type imaging device in which a photoelectric conversion region 32 and a photoelectric conversion unit 10 are stacked. In the pixel array section 100A of this photodetector 2A, for example as shown in Figure 21B, pixel units 2a consisting of four pixels arranged in, for example, 2 rows x 2 columns are repeated units and are repeatedly arranged in an array consisting of row direction and column direction.

[0129] The lower electrode 11 includes, for example, a read electrode 11A, a storage electrode 11B, and a shield electrode 11C arranged in parallel on the interlayer insulating layer 22.

[0130] The shield electrode 11C is intended to prevent capacitive coupling between adjacent pixel units 2a. The shield electrode 11C is provided, for example, between adjacent pixel units 2a and a fixed potential is applied to it. As shown in Figure 21B, for example, the shield electrode 11C extends between adjacent pixels in the row direction (Y-axis direction) and column direction (X-axis direction) of the four unit pixels P arranged in a 2x2 configuration that make up the pixel unit 2a.

[0131] In this modified light detection device 2A, above the photoelectric conversion unit 10 (light incident side S1), a color filter 56 that selectively transmits red light (R), green light (G), and blue light (B) is provided for each unit pixel P. Specifically, in a pixel unit 2a consisting of four pixels arranged in a 2x2 grid, two color filters that selectively transmit green light (G) (green filter 56G) are arranged diagonally, and one color filter each that selectively transmits red light (R) and blue light (B) (red filter 56R and blue filter 56B) are arranged on orthogonal diagonals. In the unit pixels (Pr, Pg, Pb) provided with each color filter 56R, 56G, and 56B, the corresponding color light is detected in the photoelectric conversion unit 10, for example. In other words, in the pixel array section 100A, pixels (Pr, Pg, Pb) that detect red light (R), green light (G), and blue light (B), respectively, are arranged in a Bayer configuration.

[0132] The photoelectric conversion unit 10 absorbs light corresponding to some or all of the wavelengths in the visible light region between 400 nm and 750 nm to generate excitons (electron-hole pairs), and the lower electrode 11, insulating layer 12, oxide semiconductor layer 13, photoelectric conversion layer 14, and upper electrode 15 are stacked in this order. The lower electrode 11, as in the above embodiment, has, for example, a readout electrode 11A and a storage electrode 11B that are independent of each other, and the readout electrode 11A is shared by, for example, four pixels. The oxide semiconductor layer 13 may be omitted.

[0133] The photoelectric conversion region 32 detects, for example, infrared light in the range of 750 nm to 1300 nm.

[0134] In the photodetector 2A, of the light transmitted through the color filter 56, visible light (red light (R), green light (G), and blue light (B)) is absorbed by the photoelectric conversion unit 10 of the unit pixels (Pr, Pg, Pb) equipped with the respective color filters 56R, 56G, and 56B, while other light, such as infrared light (IR) in the infrared region (e.g., 750 nm to 1000 nm), is transmitted through the photoelectric conversion unit 10. This infrared light (IR) transmitted through the photoelectric conversion unit 10 is detected in the photoelectric conversion regions 32 of each unit pixel Pr, Pg, Pb, and a signal charge corresponding to the infrared light (IR) is generated. In other words, the photodetector 100 equipped with the photodetector 2A can simultaneously generate both a visible light image and an infrared light image.

[0135] Furthermore, the light detection device 2A can acquire visible light images and infrared light images at the same position in the XZ plane. Therefore, it becomes possible to achieve high integration in the XZ plane.

[0136] (3-2. Other Modifications 2) Figure 22A schematically shows the cross-sectional configuration of the photodetector 2B according to other modification 2 of the present disclosure. Figure 22B schematically shows an example of the planar configuration of the photodetector 2B shown in Figure 22A, and Figure 22A shows a cross-section corresponding to the line II-II shown in Figure 22B. In modification 1 above, an example was shown in which the color filter 56 is provided above the photoelectric conversion unit 10 (light incident side S1), but the color filter 56 may be provided between the photoelectric conversion region 32 and the photoelectric conversion unit 10, for example, as shown in Figure 22A. Except for this point, the photodetector 2B has substantially the same configuration as the photodetector 2A of other modification 1 above.

[0137] In the light detection device 2B, for example, the color filter 56 has a configuration in which a color filter (red filter 56R) that selectively transmits at least red light (R) and a color filter (blue filter 56B) that selectively transmits at least blue light (B) are arranged diagonally to each other within the pixel unit 2a. The photoelectric conversion layer 14 of the photoelectric conversion unit 10 is configured to selectively absorb light having a wavelength corresponding to, for example, green light (G). In the photoelectric conversion region 32R, light having a wavelength corresponding to red light (R) is selectively absorbed, and in the photoelectric conversion region 32B, light having a wavelength corresponding to blue light (B) is selectively absorbed. As a result, it is possible to acquire signals corresponding to red light (R), green light (G), or blue light (B) in the photoelectric conversion regions 32 (photoelectric conversion regions 32R, 32B) located below the photoelectric conversion unit 10 and the color filters 56R, 56B, respectively. In this modified photodetector 2B, the area of ​​each RGB photoelectric conversion unit can be enlarged compared to a typical photodetector with a Bayer array, making it possible to improve the signal-to-noise ratio.

[0138] (3-3. Other Modification 3) Figure 23 schematically shows the cross-sectional configuration of the photodetector 2C according to other modification 3 of the present disclosure. The photodetector 2C is an imaging device such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, similar to the photodetector 1 of the above embodiment. In this modified photodetector 2C, two photoelectric conversion units 10, 80 and one photoelectric conversion region 32 are stacked in the vertical direction.

[0139] The photoelectric conversion units 10 and 80 and the photoelectric conversion region 32 selectively detect light in different wavelength ranges and perform photoelectric conversion. For example, the photoelectric conversion unit 10 acquires a green (G) color signal. For example, the photoelectric conversion unit 80 acquires a blue (B) color signal. For example, the photoelectric conversion region 32 acquires a red (R) color signal. As a result, the light detection device 2C can acquire multiple types of color signals in a single pixel without using a color filter.

[0140] The photoelectric conversion unit 80 has the same configuration as the photoelectric conversion unit 10. Specifically, the photoelectric conversion unit 80 has the same configuration as the photoelectric conversion unit 10, with the lower electrode 81, photoelectric conversion layer 84, and upper electrode 85 stacked in that order. The lower electrode 81 consists of multiple electrodes (for example, a read electrode 81A and a storage electrode 81B, etc.), and an insulating layer 82 and an oxide semiconductor layer 83 are stacked between the lower electrode 81 and the photoelectric conversion layer 84 in that order. Of the lower electrode 81, the read electrode 81A is electrically connected to the oxide semiconductor layer 83 via an opening 82H provided in the insulating layer 82. The oxide semiconductor layer 83 may be omitted.

[0141] A through-wire 86 is connected to the read electrode 81A, penetrating the interlayer insulating layer 87 and the photoelectric conversion unit 10, and electrically connected to the read electrode 11A of the photoelectric conversion unit 10. Furthermore, the read electrode 81A is electrically connected to a floating diffusion FD provided on the semiconductor substrate 30 via the through-wires 34 and 86, allowing it to temporarily store the charge generated in the photoelectric conversion layer 84. In addition, the read electrode 81A is electrically connected to an amplifier transistor AMP and the like provided on the semiconductor substrate 30 via the through-wires 34 and 86.

[0142] (8-4. Other Modifications 4-7) Figure 24 schematically shows an example of a cross-sectional configuration of a photodetector according to other modification 4 of the present disclosure (photodetector 2D). Figure 25A shows another example of a cross-sectional configuration of a photodetector according to other modification 5 of the present disclosure (photodetector 2E). Figure 25B schematically shows an example of a planar configuration of the photodetector 2E shown in Figure 25A. Figure 26A schematically shows another example of a cross-sectional configuration of a photodetector according to other modification 6 of the present disclosure (photodetector 2F). Figure 26B schematically shows an example of a planar configuration of the photodetector 2F shown in Figure 26A. Figure 27 schematically shows another example of a cross-sectional configuration of a photodetector according to other modification 7 of the present disclosure (photodetector 2G). Photodetectors 2D to 2G are used as imaging devices such as CMOS image sensors used in electronic devices such as digital still cameras and video cameras, similar to photodetector 1 in the above embodiment. The modified photodetector devices 2D to 2G differ from the above embodiments in that the lower electrode 11 consists of one electrode for each unit pixel P.

[0143] Similar to the light detection device 1 described above, the photodetector 2D has one photoelectric conversion unit 10 and two photoelectric conversion regions 32B and 32R stacked vertically for each unit pixel P. The photoelectric conversion unit 10 is provided on the back side (first surface 30A) of the semiconductor substrate 30. The photoelectric conversion regions 32B and 32R are embedded within the semiconductor substrate 30 and stacked in the thickness direction of the semiconductor substrate 30.

[0144] The modified photodetector 2G has the same configuration as the photodetector 1, except that the lower electrodes 11 and 81 of the photoelectric conversion units 10 and 80 consist of a single electrode, and insulating layers 12 and 82 and oxide semiconductor layers 13 and 83 are not provided between the lower electrodes 11 and 81 and the photoelectric conversion layers 14 and 84.

[0145] <4. Application Examples> (Application Example 1) The light detection device 1 described above can be applied to various electronic devices such as imaging systems like digital still cameras and digital video cameras, mobile phones equipped with imaging functions, or other devices equipped with imaging functions.

[0146] Figure 28 is a block diagram showing an example of the configuration of the electronic device 1000.

[0147] As shown in Figure 28, the electronic device 1000 includes an optical system 1001, a light detection device 1, and a DSP (Digital Signal Processor) 1002. The DSP 1002, memory 1003, display device 1004, recording device 1005, operating system 1006, and power supply system 1007 are connected via a bus 1008, and it is capable of capturing still and moving images.

[0148] The optical system 1001 is composed of one or more lenses and captures incident light (image light) from the subject and forms an image on the imaging surface of the light detection device 1.

[0149] The above-described light detection device 1 is used as the light detection device 1. The light detection device 1 converts the amount of incident light imaged on the imaging surface by the optical system 1001 into an electrical signal on a pixel-by-pixel basis and supplies it to the DSP 1002 as a pixel signal.

[0150] The DSP 1002 performs various signal processing on the signal from the light detection device 1 to acquire an image, and temporarily stores the image data in the memory 1003. The image data stored in the memory 1003 is recorded in the recording device 1005 or supplied to the display device 1004 to display the image. The operation system 1006 accepts various operations from the user and supplies operation signals to each block of the electronic device 1000, and the power supply system 1007 supplies the power necessary to drive each block of the electronic device 1000.

[0151] (Application Example 2) Figure 29A schematically shows an example of the overall configuration of a photodetection system 2000 equipped with a photodetector 1. Figure 29B shows an example of the circuit configuration of the photodetection system 2000. The photodetection system 2000 includes a light-emitting device 2001 as a light source unit that emits infrared light L2, and a photodetector 2002 as a light-receiving unit that has a photodetector. The photodetector 1 described above can be used as the photodetector 2002. The photodetection system 2000 may further include a system control unit 2003, a light source drive unit 2004, a sensor control unit 2005, a light source side optical system 2006, and a camera side optical system 2007.

[0152] The photodetector 2002 can detect light L1 and light L2. Light L1 is light reflected from ambient light from the outside by the subject (object to be measured) 2100 (Figure 29A). Light L2 is light that has been emitted by the light-emitting device 2001 and then reflected by the subject 2100. Light L1 is, for example, visible light, and light L2 is, for example, infrared light. Light L1 is detectable in the photoelectric conversion unit of the photodetector 2002, and light L2 is detectable in the photoelectric conversion region of the photodetector 2002. Image information of the subject 2100 can be obtained from light L1, and distance information between the subject 2100 and the photodetector system 2000 can be obtained from light L2. The photodetector system 2000 can be mounted on, for example, electronic devices such as smartphones or mobile devices such as cars. The light-emitting device 2001 can be, for example, a semiconductor laser, a surface-emitting semiconductor laser, or a vertical-cavity surface-emitting laser (VCSEL). As a detection method for the light L2 emitted from the light-emitting device 2001 by the photodetector 2002, for example, the iTOF method can be used, but is not limited to this. In the iTOF method, the photoelectric conversion unit can measure the distance to the subject 2100 by, for example, the time-of-flight (TOF). As a detection method for the light L2 emitted from the light-emitting device 2001 by the photodetector 2002, for example, the structured light method or the stereo vision method can also be used. For example, in the structured light method, the distance between the photodetector 2000 and the subject 2100 can be measured by projecting a predetermined pattern of light onto the subject 2100 and analyzing the degree of distortion of the pattern. In the stereo vision method, for example, the distance between the photodetector 2000 and the subject can be measured by using two or more cameras to acquire two or more images of the subject 2100 from two or more different viewpoints. Furthermore, the light-emitting device 2001 and the light-detecting device 2002 can be synchronously controlled by the system control unit 2003.

[0153] <5. Application Examples> (Application Example to Endoscopic Surgical Systems) The technology disclosed herein (this technology) can be applied to various products. For example, the technology disclosed herein may be applied to an endoscopic surgical system.

[0154] Figure 30 is a diagram showing an example of a schematic configuration of an endoscopic surgical system to which the technology described herein (the technology) may be applied.

[0155] Figure 30 illustrates a surgeon (physician) 11131 performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgical system 11000. As shown in the figure, the endoscopic surgical system 11000 consists of an endoscope 11100, other surgical instruments 11110 such as an insufflation tube 11111 and an energy treatment device 11112, a support arm device 11120 for supporting the endoscope 11100, and a cart 11200 equipped with various devices for endoscopic surgery.

[0156] The endoscope 11100 consists of a barrel 11101, the tip of which is inserted into the body cavity of the patient 11132 for a predetermined length, and a camera head 11102 connected to the base end of the barrel 11101. In the illustrated example, the endoscope 11100 is shown as a so-called rigid endoscope having a rigid barrel 11101, but the endoscope 11100 may also be configured as a so-called flexible endoscope having a flexible barrel.

[0157] An opening into which an objective lens is fitted is provided at the tip of the microscope tube 11101. A light source device 11203 is connected to the endoscope 11100, and the light generated by the light source device 11203 is guided to the tip of the microscope tube by a light guide extending inside the microscope tube 11101, and is irradiated through the objective lens towards the object to be observed inside the body cavity of the patient 11132. The endoscope 11100 may be a straight-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0158] The camera head 11102 contains an optical system and an image sensor. Reflected light from the object being observed (observation light) is focused onto the image sensor by the optical system. The image sensor converts the observation light into electrical signals, generating an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. This image signal is transmitted as RAW data to the camera control unit (CCU) 11201.

[0159] The CCU 11201 is composed of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and other components, and comprehensively controls the operation of the endoscope 11100 and the display device 11202. Furthermore, the CCU 11201 receives an image signal from the camera head 11102 and performs various image processing operations on that image signal, such as development processing (demosaic processing), to display an image based on that image signal.

[0160] The display device 11202 displays an image based on an image signal that has been processed by the CCU 11201, under control from the CCU 11201.

[0161] 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 area, etc.

[0162] The input device 11204 is an input interface for the endoscopic surgical system 11000. The user can input various types of information and instructions to the endoscopic surgical system 11000 via the input device 11204. For example, the user can input instructions to change the imaging conditions (type of light, magnification, focal length, etc.) of the endoscope 11100.

[0163] The treatment instrument control device 11205 controls the drive of the energy treatment instrument 11112 for purposes such as tissue cauterization, incision, or blood vessel sealing. The insufflation device 11206 injects gas into the body cavity of the patient 11132 via the insufflation tube 11111 to inflate the body cavity for the purpose of securing a field of view by the endoscope 11100 and securing the operator's workspace. The recorder 11207 is a device capable of recording various information related to the surgery. The printer 11208 is a device capable of printing various information related to the surgery in various formats such as text, images, or graphs.

[0164] The light source device 11203 that supplies illumination light to the endoscope 11100 when photographing the surgical area can be configured as a white light source consisting of, for example, an LED, a laser light source, or a combination thereof. When the white light source is configured as 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 this case, it is also possible to capture images corresponding to each of the RGB colors in time-division by irradiating the observation target with laser light from each of the RGB laser light sources in time-division and controlling the drive of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, a color image can be obtained without providing a color filter on the image sensor.

[0165] Furthermore, the light source device 11203 may be controlled to change the intensity of the light it outputs at predetermined time intervals. By controlling the drive of the image sensor of the camera head 11102 in synchronization with the timing of the change in light intensity, images can be acquired in time-division order, and these images can be combined to generate high dynamic range images without so-called black crushing and white clipping.

[0166] Furthermore, the light source device 11203 may be configured to supply light in a predetermined wavelength range corresponding to special light observation. In special light observation, for example, so-called narrow-band imaging is performed, in which a predetermined tissue such as blood vessels on the surface of the mucosa is imaged with high contrast by irradiating with narrow-band light compared to the irradiation light used in normal observation (i.e., white light), utilizing the wavelength dependence of light absorption in body tissue. Alternatively, fluorescence observation may be performed in special light observation, in which an image is obtained from fluorescence generated by irradiation with excitation light. In fluorescence observation, fluorescence can be obtained by irradiating body tissue with excitation light and observing the fluorescence from the body tissue (autofluorescence observation), or by locally injecting a reagent such as indocyanine green (ICG) into body tissue and irradiating the body tissue with excitation light corresponding to the fluorescence wavelength of the reagent to obtain a fluorescence image. The light source device 11203 may be configured to supply narrow-band light and / or excitation light corresponding to such special light observation.

[0167] Figure 31 is a block diagram showing an example of the functional configuration of the camera head 11102 and CCU 11201 shown in Figure 30.

[0168] The camera head 11102 includes a lens unit 11401, an imaging unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. The CCU 11201 includes 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 each other via a transmission cable 11400 so that they can communicate with each other.

[0169] The lens unit 11401 is an optical system provided at the connection point with the lens barrel 11101. Observation light taken in from the tip of the lens barrel 11101 is guided to the camera head 11102 and then 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.

[0170] The imaging unit 11402 may consist of one image sensor (a so-called single-chip type) or multiple image sensors (a so-called multi-chip type). If the imaging unit 11402 is configured as a multi-chip type, for example, each image sensor may generate image signals corresponding to RGB, and these may be combined to obtain a color image. Alternatively, the imaging unit 11402 may be configured to have a pair of image sensors for acquiring image signals for the right eye and left eye, respectively, corresponding to 3D (dimensional) display. By performing 3D display, the surgeon 11131 can more accurately grasp the depth of the biological tissue in the surgical area. In addition, if the imaging unit 11402 is configured as a multi-chip type, multiple lens units 11401 may be provided corresponding to each image sensor.

[0171] Furthermore, the imaging unit 11402 does not necessarily have to be located on the camera head 11102. For example, the imaging unit 11402 may be located inside the lens barrel 11101, directly behind the objective lens.

[0172] The drive unit 11403 is composed of actuators and, under control from the camera head control unit 11405, moves the zoom lens and focus lens of the lens unit 11401 along the optical axis by a predetermined distance. This allows the magnification and focus of the image captured by the imaging unit 11402 to be adjusted as appropriate.

[0173] The communication unit 11404 is composed of communication devices for sending and receiving various types of information with the CCU 11201. The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 as RAW data to the CCU 11201 via the transmission cable 11400.

[0174] Furthermore, the communication unit 11404 receives a control signal from the CCU 11201 to control the drive of the camera head 11102 and supplies it to the camera head control unit 11405. The control signal includes information about imaging conditions, such as information to specify the frame rate of the captured image, information to specify the exposure value at the time of imaging, and / or information to specify the magnification and focus of the captured image.

[0175] The imaging conditions such as frame rate, exposure value, magnification, and focus may be specified by the user as appropriate, or they may be automatically set by the control unit 11413 of the CCU 11201 based on the acquired image signal. In the latter case, the endoscope 11100 is equipped with so-called AE (Auto Exposure), AF (Auto Focus), and AWB (Auto White Balance) functions.

[0176] The camera head control unit 11405 controls the driving of the camera head 11102 based on the control signal received from the CCU 11201 via the communication unit 11404.

[0177] The communication unit 11411 is comprised of a communication device for sending and receiving various types of information with the camera head 11102. The communication unit 11411 receives image signals transmitted from the camera head 11102 via the transmission cable 11400.

[0178] Furthermore, the communication unit 11411 transmits control signals to the camera head 11102 to control the driving of the camera head 11102. Image signals and control signals can be transmitted by telecommunications, optical communications, etc.

[0179] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102.

[0180] The control unit 11413 performs various controls related to imaging the surgical area, etc., by the endoscope 11100, and the display of the images obtained from imaging the surgical area, etc. For example, the control unit 11413 generates a control signal to control the driving of the camera head 11102.

[0181] Furthermore, the control unit 11413 displays the captured image showing the surgical area, etc., on the display device 11202 based on the image signal processed by the image processing unit 11412. At this time, the control unit 11413 may recognize various objects in the captured image using various image recognition technologies. For example, the control unit 11413 can recognize surgical instruments such as forceps, specific biological sites, bleeding, mist when using the energy treatment device 11112, etc., by detecting the shape and color of the edges of objects included in the captured image. When the control unit 11413 displays the captured image on the display device 11202, it may use the recognition results to superimpose various surgical support information onto the image of the surgical area. By superimposing the surgical support information and presenting it to the surgeon 11131, the burden on the surgeon 11131 can be reduced, and the surgeon 11131 can proceed with the surgery reliably.

[0182] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable compatible with electrical signal communication, an optical fiber compatible with optical communication, or a composite cable thereof.

[0183] In the illustrated example, 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.

[0184] The above describes an example of an endoscopic surgical system to which the technology described herein may be applied. The technology described herein can be applied to the imaging unit 11402 of the configuration described above. By applying the technology described herein to the imaging unit 11402, the detection accuracy is improved.

[0185] While an endoscopic surgical system has been described here as an example, the technology described herein may also be applied to other systems, such as microsurgical systems.

[0186] (Examples of application to mobile devices) The technology disclosed herein can be applied to a variety of products. For example, the technology disclosed herein may be implemented as a device mounted on any type of mobile device, such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, ships, robots, construction machinery, or agricultural machinery (tractors).

[0187] Figure 32 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology described herein may be applied.

[0188] The vehicle control system 12000 comprises a plurality of electronic control units connected via a communication network 12001. In the example shown in Figure 32, the vehicle control system 12000 includes 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. The functional configuration of the integrated control unit 12050 is shown in the figure, which includes a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface 12053.

[0189] 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 drivetrain generating device that generates driving force for the vehicle, such as an internal combustion engine or a drive motor; a drivetrain transmission mechanism that transmits driving force to the wheels; a steering mechanism that adjusts the steering angle of the vehicle; and a braking device that generates braking force for the vehicle.

[0190] The body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window system, or various lamps such as headlights, reverse lights, brake lights, turn signals, or fog lights. In this case, the body system control unit 12020 may receive radio waves transmitted from a portable device that replaces a key or signals from various switches. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock system, power window system, lamps, etc.

[0191] The external information detection unit 12030 detects information from outside the vehicle equipped with the 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 causes the imaging unit 12031 to capture images of the outside of the vehicle and receives the captured images. Based on the received images, the external information detection unit 12030 may perform object detection processing such as detecting people, cars, obstacles, signs, or characters on the road surface, or distance detection processing.

[0192] The imaging unit 12031 is a light sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0193] 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 status detection unit 12041 that detects the driver's state. The driver status detection unit 12041 includes, for example, a camera that captures images of the driver, and the in-vehicle information detection unit 12040 may calculate the driver's level of fatigue or concentration, or determine whether the driver is drowsy, based on the detection information input from the driver status detection unit 12041.

[0194] The microcomputer 12051 can calculate control target values ​​for the drive force generator, steering mechanism, or braking device based on information inside and outside the vehicle acquired by the external information detection unit 12030 or the internal information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing ADAS (Advanced Driver Assistance System) functions, including collision avoidance or impact mitigation, following driving based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

[0195] Furthermore, the microcomputer 12051 can perform cooperative control for purposes such as autonomous driving, where the vehicle drives autonomously without driver intervention, by controlling the drive force generating device, steering mechanism, or braking device, etc., based on information about the vehicle's surroundings acquired by the external information detection unit 12030 or the internal information detection unit 12040.

[0196] Furthermore, the microcomputer 12051 can output control commands to the body system control unit 12020 based on external information acquired by the external information detection unit 12030. For example, the microcomputer 12051 can control the headlights according to the position of a preceding or oncoming vehicle detected by the external information detection unit 12030, and perform coordinated control aimed at reducing glare, such as switching from high beams to low beams.

[0197] The audio-image output unit 12052 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying information to the vehicle's occupants or to those outside the vehicle. In the example shown in Figure 32, the output devices include an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an onboard display and a head-up display.

[0198] Figure 33 shows an example of the installation position of the imaging unit 12031.

[0199] In Figure 33, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0200] The imaging units 12101, 12102, 12103, 12104, and 12105 are installed, for example, on the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle 12100. The imaging unit 12101 installed on the front nose and the imaging unit 12105 installed on the upper part of the windshield inside the vehicle mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 installed on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 installed on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 installed on the upper part of the windshield inside the vehicle is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, or lanes.

[0201] Figure 33 shows an example of the imaging ranges of imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of imaging unit 12101 located on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of imaging units 12102 and 12103 located on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of imaging unit 12104 located on the rear bumper or back door. For example, by superimposing the image data captured by imaging units 12101 to 12104, an overhead view image of the vehicle 12100 can be obtained.

[0202] 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 consisting of multiple image sensors, or an image sensor having pixels for phase difference detection.

[0203] For example, the microcomputer 12051, based on distance information obtained from the imaging units 12101 to 12104, can determine the distance to each object within the imaging range 12111 to 12114 and the temporal change of this distance (relative speed to the vehicle 12100). In particular, it can extract the closest object on the vehicle 12100's path that is traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or more) as the preceding vehicle. Furthermore, the microcomputer 12051 can set a predetermined distance to be maintained before the preceding vehicle and perform automatic braking control (including follow-and-stop control) and automatic acceleration control (including follow-and-start control), etc. In this way, cooperative control aimed at autonomous driving, etc., that drives autonomously without driver operation, can be performed.

[0204] For example, the microcomputer 12051 can use distance information obtained from imaging units 12101 to 12104 to classify and extract three-dimensional object data related to three-dimensional objects, such as motorcycles, passenger cars, large vehicles, pedestrians, utility poles, and other three-dimensional objects, and use this data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines the collision risk, which indicates the degree of risk of collision with each obstacle. If the collision risk is above a set value and there is a possibility of collision, the microcomputer 12051 can provide driving assistance to avoid collisions by outputting a warning to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or evasive steering via the drive system control unit 12010.

[0205] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared light. For example, the microcomputer 12051 can recognize pedestrians by determining whether or not pedestrians are present in the images captured by the imaging units 12101 to 12104. Such pedestrian recognition is performed, for example, by a procedure to extract feature points from the images captured by the imaging units 12101 to 12104 as infrared cameras, and a procedure to perform pattern matching on a series of feature points that indicate the contour of an object to determine whether or not it is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the imaging units 12101 to 12104 and recognizes a pedestrian, the audio-image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio-image output unit 12052 may also control the display unit 12062 to display an icon indicating a pedestrian at a desired position.

[0206] The above describes an example of a mobile object control system to which the technology of this disclosure may be applied. The technology of this disclosure can be applied to the imaging unit 12031 of the configuration described above. Specifically, the light detection device (for example, light detection device 1) according to the above embodiment and its modified examples 1 to 3 can be applied to the imaging unit 12031. By applying the technology of this disclosure to the imaging unit 12031, high-resolution images with low noise can be obtained, so that high-precision control using the captured images can be performed in the mobile object control system.

[0207] The present technology has been described above with reference to embodiments, modifications 1 to 3 and other modifications 1 to 7, as well as application examples and application examples. However, the contents of this disclosure are not limited to the above embodiments, and various modifications are possible. For example, the above embodiments show an example in which electrons are read out from the lower electrode 11 side as the signal charge, but the present technology is not limited to this, and holes may be read out from the lower electrode 11 side as the signal charge.

[0208] Furthermore, in the above embodiment, the photodetector 1 was configured by stacking a photoelectric conversion unit 10 made of an organic material for detecting green light (G) and a photoelectric conversion region 32B and a photoelectric conversion region 32R for detecting blue light (B) and red light (R), respectively. However, the disclosure is not limited to this structure. That is, the photoelectric conversion unit made of an organic material may be configured to detect red light (R) or blue light (B), or the photoelectric conversion region made of an inorganic material may be configured to detect green light (G).

[0209] Furthermore, the number and ratio of photoelectric conversion units made of organic materials and photoelectric conversion regions made of inorganic materials are not limited. Moreover, the structure is not limited to stacking the photoelectric conversion units made of organic materials and photoelectric conversion regions made of inorganic materials in the vertical direction; they may also be arranged in parallel along the substrate surface.

[0210] Furthermore, although the above embodiments illustrate the configuration of a back-illuminated type photodetector, the contents of this disclosure are also applicable to a front-illuminated type photodetector.

[0211] Furthermore, the light detection device 1 of the present disclosure does not need to have all of the components described in the above embodiments, and conversely, it may have other components. For example, the light detection device 1 may be equipped with a shutter for controlling the incidence of light to each unit pixel P, or it may be equipped with an optical cut filter depending on the purpose of the light detection device 1. In addition, the arrangement of pixels (Pr, Pg, Pb) that detect red light (R), green light (G), and blue light (B) may be an interline arrangement, G-stripe RB checkerboard arrangement, G-stripe RB complete checkerboard arrangement, checkerboard complementary arrangement, stripe arrangement, diagonal stripe arrangement, primary color difference arrangement, field color difference sequential arrangement, frame color difference sequential arrangement, MOS type arrangement, improved MOS type arrangement, frame interleaved arrangement, or field interleaved arrangement, in addition to the Bayer arrangement.

[0212] Furthermore, although the above embodiments show an example in which the photodetector 1 is used as an image sensor, the photodetector 1 of this disclosure may also be applied to a solar cell. When applied to a solar cell, it is preferable that the photoelectric conversion layer be designed to broadly absorb wavelengths of, for example, 400 nm to 800 nm.

[0213] Furthermore, the effects described herein are merely illustrative and not limiting, and other effects may also occur.

[0214] Furthermore, this technology can also take the following configuration. With this technology in the following configuration, the parasitic capacitance between the first through-wiring and the semiconductor substrate is reduced, thereby improving the conversion efficiency. Thus, it becomes possible to improve image quality. (1) A photodetector comprising: a semiconductor substrate having opposing first and second surfaces; a first photoelectric conversion unit disposed on the first surface side and converting light into electric charge; a first through-wiring that penetrates between the first and second surfaces of the semiconductor substrate and transfers the electric charge; a first well region having a first conductivity type provided over the entire surface of the semiconductor substrate; a second well region having the first conductivity type provided around the first through-wiring; and a third well region having a second conductivity type different from the first conductivity type, provided between the first and second well regions and electrically separating the first and second well regions. (2) The photodetector according to (1), wherein the semiconductor substrate further comprises a floating diffusion layer on the second surface for temporarily holding the charge, and a readout circuit including a first transistor that outputs a signal based on the charge. (3) The photodetector according to (2), wherein the first through-wiring transfers the charge to at least one of the floating diffusion layer and the first transistor. (4) The photodetector according to any one of (1) to (3), wherein the semiconductor substrate further comprises a first contact region provided in the first well region, a second contact region provided in the second well region, and a third contact region provided in the third well region, wherein a first voltage is applied to the first well region, a second voltage different from the first voltage is applied to the second well region, and a third voltage different from the first voltage and the second voltage is applied to the third well region. (5) The photodetector according to (4), wherein the second voltage is a voltage at which the voltage difference between the first through-wiring and the second well region decreases when the charge is transferred to the first through-wiring. (6) The photodetector according to (4) or (5), wherein the third voltage is a power supply voltage.(7) The photodetector according to any one of (2) to (6), wherein the semiconductor substrate further comprises a first contact region provided in the first well region, a second contact region provided in the second well region, and a third contact region provided in the third well region, and the source of the first transistor and the second contact region are electrically connected. (8) The photodetector according to (7), wherein the first transistor is provided in the second well region. (9) The photodetector according to any one of (1) to (8), wherein the first through-wiring comprises a first conductive portion penetrating between the first surface and the second surface of the semiconductor substrate, and a first insulating film provided around the first conductive portion. (10) The photodetector according to any one of (2) to (9), wherein the semiconductor substrate further has a second through-wiring that penetrates between the first surface and the second surface and has no electrical connection with the floating diffusion layer. (11) The photodetector according to (10), wherein the third well region is provided around the second through-wiring without passing through the second well region. (12) The photodetector according to (11), wherein the semiconductor substrate further has a pixel array portion in which a plurality of pixels are arranged in a two-dimensional array, and the first through-wiring and the second through-wiring are each disposed one or more times between adjacent pixels. (13) The photodetector according to (12), wherein the third well region extends between adjacent pixels. (14) The photodetector according to any one of (10) to (13), wherein the second through-wiring has a second conductive portion penetrating between the first surface and the second surface of the semiconductor substrate, and a second insulating film provided around the second conductive portion. (15) The photodetector according to any one of (10) to (14), wherein the semiconductor substrate further has a pixel array portion in which a plurality of pixels are arranged in a two-dimensional array, and a pixel separation portion provided between adjacent plurality of pixels, and the pixel separation portion has a third insulating film embedded in a groove extending from one of the first surface and the second surface of the semiconductor substrate to the other.(16) The photodetector according to (15), wherein the first through-wiring has a first conductive portion that penetrates between the first surface and the second surface of the semiconductor substrate and a first insulating film provided around the first conductive portion, the second through-wiring has a second conductive portion that penetrates between the first surface and the second surface of the semiconductor substrate and a second insulating film provided around the second conductive portion, the first through-wiring and the second through-wiring are each provided between the plurality of adjacent pixels, and the first insulating film, the second insulating film and the third insulating film are continuous with respect to each other. (17) An electronic device comprising a photodetector, the photodetector comprising: a semiconductor substrate having opposing first and second surfaces; a first photoelectric conversion unit disposed on the first surface side and converting light into electric charge; a first through-wiring that penetrates between the first and second surfaces of the semiconductor substrate and transfers the electric charge; a first well region having a first conductivity type provided over the entire surface of the semiconductor substrate; a second well region having the first conductivity type provided around the first through-wiring; and a third well region having a second conductivity type different from the first conductivity type, provided between the first and second well regions and electrically separating the first and second well regions.

[0215] This application claims priority based on Japanese Patent Application No. 2024-172755, filed with the Japan Patent Office on 1 October 2024, and all contents of that application are incorporated herein by reference.

[0216] Those skilled in the art will understand that various modifications, combinations, subcombinations, and changes can be conceived depending on design requirements and other factors, and that these fall within the scope of the attached claims and their equivalents.

Claims

A semiconductor substrate having opposing first and second surfaces, The first photoelectric conversion unit, which is disposed on the first surface side and converts light into electric charge, A first through-wiring that penetrates between the first and second surfaces of the semiconductor substrate and transfers the charge, A first well region having a first conductivity type is provided across the entire surface of the semiconductor substrate, A second well region having the first conductivity type is provided around the first through-wiring, A third well region of a second conductivity type different from the first conductivity type is provided between the first well region and the second well region, electrically separating the first well region and the second well region. A light detection device equipped with this device. 　 The photodetector according to claim 1, wherein the semiconductor substrate further comprises a floating diffusion layer on the second surface for temporarily holding the charge, and a readout circuit including a first transistor that outputs a signal based on the charge. 　 The photodetector according to claim 2, wherein the first through-wiring transfers the charge to at least one of the floating diffusion layer and the first transistor. 　 The semiconductor substrate further comprises a first contact region provided in the first well region, a second contact region provided in the second well region, and a third contact region provided in the third well region. A first voltage is applied to the first well region. In the second well region, a second voltage different from the first voltage is applied. The photodetector according to claim 1, wherein a third voltage different from the first voltage and the second voltage is applied to the third well region. 　 The photodetector according to claim 4, wherein the second voltage is a voltage at which the voltage difference between the first through-wiring and the second well region decreases when the charge is transferred to the first through-wiring. 　 The photodetector according to claim 4, wherein the third voltage is the power supply voltage. 　 The semiconductor substrate further comprises a first contact region provided in the first well region, a second contact region provided in the second well region, and a third contact region provided in the third well region. The photodetector according to claim 2, wherein the source of the first transistor and the second contact region are electrically connected. 　 The photodetector according to claim 7, wherein the first transistor is provided in the second well region. 　 The photodetector according to claim 1, wherein the first through-wiring has a first conductive portion that penetrates between the first surface and the second surface of the semiconductor substrate, and a first insulating film provided around the first conductive portion. 　 The photodetector according to claim 2, wherein the semiconductor substrate further has a second through-wiring that penetrates between the first surface and the second surface and has no electrical connection with the floating diffusion layer. 　 The photodetector according to claim 10, wherein the third well region is provided around the second through-wiring without passing through the second well region. 　 The semiconductor substrate further comprises a pixel array portion in which a plurality of pixels are arranged in a two-dimensional array, The photodetector according to claim 11, wherein the first through-wiring and the second through-wiring are each arranged one or more times between adjacent pixels. 　 The photodetector according to claim 12, wherein the third well region extends between adjacent pixels. 　 The photodetector according to claim 10, wherein the second through-wiring has a second conductive portion that penetrates between the first surface and the second surface of the semiconductor substrate, and a second insulating film provided around the second conductive portion. 　 The semiconductor substrate further comprises a pixel array portion in which a plurality of pixels are arranged in a two-dimensional array, and a pixel separation portion provided between adjacent plurality of pixels. The photodetector according to claim 10, wherein the pixel separation portion has a third insulating film embedded in a groove extending from one of the first and second surfaces of the semiconductor substrate to the other. 　 The first through-wiring has a first conductive portion that penetrates between the first surface and the second surface of the semiconductor substrate, and a first insulating film provided around the first conductive portion. The second through-wiring has a second conductive portion that penetrates between the first surface and the second surface of the semiconductor substrate, and a second insulating film provided around the second conductive portion. The first through-wiring and the second through-wiring are provided, respectively, between adjacent pixels. The photodetector according to claim 15, wherein the first insulating film, the second insulating film, and the third insulating film are continuous with respect to each other. 　 Equipped with a light detection device, The aforementioned light detection device is A semiconductor substrate having opposing first and second surfaces, The first photoelectric conversion unit, which is disposed on the first surface side and converts light into electric charge, A first through-wiring that penetrates between the first and second surfaces of the semiconductor substrate and transfers the charge, A first well region having a first conductivity type is provided across the entire surface of the semiconductor substrate, A second well region having the first conductivity type is provided around the first through-wiring, A third well region of a second conductivity type different from the first conductivity type is provided between the first well region and the second well region, electrically separating the first well region and the second well region. A powerful electronic device.

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