Light detection device

Abstract

This light detection device comprises: a first substrate having a first surface and a second surface facing the first surface; through wiring that penetrates from the first surface to the second surface in the first substrate and transfers, to the second surface side, a charge generated by photoelectric conversion on the first surface side; a charge discharge region, which has a first conductivity type, is disposed around the side surface of the through wiring with an insulator interposed therebetween in at least a part of the first substrate in a thickness direction from the first surface to the second surface and discharges a dark current; a potential supply region, which has the first conductivity type, is disposed apart from the charge discharge region on the second surface side of the first substrate and supplies a fixed potential to the charge discharge region; and a potential barrier region, which has a second conductivity type that is opposite conductivity type to the first conductivity type, is disposed in the first substrate between the charge discharge region and the potential supply region and generates a potential barrier to the charge discharge region.

Description

Photodetector

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

[0002] Patent Document 1 discloses a solid-state imaging element and an electronic device. In this solid-state imaging element, a plurality of photoelectric conversion elements are formed in the vertical direction in a pixel region. That is, a photoelectric conversion element that converts red wavelength light into electric charges, a photoelectric conversion element that converts green wavelength light into electric charges, and a photoelectric conversion element that converts blue wavelength light into electric charges are formed in the vertical direction. The photoelectric conversion elements that convert red and blue wavelength light are formed by photodiodes within a semiconductor substrate. The photoelectric conversion element that converts green wavelength light is disposed on one surface of the semiconductor substrate and is formed by, for example, an organic photoelectric conversion element.

[0003] In a back-illuminated solid-state imaging device, a pixel circuit including, for example, a modulation transistor and a floating diffusion is formed on the other surface of a semiconductor substrate. Charges generated in the organic photoelectric conversion element are transferred to the pixel circuit through a through-wire (through electrode) that penetrates from one surface of the semiconductor substrate to the other surface. The through-wire is formed in a through-hole that penetrates the semiconductor substrate in the thickness direction and is electrically insulated from the semiconductor substrate by an insulating film.

[0004] Japanese Patent Application Laid-Open No. 2020-174188

[0005] In the solid-state imaging device, it is desirable to effectively suppress or prevent the phenomenon in which processing damage occurs in the semiconductor substrate during the manufacture of through-hole wiring, which causes dark current. In other words, it is desirable to develop a photodetector that can improve the signal-to-noise ratio caused by dark current and enhance the quality of pixel signals.

[0006] A photodetector according to a first embodiment of the present disclosure includes a first substrate having a first surface and a second surface opposite the first surface; a through-hole wiring that penetrates from the first surface to the second surface of the first substrate and transfers charges generated by photoelectric conversion on the first surface side to the second surface side; a charge discharge region of a first conductivity type that discharges dark current and is arranged around the side of the through-hole wiring with an insulator interposed in at least a portion of the thickness direction of the first substrate from the first surface to the second surface; a potential supply region of the first conductivity type that is arranged spaced apart from the charge discharge region on the second surface side of the first substrate and supplies a fixed potential to the charge discharge region; and a potential barrier region that is arranged on the first substrate between the charge discharge region and the potential supply region and has a second conductivity type opposite to the first conductivity type and generates a potential barrier for the charge discharge region.

[0007] A photodetector according to a second embodiment of the present disclosure is the photodetector according to the first embodiment, further comprising a first transistor disposed on the second surface side of the first substrate, the first transistor having a first conductivity type, and including a pair of main electrodes, one of which is supplied with a fixed potential, and a gate electrode electrically connected to the through-wire, wherein the potential supply region is shared by one of the pair of main electrodes.

[0008] In a photodetector according to a third embodiment of the present disclosure, in the photodetector according to the first embodiment, the first transistor is disposed in a well region having a second conductivity type, and the impurity density of the potential barrier region in contact with at least the charge discharge region is higher than the impurity density of the well region.

[0009] In a photodetector according to a fourth embodiment of the present disclosure, in the photodetector according to the first embodiment, the charge discharge region is arranged across the entire thickness direction of the first substrate from the first surface to the second surface.

[0010] In a photodetector according to a fifth embodiment of the present disclosure, in the photodetector according to the first embodiment, when viewed in the thickness direction of the first substrate, the charge discharge region and the potential barrier region are arranged to overlap the first transistor.

[0011] A photodetector according to a sixth embodiment of the present disclosure is the photodetector according to the first embodiment, further comprising: a second substrate laminated on the second surface side of the first substrate; and a first transistor disposed on the second substrate, the first transistor having a first conductivity type and including a pair of main electrodes, one of which is supplied with a fixed potential, and a gate electrode electrically connected to a through-hole wiring. The potential supply region is electrically connected to one of the pair of main electrodes. Furthermore, the charge discharge region is disposed so as to overlap the first transistor when viewed in the thickness direction of the first substrate.

[0012] FIG. 1 is a longitudinal cross-sectional view of a pixel region and a pixel circuit of a photodetector according to a first embodiment of the present disclosure. FIG. 2 is a schematic diagram illustrating the longitudinal cross-sectional configuration of the pixel region and the circuit configuration of the pixel circuit shown in FIG. 1. FIG. 3 is a schematic plan view of the pixel region and the pixel circuit shown in FIGS. 1 and 2. FIG. 4 is a schematic enlarged longitudinal cross-sectional view of the pixel region and the pixel circuit shown in FIGS. 1 and 2. FIG. 5 is a schematic plan view of the pixel region shown in FIG. 3. FIG. 6 is a diagram illustrating potentials of a charge drain region, a potential supply region, and a potential barrier region in the pixel region and the pixel circuit shown in FIG. 4. FIG. 7 is a schematic plan view corresponding to FIG. 5 of a pixel region of a photodetector according to a second embodiment of the present disclosure. FIG. 8 is a schematic enlarged longitudinal cross-sectional view corresponding to FIG. 4 of a pixel region and a pixel circuit of a photodetector according to a third embodiment of the present disclosure. FIG. 9 is a schematic enlarged longitudinal cross-sectional view corresponding to FIG. 4 of a pixel region and a pixel circuit of a photodetector according to a fourth embodiment of the present disclosure. Fig. 10 is a schematic longitudinal sectional configuration diagram corresponding to Fig. 4 , in which a pixel region and a pixel circuit of a photodetector according to a fifth embodiment of the present disclosure are enlarged. Fig. 11 is a block diagram showing an example of a schematic configuration of a vehicle control system. Fig. 12 is an explanatory diagram showing an example of installation positions of an outside-vehicle information detection unit and an imaging unit. Fig. 13 is a block diagram showing an example of a schematic configuration of an in-vivo information acquisition system.

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be made in the following order. 1. First Embodiment The first embodiment describes an example in which the present technology is applied to a photodetector. The first embodiment describes in detail the circuit configuration, longitudinal cross-sectional configuration, and planar configuration of the main parts of the pixel region and pixel circuit of the photodetector. The first embodiment also describes in detail the configurations of the charge drain region, potential supply region, and potential barrier region disposed in the pixel region and pixel circuit. 2. Second Embodiment The second embodiment describes a second example in which the configuration of the charge drain region is changed in the photodetector according to the first embodiment. 3. Third Embodiment The third embodiment describes a third example in which the configuration of the charge drain region is changed in the photodetector according to the first embodiment. 4. Fourth Embodiment The fourth embodiment describes a fourth example in which the configurations of the charge drain region and potential barrier region are changed in the photodetector according to the first embodiment. 5. Fifth Embodiment The fifth embodiment describes a fifth example in which the photodetector according to the third embodiment and the photodetector according to the fourth embodiment are combined. 6. Application Example to a Mobile Body This application example is an example in which the present technology is applied to a mobile body. 7. Application Example to an In-Vivo Information Acquisition System This application example is an example in which the present technology is applied to an in-vivo information acquisition system. 8. Other Embodiments

[0014] 1. First Embodiment A photodetector 1 according to a first embodiment of the present disclosure will be described with reference to FIGS. 1 to 6. FIG.

[0015] Here, the arrow X direction shown as appropriate in the drawings indicates one planar direction of the photodetector 1 placed on a flat surface for convenience. The arrow Y direction indicates another planar direction perpendicular to the arrow X direction. The arrow Z direction indicates an upward direction perpendicular to the arrow X direction and the arrow Y direction. In other words, the arrow X direction, arrow Y direction, and arrow Z direction exactly correspond to the X-axis direction, Y-axis direction, and Z-axis direction, respectively, of a three-dimensional coordinate system. Note that these directions are shown to facilitate understanding of the explanation and do not limit the directions of the present technology.

[0016] [Configuration of the Photodetector 1 ] (1) Overall Configuration of the Photodetector 1 FIG. 1 shows an example of a vertical cross-sectional configuration of a pixel region in which one pixel 100 of the photodetector 1 is arranged and a pixel circuit 10 .

[0017] The photodetector 1 according to the first embodiment is constructed as a back-illuminated solid-state imaging device. The photodetector 1 includes a substrate (first substrate) 2 having through-wiring (through-electrodes) 21. The photodetector 1 further includes a pixel region having a first photoelectric conversion element 5, a second photoelectric conversion element 7, and a second photoelectric conversion element 8, and a pixel circuit 10. (2) Configuration of the Substrate 2

[0018] The substrate 2 has a first surface (upper surface) 2A extending in the directions of arrows X and Y in the thickness direction, which is the direction of arrow Z, and a second surface (lower surface) 2B facing the first surface 2A and parallel to the first surface 2A. The first surface 2A is the back surface of the photodetector 1, which is the light incident side. The second surface 2B is the front surface of the photodetector 1. The substrate 2 is, for example, a semiconductor substrate made of single crystal silicon (Si). A p-type well region 20p of the second conductivity type is formed in this semiconductor substrate.

[0019] (3) Configuration of the First Photoelectric Conversion Element 5, the Second Photoelectric Conversion Element 7, and the Second Photoelectric Conversion Element 8 The first photoelectric conversion element 5 is disposed on the first surface 2A of the substrate 2, with the fixed charge film 3 and the insulating film 4 interposed therebetween. A negative fixed charge is supplied to the fixed charge film 3. The fixed charge film 3 is made of one or more materials selected from, for example, hafnium oxide, aluminum oxide, zirconium oxide, tantalum oxide, titanium oxide, lanthanum oxide, praseodymium oxide, cerium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, aluminum nitride, hafnium oxynitride, and aluminum oxynitride. The fixed charge film 3 is formed of a single layer of the above material or a composite layer formed by stacking two or more different materials from the above material. The insulating film 4 is made of, for example, one or more dielectric materials selected from silicon oxide (SiO), tetraethyl orthosilicate (TEOS), silicon nitride (SiN), and silicon oxynitride (SiNO).

[0020] The first photoelectric conversion element 5 is configured by sequentially stacking a first transparent electrode 51, a photoelectric conversion film 52, and a second transparent electrode 53. The first photoelectric conversion element 5 converts light into electric charges. The first transparent electrode 51 and the second transparent electrode 53 are each formed of a transparent electrode material such as indium tin oxide (ITO). The photoelectric conversion film 52 is formed of a photoelectric conversion material that is sensitive to green light. Examples of the photoelectric conversion material include organic photoelectric conversion materials such as rhodamine dyes, melacyanine dyes, and quinacridone. That is, in the first embodiment, an organic photoelectric conversion element is used for the first photoelectric conversion element 5. The first photoelectric conversion element 5 is arranged across multiple pixels 100. A protective film 6 is formed on the first photoelectric conversion element 5.

[0021] The first photoelectric conversion element 5 is not limited to an organic photoelectric conversion element, but may be an inorganic photoelectric conversion element.

[0022] A plurality of photoelectric conversion elements, namely, second photoelectric conversion elements 7 and second photoelectric conversion elements 8, are formed in the substrate 2 corresponding to one pixel 100. Each of the second photoelectric conversion elements 7 and second photoelectric conversion elements 8 converts light into electric charges.

[0023] Although detailed structural description will be omitted, the second photoelectric conversion element 7 is formed of a photodiode disposed on the first surface 2A side of the substrate 2. The photodiode is formed at a pn junction between an n-type semiconductor region and a p-type semiconductor region. The second photoelectric conversion element 7 is configured to be sensitive to, for example, blue light.

[0024] Furthermore, the second photoelectric conversion element 8 is disposed on the second surface 2B side of the substrate 2 at a position overlapping the second photoelectric conversion element 7 when viewed in the thickness direction of the substrate 2, i.e., the direction of the arrow Z (hereinafter simply referred to as "in a plan view"). The second photoelectric conversion element 8 is formed of a photodiode having a different absorption coefficient from the photodiode of the second photoelectric conversion element 7. Like the photodiode of the second photoelectric conversion element 7, the photodiode is formed at a pn junction between an n-type semiconductor region and a p-type semiconductor region. The second photoelectric conversion element 8 is configured to be sensitive to, for example, red light.

[0025] The p-type well region 20p is also used as a charge storage portion that stores the charges converted by the second photoelectric conversion element 7 and the second photoelectric conversion element 8, respectively.

[0026] In the second photoelectric conversion element 7, the charge generated by photoelectric conversion from light is output to a pixel circuit (not shown). Similarly, in the second photoelectric conversion element 8, the charge generated by photoelectric conversion from light is output to a pixel circuit (not shown).

[0027] Either the second photoelectric conversion element 7 or the second photoelectric conversion element 8 may be disposed within the substrate 2. Either the second photoelectric conversion element 7 or the second photoelectric conversion element 8 may be configured to be sensitive to near-infrared light.

[0028] (4) Configuration of Pixel Circuit 10 FIG. 2 shows an example of a longitudinal cross-sectional configuration of the pixel region shown in FIG. 1 and a circuit configuration of the pixel circuit 10. FIG. 3 shows an example of a schematic planar configuration of the pixel region and pixel circuit 10. As shown in FIGS. 1 to 3, the pixel circuit 10 is disposed on the second surface 2B side of the substrate 2. In the first embodiment, the pixel circuit 10 includes a floating diffusion 101, an amplifier transistor 102, a reset transistor 103, and a select transistor 104 (see FIGS. 2 and 3). The pixel circuit 10 receives and processes electric charges photoelectrically converted from light by the first photoelectric conversion element 5.

[0029] An insulating layer 200 is formed on the second surface 2B of the substrate 2. The insulating layer 200 is actually formed by a plurality of insulating layers. Multilayer wiring 201 is disposed within the insulating layer 200. The floating diffusion 101 is formed to include the through wiring 21 and the wiring 201 electrically connected to the through wiring 21.

[0030] The amplifier transistor 102 is disposed on the second surface 2B and is formed of an n-channel insulated gate field effect transistor (IGFET) of a first conductivity type. Here, the term IGFET is used to include a metal insulator semiconductor field effect transistor (MISFET) and a metal oxide semiconductor field effect transistor (MOSFET).

[0031] The amplifier transistor 102 includes a channel formation region (not shown) formed in a p-type well region, a gate insulating film 110, a control electrode (gate electrode) 111, and a pair of main electrodes 112. The gate insulating film 110 is formed in the channel formation region. The gate insulating film 110 is made of a dielectric material such as SiO or SiN. The control electrode 111 is formed on the opposite side of the gate insulating film 110 from the channel formation region. The floating diffusion 101 is electrically connected to the control electrode 111. The control electrode 111 is made of a gate electrode material such as polycrystalline Si. The pair of main electrodes 112 are disposed on the second surface 2B side of the substrate 2 and are formed of n-type semiconductor regions. The pair of main electrodes 112 serve as a source region (S) and a drain region (D). One of the pair of main electrodes 112 is electrically connected to a power supply voltage VDD that supplies a fixed potential.

[0032] As will be described in detail later, one of the pair of main electrodes 112 of the amplifier transistor 102 is also used as the potential supply region 13 that supplies a fixed potential to the charge discharge region 22. In other words, one of the pair of main electrodes 112 is shared with the potential supply region 13.

[0033] The reset transistor 103 is disposed on the second surface 2B and is formed by an n-channel IGFET. Similar to the amplifier transistor 102, the reset transistor 103 includes a channel formation region (not shown), a gate insulating film 110, a control electrode 111, and a pair of main electrodes 112. A reset signal line RST is electrically connected to the control electrode 111 (see FIG. 2). One of the pair of main electrodes 112 is electrically connected to the floating diffusion 101 and the control electrode 111 of the amplifier transistor 102. The other of the pair of main electrodes 112 is electrically connected to the power supply voltage VDD.

[0034] The select transistor 104 is disposed on the second surface 2B and is formed by an n-channel IGFET. Similar to the amplifier transistor 102, the select transistor 104 includes a channel formation region (not shown), a gate insulating film 110, a control electrode 111, and a pair of main electrodes 112. A select signal line SEL is electrically connected to the control electrode 111 (see FIG. 2). One of the pair of main electrodes 112 is electrically connected to the other of the pair of main electrodes 112 of the amplifier transistor 102. One of the pair of main electrodes 112 is connected to a vertical signal line SL. The vertical signal line SL is connected to a current source load LC.

[0035] The pixel circuit 10 may further include a floating diffusion conversion gain switching transistor electrically connected in series between the floating diffusion 101 and the reset transistor 103 .

[0036] (5) Configuration of the Through Wiring 21 As shown in FIGS. 1 to 3 , the through wiring 21 is configured as a wiring that penetrates the substrate 2 in the thickness direction. One end of the through wiring 21 on the first surface 2A side is electrically connected to the first transparent electrode 51 of the first photoelectric conversion element 5. Specifically, the through wiring 21 is electrically connected to the first transparent electrode 51 via an electrode 510. The other end of the through wiring 21 on the second surface 2B side is electrically connected to the floating diffusion 101. The through wiring 21 configured in this manner transfers charges generated by photoelectric conversion of light in the first photoelectric conversion element 5 to the floating diffusion 101.

[0037] More specifically, the through wiring 21 is formed in a through groove (through hole) 210 that penetrates from the first surface 2A to the second surface 2B of the substrate 2, extending in the thickness direction of the substrate 2. The through wiring 21 is electrically isolated from the substrate 2 by an insulator 212 formed on the side wall of the through groove 210. The planar shapes of the through wiring 21 and the through groove 210 are not particularly limited, but here they are formed in a circular shape in a planar view. In other words, the through wiring 21 extends in the thickness direction of the substrate 2 and is therefore formed in a cylindrical shape as a whole.

[0038] The through-hole wiring 21 is formed of one or more metal materials selected from the group consisting of Si, aluminum (Al), tungsten (W), titanium (Ti), cobalt (Co), platinum (Pt), palladium (Pd), copper (Cu), hafnium (Hf), and tantalum (Ta). Here, the Si contains impurities that reduce the resistance value, such as phosphorus (P) as an n-type impurity.

[0039] The insulator 212 is made of, for example, one or more insulating materials selected from SiO, TEOS, SiN, and SiNO. The insulator 212 may be formed of a single layer or a composite layer in which different types of insulating materials are stacked.

[0040] [Configuration of the charge drain region 22, the potential supply region 23, and the potential barrier region 24] Fig. 4 shows an example of a schematic enlarged longitudinal cross-sectional configuration of the pixel region and the main part of the pixel circuit 10 shown in Fig. 1 and Fig. 2. Fig. 5 shows an example of a schematic planar configuration that simplifies the pixel region shown in Fig. 3.

[0041] 1 to 5, the photodetector 1 according to the first embodiment includes a charge drain region 22 and a potential supply region 23 in each pixel 100, and further includes a potential barrier region 24. These will be described in detail below.

[0042] (1) Configuration of the Charge Discharge Region 22 The charge discharge region 22 is disposed on the second surface 2B side, which is part of the thickness direction of the substrate 2, around the side surface of the through-hole wiring 21, with an insulator 212 interposed therebetween. A detailed description will be given. The charge discharge region 22 is disposed from the middle of the thickness direction of the substrate 2 to the second surface 2B. The junction depth xj1 of the charge discharge region 22 in the direction of arrow Z is deeper than the junction depth xj2 of the potential supply region 23 (the pair of main electrodes 112 of the amplifier transistor 102).

[0043] 5 , in the first embodiment, the planar shape of the pixel 100 is formed into an effectively square rectangular shape, and through-hole wirings 21 are disposed at the four corners of the pixel 100. The through-hole wirings 21 are shared between the pixels 100 adjacent to each other in the directions of arrows X and Y. In plan view, the charge discharge region 22 surrounds the side surfaces of each of the plurality of through-hole wirings 21 and is disposed for each through-hole wiring 21.

[0044] The charge discharging region 22 is formed of an n-type semiconductor region having an impurity density equivalent to that of the n-type semiconductor regions of the second photoelectric conversion element 7 and the second photoelectric conversion element 8. For example, the charge discharging region 22 has an impurity density of 1×10 １６ atoms / cm ３ 1x10 or more １８ atoms / cm ３ It is formed by an n-type semiconductor region having the following impurity concentration:

[0045] The charge discharging region 22 supplies a fixed potential to the potential supply region 23 to discharge dark current generated in the p-type well region 20 p along the periphery of the side surface of the through-wire 21 .

[0046] (2) Configuration of the Potential Supply Region 23 The potential supply region 23 is disposed on the second surface 2B side of the substrate 2, separated from the charge discharge region 22, within the pixel 100. The potential supply region 23 is formed of an n-type semiconductor region having a higher impurity density than the charge discharge region 22. For example, the potential supply region 23 has a density of 1×10 １８ atoms / cm ３ 1x10 or more ２０ atoms / cm ３ It is formed by an n-type semiconductor region having the following impurity concentration:

[0047] In the first embodiment, the potential supply region 23 is formed by and shared with one of the pair of main electrodes 112 of the amplifier transistor 102. Therefore, a fixed potential is supplied to the potential supply region 23.

[0048] (3) Configuration of Potential Barrier Region 24 The potential barrier region 24 is disposed in the substrate 2 between the charge discharge region 22 and the potential supply region 23. In other words, the depth D of the potential barrier region 24 is set between the junction depth xj1 of the charge discharge region 22 and the junction depth xj2 of the potential supply region 23. The potential barrier region 24 is formed of a p-type semiconductor region of a conductivity type opposite to that of the charge discharge region 22 and the potential supply region 23. The potential barrier region 24 generates a potential barrier at least for the charge discharge region 22, and effectively suppresses or prevents leakage of dark current generated in the charge discharge region 22.

[0049] The potential barrier region 24 is formed of a p-type semiconductor region having a higher impurity density than the p-type well region 20p. １６ atoms / cm ３ 1x10 or more １８ atoms / cm ３ It is formed by a p-type semiconductor region having the following impurity concentration:

[0050] 6 shows an example of the potentials of the p-type well region 20p, the charge discharge region 22, the potential supply region 23, and the potential barrier region 24. The horizontal axis shown in Fig. 6 indicates the region on line A-A and the region on line B-B extending in the direction of arrow X in Fig. 4.

[0051] As shown in FIG. 6, the potential barrier region 24 is formed of a p-type semiconductor region having a higher impurity density than the p-type well region 20 p, and forms a potential barrier with respect to the charge discharging region 22 .

[0052] The potential barrier region 24 is disposed so as to cover at least one of the charge discharge region 22 and the potential supply region 23, and is disposed in a layout in which one cannot be directly seen from the other. In other words, the potential barrier region 24 is configured to effectively suppress leakage of dark current from the charge discharge region 22 to the potential supply region 23.

[0053] [Effects] As shown in FIGS. 1 to 6 , the photodetector 1 according to the first embodiment includes a substrate (first substrate) 2, through-hole wiring 21, a charge drain region 22, a potential supply region 23, and a potential barrier region 24. The substrate 2 has a first surface 2A and a second surface 2B facing the first surface 2A. The through-hole wiring 21 penetrates the substrate 2 from the first surface 2A to the second surface 2B and transfers charges generated by photoelectric conversion on the first surface 2A side to the second surface 2B side. The charge drain region 22 is disposed around the side surface of the through-hole wiring 21, with an insulator 212 interposed therebetween, in at least a portion of the thickness direction of the substrate 2 from the first surface 2A to the second surface 2B. The charge drain region 22 is formed by an n-type semiconductor region that drains dark current. The potential supply region 23 is disposed on the second surface 2B side of the substrate 2, spaced apart from the charge drain region 22. The potential supply region 23 is formed of an n-type semiconductor region and supplies a fixed potential (VDD) to the charge drain region 22. The potential barrier region 24 is disposed on the substrate 2 between the charge drain region 22 and the potential supply region 23. The potential barrier region 24 is formed of a p-type semiconductor region and generates a potential barrier for the charge drain region 22. With the photodetector 1 configured in this manner, a potential barrier can be generated in the pn junction region between the charge drain region 22 and the potential barrier region 24. Even if processing damage occurs in the substrate 2 during the manufacturing of the through-hole wiring 21 and dark current is generated around the side of the through-hole wiring 21, particularly on the second surface 2B side, the potential barrier can effectively suppress or prevent leakage of the dark current. This improves the signal-to-noise ratio caused by dark current and improves the quality of the pixel signal.

[0054] As shown in FIGS. 1 to 6 , the photodetector 1 also includes an amplifier transistor 102 (first transistor). The amplifier transistor 102 is disposed on the second surface 2B side of the substrate 2, has an n-channel conductivity type, and includes a pair of main electrodes 112, one of which is supplied with a fixed potential (VDD), and a control electrode (gate electrode) 111 electrically connected to the through-hole wiring 21. The potential supply region 23 is shared by one of the pair of main electrodes 112. With the photodetector 1 configured in this manner, the potential supply region 23 can be formed using the pair of main electrodes 112 of the amplifier transistor 102, eliminating the need to provide a separate potential supply region 23. This allows for effective use of the pixel area, thereby reducing the area occupied by the pixel 100.

[0055] 1 to 6, in the photodetector 1, the impurity density of the charge discharge region 22 is lower than the impurity density of the potential supply region 23. The amplifier transistor 102 is disposed in the p-type well region 20p. The impurity density of at least the potential barrier region 24 in contact with the charge discharge region 22 is higher than the impurity density of the p-type well region 20p. With the photodetector 1 configured in this manner, the potential barrier region 24 can generate a higher potential barrier at the junction region with the charge discharge region 22 than at the junction region with the p-type well region 20p. This makes it possible to effectively suppress or prevent dark current leakage.

[0056] As shown in FIGS. 1 and 4 , the photodetector 1 also includes a reset transistor 103 (second transistor) in the pixel circuit 10. The reset transistor 103 is disposed on the second surface 2B of the substrate 2, has n-channel conductivity, and includes a pair of main electrodes 112, one of which is electrically connected to the first photoelectric conversion element 5. In other words, the potential barrier region 24 is disposed between the other of the pair of main electrodes 112 of the reset transistor 103 and the charge drain region 22. With the photodetector 1 configured in this manner, a potential barrier can be generated in the pn junction region between the charge drain region 22 and the potential barrier region 24. Even if processing damage occurs in the substrate 2 during the manufacturing of the through-hole wiring 21, causing dark current to occur around the side of the through-hole wiring 21, particularly on the second surface 2B side, the potential barrier can effectively suppress or prevent leakage of the dark current. This improves the signal-to-noise ratio caused by dark current and improves the quality of the pixel signal.

[0057] 7 , a photodetector 1 according to a second embodiment of the present disclosure will be described. The second embodiment describes an example in which the configuration of the charge drain region 22 in the photodetector 1 according to the first embodiment is changed. Note that in the photodetector 1 according to the second embodiment and subsequent embodiments, components that are the same as or substantially the same as components of the photodetector 1 according to the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

[0058] [Configuration of Photodetector 1] Fig. 7 shows an example of a simplified schematic planar configuration of the pixel region of the photodetector 1. As with the photodetector 1 according to the first embodiment, the planar shape of the pixel 100 of the photodetector 1 is formed into a rectangular shape, as shown in Fig. 7. Through-wires 21 are disposed at four corners of the pixel 100. In other words, a plurality of through-wires 21 are disposed at predetermined intervals along the periphery of the side surface of the pixel 100.

[0059] A charge discharge region 22 is disposed around the side surface of the through-wire 21. The charge discharge region 22 is also disposed between adjacent through-wires 21. In other words, the charge discharge region 22 is disposed surrounding the side surface of the pixel 100.

[0060] The other components are the same as those of the photodetector 1 according to the first embodiment, and therefore a description thereof will be omitted here.

[0061] [Operational Effects] According to the photodetector 1 of the second embodiment, it is possible to obtain the same operational effects as those obtained by the photodetector 1 of the first embodiment.

[0062] 8, a photodetector 1 according to a third embodiment of the present disclosure will be described. In the third embodiment, an example will be described in which the configuration of the charge drain region 22 in the photodetector 1 according to the first embodiment is changed.

[0063] [Configuration of Photodetector 1] Fig. 8 shows an example of a schematic enlarged longitudinal cross-sectional configuration of a pixel region and a main part of the pixel circuit 10 of the photodetector 1. As with the photodetector 1 according to the first embodiment, as shown in Fig. 8, the photodetector 1 has a charge discharge region 22 around the side surface of the through-wire 21. The charge discharge region 22 is disposed over the entire area in the thickness direction of the substrate 2 from the first surface 2A to the second surface 2B.

[0064] The other components are the same as those of the photodetector 1 according to the first embodiment, and therefore a description thereof will be omitted here.

[0065] [Operational Effects] According to the photodetector 1 of the third embodiment, it is possible to obtain the same operational effects as those obtained by the photodetector 1 of the first embodiment.

[0066] 9, a photodetector 1 according to a fourth embodiment of the present disclosure will be described. In the fourth embodiment, an example will be described in which the configurations of the charge drain region 22 and the potential barrier region 24 in the photodetector 1 according to the first embodiment are changed.

[0067] 9 shows an example of a schematic enlarged longitudinal cross-sectional configuration of a pixel region and a main part of the pixel circuit 10 of the photodetector 1. As in the photodetector 1 according to the first embodiment, as shown in FIG. 9 , the photodetector 1 includes a charge drain region 22 around the side surface of the through-wire 21, and a potential barrier region 24 between the charge drain region 22 and the potential supply region 23.

[0068] In plan view, the charge discharge region 22 and the potential barrier region 24 are arranged to overlap the amplifier transistor 102. A detailed explanation will be given below. In the fourth embodiment, the charge discharge region 22 covers one of the pair of main electrodes 112 and the channel formation region of the amplifier transistor 102, and is arranged to overlap both of them. The potential barrier region 24 is formed in the same shape as the charge discharge region 22, and is arranged to cover one of the pair of main electrodes 112 and the channel formation region of the amplifier transistor 102, and is arranged to overlap both of them.

[0069] The other components are the same as those of the photodetector 1 according to the first embodiment, and therefore a description thereof will be omitted here.

[0070] [Operational Effects] According to the photodetector 1 of the fourth embodiment, it is possible to obtain the same operational effects as those obtained by the photodetector 1 of the first embodiment.

[0071] 9 , in the photodetector 1, the charge drain region 22 and the potential barrier region 24 are arranged to overlap the amplifier transistor 102. Therefore, even if the amplifier transistor 102 has an opposite conductivity type, a transistor such as the amplifier transistor 102 can be arranged within the pixel 100, and the area of ​​the second photoelectric conversion element 7 or the second photoelectric conversion element 8 can be used effectively.

[0072] 5. Fifth Embodiment A photodetector 1 according to a fifth embodiment of the present disclosure will be described with reference to Fig. 10. In the fifth embodiment, an example will be described in which the photodetector 1 according to the third embodiment and the photodetector 1 according to the fourth embodiment are combined.

[0073] [Configuration of Photodetector 1] Fig. 10 shows an example of a schematic enlarged longitudinal cross-sectional configuration of a pixel region and a main portion of a pixel circuit 10 of the photodetector 1. As shown in Fig. 10, the photodetector 1 according to the fifth embodiment includes a substrate (second substrate) 9 on which a substrate (first substrate) 2 is stacked in the direction of the arrow Z. In other words, the substrate 9 is stacked on the second surface 2B side of the substrate 2. The substrate 9, like the substrate 2, is a semiconductor substrate made of single-crystal Si. A p-type well region 90p is formed in this semiconductor substrate.

[0074] The substrate 2 and the substrate 9 are provided with through-hole wiring 21 that penetrates both of them. Around the side surfaces of the through-hole wiring 21, the substrate 2 is provided with a charge discharge region 22, a potential supply region 23, and a potential barrier region 24. The charge discharge region 22 includes a charge discharge region 22A that corresponds to the charge discharge region 22 of the photodetector 1 according to the third embodiment, and a charge discharge region 22B that corresponds to the charge discharge region 22 of the photodetector 1 according to the fourth embodiment. The charge discharge region 22A is provided over the entire thickness direction of the substrate 2. The charge discharge region 22B is provided so as to overlap, for example, with the amplifier transistor 102 in a plan view. The charge discharge region 22A and the charge discharge region 22B are electrically connected to each other.

[0075] Furthermore, the potential supply region 23 is not shared with the pair of main electrodes 112 of the amplifier transistor 102 .

[0076] The amplifier transistor 102 and other components that constitute the pixel circuit 10 are disposed in a p-type well region 90p of the substrate 9. Like the amplifier transistor 102 of the photodetector 1 according to the first embodiment, the amplifier transistor 102 includes a channel formation region, a gate insulating film 110, a control electrode (gate electrode) 111, and a pair of main electrodes 112.

[0077] The power supply voltage VDD, which is electrically connected to one of the pair of main electrodes 112 of the amplifier transistor 102, is electrically connected to the potential supply region 23 through wiring 901 arranged in the wiring layer 900 of the substrate 9, wiring 201 arranged in the insulating layer 200 of the substrate 2, etc.

[0078] The other components are the same as those of the photodetector 1 according to the third embodiment or the photodetector 1 according to the fourth embodiment, and therefore a description thereof will be omitted here.

[0079] [Effects] According to the photodetector 1 of the fifth embodiment, it is possible to obtain an effect that combines the effects obtained by the photodetector 1 of the third embodiment and the effects obtained by the photodetector 1 of the fourth embodiment.

[0080] 10 , the photodetector 1 has a two-tier structure in which the first photoelectric conversion element 5, the second photoelectric conversion element 7, and the second photoelectric conversion element 8 are disposed on a substrate 2, and the pixel circuit 10 is disposed on a substrate 9. Even with the photodetector 1 configured in this manner, it is possible to improve the signal-to-noise ratio caused by dark current and enhance the quality of pixel signals.

[0081] 6. Application Examples to Mobile Bodies 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 realized as a device mounted on any type of mobile body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, or a robot.

[0082] FIG. 11 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.

[0083] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 11, 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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 the passengers of the vehicle or the outside of the vehicle of information. In the example of Fig. 11, 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.

[0093] FIG. 12 is a diagram showing an example of the installation position of the imaging unit 12031.

[0094] In FIG. 12, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0095] 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.

[0096] 12 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.

[0097] 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.

[0098] 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 allows the vehicle to travel autonomously without relying on driver operation.

[0099] 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.

[0100] 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.

[0101] The above describes an example of a vehicle 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, for example, the image capturing unit 12031, etc., among the components described above. By applying the technology according to the present disclosure to the image capturing unit 12031, etc., it is possible to improve the signal-to-noise ratio caused by dark current and enhance the quality of pixel signals.

[0102] 7. Application Example to Intra-Vivo Information Acquisition 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.

[0103] FIG. 13 is a block diagram showing an example of a schematic configuration of a system for acquiring information from within a patient's body using a capsule endoscope, to which the technology according to the present disclosure (the present technology) can be applied.

[0104] The in-vivo information acquisition system 10001 includes a capsule endoscope 10100 and an external control device 10200 .

[0105] The capsule endoscope 10100 is swallowed by a patient during an examination. The capsule endoscope 10100 has an imaging function and a wireless communication function, and moves through the inside of organs such as the stomach and intestines by peristaltic movement or the like until it is naturally expelled from the patient, sequentially capturing images of the inside of the organs (hereinafter also referred to as in-vivo images) at predetermined intervals, and sequentially wirelessly transmitting information about the in-vivo images to an external control device 10200 outside the body.

[0106] The external control device 10200 comprehensively controls the operation of the in-vivo information acquisition system 10001. The external control device 10200 also receives information about the in-vivo images transmitted from the capsule endoscope 10100, and generates image data for displaying the in-vivo images on a display device (not shown) based on the received information about the in-vivo images.

[0107] In this way, the in-vivo information acquisition system 10001 can obtain in-vivo images of the state inside the patient's body at any time from the time the capsule endoscope 10100 is swallowed until it is expelled.

[0108] The configurations and functions of the capsule endoscope 10100 and the external control device 10200 will be described in more detail.

[0109] The capsule endoscope 10100 has a capsule-shaped housing 10101, which houses a light source unit 10111, an imaging unit 10112, an image processing unit 10113, a wireless communication unit 10114, a power supply unit 10115, a power supply unit 10116, and a control unit 10117.

[0110] The light source unit 10111 is composed of a light source such as an LED (light emitting diode), and irradiates the imaging field of the imaging unit 10112 with light.

[0111] The imaging unit 10112 is composed of an imaging element and an optical system consisting of multiple lenses provided in front of the imaging element. Reflected light (hereinafter referred to as observation light) of light irradiated onto the body tissue to be observed is collected by the optical system and incident on the imaging element. In the imaging unit 10112, the imaging element photoelectrically converts the incident observation light, generating an image signal corresponding to the observation light. The image signal generated by the imaging unit 10112 is provided to the image processing unit 10113.

[0112] The image processing unit 10113 is configured with processors such as a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit), and performs various signal processing on the image signal generated by the imaging unit 10112. The image processing unit 10113 provides the image signal that has been subjected to the signal processing to the wireless communication unit 10114 as RAW data.

[0113] The wireless communication unit 10114 performs predetermined processing such as modulation on the image signal that has been subjected to signal processing by the image processing unit 10113, and transmits the image signal to the external control device 10200 via the antenna 10114A. The wireless communication unit 10114 also receives a control signal related to drive control of the capsule endoscope 10100 from the external control device 10200 via the antenna 10114A. The wireless communication unit 10114 provides the control signal received from the external control device 10200 to the control unit 10117.

[0114] The power supply unit 10115 is composed of an antenna coil for receiving power, a power regeneration circuit that regenerates power from the current generated in the antenna coil, a boost circuit, etc. The power supply unit 10115 generates power using the principle of so-called contactless charging.

[0115] The power supply unit 10116 is configured by a secondary battery and stores the power generated by the power supply unit 10115. In Fig. 13, to avoid cluttering the drawing, arrows and the like indicating the destinations of the power supply unit 10116 are omitted, but the power stored in the power supply unit 10116 is supplied to the light source unit 10111, the imaging unit 10112, the image processing unit 10113, the wireless communication unit 10114, and the control unit 10117 and can be used to drive these units.

[0116] The control unit 10117 is composed of a processor such as a CPU, and appropriately controls the operation of the light source unit 10111, the imaging unit 10112, the image processing unit 10113, the wireless communication unit 10114, and the power supply unit 10115 in accordance with control signals transmitted from the external control device 10200.

[0117] The external control device 10200 is configured with a processor such as a CPU or a GPU, or a microcomputer or control board equipped with a processor and a storage element such as a memory. The external control device 10200 controls the operation of the capsule endoscope 10100 by transmitting a control signal to the control unit 10117 of the capsule endoscope 10100 via the antenna 10200A. In the capsule endoscope 10100, for example, the light irradiation conditions of the light source unit 10111 for the observation object can be changed by the control signal from the external control device 10200. Furthermore, the imaging conditions (e.g., the frame rate and exposure value of the imaging unit 10112) can be changed by the control signal from the external control device 10200. Furthermore, the control signal from the external control device 10200 can change the content of processing in the image processing unit 10113 and the conditions for transmitting image signals from the wireless communication unit 10114 (e.g., the transmission interval, the number of transmitted images, etc.).

[0118] The external control device 10200 also performs various image processing on the image signal transmitted from the capsule endoscope 10100 to generate image data for displaying the captured in-vivo image on a display device. The image processing can include various signal processing such as development processing (demosaic processing), image quality improvement processing (band enhancement processing, super-resolution processing, NR (Noise Reduction) processing, and / or image stabilization processing), and / or enlargement processing (electronic zoom processing). The external control device 10200 controls the driving of the display device to display the captured in-vivo image based on the generated image data. Alternatively, the external control device 10200 may record the generated image data in a recording device (not shown) or print it out on a printing device (not shown).

[0119] The above describes an example of an in-vivo information acquisition 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 10112 among the configurations described above. By applying the technology according to the present disclosure to the imaging unit 10112, it is possible to improve the signal-to-noise ratio caused by dark current and improve the quality of pixel signals.

[0120] 8. Other Embodiments The present technology is not limited to the above-described embodiments, and various modifications are possible within the scope of the present technology. For example, among the photodetection devices according to the first to fifth embodiments, photodetection devices according to two or more of the above-described embodiments may be combined.

[0121] A photodetector according to a first embodiment of the present disclosure includes a first substrate, a through-hole interconnect, a charge drain region, a potential supply region, and a potential barrier region. The first substrate has a first surface and a second surface opposite the first surface. The through-hole interconnect penetrates the first substrate from the first surface to the second surface and transfers charges generated by photoelectric conversion on the first surface side to the second surface side. The charge drain region is disposed around the side surface of the through-hole interconnect with an insulator interposed therebetween in at least a portion of the thickness direction of the first substrate from the first surface to the second surface. The charge drain region is formed of a first conductivity type that drains dark current. The potential supply region is disposed on the second surface side of the first substrate, spaced apart from the charge drain region. The potential supply region is formed of the first conductivity type and supplies a fixed potential to the charge drain region. The potential barrier region is disposed on the first substrate between the charge drain region and the potential supply region. The potential barrier region is formed of a second conductivity type and generates a potential barrier for the charge drain region. With this photodetector device, a potential barrier can be generated at the junction between the charge drain region and the potential barrier region. Even if dark current occurs around the side of the through-hole, the potential barrier can effectively suppress or prevent the dark current from leaking. This improves the signal-to-noise ratio caused by dark current and improves the quality of the pixel signal.

[0122] A photodetector according to a second embodiment of the present disclosure is the photodetector according to the first embodiment, further comprising a first transistor disposed on the second surface side of the first substrate, the first transistor having a first conductivity type, and including a pair of main electrodes, one of which is supplied with a fixed potential, and a gate electrode electrically connected to the through-hole wiring. The potential supply region is shared by one of the pair of main electrodes. In this way, with this photodetector, the pair of main electrodes of the first transistor can be used to form the potential supply region, thereby making it possible to effectively utilize the pixel region and reduce the area occupied by the pixel.

[0123] In a photodetector according to a third embodiment of the present disclosure, the first transistor in the photodetector according to the first embodiment is disposed in a well region having a second conductivity type. The impurity density of the potential barrier region, at least in contact with the charge drain region, is higher than the impurity density of the well region. With this photodetector configured in this manner, the potential barrier region can generate a higher potential barrier at the junction region with the charge drain region than at the junction region with the well region. This effectively suppresses or prevents dark current leakage.

[0124] In a photodetector according to a fourth embodiment of the present disclosure, the charge drain region is disposed across the entire thickness of the first substrate from the first surface to the second surface, thereby effectively suppressing or preventing dark current leakage across a wide area across the entire thickness of the first substrate.

[0125] In a photodetector according to a fifth embodiment of the present disclosure, the charge drain region and the potential barrier region are arranged to overlap with the first transistor when viewed in the thickness direction of the first substrate in the photodetector according to the first embodiment, and the photodetector configured in this manner can effectively utilize the pixel area.

[0126] A photodetector according to a sixth embodiment of the present disclosure is the photodetector according to the first embodiment, further comprising: a second substrate stacked on the second surface side of the first substrate; and a first transistor disposed on the second substrate, the first transistor having a first conductivity type and including a pair of main electrodes, one of which is supplied with a fixed potential, and a gate electrode electrically connected to a through-hole wiring. The potential supply region is electrically connected to one of the pair of main electrodes. Furthermore, the charge drain region is disposed so as to overlap the first transistor when viewed in the thickness direction of the first substrate. According to the photodetector 1 configured in this manner, even in a two-stage structure including the first and second substrates, it is possible to improve the signal-to-noise ratio due to dark current and enhance the quality of pixel signals.

[0127] <Configuration of the Present Technology> The present technology has the following configuration. By providing the following configuration, it is possible to provide a photodetector device that can improve the signal-to-noise ratio caused by dark current and enhance the quality of pixel signals. (1) A photodetector device comprising: a first substrate having a first surface and a second surface opposite to the first surface; a through-hole wiring that penetrates from the first surface to the second surface of the first substrate and transfers charge generated by photoelectric conversion on the first surface side to the second surface side; a charge drain region of a first conductivity type that drains dark current and is arranged around a side surface of the through-hole wiring with an insulator interposed therebetween in at least a part of a thickness direction of the first substrate from the first surface to the second surface; a potential supply region of the first conductivity type that is arranged spaced apart from the charge drain region on the second surface side of the first substrate and supplies a fixed potential to the charge drain region; and a potential barrier region that is arranged on the first substrate between the charge drain region and the potential supply region and has a second conductivity type opposite to the first conductivity type and generates a potential barrier for the charge drain region. (2) The photodetector according to (1), further comprising: a first photoelectric conversion element disposed on the first surface side of the first substrate and generating electric charges through photoelectric conversion. (3) The photodetector according to (2), further comprising: an organic photoelectric conversion element. (4) The photodetector according to any one of (1) to (3), further comprising: a first transistor disposed on the second surface side of the first substrate, the first transistor having a first conductivity type and including a pair of main electrodes, one of which is supplied with a fixed potential, and a gate electrode electrically connected to the through-hole wiring, wherein the potential supply region is shared by one of the pair of main electrodes. (5) The photodetector according to (2) or (3), further comprising: a first photoelectric conversion element configured as a pixel; a plurality of through-hole wirings disposed at predetermined intervals along a lateral periphery of the pixel; and a charge discharge region also disposed between adjacent through-hole wirings. (6) The photodetector according to (5), further comprising: a first transistor disposed on the second surface side of the first substrate, the first transistor having a first conductivity type and including a pair of main electrodes, one of which is supplied with a fixed potential, and a gate electrode electrically connected to the through-hole wiring, wherein the potential supply region is shared by one of the pair of main electrodes. (7) The photodetector according to any one of (1) to (6), wherein the impurity density of the charge discharging region is lower than the impurity density of the potential supply region.(8) The photodetector according to (4), wherein the first transistor is disposed in a well region having a second conductivity type, and the impurity density of at least the portion of the potential barrier region in contact with the charge drain region is higher than the impurity density of the well region. (9) The photodetector according to (1), wherein the first substrate includes one or more second photoelectric conversion elements that generate charges by photoelectric conversion. (10) The photodetector according to (9), wherein the second transistor is disposed on the second surface side of the first substrate, has the first conductivity type, and is formed including a pair of main electrodes, one of which is electrically connected to the first photoelectric conversion element, and the potential barrier region is disposed between the other of the pair of main electrodes and the charge drain region. (11) The photodetector according to any one of (1) to (10), wherein the charge drain region is disposed throughout the thickness direction of the first substrate from the first surface to the second surface. (12) The photodetector according to any one of (1) to (11), wherein the charge discharge region and the potential barrier region are arranged to overlap the first transistor when viewed in the thickness direction of the first substrate. (13) The photodetector according to any one of (1) to (11), comprising: a second substrate stacked on the second surface side of the first substrate; and a first transistor arranged on the second substrate, the first transistor having a first conductivity type and including a pair of main electrodes, one of which is supplied with a fixed potential, and a gate electrode electrically connected to the through-hole wiring, the potential supply region being electrically connected to one of the pair of main electrodes, and the charge discharge region being arranged to overlap the first transistor when viewed in the thickness direction of the first substrate. (14) The photodetector according to (13), wherein the potential barrier region is arranged to overlap the first transistor when viewed in the thickness direction of the first substrate.

[0128] This application claims priority based on Japanese Patent Application No. 2024-022252, filed on February 16, 2024, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0129] 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 first substrate having a first surface and a second surface opposite to the first surface; a through-hole wiring that penetrates from the first surface to the second surface of the first substrate and transfers charges generated by photoelectric conversion on the first surface side to the second surface side; a charge drain region of a first conductivity type that drains dark current and is arranged around the side of the through-hole wiring with an insulator interposed in at least a part of the thickness direction of the first substrate from the first surface to the second surface; a potential supply region of the first conductivity type that is arranged spaced apart from the charge drain region on the second surface side of the first substrate and supplies a fixed potential to the charge drain region; and a potential barrier region that is arranged on the first substrate between the charge drain region and the potential supply region and has a second conductivity type opposite to the first conductivity type and creates a potential barrier for the charge drain region.

2. The photodetector according to claim 1, further comprising a first photoelectric conversion element disposed on the first surface side of the first substrate and generating electric charges through photoelectric conversion.

3. The photodetector according to claim 2, wherein the first photoelectric conversion element is an organic photoelectric conversion element.

4. The photodetector according to claim 1, further comprising a first transistor disposed on the second surface side of the first substrate, having a first conductivity type, and formed including a pair of main electrodes, one of which is supplied with a fixed potential, and a gate electrode electrically connected to the through-hole wiring, wherein the potential supply region is shared by one of the pair of main electrodes.

5. The photodetector according to claim 2, wherein the first photoelectric conversion element constitutes a pixel, the through wirings are arranged at predetermined intervals along the periphery of the side surface of the pixel, and the charge discharge region is also arranged between adjacent through wirings.

6. The photodetector device according to claim 5, wherein the charge discharging region is disposed surrounding the lateral periphery of the pixel.

7. The photodetector according to claim 1, wherein the impurity density of the charge discharging region is lower than the impurity density of the potential supply region.

8. The photodetector according to claim 4, wherein the first transistor is disposed in a well region of the second conductivity type, and the impurity density of the potential barrier region in contact with at least the charge discharge region is higher than the impurity density of the well region.

9. The photodetector according to claim 1, further comprising one or more second photoelectric conversion elements disposed within the first substrate, the second photoelectric conversion elements generating electric charges through photoelectric conversion.

10. A photodetector according to claim 9, further comprising a second transistor disposed on the second surface side of the first substrate, having a first conductivity type, and including a pair of main electrodes, one of which is electrically connected to the first photoelectric conversion element, and wherein the potential barrier region is disposed between the other of the pair of main electrodes and the charge discharge region.

11. The photodetector according to claim 1, wherein the charge discharging region is disposed over the entire area in the thickness direction of the first substrate from the first surface to the second surface.

12. The photodetector according to claim 1, wherein the charge discharging region and the potential barrier region are arranged to overlap the first transistor when viewed in the thickness direction of the first substrate.

13. A photodetector as described in claim 1, comprising: a second substrate stacked on the second surface side of the first substrate; and a first transistor disposed on the second substrate, having a first conductivity type, and formed including a pair of main electrodes, one of which is supplied with a fixed potential, and a gate electrode electrically connected to the through-wiring, wherein the potential supply region is electrically connected to one of the pair of main electrodes, and the charge discharge region is disposed so as to overlap the first transistor when viewed in the thickness direction of the first substrate.

14. The photodetector according to claim 13, wherein the potential barrier region is disposed so as to overlap the first transistor when viewed in the thickness direction of the first substrate.

Images