Light detection device

Abstract

A light detection device according to a first embodiment of the present disclosure comprises: a semiconductor substrate that includes a first surface and a second surface which are opposing; a first photoelectric conversion unit that is provided on the first surface side of the semiconductor substrate, and that detects light in a first wavelength region and performs photoelectric conversion; a first floating diffusion layer that is provided on the second surface of the semiconductor substrate, and that accumulates signal charges generated in the first photoelectric conversion unit; a first through electrode that includes a first conductor penetrating between the first surface and the second surface of the semiconductor substrate and a first insulation film surrounding the first conductor, the first through electrode electrically connecting the first photoelectric conversion unit and the first floating diffusion layer; and a second through electrode that includes a second conductor penetrating between the first surface and the second surface of the semiconductor substrate and a second insulation film which surrounds the second conductor and which includes at least a portion that is thinner than the first insulation film, the second through electrode electrically connecting the first photoelectric conversion unit and an active element other than the first floating diffusion layer provided on the second surface of the semiconductor substrate.

Description

Photodetector

[0001] The present disclosure relates to a light detection device.

[0002] For example, Patent Document 1 discloses a photodetector in which an organic photoelectric conversion unit having an organic photoelectric conversion layer is stacked on one side of a semiconductor substrate on which a photoelectric conversion region is formed, and RGB signals acquired by this organic photoelectric conversion unit are conveyed to a charge-voltage conversion unit provided on the other side of the semiconductor substrate using through electrodes.

[0003] International Publication No. 2022 / 131268

[0004] Incidentally, there is a demand for reducing random noise in photodetection devices.

[0005] Therefore, it is desirable to provide a photodetector that can reduce random noise.

[0006] A first photodetector according to one embodiment of the present disclosure includes a semiconductor substrate having opposing first and second surfaces; a first photoelectric conversion unit provided on the first surface of the semiconductor substrate and configured to detect light in a first wavelength range and perform photoelectric conversion; a first floating diffusion layer provided on the second surface of the semiconductor substrate and configured to accumulate signal charges generated in the first photoelectric conversion unit; a first through electrode including a first conductor penetrating between the first and second surfaces of the semiconductor substrate and a first insulating film surrounding the first conductor, and electrically connecting the first photoelectric conversion unit and the first floating diffusion layer; and a second through electrode including a second conductor penetrating between the first and second surfaces of the semiconductor substrate and a second insulating film surrounding the second conductor, at least a portion of which has a thickness thinner than the thickness of the first insulating film, and electrically connecting the first photoelectric conversion unit and an active element other than the first floating diffusion layer provided on the second surface of the semiconductor substrate.

[0007] A second photodetector according to one embodiment of the present disclosure includes a semiconductor substrate having opposing first and second surfaces; a first photoelectric conversion unit provided on the first surface of the semiconductor substrate and configured to detect light in a first wavelength range and perform photoelectric conversion; a floating diffusion layer provided on the second surface of the semiconductor substrate and configured to accumulate signal charges generated in the first photoelectric conversion unit; a first through electrode including a first conductor penetrating between the first and second surfaces of the semiconductor substrate and a first insulating film surrounding the first conductor, and electrically connecting the first photoelectric conversion unit and the floating diffusion layer; and a second through electrode including a second conductor penetrating between the first and second surfaces of the semiconductor substrate and a second insulating film surrounding the second conductor and having a higher dielectric constant than the first insulating film, and electrically connecting the first photoelectric conversion unit and an active element other than the first floating diffusion layer provided on the second surface of the semiconductor substrate.

[0008] In a first photodetector according to an embodiment of the present disclosure, a first through electrode electrically connecting a first photoelectric conversion unit provided on a first surface side of a semiconductor substrate to a first floating diffusion layer provided on a second surface of the semiconductor substrate and penetrating between the first and second surfaces of the semiconductor substrate is configured such that the thickness of the insulating film surrounding the conductor is thicker than that of the second through electrode penetrating between the first and second surfaces of the semiconductor substrate. Also, in a second photodetector according to an embodiment of the present disclosure, a first insulating film surrounding a first conductor constituting the first through electrode electrically connecting a first photoelectric conversion unit provided on a first surface side of the semiconductor substrate to a first floating diffusion layer provided on a second surface of the semiconductor substrate and penetrating between the first and second surfaces of the semiconductor substrate is configured such that the dielectric constant is smaller than that of a second insulating film surrounding a second conductor constituting a second through electrode penetrating between the first and second surfaces of the semiconductor substrate. This makes the capacitance of the first through electrode smaller than the capacitance of the other through electrodes.

[0009] FIG. 1A is a schematic diagram illustrating an example of a photodetector according to an embodiment of the present disclosure. FIG. 1B is an explanatory diagram illustrating a schematic configuration example of a pixel unit illustrated in FIG. 1A. FIG. 2A is a cross-sectional schematic diagram illustrating an example of the configuration of the photodetector illustrated in FIG. 1A. FIG. 2B is a plan view schematic diagram illustrating a layout of through-electrodes in Sec1 illustrated in FIG. 2A. FIG. 3 is a diagram illustrating the relationship between capacitance and conductors and insulators constituting the through-electrodes. FIG. 4A is a schematic diagram illustrating an example of a planar shape of a through-electrode. FIG. 4B is a schematic diagram illustrating another example of a planar shape of a through-electrode. FIG. 4C is a schematic diagram illustrating another example of a planar shape of a through-electrode. FIG. 5A is a schematic diagram illustrating an example of a cross-sectional shape of a through-electrode. FIG. 5B is a schematic diagram illustrating another example of a cross-sectional shape of a through-electrode. FIG. 5C is a schematic diagram illustrating another example of a cross-sectional shape of a through-electrode. FIG. 6 is a circuit diagram illustrating an example of a readout circuit of the iTOF sensor unit illustrated in FIG. 2A. FIG. 7 is a circuit diagram illustrating an example of a readout circuit of the organic photoelectric conversion unit illustrated in FIG. 2A. FIG. 8 is a schematic plan view showing a layout of through electrodes according to Modification 1 of the present disclosure. FIG. 9 is a schematic plan view showing a layout of through electrodes according to Modification 2 of the present disclosure. FIG. 10 is a schematic plan view showing a layout of through electrodes according to Modification 3 of the present disclosure. FIG. 11 is a schematic plan view showing a layout of through electrodes according to Modification 4 of the present disclosure. FIG. 12 is a schematic plan view showing a layout of through electrodes according to Modification 4 of the present disclosure. FIG. 13 is a schematic plan view showing a layout of through electrodes according to Modification 4 of the present disclosure. FIG. 14 is a schematic plan view showing a layout of through electrodes according to Modification 4 of the present disclosure. FIG. 15 is a schematic plan view showing a layout of through electrodes according to Modification 5 of the present disclosure. FIG. 16 is a schematic plan view showing a layout of through electrodes according to Modification 6 of the present disclosure. FIG. 17 is a schematic plan view showing a layout of through electrodes according to Modification 6 of the present disclosure. FIG. 18 is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 7 of the present disclosure. Fig. 19A is a schematic plan view showing an example of the layout of the through electrodes in Sec1 shown in Fig. 18. Fig. 19B is a schematic plan view showing another example of the layout of the through electrodes in Sec1 shown in Fig. 18. Fig. 20 is a schematic plan view showing another example of the layout of the through electrodes in Sec1 shown in Fig. 18.FIG. 21 is a cross-sectional schematic diagram illustrating a configuration of a photodetector according to Modification 8 of the present disclosure. FIG. 22 is a cross-sectional schematic diagram illustrating a configuration of a photodetector according to Modification 9 of the present disclosure. FIG. 23 is a plan schematic diagram illustrating an example of a layout of the through electrodes shown in FIG. 22. FIG. 24 is a block diagram illustrating an example of a configuration of an electronic device using the photodetector shown in FIG. 1A. FIG. 25A is a schematic diagram illustrating an example of an overall configuration of a photodetection system using the photodetector shown in FIG. 1A. FIG. 25B is a diagram illustrating an example of a circuit configuration of the photodetection system shown in FIG. 25A. FIG. 26 is a diagram illustrating an example of a schematic configuration of an endoscopic surgery system. FIG. 27 is a block diagram illustrating an example of a functional configuration of a camera head and a CCU. FIG. 28 is a block diagram illustrating an example of a schematic configuration of a vehicle control system. FIG. 29 is an explanatory diagram illustrating an example of installation positions of an outside vehicle information detection unit and an imaging unit.

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The following description is a specific example of the present disclosure, and the present disclosure is not limited to the following aspects. Furthermore, the present disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc. of the components shown in the drawings. The description will be given in the following order: 1. Embodiment (Example of a photodetector in which the thickness of the insulating film of the through electrode connected to the FD is greater than the thickness of the insulating film of the other through electrodes) 2. Modifications 2-1. Modification 1 (Another example of the configuration of the through electrode) 2-2. Modification 2 (Another example of the configuration of the through electrode) 2-3. Modification 3 (Another example of the configuration of the through electrode) 2-4. Modification 4 (Another example of the configuration of the through electrode) 2-5. Modification 5 (Another example of the configuration of the through electrode) 2-6. Modification 6 (Another example of the configuration of the through electrode) 2-7. Modification 7 (Another example of the configuration of the through electrode) 2-8. Modification 8 (Another example of the configuration of the photodetector) 2-9. Modification 9 (Another example of the configuration of the photodetector) 3. Application examples 4. Application examples

[0011] 1. Embodiments [Configuration of Photodetector] (Overall Configuration Example) FIG. 1A illustrates an overall configuration example of a photodetector 1 according to an embodiment of the present disclosure. The photodetector 1 is, for example, a complementary metal oxide semiconductor (CMOS) image sensor. The photodetector 1 captures incident light (image light) from a subject via, for example, an optical lens system, converts the incident light imaged on an imaging surface into an electrical signal on a pixel-by-pixel basis, and outputs the electrical signal as a pixel signal. The photodetector 1 includes, for example, a pixel unit 100 as an imaging area on a semiconductor substrate 11, and 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 an input / output terminal 116 arranged in a peripheral region of the pixel unit 100. The photodetector 1 corresponds to a specific example of a "photodetector" according to an embodiment of the present disclosure.

[0012] FIG. 1B is a schematic diagram illustrating an example of the configuration of a pixel unit 100. As shown in FIG. 1B , the pixel unit 100 includes an effective area 100A having a plurality of unit pixels P arranged two-dimensionally in a matrix, for example, and a peripheral area 100B located around the effective area 100A. The effective area 100A of the pixel unit 100 includes a plurality of pixel rows each consisting of a plurality of unit pixels P arranged horizontally (horizontally on the page) and a plurality of pixel columns each consisting of a plurality of unit pixels P arranged vertically (vertically on the page). The pixel unit 100 includes, for example, one pixel drive line Lread (a row selection line and a reset control line) for each pixel row and one vertical signal line Lsig for each pixel column. The pixel drive line Lread transmits a drive signal for reading out a signal from each unit pixel P. The ends of the plurality of pixel drive lines Lread are connected to a plurality of output terminals of the vertical drive circuit 111 corresponding to each pixel row.

[0013] The vertical drive circuit 111 is configured with a shift register, an address decoder, etc., and is a pixel drive section that drives each unit pixel P in the pixel section 100, for example, in units of pixel rows. Signals output from each unit pixel P in a pixel row selected and scanned by the vertical drive circuit 111 are supplied to a column signal processing circuit 112 through each vertical signal line Lsig.

[0014] The column signal processing circuit 112 is configured by an amplifier, a horizontal selection switch, and the like, which are provided for each vertical signal line Lsig.

[0015] The horizontal drive circuit 113 is configured with a shift register, an address decoder, etc., and scans and sequentially drives each horizontal selection switch of the column signal processing circuit 112. By selective scanning by this horizontal drive circuit 113, signals of each unit pixel P transmitted through each of the multiple vertical signal lines Lsig are output in sequence to a horizontal signal line 121, and are transmitted to the outside of the semiconductor substrate 11 through the horizontal signal line 121.

[0016] The output circuit 114 processes and outputs signals sequentially supplied from each of the column signal processing circuits 112 via the horizontal signal line 121. The output circuit 114 may perform only buffering, or may perform black level adjustment, column variation correction, various digital signal processing, and the like, for example.

[0017] The circuit portion consisting of the vertical drive circuit 111, the column signal processing circuit 112, the horizontal drive circuit 113, the horizontal signal line 121, and the output circuit 114 may be formed directly on the semiconductor substrate 11, or may be disposed on an external control IC. Furthermore, these circuit portions may be formed on another substrate connected by a cable or the like.

[0018] The control circuit 115 receives a clock and data instructing an operation mode from outside the semiconductor substrate 11, and outputs data such as internal information of the unit pixel P, which is an image sensor. The control circuit 115 further has a timing generator that generates various timing signals, and controls the driving 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.

[0019] The input / output terminal 116 is used to exchange signals with the outside.

[0020] (Example of Cross-Sectional Configuration of Unit Pixel) FIG. 2A schematically illustrates an example of a cross-sectional configuration of the photodetector 1 along the thickness direction of a plurality of unit pixels P arranged in a matrix in the pixel section 100. FIG. 2B schematically illustrates a planar layout of the through-electrodes 16 at the position of Sec1 shown in FIG. 2A. Note that FIG. 2A corresponds to line II' shown in FIG. 2B. In FIGS. 2A and 2B, the thickness direction (stacking direction) of the unit pixel P1 is defined as the Z-axis direction, and the plane directions parallel to the stacking plane perpendicular to the Z-axis direction are defined as the X-axis direction and the Y-axis direction. Note that the X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to one another.

[0021] 2A , the unit pixel P is a so-called vertical spectroscopic imaging element having a structure in which, for example, one photoelectric conversion unit 10 as pixel P1 and four organic photoelectric conversion units 20 arranged in 2 rows and 2 columns as pixel P2 are stacked in the Z-axis direction, which is the thickness direction. Here, the photoelectric conversion unit 10 corresponds to a specific example of a “second photoelectric conversion unit” in the embodiment of the present disclosure, and the organic photoelectric conversion unit 20 corresponds to a specific example of a “first photoelectric conversion unit” in the embodiment of the present disclosure. The unit pixel P further includes an intermediate layer 40 provided between the photoelectric conversion unit 10 and the organic photoelectric conversion unit 20, and a multilayer wiring layer 30 provided on the opposite side of the photoelectric conversion unit 10 from the organic photoelectric conversion unit 20. Furthermore, on the light incident side opposite the photoelectric conversion unit 10 as viewed from the organic photoelectric conversion unit 20, for example, a sealing film 51, a low-refractive index layer 52, a plurality of color filters (CFs) 53, and on-chip lenses (OCLs) 54 provided corresponding to each of the plurality of CFs 53 are stacked along the Z-axis direction in this order from a position closest to the organic photoelectric conversion unit 20. The sealing film 51 and the low-refractive index layer 52 may each be provided in common to a plurality of unit pixels P. The sealing film 51 has a configuration in which transparent insulating films such as AlOx are stacked. An anti-reflection film may also be provided to cover the OCLs 54. A black filter may be provided in the peripheral region 100B. Each of the plurality of CFs 53 includes, for example, a red filter 53R that mainly transmits red light, a green filter 53G that mainly transmits green light, and a blue filter 53B that mainly transmits blue light. In addition, the unit pixel P1 of this embodiment is equipped with red, green and blue CFs 53 (red filter 53R, green filter 53G and blue filter 53B), respectively, and receives red light, green light and blue light in the organic photoelectric conversion section 20, respectively, to obtain a color visible light image.

[0022] (Photoelectric Conversion Unit 10) The photoelectric conversion unit 10 is, for example, an indirect TOF (hereinafter referred to as iTOF) sensor that acquires a distance image (distance information) by optical time-of-flight (TOF). The photoelectric conversion unit 10 has, for example, a semiconductor substrate 11, a photoelectric conversion region 12, a fixed charge layer 13, a pair of transfer transistors (TG) 14 (TG14A, TG14B), and charge-voltage conversion units (FD) 15A (FD15A-1, FD15A-2) that are floating diffusion regions.

[0023] The semiconductor substrate 11 is, for example, an n-type silicon (Si) substrate including a pair of opposing surfaces 11S1 and 11S2, and has a p-well in a predetermined region. Here, the surface 11S1 corresponds to a specific example of a "first surface" in the embodiment of the present disclosure and is the back surface of the semiconductor substrate 11 facing the intermediate layer 40. The surface 11S2 corresponds to a specific example of a "second surface" in the embodiment of the present disclosure and is the front surface of the semiconductor substrate 11 facing the multilayer wiring layer 30. For example, as shown in FIG. 2A , the surface 11S1 may have a fine uneven structure formed thereon. This is because it is effective in confining infrared light incident on the semiconductor substrate 11 within the semiconductor substrate 11. A similar fine uneven structure may also be formed on the surface 11S2.

[0024] The photoelectric conversion region 12 is a photoelectric conversion element configured by, for example, a PIN (Positive Intrinsic Negative) type photodiode (PD), and includes a pn junction formed in a predetermined region of the semiconductor substrate 11. The photoelectric conversion region 12 detects and receives light from the subject, particularly light having a wavelength in the infrared light region, and generates and accumulates electric charges according to the amount of received light through photoelectric conversion.

[0025] The fixed charge layer 13 is provided to cover the surface 11S1 of the semiconductor substrate 11 and the like. The fixed charge layer 13 has, for example, a negative fixed charge in order to suppress the generation of dark current due to interface states of the surface 11S1, which is the light-receiving surface of the semiconductor substrate 11. An electric field induced by the fixed charge layer 13 forms a hole accumulation layer near the surface 11S1 of the semiconductor substrate 11. This hole accumulation layer suppresses the generation of electrons from the surface 11S1. The fixed charge layer 13 also includes a portion extending in the Z-axis direction along the sidewall of the through hole 11H in which the through electrode 16 is formed. The fixed charge layer 13 is preferably formed using an insulating material. Specifically, examples of the material for the fixed charge layer 13 include hafnium oxide (HfOx), aluminum oxide (AlOx), zirconium oxide (ZrOx), tantalum oxide (TaOx), titanium oxide (TiOx), lanthanum oxide (LaOx), praseodymium oxide (PrOx), cerium oxide (CeOx), neodymium oxide (NdOx), promethium oxide (PmOx), samarium oxide (SmOx), and europium oxide (EuO x), gadolinium oxide (GdOx), terbium oxide (TbOx), dysprosium oxide (DyOx), holmium oxide (HoOx), thulium oxide (TmOx), ytterbium oxide (YbOx), lutetium oxide (LuOx), yttrium oxide (YOx), hafnium nitride (HfNx), aluminum nitride (AlNx), hafnium oxynitride (HfOxNy), and aluminum oxynitride (AlOxNy).

[0026] The pair of TGs 14A and 14B each extend in the Z-axis direction, for example, from the surface 11S2 to the photoelectric conversion region 12. The TGs 14A and 14B transfer the electric charges accumulated in the photoelectric conversion region 12 to the pair of FDs 15A-1 and 15A-2 in response to an applied drive signal.

[0027] The pair of FDs 15A-1 and 15A-2 are floating diffusion regions that convert charges transferred from the photoelectric conversion region 12 via TGs 14A and 14B into electrical signals (e.g., voltage signals) and output the signals. FD 15B is a floating diffusion region that converts charges transferred from the organic photoelectric conversion unit 20 via a through electrode 16A (described later) into electrical signals (e.g., voltage signals) and output the signals. As shown in FIG. 6 (described later), reset transistors (RST) 143-1 and 143-2 are connected to FDs 15A-1 and 15A-2, and vertical signal lines Lsig (FIG. 1A) are connected to FDs 15A-1 and 15A-2 via amplification transistors (AMP) 144-1 and 144-2 and selection transistors (SEL) 145-1 and 145-2. As shown in FIG. 7, which will be described later, a reset transistor (RST) 132 is connected to the FD 15B, and also connected to the vertical signal line Lsig (FIG. 1A) via an amplification transistor (AMP) 133 and a selection transistor (SEL) 134.

[0028] The through electrode 16 is a connection member that electrically connects the organic photoelectric conversion unit 20 provided on the surface 11S1 side of the semiconductor substrate 11 with an active element provided on the surface 11S2 of the semiconductor substrate 11. The through electrode 16 can be provided, for example, so as to extend in the Z-axis direction from the readout electrode 21A of the organic photoelectric conversion unit 20 through the semiconductor substrate 11 to the multilayer wiring layer 30. For example, the through electrode 16 has a through wire 161 that penetrates between the surface 11S1 and the surface 11S2 of the semiconductor substrate 11, a through wire 162 that penetrates the intermediate layer 40, and a connection electrode 163 that connects the through wire 161 and the through wire 162.

[0029] The through electrode 16 serves as a transmission path for transmitting, for example, signal charges generated in the organic photoelectric conversion unit 20 and a voltage for driving the charge storage electrode 21B. Specifically, the through electrode 16 includes a through electrode 16A that electrically connects the readout electrode 21A of the organic photoelectric conversion unit 20 provided on the surface 11S1 side of the semiconductor substrate 11 with the FD 15B and AMP 133 provided on the surface 11S2 of the semiconductor substrate 11, and a through electrode 16B that electrically connects the organic photoelectric conversion unit 20 provided on the surface 11S1 side of the semiconductor substrate 11 with active elements other than the FD 15B. As an example, the through electrode 16B electrically connects the charge storage electrode 21B of the organic photoelectric conversion unit 20 provided on the surface 11S1 side of the semiconductor substrate 11 with the vertical drive circuit 111. In the photodetector 1, as shown in FIG. 2B, a plurality of through electrodes 16A and a plurality of through electrodes 16B are arranged, for example, alternately at the boundary between adjacent pixels P1 in which the photoelectric conversion regions 12 are respectively provided.

[0030] In this embodiment, the through electrode 16A electrically connecting the readout electrode 21A of the organic photoelectric conversion unit 20 to the FD 15B and AMP 133 provided on the surface 11S2 of the semiconductor substrate 11 is configured to have a smaller capacitance than the through electrode 16B. The through electrode 16A and the through electrode 16B each have conductors 161a and 161c that penetrate between the surfaces 11S1 and 11S2 of the semiconductor substrate 11 as a through wiring 161, and insulating films 161b and 161d that surround the conductors 161a and 161c, respectively. In this embodiment, the through electrode 16A has a larger diameter (R Ａ >R Ｂ Specifically, the diameter Ra of the conductor 161a constituting the through electrode 16A is equal to the diameter Rb of the conductor 161c constituting the through electrode 6B (Ra=Rb), and the thickness ta of the insulating film 161b surrounding the conductor 161a is greater than the thickness tb of the insulating film 161d surrounding the conductor 161c (ta>tb).

[0031] 4A to 4C are schematic diagrams showing examples of the planar shape of the through electrode 16A. As shown in FIGS. 4A to 4C, the conductor 161a may be circular or polygonal (e.g., rectangular (FIG. 4B) and octagonal (FIG. 4C)). The outer shape of the through electrode 16A may also be circular as shown in FIG. 2B, or polygonal (e.g., octagonal) as shown in FIGS. 4A to 4C. The through electrode 16B may also have a similar planar shape.

[0032] 5A to 5C are schematic diagrams illustrating an example of the cross-sectional shape of the through electrode 16A and the through electrode 16B corresponding to the line II-II' shown in FIG. 2B. While FIG. 5A illustrates an example in which the through electrode 16A and the through electrode 16B are composed of conductors 161a and 161c having a constant diameter and insulating films 161b and 161d having a constant thickness, the through electrode 16A is not limited to this. For example, the through electrode 16A may have a portion of the insulating film 161b that is thicker than the insulating film 161d of the through electrode 16B. Therefore, the through electrode 16A may have a tapered cross-sectional shape in which the thickness of the insulating film 161b varies between the surface 11S1 side and the surface 11S2 side of the semiconductor substrate 11, as shown in FIGS. 5B and 5C.

[0033] The conductors 161a and 161c can be formed using, for example, silicon material doped with impurities such as PDAS (Phosphorus Doped Amorphous Silicon), as well as one or more metal materials such as aluminum (Al), tungsten (W), titanium (Ti), cobalt (Co), platinum (Pt), palladium (Pd), copper (Cu), hafnium (Hf), and tantalum (Ta).

[0034] The insulating films 161b and 161d are each composed of a single layer film made of one of inorganic insulating materials such as silicon oxide (SiOx), silicon nitride (SiNx), and silicon oxynitride (SiON), or a laminated film made of two or more of these materials.

[0035] (Multilayer wiring layer 30) The multilayer wiring layer 30 includes, for example, RST143, AMP144, and SEL145 which, together with TG14, constitute the readout circuit of the photoelectric conversion unit 10, and RST132, AMP133, and SEL134 which constitute the readout circuit of the organic photoelectric conversion unit 20.

[0036] (Intermediate Layer 40) The intermediate layer 40 may include, for example, an interlayer insulating layer 41 and an optical filter 42 embedded in the interlayer insulating layer 41. The interlayer insulating layer 41 may be a single layer made of one of inorganic insulating materials such as silicon oxide (SiOx), silicon nitride (SiNx), and silicon oxynitride (SiON), or a laminated film made of two or more of these materials. Furthermore, the interlayer insulating layer 41 may be made of an organic insulating material such as polymethyl methacrylate (PMMA), polyvinylphenol (PVP), polyvinyl alcohol (PVA), polyimide, polycarbonate (PC), polyethylene terephthalate (PET), polystyrene, N-2(aminoethyl)3-aminopropyltrimethoxysilane (AEAPTMS), 3-mercaptopropyltrimethoxysilane (MPTMS), tetraethoxysilane (TEOS), or octadecyltrichlorosilane (OTS). The interlayer insulating layer 41 further includes a wiring layer M embedded therein, which includes various wirings made of a transparent conductive material and is connected to the charge storage electrode 21B and the like, which will be described later.

[0037] The optical filter 42 has a transmission band in the infrared light range in which photoelectric conversion occurs in the photoelectric conversion region 12. That is, the optical filter 42 transmits light having wavelengths in the infrared light range more easily than light having wavelengths in the visible light range (e.g., wavelengths of 400 nm to 700 nm) as the first wavelength range. Specifically, the optical filter 42 can be made of, for example, an organic material, and is configured to selectively transmit light in the infrared light range while absorbing at least a portion of light with wavelengths in the visible light range. The optical filter 42 is made of, for example, an organic material such as a phthalocyanine derivative.

[0038] (Organic Photoelectric Conversion Unit 20) The organic photoelectric conversion unit 20 includes, for example, a lower electrode 21, an insulating layer 22, a semiconductor layer 23, an organic photoelectric conversion layer 24, and an upper electrode 25, which are stacked in this order from the position closest to the photoelectric conversion unit 10. The lower electrode 21 includes, for example, a readout electrode 21A, a charge storage electrode 21B, and a shield electrode 21C, which are spaced apart from one another. The readout electrode 21A, the charge storage electrode 21B, and the shield electrode 21C are provided, for example, on the same layer. The readout electrode 21A is electrically connected to the semiconductor layer 23 through an opening 22H provided in the insulating layer 22 and is in contact with the upper end of the through electrode 16A. The charge storage electrode 21B faces the semiconductor layer 23 via the insulating layer 22. The charge storage electrode 21B, together with the insulating layer 22 and the semiconductor layer 23, forms a type of capacitor, and accumulates charges generated in the organic photoelectric conversion layer 24 in a portion of the semiconductor layer 23, for example, a region of the semiconductor layer 23 that corresponds to the charge storage electrode 21B via the insulating layer 22. In this embodiment, for example, one charge storage electrode 21B is provided corresponding to each CF 53 and each on-chip lens 54. The charge storage electrode 21B is connected to, for example, the vertical drive circuit 111. A predetermined potential is applied to the shield electrode 21C, electrically isolating adjacent pixels P2. The organic photoelectric conversion unit 20 is connected to, for example, an extraction wiring in the peripheral region 100B.

[0039] The semiconductor layer 23, the organic photoelectric conversion layer 24, and the upper electrode 25 may be provided in common to some of the unit pixels P in the pixel section 100, or may be provided in common to all of the unit pixels P in the pixel section 100. The same applies to the modified examples described later in this embodiment.

[0040] Further, other organic layers may be provided between the semiconductor layer 23 and the organic photoelectric conversion layer 24 and between the organic photoelectric conversion layer 24 and the upper electrode 25 .

[0041] The lower electrode 21 and the upper electrode 25 are made of a light-transmitting conductive film, for example, ITO (indium tin oxide). However, in addition to ITO, the lower electrode 21 and the upper electrode 25 may be made of a tin oxide (SnOx) material with a dopant added thereto, or a zinc oxide material obtained by adding a dopant to zinc oxide (ZnO). Examples of zinc oxide materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, and indium zinc oxide (IZO) with indium (In) added. Examples of materials for the lower electrode 21 and the upper electrode 25 include CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３ or TiO ２ The lower electrode 21 and the upper electrode 25 may further include spinel oxides and YbFe ２ O ４ Oxides having such a structure may also be used.

[0042] The insulating layer 22 can be formed of, for example, the same inorganic insulating material and organic insulating material as the interlayer insulating layer 41 .

[0043] The material constituting the semiconductor layer 23 preferably has a large band gap (for example, a band gap of 3.0 eV or more) and a higher mobility than the material constituting the organic photoelectric conversion layer 24. Specific examples of such a material include oxide semiconductor materials such as IGZO, transition metal dichalcogenides, silicon carbide, diamond, graphene, and carbon nanotubes, as well as organic semiconductor materials such as condensed polycyclic hydrocarbon compounds and condensed heterocyclic compounds.

[0044] The organic photoelectric conversion layer 24 converts light energy into electrical energy and is formed, for example, by including two or more organic materials that function as p-type and n-type semiconductors. The p-type semiconductor functions relatively as an electron donor, and the n-type semiconductor functions relatively as an electron acceptor. The organic photoelectric conversion layer 24 has a bulk heterojunction structure within the layer. The bulk heterojunction structure is a p / n junction interface formed by mixing a p-type semiconductor and an n-type semiconductor, and excitons generated upon light absorption separate into electrons and holes at this p / n junction interface.

[0045] In addition to the p-type and n-type semiconductors, the organic photoelectric conversion layer 24 may further include three types of so-called dye materials that photoelectrically convert light in a predetermined wavelength band while transmitting light in other wavelength bands. The p-type semiconductor, n-type semiconductor, and dye material preferably have different maximum absorption wavelengths. This allows absorption of light in a wide range of wavelengths in the visible light region.

[0046] The organic photoelectric conversion layer 24 can be formed by, for example, mixing the various organic semiconductor materials described above and using a spin coating technique. Alternatively, the organic photoelectric conversion layer 24 may be formed by, for example, vacuum deposition or printing.

[0047] As described above, the organic photoelectric conversion unit 20 detects some or all of the wavelengths in the visible light range. In addition, it is preferable that the organic photoelectric conversion unit 20 does not have sensitivity to the infrared light range.

[0048] In the organic photoelectric conversion unit 20, light incident from the upper electrode 25 side is absorbed by the organic photoelectric conversion layer 24. The resulting excitons (electron-hole pairs) migrate to the interface between the electron donor and electron acceptor constituting the organic photoelectric conversion layer 24, where they undergo exciton dissociation, i.e., dissociation into electrons and holes. The generated charges, i.e., electrons and holes, migrate to the upper electrode 25 or the semiconductor layer 23 due to diffusion caused by a difference in carrier concentration or an internal electric field caused by a potential difference between the upper electrode 25 and the charge storage electrode 21B, and are detected as photocurrent. For example, the readout electrode 21A is set to a positive potential, and the upper electrode 25 is set to a negative potential. In this case, holes generated by photoelectric conversion in the organic photoelectric conversion layer 24 migrate to the upper electrode 25. Electrons generated by photoelectric conversion in the organic photoelectric conversion layer 24 are attracted to the charge storage electrode 21B and accumulated in a portion of the semiconductor layer 23, for example, a region of the semiconductor layer 23 corresponding to the charge storage electrode 21B via the insulating layer 22.

[0049] Charges (e.g., electrons) stored in the region of the semiconductor layer 23 corresponding to the charge storage electrode 21B via the insulating layer 22 are read out as follows. Specifically, a potential V2 is applied to the read electrode 21A, and a potential V25 is applied to the charge storage electrode 21B. Here, the potential V2 is made higher than the potential V25 (V1<V2). In this way, the electrons stored in the region of the semiconductor layer 23 corresponding to the charge storage electrode 21B are transferred to the read electrode 21A.

[0050] By providing the semiconductor layer 23 below the organic photoelectric conversion layer 24 and storing charges (e.g., electrons) in the region of the semiconductor layer 23 corresponding to the charge storage electrode 21B via the insulating layer 22, the following effects can be obtained. That is, compared to storing charges (e.g., electrons) in the organic photoelectric conversion layer 24 without providing the semiconductor layer 23, recombination of holes and electrons during charge storage is prevented, the transfer efficiency of the stored charges (e.g., electrons) to the readout electrode 21A can be increased, and the generation of dark current can be suppressed. While the above description illustrates the case where electrons are read out, holes may also be read out. When holes are read out, the potential in the above description is described as the potential sensed by the holes.

[0051] (Readout Circuit of Photoelectric Conversion Unit 10) FIG. 6 shows an example of a readout circuit of the photoelectric conversion unit 10 that constitutes the pixel P1 shown in FIG. 2A.

[0052] The readout circuit of the photoelectric conversion unit 10 includes, for example, TGs 14A and 14B, an OFG 146, FDs 15A-1 and 15A-2, RSTs 143-1 and 143-2, AMPs 144-1 and 144-2, and SELs 145-1 and 145-2.

[0053] TGs 14A and 14B are connected between the photoelectric conversion region 12 and FDs 15A-1 and 15A-2. When a drive signal is applied to the gate electrodes of TGs 14A and 14B, and TGs 14A and 14B enter an active state, the transfer gates of TGs 14A and 14B enter a conductive state. As a result, signal charges converted in the photoelectric conversion region 12 are transferred to FDs 15A-1 and 15A-2 via TGs 14A and 14B.

[0054] The OFG 146 is connected between the photoelectric conversion region 12 and a power supply. When a drive signal is applied to the gate electrode of the OFG 146 and the OFG 146 is activated, the OFG 146 is turned on. As a result, the signal charge converted in the photoelectric conversion region 12 is discharged to the power supply via the OFG 146.

[0055] The FDs 15A-1 and 15A-2 are connected between the TGs 14A and 14B and the AMPs 144-1 and 144-2. The FDs 15A-1 and 15A-2 convert the signal charges transferred by the TGs 14A and 14B into voltage signals and output them to the AMPs 144-1 and 144-2.

[0056] RST143-1, 143-2 are connected between FD15A-1, 15A-2 and the power supply. When a drive signal is applied to the gate electrodes of RST143-1, 143-2 and RST143-1, 143-2 enters an active state, the reset gates of RST143-1, 143-2 enter a conductive state. As a result, the potential of FD15A-1, 15A-2 is reset to the power supply level.

[0057] The AMPs 144-1 and 144-2 have gate electrodes connected to the FDs 15A-1 and 15A-2, respectively, and drain electrodes connected to a power supply. The AMPs 144-1 and 144-2 serve as input sections of a readout circuit for the voltage signals held by the FDs 15A-1 and 15A-2, or what is called a source follower circuit. That is, the source electrodes of the AMPs 144-1 and 144-2 are connected to the vertical signal lines Lsig via the SELs 145-1 and 145-2, respectively, thereby constituting a source follower circuit together with a constant current source connected to one end of the vertical signal line Lsig.

[0058] SEL145-1 and 145-2 are connected between the source electrodes of AMP144-1 and 144-2 and the vertical signal line Lsig, respectively. When a drive signal is applied to each gate electrode of SEL145-1 and 145-2 and SEL145-1 and 145-2 enter an active state, SEL145-1 and 145-2 enter a conductive state and pixel P enters a selected state. As a result, readout signals (pixel signals) output from AMP144-1 and 144-2 are output to the vertical signal line Lsig via SEL145-1 and 145-2.

[0059] In the photodetector 1, an infrared light pulse is irradiated onto a subject, and the light pulse reflected from the subject is received by the photoelectric conversion region 12 of the photoelectric conversion unit 10. In the photoelectric conversion region 12, multiple electric charges are generated in response to the incident infrared light pulse. The multiple electric charges generated in the photoelectric conversion region 12 are alternately distributed to the FDs 15A-1 and 15A-2 by alternately supplying drive signals to the pair of TGs 14A and 14B for equal periods of time. By changing the shutter phase of the drive signals applied to the TGs 14A and 14B relative to the irradiated light pulse, the amount of electric charge accumulated in the FDs 15A-1 and 15A-2 becomes a phase-modulated value. By demodulating these values, the round-trip time of the light pulse can be estimated, thereby determining the distance between the photodetector 1 and the subject.

[0060] (Readout Circuit of Organic Photoelectric Conversion Unit 20) FIG. 7 shows an example of a readout circuit of the organic photoelectric conversion unit 20 constituting the pixel P2 shown in FIG. 2A.

[0061] The readout circuit of the organic photoelectric conversion unit 20 includes, for example, an FD 15B, an RST 132, an AMP 133, and a SEL 134.

[0062] The FD 15B is connected between the read electrode 21A and the AMP 133. The FD 15B converts the signal charge transferred by the read electrode 21A into a voltage signal and outputs the voltage signal to the AMP 133.

[0063] RST 132 is connected between FD 15B and the power supply. When a drive signal is applied to the gate electrode of RST 132 and RST 132 enters an active state, the reset gate of RST 132 enters a conductive state. As a result, the potential of FD 15B is reset to the power supply level.

[0064] The AMP 133 has a gate electrode connected to the FD 15B and a drain electrode connected to a power supply, and a source electrode connected to the vertical signal line Lsig via the SEL 134.

[0065] SEL134 is connected between the source electrode of AMP133 and the vertical signal line Lsig. When a drive signal is applied to the gate electrode of SEL134 and SEL134 enters an active state, SEL134 enters a conductive state and pixel P2 enters a selected state. As a result, a readout signal (pixel signal) output from AMP133 is output to the vertical signal line Lsig via SEL134.

[0066] [Actions and Effects] As described above, when signal charges generated in the organic photoelectric conversion unit 20 provided on the surface 11S1 side of the semiconductor substrate 11 are transmitted to the FD 15B provided on the surface 11S2 of the semiconductor substrate 11 via the through electrode 16A, the capacitance of the through electrode 16A is included in the FD capacitance component of the pixel P2. If the FD capacitance component is large, the conversion efficiency decreases, and even if the AMP noise and circuit noise from the viewpoint of voltage are the same, the random noise when converted into the number of electrons may worsen. Therefore, from the viewpoint of conversion efficiency and random noise, it is desirable to reduce the capacitance component of the through electrode 16A.

[0067] The capacitance of a through electrode can be easily calculated manually using cylindrical capacitance components as shown in FIG. 3 . For example, if the length of the through electrode is L, the radius of the conductor is ra, and the radius of the insulating film is rb, the capacitance of the through electrode can be calculated using the following formula (1). Specifically, the capacitance (C) is determined by the formula: outer diameter = inner diameter + insulating film thickness. Therefore, in order to reduce the capacitance of the through electrode, the thickness of the insulating film can be increased. However, if the insulating film thickness of all the through electrodes 16 in the photodetector 1 is increased, it will constrain the FEOL layout and reduce the degree of freedom in the layout of the semiconductor substrate 11.

[0068]

[0069] In contrast, in the photodetector 1 of this embodiment, the film thickness ta of the insulating film 161b constituting the through electrode 16A electrically connecting the read electrode 21A of the organic photoelectric conversion unit 20 to the FD15B and AMP133 provided on the surface 11S2 of the semiconductor substrate 11 is made larger than the film thickness tb of the through electrode 16B electrically connecting the organic photoelectric conversion unit 20 provided on the surface 11S1 side of the semiconductor substrate 11 to active elements other than FD15B (ta > tb).

[0070] As a result, in the photodetector 1 of this embodiment, the capacitance of the through electrode 16A that electrically connects the read electrode 21A of the organic photoelectric conversion unit 20 to the FD15B and AMP133 provided on the surface 11S2 of the semiconductor substrate 11 is reduced, making it possible to reduce random noise.

[0071] Furthermore, in the photodetector 1 of the present embodiment, only the insulating film 161b constituting the through electrode 16A that electrically connects the readout electrode 21A of the organic photoelectric conversion unit 20 with the FD 15B and AMP 133 provided on the surface 11S2 of the semiconductor substrate 11 is selectively thickened, thereby reducing an increase in the area occupied by the through electrode 16 on the semiconductor substrate 11. This allows for greater flexibility in layout on the semiconductor substrate 11 compared to when all of the insulating films of the through electrode 16 are thickened.

[0072] Next, modified examples 1 to 9 and application examples of the present disclosure will be described. Note that components corresponding to those in the above embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

[0073] 2. Modifications (2-1. Modification 1) FIG. 8 is a diagram schematically illustrating a planar layout of the through electrodes 16 according to Modification 1 of the present disclosure.

[0074] In the above embodiment, the diameter Ra of the conductor 161a is equal to the diameter Rb of the conductor 161c constituting the through electrode 6B (Ra=Rb), and the thickness ta of the insulating film 161b surrounding the conductor 161a is made larger than the thickness tb of the insulating film 161d surrounding the conductor 161c (ta>tb), thereby reducing the capacitance of the through electrode 16A. Ａ and the diameter R of the through electrode 16B Ｂ and (R Ａ =R Ｂ ), the diameter Ra of the conductor 161a is made smaller than the diameter Rb of the conductor 161c constituting the through electrode 6B (Ra<Rb), and the film thickness ta of the insulating film 161b surrounding the conductor 161a is made thicker than the film thickness tb of the insulating film 161d surrounding the conductor 161c (ta>tb).

[0075] This makes it possible to reduce random noise, as in the above embodiment. Furthermore, compared to the case where the insulating film 161b of the through electrode 16A is made thicker as in the above embodiment, the degree of freedom in layout on the semiconductor substrate 11 can be improved.

[0076] (2-2. Modification 2) FIG. 9 is a diagram schematically illustrating a planar layout of the through electrodes 16 according to Modification 3 of the present disclosure.

[0077] The above embodiment and Modification 1 can be combined with each other. For example, the diameter Ra of the conductor 161a may be smaller than the diameter Rb of the conductor 161c constituting the through electrode 6B (Ra<Rb), while the thickness ta of the insulating film 161b surrounding the conductor 161a may be larger than the thickness tb of the insulating film 161d surrounding the conductor 161c (ta>tb).

[0078] In this configuration, random noise can be reduced, as in the above embodiment. Also, as in the above embodiment, the degree of freedom in layout on the semiconductor substrate 11 can be improved compared to when all insulating films of the through electrodes 16 are made thick.

[0079] (2-3. Modification 3) FIG. 10 is a diagram schematically illustrating a planar layout of the through electrodes 16 according to Modification 3 of the present disclosure.

[0080] In the above embodiment, the diameter Ra of the conductor 161a and the diameter Rb of the conductor 161c constituting the through electrode 6B are equal (Ra=Rb), and the thickness ta of the insulating film 161b surrounding the conductor 161a is greater than the thickness tb of the insulating film 161d surrounding the conductor 161c (ta>tb), thereby reducing the capacitance of the through electrode 16A. In contrast, in this modified example, instead of making the diameter Ra of the conductor 161a and the thickness ta of the insulating film 161b constituting the through electrode 16A equal to the diameter Rb of the conductor 161c and the thickness tb of the insulating film 161d constituting the through electrode 6B (Ra=Rb, ta=tb), the insulating film 161b of the through electrode 16A is formed using a dielectric material having a smaller relative dielectric constant than the insulating material constituting the insulating film 161d of the through electrode 16B.

[0081] When the insulating film 161d is formed using silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiON), or the like, the insulating film 161b may be made of SiOC or SiOCH-based materials.

[0082] This makes it possible to reduce random noise, as in the above embodiment. Furthermore, compared to the case where the insulating film 161b of the through electrode 16A is made thicker as in the above embodiment, the degree of freedom in layout on the semiconductor substrate 11 can be improved.

[0083] (2-4. Modification 4) FIGS. 11 and 12 are diagrams schematically illustrating an example of a planar layout of the through electrodes 16 according to Modification 4 of the present disclosure.

[0084] In the above embodiment, an example is shown in which a plurality of through electrodes 16A and a plurality of through electrodes 16B are alternately arranged at the boundary between adjacent pixels P1 in which photoelectric conversion regions 12 are respectively provided, but this is not limited to this, and layouts of a plurality of through electrodes 16A and a plurality of through electrodes 16B such as those shown in Figures 11 and 12 are also possible.

[0085] 13, for example, when pixel P1 has a substantially square shape, through electrodes 16A that electrically connect the readout electrode 21A of the organic photoelectric conversion unit 20 to the FD 15B and AMP 133 provided on the surface 11S2 of the semiconductor substrate 11 may be arranged at the four corners, and through electrodes 16B that electrically connect the organic photoelectric conversion unit 20 provided on the surface 11S1 side of the semiconductor substrate 11 to active elements other than FD 15B may be arranged on the four sides. This makes it possible to reduce the capacitance of the through electrodes 16A.

[0086] In addition, when pixel P1 is made substantially square and through electrodes 16A electrically connecting readout electrode 21A of organic photoelectric conversion unit 20 to FD 15B and AMP 133 provided on surface 11S2 of semiconductor substrate 11 are arranged at the four corners, even if through electrodes 16A and 16B have the same shape, insulating film 161d of through electrode 16B is present around the pixel P1, so that the thickness of the insulating film of through electrode 16A can be effectively increased, as shown in Fig. 14. Therefore, the capacitance of through electrode 16A can be reduced, and a certain effect can be obtained.

[0087] (2-5. Modification 5) FIG. 15 is a schematic diagram showing a planar layout of a through electrode 16 according to modification 5 of the present disclosure.

[0088] A partition wall 161M may be provided at the boundary between adjacent pixels P1. The partition wall 161M is intended to suppress oblique incidence of unnecessary light into the photoelectric conversion region 12 between adjacent pixels P and prevent color mixing. When the partition wall 161M is provided at the boundary between adjacent pixels P1, as shown in FIG. 15 , the thickness of the partition wall 161M surrounding the through electrode 16A is made smaller than the thickness of the partition wall 161M surrounding the through electrode 16B to ensure the thickness of the insulating film 161b. This makes it possible to reduce the capacitance of the through electrode 16A and obtain the same effect as in the above embodiment.

[0089] The partition 161M is made of a material containing at least one of a light-shielding elemental metal, a metal alloy, a metal nitride, and a metal silicide. More specifically, the material of the partition 161M may be Al (aluminum), Cu (copper), Co (cobalt), W (tungsten), Ti (titanium), Ta (tantalum), Ni (nickel), Mo (molybdenum), Cr (chromium), Ir (iridium), platinum-iridium, TiN (titanium nitride), or a tungsten-silicon compound. The material of the partition 161M is not limited to a metal material and may be graphite. The partition 161M is not limited to a conductive material and may be made of a light-shielding non-conductive material such as an organic material. An insulating film may be provided outside the partition 161M, i.e., between the partition 161M and the fixed charge layer 13. The insulating film may be made of an insulating material such as SiOx (silicon oxide) or aluminum oxide. Alternatively, the partition wall 161M may be insulated from the fixed charge layer 13 by providing a gap between the partition wall 161M and the fixed charge layer 13. When the partition wall 161M is made of a conductive material, this insulating film ensures electrical insulation between the partition wall 161M and the semiconductor substrate 11.

[0090] (2-6. Modification 6) FIGS. 16 and 17 are diagrams schematically illustrating an example of a planar layout of the through electrodes 16 according to Modification 6 of the present disclosure.

[0091] In the above embodiment, an example in which both the through electrode 16A and the through electrode 16B are circular has been shown, but this is not limiting. For example, as shown in Fig. 16, the through electrode 16A may be substantially square and the through electrode 16B may be circular. Also, for example, as shown in Fig. 17, the through electrode 16A may be oval and the through electrode 16B may be circular.

[0092] In this way, by making a portion of the film thickness of the insulating film 161b surrounding the conductor 161a that constitutes the through electrode 16A larger than the film thickness of the insulating film 161d of the through electrode 16B, the capacitance of the through electrode 16A can be reduced, and the same effect as in the above embodiment can be obtained.

[0093] (2-7. Modification 7) FIG. 18 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector 1A according to Modification 7 of the present disclosure.

[0094] In the above-described embodiment, an example was shown in which the unit pixel P has a structure in which, for example, one photoelectric conversion unit 10 as pixel P1 and four organic photoelectric conversion units 20 arranged in two rows and two columns as pixel P2 are stacked in the Z-axis direction, which is the thickness direction. However, this is not limited to this. In the photodetector 1A of this modified example, the unit pixel P has, for example, one photoelectric conversion unit 10 as pixel P1 and one organic photoelectric conversion unit 20 as pixel P2 stacked in the Z-axis direction, which is the thickness direction. In this case, four through-hole electrodes 16A and four through-hole electrodes 16B described in the above-described embodiment and modified examples 1 to 6 are alternately arranged at the boundary of pixel P1. For example, as shown in FIGS. 19A and 19B , four through-hole electrodes 16A and four through-hole electrodes 16B having insulating films 161b and 161d with different thicknesses may be alternately arranged. For example, as shown in FIG. 20, the four through electrodes 16A and four through electrodes 16B having different relative dielectric constants may be arranged alternately.

[0095] (2-8. Eighth Modification) FIG. 21 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector 1B according to an eighth modification of the present disclosure.

[0096] In the above embodiment, an example was shown in which the lower electrode of the organic photoelectric conversion unit 20 has three electrodes, namely, the readout electrode 21A, the charge storage electrode 21B, and the shield electrode 21C, which are spaced apart from one another, but the present invention is not limited to this. The photodetector 1B of this modified example has the same configuration as the photodetector 1, except that the lower electrode 21 consists of one electrode for each unit pixel P, and the insulating layer 22 and the semiconductor layer 23 between the lower electrode 21 and the organic photoelectric conversion layer 24 are omitted.

[0097] As such, the configuration of the organic photoelectric conversion unit 20 is not limited to the photodetector 1 of the above embodiment, and the configuration of the organic photoelectric conversion unit 20 of this modified example can also achieve the same effects as those of the above embodiment.

[0098] (2-9. Ninth Modification) FIG. 22 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector 1C according to a ninth modification of the present disclosure.

[0099] In the above embodiment, an example in which one organic photoelectric conversion unit 20 is provided on the surface 11S1 side of the semiconductor substrate 11 has been described, but the present invention is not limited to this. In the photodetector 1C of this modified example, for example, two organic photoelectric conversion units (organic photoelectric conversion units 20, 60) that selectively detect light in different wavelength ranges and perform photoelectric conversion are stacked on the surface 11S1 side of the semiconductor substrate 11.

[0100] In this case, the capacitance of the through electrode 16A-2, which has a longer transmission path for signal charges, is reduced for the through electrode 16A-1 that electrically connects the readout electrode 21A of the organic photoelectric conversion unit 20 and the FD provided on the surface 11S2 of the semiconductor substrate 11, and the through electrode 16A-2 that electrically connects the readout electrode 61A of the organic photoelectric conversion unit 60 and the FD provided on the surface 11S2 of the semiconductor substrate 11. For example, as shown in FIG. 23 , the thickness of the insulating film that constitutes the through electrode 16A-2 is made larger than the thickness of the insulating film of the through electrode 16A-1.

[0101] For example, three organic photoelectric conversion units that selectively detect red light, green light, and blue light and perform photoelectric conversion may be stacked on the surface 11S1 side of the semiconductor substrate 11. This makes it possible to simultaneously generate both a visible light image and an infrared light image in one pixel without using a color filter.

[0102] 3. Application Examples (Application Example 1) The light detection device 1 as described above can be applied to various electronic devices, such as imaging systems such as digital still cameras and digital video cameras, mobile phones with imaging functions, and other devices with imaging functions.

[0103] FIG. 24 is a block diagram showing an example of the configuration of electronic device 1000. As shown in FIG.

[0104] As shown in Figure 24, the electronic device 1000 includes an optical system 1001, a photodetector 1, and a DSP (Digital Signal Processor) 1002, and is configured by connecting the DSP 1002, memory 1003, display device 1004, recording device 1005, operation system 1006, and power supply system 1007 via a bus 1008, and is capable of capturing still images and moving images.

[0105] The optical system 1001 is configured to have one or more lenses, and receives incident light (image light) from a subject and forms an image on the imaging surface of the photodetector 1 .

[0106] The photodetector 1 converts the amount of incident light imaged on the imaging surface by the optical system 1001 into an electrical signal for each pixel, and supplies the signal to the DSP 1002 as a pixel signal.

[0107] The DSP 1002 performs various signal processing on the signal from the photodetector 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. In addition, the operation system 1006 accepts various operations by 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.

[0108] 25A is a schematic diagram illustrating an example of the overall configuration of a light detection system 2000 including the light detection device 1. FIG. 25B is a diagram illustrating an example of the circuit configuration of the light detection system 2000. The light detection system 2000 includes a light emitting device 2001 serving as a light source unit that emits infrared light L2, and an organic photoelectric conversion unit 2002 serving as a light receiving unit having a photoelectric conversion element. The organic photoelectric conversion unit 2002 may be the above-described light detection device 1. The light detection system 2000 may further include a system control unit 2003, a light source driving unit 2004, a sensor control unit 2005, a light source side optical system 2006, and a camera side optical system 2007.

[0109] The organic photoelectric conversion unit 2002 can detect light L1 and light L2. Light L1 is external ambient light reflected by a subject (object to be measured) 2100 ( FIG. 25A ). Light L2 is light 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 can be detected by a photoelectric conversion unit in the organic photoelectric conversion unit 2002, and light L2 can be detected by a photoelectric conversion region in the organic photoelectric conversion unit 2002. Image information of the subject 2100 can be obtained from light L1, and distance information between the subject 2100 and the photodetection system 2000 can be obtained from light L2. The photodetection system 2000 can be mounted on, for example, an electronic device such as a smartphone or a mobile object such as a car. The light-emitting device 2001 may be configured, for example, with a semiconductor laser, a surface-emitting semiconductor laser, or a vertical-cavity surface-emitting laser (VCSEL). The detection method of the light L2 emitted from the light-emitting device 2001 by the organic photoelectric conversion unit 2002 may be, for example, an iTOF system, but is not limited to this. In the iTOF system, the photoelectric conversion unit can measure the distance to the subject 2100 using, for example, time-of-flight (TOF). The detection method of the light L2 emitted from the light-emitting device 2001 by the organic photoelectric conversion unit 2002 may also be, for example, a structured light system or a stereo vision system. For example, in the structured light system, a predetermined pattern of light is projected onto the subject 2100, and the distance between the light detection system 2000 and the subject 2100 can be measured by analyzing the distortion of the pattern. In addition, in the stereo vision method, for example, two or more cameras are used to acquire two or more images of the subject 2100 viewed from two or more different viewpoints, thereby making it possible to measure the distance between the light detection system 2000 and the subject. Note that the light emitting device 2001 and the organic photoelectric conversion unit 2002 can be synchronously controlled by a system control unit 2003.

[0110] 4. Application Example Application Example to Endoscopic Surgery System The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

[0111] FIG. 26 is a diagram showing an example of a schematic configuration of an endoscopic surgery system to which the technology according to the present disclosure (the present technology) can be applied.

[0112] 26 shows an operator (doctor) 11131 performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgery system 11000. As shown in the figure, the endoscopic surgery system 11000 is composed of an endoscope 11100, other surgical tools 11110 such as an insufflation tube 11111 and an energy treatment tool 11112, a support arm device 11120 that supports the endoscope 11100, and a cart 11200 on which various devices for endoscopic surgery are mounted.

[0113] The endoscope 11100 is composed of a lens barrel 11101, a region of a predetermined length from the tip of which is inserted into a body cavity of a patient 11132, and a camera head 11102 connected to the base end of the lens barrel 11101. In the example shown, the endoscope 11100 is configured as a so-called rigid scope having a rigid lens barrel 11101, but the endoscope 11100 may also be configured as a so-called flexible scope having a flexible lens barrel.

[0114] An opening into which an objective lens is fitted is provided at the tip of the lens barrel 11101. A light source device 11203 is connected to the endoscope 11100, and light generated by the light source device 11203 is guided to the tip of the lens barrel by a light guide extending inside the lens barrel 11101, and is irradiated via the objective lens toward an object to be observed inside the body cavity of the patient 11132. The endoscope 11100 may be a direct-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0115] An optical system and an image sensor are provided inside the camera head 11102, and light reflected from the object of observation (observation light) is collected onto the image sensor by the optical system. The observation light is photoelectrically converted by the image sensor to generate an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. The image signal is sent to a camera control unit (CCU) 11201 as RAW data.

[0116] The CCU 11201 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and comprehensively controls the operations 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 types of image processing on the image signal, such as development processing (demosaic processing), to display an image based on the image signal.

[0117] Under the control of the CCU 11201, the display device 11202 displays an image based on an image signal that has been subjected to image processing by the CCU 11201.

[0118] The light source device 11203 is composed of a light source such as an LED (light emitting diode), and supplies irradiation light to the endoscope 11100 when photographing the surgical site, etc.

[0119] The input device 11204 is an input interface for the endoscopic surgery system 11000. A user can input various information and instructions to the endoscopic surgery system 11000 via the input device 11204. For example, the user inputs an instruction to change the imaging conditions (type of irradiation light, magnification, focal length, etc.) of the endoscope 11100.

[0120] The treatment tool control device 11205 controls the driving of the energy treatment tool 11112 for cauterizing tissue, incising, sealing blood vessels, etc. The insufflation device 11206 inflates the body cavity of the patient 11132 through the insufflation tube 11111 in order to ensure a clear field of view for the endoscope 11100 and a working space for the surgeon. The recorder 11207 is a device capable of recording various types of information related to the surgery. The printer 11208 is a device capable of printing various types of information related to the surgery in various formats such as text, images, or graphs.

[0121] The light source device 11203, which supplies illumination light to the endoscope 11100 when photographing the surgical site, can be configured from a white light source, such as an LED, a laser light source, or a combination of these. When the white light source is configured from a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, allowing the light source device 11203 to adjust the white balance of the captured image. In this case, it is also possible to time-share images corresponding to each RGB by irradiating the object of observation with laser light from each RGB laser light source and controlling the drive of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, color images can be obtained without providing a color filter to the image sensor.

[0122] Furthermore, the light source device 11203 may be controlled to change the intensity of light it outputs at predetermined time intervals. By controlling the driving of the image sensor of the camera head 11102 in synchronization with the timing of the change in light intensity to acquire images in a time-division manner and combining the images, it is possible to generate an image with a high dynamic range that is free from so-called blocked-up shadows and blown-out highlights.

[0123] The light source device 11203 may also be configured to provide light in a predetermined wavelength range compatible with special light observation. Special light observation, for example, utilizes the wavelength dependence of light absorption in body tissues to irradiate light with a narrower band than the light irradiated during normal observation (i.e., white light), thereby capturing high-contrast images of specific tissues, such as blood vessels on the surface of mucous membranes, known as narrow-band imaging. Alternatively, special light observation may involve fluorescence observation, in which images are obtained using fluorescence generated by irradiating excitation light onto the body tissue. Fluorescence observation can involve irradiating excitation light onto the body tissue and observing the fluorescence from the tissue (autofluorescence observation), or by locally injecting a reagent such as indocyanine green (ICG) into the body tissue and irradiating the tissue with excitation light corresponding to the fluorescent wavelength of the reagent to obtain a fluorescent image. The light source device 11203 may be configured to provide narrow-band light and / or excitation light compatible with such special light observation.

[0124] FIG. 27 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG.

[0125] The camera head 11102 has 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 has a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are connected to each other via a transmission cable 11400 so that they can communicate with each other.

[0126] The lens unit 11401 is an optical system provided at the connection portion 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 enters the lens unit 11401. The lens unit 11401 is composed of a combination of multiple lenses including a zoom lens and a focus lens.

[0127] The imaging unit 11402 may include one imaging element (a so-called single-chip type) or multiple imaging elements (a so-called multi-chip type). When the imaging unit 11402 is configured as a multi-chip type, for example, each imaging element may generate an image signal corresponding to each of RGB, and a color image may be obtained by combining these signals. Alternatively, the imaging unit 11402 may be configured to have a pair of imaging elements for acquiring image signals for the right eye and the left eye corresponding to a 3D (dimensional) display. The 3D display allows the surgeon 11131 to more accurately grasp the depth of the biological tissue at the surgical site. Note that when the imaging unit 11402 is configured as a multi-chip type, multiple lens units 11401 may be provided corresponding to each imaging element.

[0128] Furthermore, the imaging unit 11402 does not necessarily have to be provided in the camera head 11102. For example, the imaging unit 11402 may be provided inside the lens barrel 11101, immediately after the objective lens.

[0129] The driving unit 11403 is configured by an actuator, and moves the zoom lens and focus lens of the lens unit 11401 by a predetermined distance along the optical axis under the control of the camera head control unit 11405. This allows the magnification and focus of the image captured by the imaging unit 11402 to be adjusted appropriately.

[0130] The communication unit 11404 is configured by a communication device for transmitting and receiving various types of information to and from the CCU 11201. The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 to the CCU 11201 via the transmission cable 11400 as RAW data.

[0131] Furthermore, the communication unit 11404 receives a control signal for controlling the driving of the camera head 11102 from the CCU 11201 and supplies the control signal to the camera head control unit 11405. The control signal includes information on the imaging conditions, such as information specifying the frame rate of the captured image, information specifying the exposure value at the time of imaging, and / or information specifying the magnification and focus of the captured image.

[0132] The image capturing conditions such as the frame rate, exposure value, magnification, and focus may be appropriately specified by the user, or may be automatically set by the control unit 11413 of the CCU 11201 based on the acquired image signal. In the latter case, the endoscope 11100 is equipped with a so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function.

[0133] The camera head control unit 11405 controls the driving of the camera head 11102 based on a control signal received from the CCU 11201 via the communication unit 11404 .

[0134] The communication unit 11411 is configured by a communication device for transmitting and receiving various information to and from the camera head 11102. The communication unit 11411 receives an image signal transmitted from the camera head 11102 via the transmission cable 11400.

[0135] Furthermore, the communication unit 11411 transmits to the camera head 11102 a control signal for controlling the driving of the camera head 11102. The image signal and the control signal can be transmitted by electrical communication, optical communication, or the like.

[0136] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102 .

[0137] The control unit 11413 performs various controls related to the imaging of the surgical site, etc. by the endoscope 11100 and the display of the captured image obtained by imaging the surgical site, etc. For example, the control unit 11413 generates a control signal for controlling the driving of the camera head 11102.

[0138] Furthermore, the control unit 11413 displays the captured image showing the surgical site, etc., on the display device 11202 based on the image signal subjected to image processing 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 tools such as forceps, specific biological parts, bleeding, mist generated when using the energy treatment tool 11112, etc., by detecting the shape and color of the edges of objects included in the captured image. When displaying the captured image on the display device 11202, the control unit 11413 may use the recognition results to superimpose various surgical support information on the image of the surgical site. 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.

[0139] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable for electrical signal communication, an optical fiber for optical communication, or a composite cable of these.

[0140] In the illustrated example, communication is performed wired using a transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may also be performed wirelessly.

[0141] The above describes an example of an endoscopic surgery system to which the technology according to the present disclosure can be applied. The technology according to the present disclosure can be applied to the imaging unit 11402 among the components described above. By applying the technology according to the present disclosure to the imaging unit 11402, detection accuracy is improved.

[0142] Although an endoscopic surgery system has been described as an example here, the technology according to the present disclosure may also be applied to other systems, such as a microsurgery system.

[0143] (Application Example to Mobile Object) The technology according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of mobile object, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, a robot, construction machinery, or agricultural machinery (tractor).

[0144] FIG. 28 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology according to the present disclosure can be applied.

[0145] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 28, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional components of the integrated control unit 12050 are a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (interface) 12053.

[0146] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

[0147] The body system control unit 12020 controls the operation of various devices equipped in 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 device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0148] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture images outside the vehicle and receives the captured images. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, characters on the road surface, etc. based on the received images.

[0149] The imaging unit 12031 is an optical 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.

[0150] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

[0151] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the outside-vehicle information detection unit 12030 or the inside-vehicle 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 the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the distance between vehicles, maintaining vehicle speed, vehicle collision warning, vehicle lane departure warning, etc.

[0152] In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle obtained by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0153] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the outside information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside information detection unit 12030, and perform cooperative control aimed at preventing glare, such as switching from high beams to low beams.

[0154] The audio / video output unit 12052 transmits at least one of audio and video output signals to an output device capable of visually or audibly notifying information to vehicle occupants or the outside of the vehicle. In the example of Fig. 28, the output devices are exemplified by 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 on-board display and a head-up display.

[0155] FIG. 29 is a diagram showing an example of the installation position of the imaging unit 12031.

[0156] In FIG. 29, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0157] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided on the front nose and the imaging unit 12105 provided on the top of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 provided on the top of the windshield inside the vehicle cabin is mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0158] 29 shows an example of the imaging ranges of the imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 12101 to 12104, an overhead image of the vehicle 12100 viewed from above can be obtained.

[0159] At least one of the image capturing units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the image capturing units 12101 to 12104 may be a stereo camera made up of multiple image capturing elements, or may be an image capturing element having pixels for phase difference detection.

[0160] For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 can calculate the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the change in this distance over time (relative speed with respect to the vehicle 12100), thereby extracting as a preceding vehicle, in particular, the three-dimensional object that is the closest three-dimensional object on the path of the vehicle 12100 and traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or higher). Furthermore, the microcomputer 12051 can set a vehicle-to-vehicle distance to be maintained in advance in front of the preceding vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. In this way, cooperative control can be performed for the purpose of autonomous driving, which runs autonomously without relying on driver operation.

[0161] For example, the microcomputer 12051 classifies and extracts three-dimensional object data regarding three-dimensional objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from the imaging units 12101 to 12104, and can use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes 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 a collision risk that indicates the risk of collision with each obstacle, and when the collision risk is equal to or greater than a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drive system control unit 12010.

[0162] At least one of the image capturing units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether a pedestrian is present in the images captured by the image capturing units 12101 to 12104. Such pedestrian recognition is performed, for example, by extracting feature points from the images captured by the image capturing units 12101 to 12104 as infrared cameras and performing pattern matching on a series of feature points that indicate the outline of an object to determine whether the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the image capturing units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular outline on the recognized pedestrian for emphasis. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating the pedestrian at a desired position.

[0163] The foregoing has described an example of a mobile object control system to which the technology according to the present disclosure can be applied. The technology according to the present disclosure can be applied to the image capture unit 12031 of the above-described configuration. Specifically, the photodetection devices according to the above-described embodiments and their modifications (e.g., photodetection device 1) can be applied to the image capture unit 12031. By applying the technology according to the present disclosure to the image capture unit 12031, it is possible to obtain high-resolution captured images with little noise, thereby enabling high-precision control using the captured images in the mobile object control system.

[0164] The present disclosure has been described above by giving the embodiments and modifications 1 to 9, as well as examples of their applications or applications (hereinafter referred to as "embodiments, etc."), but the present disclosure is not limited to the above-described embodiments, etc., and various modifications are possible. For example, the present disclosure is not limited to back-illuminated image sensors, but can also be applied to front-illuminated image sensors.

[0165] In addition, in the above embodiment, red, green, and blue CFs 53 are provided, and red light, green light, and blue light are received, respectively, to obtain a color visible light image, but a black and white visible light image may also be obtained without providing CFs 53.

[0166] Furthermore, the imaging device according to the present disclosure may be in the form of a module in which the imaging section and the signal processing section or the optical system are packaged together.

[0167] In addition, in the above-described embodiments, a solid-state imaging device that converts the amount of incident light focused on an imaging surface via an optical lens system into an electrical signal on a pixel-by-pixel basis and outputs the signal as a pixel signal, and an imaging element mounted thereon have been described as examples. However, the photoelectric conversion element of the present disclosure is not limited to such an imaging element. For example, it may be an imaging element that detects and receives light from a subject, generates and accumulates electric charges according to the amount of received light through photoelectric conversion, and stores the electric charges. The output signal may be a signal of image information or a signal of ranging information.

[0168] Furthermore, in the above-described embodiments, the photoelectric conversion unit 10 serving as the second photoelectric conversion unit is an iTOF sensor, but the present disclosure is not limited to this. That is, the second photoelectric conversion unit is not limited to one that detects light having a wavelength in the infrared light range, and may be one that detects light having a wavelength in another wavelength range. Furthermore, if the photoelectric conversion unit 10 is not an iTOF sensor, only one transfer transistor (TG) may be provided.

[0169] Furthermore, the constituent materials of each component of the photoelectric conversion element of the present disclosure are not limited to the materials listed in the above embodiments, etc. For example, when the first photoelectric conversion unit or the second photoelectric conversion unit receives light in the visible light region and performs photoelectric conversion, the first photoelectric conversion unit or the second photoelectric conversion unit may contain quantum dots.

[0170] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0171] The present technology can also be configured as follows. According to the present technology having the following configuration, there is provided a semiconductor substrate having a first surface and a second surface opposite to each other; a first photoelectric conversion unit provided on the first surface side of the semiconductor substrate, the first photoelectric conversion unit detecting light in a first wavelength range and performing photoelectric conversion; a first floating diffusion layer provided on the second surface of the semiconductor substrate, accumulating signal charges generated in the first photoelectric conversion unit; a first through electrode including a first conductor penetrating between the first surface and the second surface of the semiconductor substrate and a first insulating film surrounding the first conductor, and electrically connecting the first photoelectric conversion unit and the first floating diffusion layer; and a second through electrode including a second conductor penetrating between the first surface and the second surface of the semiconductor substrate and a second insulating film surrounding the second conductor, at least a portion of which has a thickness thinner than that of the first insulating film, and electrically connecting the first photoelectric conversion unit and an active element other than the first floating diffusion layer provided on the second surface of the semiconductor substrate. (2) The photodetector according to (1), wherein the diameter of the first through electrode is larger than the diameter of the second through electrode. (3) The photodetector according to (1) or (2), wherein the thickness of the first insulating film is larger than the thickness of the second insulating film. (4) The photodetector according to any one of (1) to (3), wherein the diameter of the first conductor is smaller than the diameter of the second conductor. (5) The photodetector according to any one of (1) to (4), wherein the first through electrode has different diameters on the first surface side and the second surface side. (6) The photodetector according to any one of (1) to (5), wherein the first through electrode has a tapered cross-sectional shape. (7) The photodetector according to any one of (1) to (6), wherein the first through electrode and the second through electrode have different planar shapes. (8) The photodetector according to any one of (1) to (7), wherein the first through electrode has a circular or polygonal planar shape. (9) The photodetector according to any one of (1) to (8), wherein the conductor is made of a metal material or a conductive material.(10) The photodetector according to any one of (1) to (9), wherein the insulating film is made of a dielectric material. (11) The photodetector according to any one of (1) to (10), further comprising a first partition wall surrounding the first through-electrode and a second partition wall surrounding the second through-electrode, wherein the film thickness of the second partition wall is thicker than the film thickness of the first partition wall. (12) The photodetector according to (11), wherein the first partition wall and the second partition wall are made of a metal material or a conductive material having light-blocking properties. (13) The photodetector according to any one of (1) to (12), further comprising a second photoelectric conversion unit provided in the semiconductor substrate overlapping with the first photoelectric conversion unit in a plan view, the second photoelectric conversion unit detecting light in a second wavelength range and performing photoelectric conversion. (14) The photodetector according to (13), wherein the semiconductor substrate includes a plurality of pixels arranged in a matrix, the second photoelectric conversion unit is provided for each pixel, and the first through electrode and the second through electrode are provided at boundaries between adjacent pixels. (15) The photodetector according to (14), wherein the pixel has a substantially square shape, and the first through electrode is provided at four corners of the pixel. (16) The photodetector according to any one of (1) to (13), wherein the first wavelength range includes a visible light range, and the second wavelength range includes an infrared light range. (17) The photodetector according to any one of (13) to (16), further including a third photoelectric conversion unit provided between the first surface of the semiconductor substrate and the first photoelectric conversion unit, which detects light in a third wavelength range and performs photoelectric conversion. (18) The photodetector device described in (17) further comprises: a second floating diffusion layer provided on the second surface of the semiconductor substrate and accumulating signal charges generated in the third photoelectric conversion unit; and a third through electrode electrically connecting the third photoelectric conversion unit and the second floating diffusion layer, wherein the capacitance per length of the first through electrode is smaller than the capacitance per length of the third through electrode.(19) A photodetector comprising: a semiconductor substrate having a first surface and a second surface opposite to each other; a first photoelectric conversion unit provided on the first surface side of the semiconductor substrate, the first photoelectric conversion unit detecting light in a first wavelength range and performing photoelectric conversion; a floating diffusion layer provided on the second surface of the semiconductor substrate, the floating diffusion layer storing signal charges generated in the first photoelectric conversion unit; a first through electrode including a first conductor penetrating between the first surface and the second surface of the semiconductor substrate and a first insulating film surrounding the first conductor, electrically connecting the first photoelectric conversion unit and the floating diffusion layer; and a second through electrode including a second conductor penetrating between the first surface and the second surface of the semiconductor substrate and a second insulating film surrounding the second conductor and having a higher dielectric constant than the first insulating film, electrically connecting the first photoelectric conversion unit and an active element other than the first floating diffusion layer provided on the second surface of the semiconductor substrate.

[0172] This application claims priority based on Japanese Patent Application No. 2023-132216, filed on August 15, 2023, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0173] Those skilled in the art will recognize that various modifications, combinations, subcombinations, and variations may occur depending on design requirements and other factors, and are intended to be within the scope of the appended claims and their equivalents.

Claims

1. A photodetector comprising: a semiconductor substrate having a first surface and a second surface opposed to each other; a first photoelectric conversion unit provided on the first surface side of the semiconductor substrate for detecting light in a first wavelength range and performing photoelectric conversion; a first floating diffusion layer provided on the second surface of the semiconductor substrate for accumulating signal charges generated in the first photoelectric conversion unit; a first through electrode including a first conductor penetrating between the first surface and the second surface of the semiconductor substrate and a first insulating film surrounding the first conductor, electrically connecting the first photoelectric conversion unit and the first floating diffusion layer; and a second through electrode including a second conductor penetrating between the first surface and the second surface of the semiconductor substrate and a second insulating film surrounding the second conductor, at least a portion of which is thinner than the thickness of the first insulating film, electrically connecting the first photoelectric conversion unit and an active element other than the first floating diffusion layer provided on the second surface of the semiconductor substrate.

2. The photodetector according to claim 1, wherein the diameter of said first through electrode is larger than the diameter of said second through electrode.

3. The photodetector according to claim 1, wherein the first insulating film has a thickness greater than that of the second insulating film.

4. The optical detection device of claim 1, wherein the diameter of said first conductor is smaller than the diameter of said second conductor.

5. The photodetector according to claim 1, wherein the first through electrode has a different diameter on the first surface side and on the second surface side.

6. The photodetector according to claim 1, wherein said first through electrode has a tapered cross-sectional shape.

7. The photodetector according to claim 1, wherein the first through electrode and the second through electrode have different planar shapes.

8. The photodetector according to claim 1, wherein the first through electrode has a circular or polygonal planar shape.

9. The optical detection device according to claim 1, wherein the conductor is made of a metallic material or a conductive material.

10. The photodetector device of claim 1, wherein the insulating film is made of a dielectric material.

11. The photodetector according to claim 1, further comprising a first partition surrounding the first through electrode and a second partition surrounding the second through electrode, the second partition having a thickness greater than the thickness of the first partition.

12. The light detection device according to claim 11, wherein the first partition and the second partition are made of a metal material or a conductive material having light blocking properties.

13. The photodetector device of claim 1, further comprising a second photoelectric conversion section provided within the semiconductor substrate overlapping the first photoelectric conversion section in a plan view, the second photoelectric conversion section detecting light in a second wavelength range and performing photoelectric conversion.

14. The photodetector device described in claim 13, wherein the semiconductor substrate comprises a plurality of pixels arranged in a matrix, the second photoelectric conversion portion is provided for each of the pixels, and the first through electrode and the second through electrode are provided at the boundary between adjacent pixels.

15. The photodetector according to claim 14, wherein the pixel has a substantially square shape, and the first through electrodes are provided at the four corners of the pixel.

16. The optical detection device of claim 13, wherein the first wavelength range includes a visible light range and the second wavelength range includes an infrared light range.

17. The photodetector according to claim 13, further comprising a third photoelectric conversion section provided between the first surface of the semiconductor substrate and the first photoelectric conversion section, which detects light in a third wavelength range and performs photoelectric conversion.

18. The photodetection device described in claim 17, further comprising: a second floating diffusion layer provided on the second surface of the semiconductor substrate, which accumulates signal charges generated in the third photoelectric conversion unit; and a third through electrode electrically connecting the third photoelectric conversion unit and the second floating diffusion layer, wherein the capacitance per length of the first through electrode is smaller than the capacitance per length of the third through electrode.

19. A photodetector comprising: a semiconductor substrate having a first surface and a second surface opposed to each other; a first photoelectric conversion unit provided on the first surface side of the semiconductor substrate and configured to detect light in a first wavelength range and perform photoelectric conversion; a floating diffusion layer provided on the second surface of the semiconductor substrate and configured to accumulate signal charges generated in the first photoelectric conversion unit; a first through electrode including a first conductor penetrating between the first surface and the second surface of the semiconductor substrate and a first insulating film surrounding the first conductor, electrically connecting the first photoelectric conversion unit and the floating diffusion layer; and a second through electrode including a second conductor penetrating between the first surface and the second surface of the semiconductor substrate and a second insulating film surrounding the second conductor and having a relative dielectric constant greater than that of the first insulating film, electrically connecting the first photoelectric conversion unit and an active element other than the first floating diffusion layer provided on the second surface of the semiconductor substrate.

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