WO2025037544A1 - Light detection device - Google Patents

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

This disclosure relates to a light detection device.

For example, Patent Document 1 discloses a photodetector in which an organic photoelectric conversion unit having an organic photoelectric conversion layer is laminated 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.

International Publication No. 2022/131268

Incidentally, there is a demand for reducing random noise in optical detection devices.

Therefore, it is desirable to provide a photodetection device that can reduce random noise.

A first photodetector according to an embodiment of the present disclosure includes a semiconductor substrate having a first surface and a second surface facing each other, 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 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 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.

The second photodetector according to an embodiment of the present disclosure includes a semiconductor substrate having a first surface and a second surface facing each other, 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 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 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, 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.

In a first photodetector according to an embodiment of the present disclosure, a first through electrode electrically connects a first photoelectric conversion unit provided on the first surface side of a semiconductor substrate with a first floating diffusion layer provided on the second surface of the semiconductor substrate and penetrates between the first surface and the second surface of the semiconductor substrate, and similarly, the thickness of the insulating film surrounding the conductor is made thicker than that of the second through electrode that penetrates between the first surface and the second surface of the semiconductor substrate. In a second photodetector according to an embodiment of the present disclosure, a first insulating film surrounding a first conductor that electrically connects a first photoelectric conversion unit provided on the first surface side of a semiconductor substrate with a first floating diffusion layer provided on the second surface of the semiconductor substrate and constitutes a first through electrode that penetrates between the first surface and the second surface of the semiconductor substrate is similarly made to have a smaller relative dielectric constant than that of a second insulating film surrounding a second conductor that constitutes a second through electrode that penetrates between the first surface and the second surface of the semiconductor substrate. This makes the capacitance of the first through electrode smaller than the capacitance of the other through electrodes.

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

Hereinafter, the 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 embodiment. Furthermore, the present disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc. of each component shown in each drawing. The order of description is as follows.
1. Embodiment (Example of a photodetector in which the thickness of the insulating film of the through electrode connected to the FD is made larger 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 photodetector)
2-9. Modification 9 (another example of the photodetector)
3. Application examples 4. Application examples

1. Preferred embodiment
[Configuration of the light detection device]
(Overall configuration example)
FIG. 1A illustrates an example of the overall configuration 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 in pixel units, and outputs the electrical signal as a pixel signal. The photodetector 1 has, for example, a pixel unit 100 as an imaging area on a semiconductor substrate 11, 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" in the embodiment of the present disclosure.

FIG. 1B is a schematic diagram of an example of the configuration of the pixel section 100. As shown in FIG. 1B, the pixel section 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 section 100 includes a plurality of pixel rows each composed of a plurality of unit pixels P arranged in a horizontal direction (horizontal direction on the paper) and a plurality of pixel columns each composed of a plurality of unit pixels P arranged in a vertical direction (vertical direction on the paper). In the pixel section 100, for example, one pixel drive line Lread (row selection line and reset control line) is wired for each pixel row, and one vertical signal line Lsig is wired 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 corresponding to each pixel row of the vertical drive circuit 111, respectively.

The vertical drive circuit 111 is composed of 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, on a pixel row basis. The signals output from each unit pixel P in the pixel row selected and scanned by the vertical drive circuit 111 are supplied to the column signal processing circuit 112 through each of the vertical signal lines Lsig.

The column signal processing circuit 112 is composed of an amplifier and a horizontal selection switch provided for each vertical signal line Lsig.

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

The output circuit 114 processes and outputs the 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, etc., for example.

The circuit portion consisting of the vertical drive circuit 111, column signal processing circuit 112, horizontal drive circuit 113, horizontal signal line 121, and output circuit 114 may be formed directly on the semiconductor substrate 11, or may be disposed on an external control IC. In addition, these circuit portions may be formed on other substrates connected by cables or the like.

The control circuit 115 receives a clock and data instructing the operation mode provided from outside the semiconductor substrate 11, and also 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, column signal processing circuit 112, and horizontal drive circuit 113 based on the various timing signals generated by the timing generator.

The input/output terminal 116 is used to exchange signals with the outside world.

(Example of cross-sectional configuration of unit pixel)
2A is a schematic diagram showing 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 is a schematic diagram showing a planar layout of the through-electrode 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 the Z-axis direction, and the plane directions parallel to the stacking plane perpendicular to the Z-axis direction are 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 each other.

As shown in FIG. 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 an embodiment of the present disclosure, and the organic photoelectric conversion unit 20 corresponds to a specific example of a "first photoelectric conversion unit" in an embodiment of the present disclosure. The unit pixel P further has 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 organic photoelectric conversion unit 20 as viewed from the photoelectric conversion unit 10. Furthermore, on the light incident side opposite to 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 (CF) 53, and an on-chip lens (OCL) 54 provided corresponding to each of the plurality of CFs 53 are laminated along the Z-axis direction in order from a position close to the organic photoelectric conversion unit 20. The sealing film 51 and the low refractive index layer 52 may be provided in common in a plurality of unit pixels P. The sealing film 51 has a configuration in which transparent insulating films such as AlOx are laminated. In addition, an anti-reflection film may be provided so as to cover the OCL 54. A black filter may be provided in the peripheral region 100B. The plurality of CFs 53 each include, 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 provided with red, green, and blue CFs 53 (red filter 53R, green filter 53G, and blue filter 53B), and the organic photoelectric conversion section 20 receives red light, green light, and blue light, respectively, to obtain a color visible light image.

(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 using the time-of-flight (TOF) of light. 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 (TG 14A, 14B), and a charge-voltage conversion unit (FD) 15A (FD 15A-1, 15A-2) that is a floating diffusion region.

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, a fine uneven structure may be formed on the surface 11S1, as shown in FIG. 2A. This is because it is effective in confining infrared light incident on the semiconductor substrate 11 inside the semiconductor substrate 11. Note that a similar fine uneven structure may also be formed on the surface 11S2.

The photoelectric conversion region 12 is a photoelectric conversion element constituted 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 range, and generates and accumulates an electric charge according to the amount of light received through photoelectric conversion.

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 the interface state of the surface 11S1, which is the light receiving surface of the semiconductor substrate 11. A hole accumulation layer is formed near the surface 11S1 of the semiconductor substrate 11 due to the electric field induced by the fixed charge layer 13. 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 side wall 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 materials constituting 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), 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).

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

The pair of FDs 15A-1 and 15A-2 are floating diffusion regions that convert the charges transferred from the photoelectric conversion region 12 via TGs 14A and 14B into an electrical signal (e.g., a voltage signal) and output the signal. FD 15B is a floating diffusion region that converts the charges transferred from the organic photoelectric conversion unit 20 via a through electrode 16A (described later) into an electrical signal (e.g., a voltage signal) and output the signal. 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 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 FD15B, and a vertical signal line Lsig (FIG. 1A) is connected to FD15B via an amplification transistor (AMP) 133 and a selection transistor (SEL) 134.

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 to 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 read 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 wiring 161 that penetrates between the surface 11S1 and the surface 11S2 of the semiconductor substrate 11, a through wiring 162 that penetrates the intermediate layer 40, and a connection electrode 163 that connects the through wiring 161 and the through wiring 162.

The through electrode 16 is, for example, a transmission path for transmitting signal charges generated in the organic photoelectric conversion unit 20 and transmitting a voltage for driving the charge storage electrode 21B. Specifically, the through electrode 16 includes a through electrode 16A that electrically connects the read electrode 21A of the organic photoelectric conversion unit 20 provided on the surface 11S1 side of the semiconductor substrate 11 with the FD15B and AMP133 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 FD15B. 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 provided.

In this embodiment, the through electrode 16A electrically connecting the read 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 ) than the through electrode 16B. In detail, 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).

FIGS. 4A to 4C are schematic diagrams showing an example of the planar shape of the through electrode 16A. As shown in FIG. 4A to FIG. 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 FIG. 4A to FIG. 4C. The through electrode 16B may also have a similar planar shape.

FIGS. 5A to 5C are schematic diagrams showing 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. FIG. 5A shows an example in which the through electrode 16A and the through electrode 16B are made of conductors 161a and 161c having a certain diameter and insulating films 161b and 161d having a certain thickness, but the through electrode 16A is not limited to this. For example, the through electrode 16A only needs to have a portion of the insulating film 161b larger in thickness 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 differs between the surface 11S1 side and the surface 11S2 side of the semiconductor substrate 11, as shown in FIG. 5B and FIG. 5C.

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 of metal materials such as aluminum (Al), tungsten (W), titanium (Ti), cobalt (Co), platinum (Pt), palladium (Pd), copper (Cu), hafnium (Hf), and tantalum (Ta).

The insulating films 161b and 161d are 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 laminate film made of two or more of these materials.

(Multilayer Wiring Layer 30)
The multilayer wiring layer 30 includes, for example, an RST 143 , an AMP 144 , and a SEL 145 which, together with a TG 14 , constitute a readout circuit for the photoelectric conversion unit 10 , and an RST 132 , an AMP 133 , and a SEL 134 which constitute a readout circuit for the organic photoelectric conversion unit 20 .

(Intermediate layer 40)
The intermediate layer 40 may have, for example, an interlayer insulating layer 41 and an optical filter 42 embedded in the interlayer insulating layer 41. The interlayer insulating layer 41 is, for example, 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. Furthermore, organic insulating materials 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), and octadecyltrichlorosilane (OTS) may be used as the material constituting the interlayer insulating layer 41. The interlayer insulating layer 41 further includes a wiring layer M embedded therein, the wiring layer M including various wirings made of a transparent conductive material, which are connected to the charge storage electrodes 21B described later and the like.

The optical filter 42 has a transmission band in the infrared light range where photoelectric conversion takes place 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 or more and 700 nm or less) 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 having wavelengths in the visible light range. The optical filter 42 is made of an organic material such as a phthalocyanine derivative.

(Organic photoelectric conversion unit 20)
The organic photoelectric conversion unit 20 has, 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 has, for example, a read electrode 21A, a charge storage electrode 21B, and a shield electrode 21C, which are spaced apart from each other. The read electrode 21A, the charge storage electrode 21B, and the shield electrode 21C are provided, for example, in the same layer. The read 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 forms a kind of capacitor together with the insulating layer 22 and the semiconductor layer 23, and accumulates the charge generated in the organic photoelectric conversion layer 24 in a part of the semiconductor layer 23, for example, a region of the semiconductor layer 23 corresponding to the charge storage electrode 21B through the insulating layer 22. In the present embodiment, for example, one charge storage electrode 21B is provided corresponding to each of one CF 53 and one 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, and the shield electrode 21C electrically separates the adjacent pixels P2. The organic photoelectric conversion unit 20 is connected to, for example, a lead-out wiring in the peripheral region 100B.

The semiconductor layer 23, the organic photoelectric conversion layer 24, and the upper electrode 25 may each 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. This also applies to the modified examples described in the present embodiment and subsequent embodiments.

Furthermore, 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.

The lower electrode 21 and the upper electrode 25 are made of a conductive film having optical transparency, and are made of, for example, ITO (indium tin oxide). However, as the constituent material of the lower electrode 21 and the upper electrode 25, in addition to ITO, a tin oxide (SnOx)-based material with a dopant added, or a zinc oxide-based material made by adding a dopant to zinc oxide (ZnO) may be used. As the zinc oxide-based material, for example, 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 may be used. As the constituent material of the lower electrode 21 and the upper electrode 25, CuI, InSbO ₄ , ZnMgO, CuInO ₂ , MgIN ₂ O ₄ , CdO, ZnSnO ₃ , TiO ₂ , etc. may be used. The constituent materials of the lower electrode 21 and the upper electrode 25 may further include a spinel oxide or an oxide having a YbFe ₂ O ₄ structure.

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

The material constituting the semiconductor layer 23 is preferably one having a large band gap (e.g., a band gap value of 3.0 eV or more) and a higher mobility than the material constituting the organic photoelectric conversion layer 24. Specific examples include oxide semiconductor materials such as IGZO, transition metal dichalcogenides, silicon carbide, diamond, graphene, carbon nanotubes, and organic semiconductor materials such as condensed polycyclic hydrocarbon compounds and condensed heterocyclic compounds.

The organic photoelectric conversion layer 24 converts light energy into electrical energy, and is formed, for example, containing 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 surface formed by mixing a p-type semiconductor and an n-type semiconductor, and excitons generated when light is absorbed are separated into electrons and holes at this p/n junction interface.

The organic photoelectric conversion layer 24 may be configured to contain, in addition to the p-type and n-type semiconductors, three types of so-called dye materials that perform photoelectric conversion of light in a specific wavelength band while transmitting light in other wavelength bands. It is preferable that the p-type semiconductor, n-type semiconductor, and dye material have mutually different maximum absorption wavelengths. This makes it possible to absorb a wide range of wavelengths in the visible light region.

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

As described above, the organic photoelectric conversion unit 20 detects some or all of the wavelengths in the visible light range. It is also preferable that the organic photoelectric conversion unit 20 does not have sensitivity to the infrared light range.

In the organic photoelectric conversion section 20, light incident from the upper electrode 25 side is absorbed by the organic photoelectric conversion layer 24. The excitons (electron-hole pairs) generated by this move to the interface between the electron donor and electron acceptor that constitute the organic photoelectric conversion layer 24, and are dissociated into excitons, that is, electrons and holes. The charges generated here, that is, electrons and holes, move to the upper electrode 25 or the semiconductor layer 23 due to diffusion caused by the difference in carrier concentration or an internal electric field caused by the potential difference between the upper electrode 25 and the charge storage electrode 21B, and are detected as a 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 that case, the holes generated by the photoelectric conversion in the organic photoelectric conversion layer 24 move to the upper electrode 25. The electrons generated by the photoelectric conversion in the organic photoelectric conversion layer 24 are attracted to the charge storage electrode 21B and are accumulated in a part of the semiconductor layer 23, for example, the region of the semiconductor layer 23 that corresponds to the charge storage electrode 21B via the insulating layer 22.

The charge (e.g., electrons) stored in the region of the semiconductor layer 23 corresponding to the charge storage electrode 21B via the insulating layer 22 is 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.

In this way, 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. Although the above explanation has been given as an example of reading out electrons, holes may also be read out. When reading out holes, the potential in the above explanation is described as the potential sensed by the holes.

(Readout circuit of photoelectric conversion unit 10)
FIG. 6 shows an example of a readout circuit of the photoelectric conversion unit 10 constituting the pixel P1 shown in FIG. 2A.

The readout circuit of the photoelectric conversion unit 10 includes, for example, TG14A and 14B, OFG146, FD15A-1 and 15A-2, RST143-1 and 143-2, AMP144-1 and 144-2, and SEL145-1 and 145-2.

TG14A and 14B are connected between the photoelectric conversion region 12 and FD15A-1 and 15A-2. When a drive signal is applied to the gate electrodes of TG14A and 14B and TG14A and 14B enter an active state, the transfer gates of TG14A and 14B enter a conductive state. As a result, the signal charge converted in the photoelectric conversion region 12 is transferred to FD15A-1 and 15A-2 via TG14A and 14B.

OFG146 is connected between the photoelectric conversion region 12 and the power supply. When a drive signal is applied to the gate electrode of OFG146 and OFG146 enters an active state, OFG146 enters a conductive state. As a result, the signal charge converted in the photoelectric conversion region 12 is discharged to the power supply via OFG146.

FD15A-1, 15A-2 are connected between TG14A, 14B and AMP144-1, 144-2. FD15A-1, 15A-2 convert the signal charges transferred by TG14A, 14B into voltage signals and output them to AMP144-1, 144-2.

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 enter 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.

AMP144-1, 144-2 have gate electrodes connected to FD15A-1, 15A-2, respectively, and drain electrodes connected to a power supply. AMP144-1, 144-2 are inputs of a readout circuit for the voltage signals held by FD15A-1, 15A-2, a so-called source follower circuit. In other words, AMP144-1, 144-2 have their source electrodes connected to the vertical signal line Lsig via SEL145-1, 145-2, respectively, and thus form a constant current source and source follower circuit connected to one end of the vertical signal line Lsig.

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, the 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.

In the photodetector 1, an infrared light pulse is irradiated onto the 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 charges are generated by the incidence of the infrared light pulse. The multiple charges generated in the photoelectric conversion region 12 are alternately distributed to FD15A-1 and FD15A-2 by supplying a drive signal alternately to the pair of TGs 14A and 14B for an equal period of time. By changing the shutter phase of the drive signal applied to TGs 14A and 14B relative to the irradiated light pulse, the amount of charge accumulated in FD15A-1 and the amount of charge accumulated in FD15A-2 become phase-modulated values. By demodulating these, the round-trip time of the light pulse can be estimated, and the distance between the photodetector 1 and the subject can be obtained.

(Readout circuit of organic photoelectric conversion unit 20)
FIG. 7 illustrates an example of a readout circuit for the organic photoelectric conversion unit 20 constituting the pixel P2 illustrated in FIG. 2A.

The readout circuit of the organic photoelectric conversion unit 20 has, for example, FD15B, RST132, AMP133, and SEL134.

FD15B is connected between the read electrode 21A and the AMP 133. FD15B converts the signal charge transferred by the read electrode 21A into a voltage signal and outputs it to the AMP 133.

RST132 is connected between FD15B and the power supply. When a drive signal is applied to the gate electrode of RST132 and RST132 enters an active state, the reset gate of RST132 enters a conductive state. As a result, the potential of FD15B is reset to the power supply level.

AMP133 has a gate electrode connected to FD15B and a drain electrode connected to a power supply. The source electrode of AMP133 is connected to the vertical signal line Lsig via SEL134.

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, the read signal (pixel signal) output from AMP133 is output to the vertical signal line Lsig via SEL134.

[Action and Effects]
As described above, when the signal charge generated in the organic photoelectric conversion unit 20 provided on the surface 11S1 side of the semiconductor substrate 11 is 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 become worse. Therefore, it is desirable to reduce the capacitance component of the through electrode 16A from the viewpoint of conversion efficiency and random noise.

The capacitance of the through electrode can be easily calculated manually using cylindrical capacitance components as shown in Figure 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 found from the following formula (1). Specifically, the capacitance (C) is determined by the 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 films of all the through electrodes 16 in the photodetector 1 are made large, this puts pressure on the FEOL layout and reduces the freedom of layout on the semiconductor substrate 11.

In contrast, in the photodetector 1 of this embodiment, the thickness ta of the insulating film 161b constituting 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 made larger than the thickness tb of the through electrode 16B that electrically connects the organic photoelectric conversion unit 20 provided on the surface 11S1 side of the semiconductor substrate 11 to active elements other than the FD15B (ta>tb).

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 FD 15B and AMP 133 provided on the surface 11S2 of the semiconductor substrate 11 is reduced, making it possible to reduce random noise.

In addition, in the photodetector 1 of this embodiment, only the insulating film 161b constituting the through electrode 16A that electrically connects the read 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 selectively thickened, thereby reducing the increase in the area occupied by the through electrode 16 in the semiconductor substrate 11. This improves the degree of freedom in the layout of the semiconductor substrate 11 compared to when all the insulating films of the through electrode 16 are thickened.

Next, we will explain modified examples 1 to 9 of the present disclosure and examples of application and use. Note that components corresponding to the above embodiment are given the same reference numerals and their explanations will be omitted.

2. Modifications
(2-1. Modification 1)
FIG. 8 is a schematic diagram showing a planar layout of the through electrodes 16 according to the first modification of the present disclosure.

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 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 through electrode 16A and the diameter _RB of the through electrode 16B equal ( _RA = _RB ), 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 thickness ta of the insulating film 161b surrounding the conductor 161a is made thicker than the thickness tb of the insulating film 161d surrounding the conductor 161c (ta>tb).

As a result, it is possible to reduce random noise, as in the above embodiment. Also, compared to the above embodiment in which the insulating film 161b of the through electrode 16A is made thicker, the degree of freedom in layout on the semiconductor substrate 11 can be improved.

(2-2. Modification 2)
FIG. 9 is a schematic diagram showing a planar layout of the through electrodes 16 according to the third modification of the present disclosure.

The above embodiment and modification 1 can be combined with each other. For example, the diameter Ra of the conductor 161a can be made smaller than the diameter Rb of the conductor 161c that constitutes the through electrode 6B (Ra<Rb), while the thickness ta of the insulating film 161b surrounding the conductor 161a can be made thicker than the thickness tb of the insulating film 161d surrounding the conductor 161c (ta>tb).

Even with this configuration, it is possible to reduce random noise, as in the above embodiment. Also, as in the above embodiment, it is possible to improve the degree of freedom in layout on the semiconductor substrate 11, compared to the case where all the insulating films of the through electrodes 16 are made thick.

(2-3. Modification 3)
FIG. 10 is a schematic diagram showing a planar layout of the through electrodes 16 according to the third modification of the present disclosure.

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 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 constituting the through electrode 16A and the thickness ta of the insulating film 161b of the insulating film 161b of the through electrode 16A equal to the diameter Rb of the conductor 161c constituting the through electrode 6B and the thickness tb of the insulating film 161d of the through electrode 16A (Ra=Rb, ta=tb), the insulating film 161b of the through electrode 16A is formed using a dielectric material with a smaller relative dielectric constant than the insulating material constituting the insulating film 161d of the through electrode 16B.

When the insulating film 161d is formed using silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiON), or the like, the constituent material of the insulating film 161b may be SiOC or SiOCH, etc.

As a result, it is possible to reduce random noise, as in the above embodiment. Also, compared to the above embodiment in which the insulating film 161b of the through electrode 16A is made thicker, the degree of freedom in layout on the semiconductor substrate 11 can be improved.

(2-4. Modification 4)
11 and 12 are schematic diagrams illustrating an example of a planar layout of the through electrodes 16 according to the fourth modification of the present disclosure.

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 provided, but this is not limited to this, and a layout of a plurality of through electrodes 16A and a plurality of through electrodes 16B as shown in Figures 11 and 12 may also be used.

In addition, for example, as shown in FIG. 13, when pixel P1 has a substantially square shape, through electrodes 16A electrically connecting readout electrode 21A of organic photoelectric conversion unit 20 to FD15B and AMP133 provided on surface 11S2 of semiconductor substrate 11 may be arranged at the four corners, and through electrodes 16B electrically connecting organic photoelectric conversion unit 20 provided on surface 11S1 side of semiconductor substrate 11 to active elements other than FD15B may be arranged on the four sides. This can reduce the capacitance of through electrodes 16A.

In addition, when pixel P1 is made approximately square and through electrodes 16A electrically connecting read electrode 21A of organic photoelectric conversion unit 20 to FD15B and AMP133 provided on surface 11S2 of semiconductor substrate 11 are arranged at the four corners, as shown in FIG. 14, even if through electrodes 16A and 16B have the same shape, the insulating film 161d of through electrode 16B is present around the periphery, so the thickness of the insulating film of through electrode 16A can be effectively made thicker. Therefore, the capacitance of through electrode 16A can be reduced, and a certain effect can be obtained.

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

A partition 161M may be provided at the boundary between adjacent pixels P1. The partition 161M is intended to suppress oblique incidence of unwanted light into the photoelectric conversion region 12 between adjacent pixels P and prevent color mixing. When the partition 161M is provided at the boundary between adjacent pixels P1, as shown in FIG. 15, the thickness of the partition 161M surrounding the through electrode 16A is made smaller than the thickness of the partition 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 to obtain the same effect as in the above embodiment.

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 made of graphite. The partition 161M is not limited to a conductive material, and may be made of a non-conductive material having a light-shielding property, such as an organic material. An insulating film may be provided on the outside of the partition 161M, that is, between the partition 161M and the fixed charge layer 13. The insulating film is 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.

(2-6. Modification 6)
16 and 17 are schematic diagrams showing an example of a planar layout of the through electrodes 16 according to the sixth modification of the present disclosure.

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

In this way, by making a portion of the thickness of the insulating film 161b surrounding the conductor 161a constituting the through electrode 16A larger than the 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.

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

In the above 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 2 rows and 2 columns as pixel P2 are stacked in the Z-axis direction, which is the thickness direction, but this is not limited to this. In the light detection device 1A of this modification, 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, the four through electrodes 16A and four through electrodes 16B described in the above embodiment and modifications 1 to 6 are alternately arranged at the boundary of pixel P1. For example, as shown in Figures 19A and 19B, four through electrodes 16A and four through electrodes 16B having insulating films 161b and 161d with different thicknesses may be alternately arranged. For example, the through electrodes 16A and the four through electrodes 16B may be arranged alternately, with the four through electrodes 16A and the four through electrodes 16B having different relative dielectric constants, as shown in FIG. 20.

(2-8. Modification 8)
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.

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

In this way, the configuration of the organic photoelectric conversion unit 20 is not limited to the photodetector 1 of the above embodiment, and the same effects as those of the above embodiment can be obtained with the configuration of the organic photoelectric conversion unit 20 of this modified example.

(2-9. Modification 9)
FIG. 22 is a schematic diagram illustrating an example of a cross-sectional configuration of a light detection device 1C according to a ninth modification of the present disclosure.

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 is shown, but the present invention is not limited to this. The light detection device 1C of this modified example has, 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, stacked on the surface 11S1 side of the semiconductor substrate 11.

In this case, the through electrode 16A-1 electrically connecting the read 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 electrically connecting the read electrode 61A of the organic photoelectric conversion unit 60 and the FD provided on the surface 11S2 of the semiconductor substrate 11, reduce the capacitance of the through electrode 16A-2, which has a longer transmission path for signal charges. For example, as shown in FIG. 23, the thickness of the insulating film constituting the through electrode 16A-2 is made larger than the thickness of the insulating film of the through electrode 16A-1.

In addition, 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.

<3. Application Examples>
(Application Example 1)
The photodetector 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.

FIG. 24 is a block diagram showing an example of the configuration of electronic device 1000.

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

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

The light detection device 1 converts the amount of incident light focused on the imaging surface by the optical system 1001 into an electrical signal on a pixel-by-pixel basis and supplies the signal to the DSP 1002 as a pixel signal.

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

(Application Example 2)
FIG. 25A is a schematic diagram showing an example of the overall configuration of a light detection system 2000 including a light detection device 1. FIG. 25B is a diagram showing an example of the circuit configuration of the light detection system 2000. The light detection system 2000 includes a light emitting device 2001 as a light source unit that emits infrared light L2, and an organic photoelectric conversion unit 2002 as a light receiving unit having a photoelectric conversion element. The organic photoelectric conversion unit 2002 may be the light detection device 1 described above. 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.

The organic photoelectric conversion unit 2002 can detect light L1 and light L2. Light L1 is external ambient light reflected by the subject (object to be measured) 2100 (Figure 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 in the photoelectric conversion unit in the organic photoelectric conversion unit 2002, and light L2 can be detected in the 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 moving object such as a car. The light emitting device 2001 may be configured with, for example, 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 method, but is not limited thereto. In the iTOF method, the photoelectric conversion unit may measure the distance to the subject 2100 by, for example, the time of flight (TOF). As a detection method of the light L2 emitted from the light emitting device 2001 by the organic photoelectric conversion unit 2002, for example, a structured light method or a stereo vision method may be adopted. For example, in the structured light method, 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 degree of 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 the system control unit 2003.

＜4. Application Examples＞
(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.

FIG. 26 is a diagram showing an example of the general configuration of an endoscopic surgery system to which the technology disclosed herein (the present technology) can be applied.

In FIG. 26, an operator (doctor) 11131 is shown using an endoscopic surgery system 11000 to perform surgery on a patient 11132 on a patient bed 11133. 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.

The endoscope 11100 is composed of a lens barrel 11101, the tip of which is inserted into the body cavity of the patient 11132 at a predetermined length, and a camera head 11102 connected to the base end of the lens barrel 11101. In the illustrated example, 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.

The tip of the tube 11101 has an opening into which an objective lens is fitted. A light source device 11203 is connected to the endoscope 11100, and light generated by the light source device 11203 is guided to the tip of the tube by a light guide extending inside the tube 11101, and is irradiated via the objective lens towards 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.

An optical system and an image sensor are provided inside the camera head 11102, and reflected light (observation light) from the object being observed is focused onto the image sensor by the optical system. The image sensor converts the observation light into an electric signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. The image signal is sent to the camera control unit (CCU: Camera Control Unit) 11201 as RAW data.

The CCU 11201 is composed of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and controls the overall operation of the endoscope 11100 and the display device 11202. Furthermore, the CCU 11201 receives an image signal from the camera head 11102, and performs various types of image processing on the image signal, such as development processing (demosaic processing), in order to display an image based on the image signal.

The display device 11202, under the control of the CCU 11201, displays an image based on the image signal that has been subjected to image processing by the CCU 11201.

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

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.

The treatment tool control device 11205 controls the operation of the energy treatment tool 11112 for cauterizing tissue, incising, sealing blood vessels, etc. The insufflation device 11206 sends gas into the body cavity of the patient 11132 via the insufflation tube 11111 to inflate the body cavity in order to ensure a clear field of view for the endoscope 11100 and to ensure 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.

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

The light source device 11203 may be controlled to change the intensity of the light it outputs at predetermined time intervals. The image sensor of the camera head 11102 may be controlled to acquire images in a time-division manner in synchronization with the timing of the change in the light intensity, and the images may be synthesized to generate an image with a high dynamic range that is free of so-called blackout and whiteout.

The light source device 11203 may also be configured to supply light in a predetermined wavelength range corresponding to special light observation. In special light observation, for example, by utilizing the wavelength dependency of light absorption in body tissue, a narrow band of light is irradiated compared to the light irradiated during normal observation (i.e., white light), and a specific tissue such as blood vessels on the surface of the mucosa is photographed with high contrast, so-called narrow band imaging is performed. Alternatively, in special light observation, fluorescence observation may be performed in which an image is obtained by fluorescence generated by irradiating excitation light. In fluorescence observation, excitation light is irradiated to body tissue and the fluorescence from the body tissue is observed (autofluorescence observation), or a reagent such as indocyanine green (ICG) is locally injected into the body tissue and excitation light corresponding to the fluorescent wavelength of the reagent is irradiated to the body tissue to obtain a fluorescent image. The light source device 11203 may be configured to supply narrow band light and/or excitation light corresponding to such special light observation.

FIG. 27 is a block diagram showing an example of the functional configuration of the camera head 11102 and CCU 11201 shown in FIG. 26.

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.

The lens unit 11401 is an optical system provided at the connection 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.

The imaging unit 11402 may include one imaging element (a so-called single-plate type) or multiple imaging elements (a so-called multi-plate type). When the imaging unit 11402 is configured as a multi-plate 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. 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. By performing a 3D display, the surgeon 11131 can more accurately grasp the depth of the biological tissue in the surgical site. Note that when the imaging unit 11402 is configured as a multi-plate type, multiple lens units 11401 may be provided corresponding to each imaging element.

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.

The driving unit 11403 is composed of an actuator, and moves the zoom lens and focus lens of the lens unit 11401 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.

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

The communication unit 11404 also receives control signals for controlling the operation of the camera head 11102 from the CCU 11201, and supplies them to the camera head control unit 11405. The control signals include information on the imaging conditions, such as information specifying the frame rate of the captured image, information specifying the exposure value during imaging, and/or information specifying the magnification and focus of the captured image.

The above-mentioned frame rate, exposure value, magnification, focus, and other imaging conditions 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 the so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function.

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

The communication unit 11411 is configured with 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.

The communication unit 11411 also transmits to the camera head 11102 a control signal for controlling the operation of the camera head 11102. The image signal and the control signal can be transmitted by electrical communication, optical communication, etc.

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

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 images 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.

The control unit 11413 also causes the display device 11202 to display the captured image showing the surgical site, etc., based on the image signal that has been image-processed by the image processing unit 11412. At this time, the control unit 11413 may recognize various objects in the captured image using various image recognition techniques. For example, the control unit 11413 can recognize surgical tools such as forceps, specific body parts, bleeding, mist generated when the energy treatment tool 11112 is used, etc., by detecting the shape and color of the edges of objects included in the captured image. When the control unit 11413 causes the display device 11202 to display the captured image, it may use the recognition result to superimpose various types of 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.

The transmission cable 11400 that connects the camera head 11102 and the CCU 11201 is an electrical signal cable that supports electrical signal communication, an optical fiber that supports optical communication, or a composite cable of these.

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.

Above, an example of an endoscopic surgery system to which the technology disclosed herein can be applied has been described. Of the configurations described above, the technology disclosed herein can be applied to the imaging unit 11402. By applying the technology disclosed herein to the imaging unit 11402, detection accuracy is improved.

Note that although an endoscopic surgery system has been described here as an example, the technology disclosed herein may also be applied to other systems, such as a microsurgery system.

(Example of application to moving objects)
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 moving body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility device, an airplane, a drone, a ship, a robot, a construction machine, or an agricultural machine (tractor).

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 disclosed herein can be applied.

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.

The drive system control unit 12010 controls the operation of devices related to the drive system of the vehicle according to various programs. For example, the drive system control unit 12010 functions as a control device for a drive force generating device for generating the 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 for the vehicle.

The body system control unit 12020 controls the operation of various devices installed 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, tail lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves or signals from various switches transmitted from a portable device that replaces a key can be input to the body system control unit 12020. The body system control unit 12020 accepts the input of these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, the image capturing unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the image capturing 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.

The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal according 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 may be invisible light such as infrared light.

The in-vehicle information detection unit 12040 detects information inside the vehicle. To the in-vehicle information detection unit 12040, for example, a driver state detection unit 12041 that detects the state of the driver is connected. 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 driver's degree of fatigue or concentration based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

The microcomputer 12051 can calculate control target values for the driving force generating device, steering mechanism, or braking device based on 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, or vehicle lane departure warning.

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

The microcomputer 12051 can also output control commands to the body system control unit 12020 based on 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.

The audio/image output unit 12052 transmits at least one output signal of audio and image to an output device capable of visually or audibly notifying the occupants of the vehicle or the outside of the vehicle of information. In the example of FIG. 28, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are exemplified as output devices. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.

FIG. 29 shows an example of the installation position of the imaging unit 12031.

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

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

Note that FIG. 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, an overhead image of the vehicle 12100 viewed from above is obtained by superimposing the image data captured by the imaging units 12101 to 12104.

At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera consisting of multiple imaging elements, or an imaging element having pixels for phase difference detection.

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

For example, the microcomputer 12051 classifies and extracts three-dimensional object data on three-dimensional objects, such as two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects, based on the distance information obtained from the imaging units 12101 to 12104, and can use the data to automatically avoid obstacles. 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 the collision risk, which indicates the risk of collision with each obstacle, and when the collision risk is equal to or exceeds a set value and there is a possibility of a collision, it 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.

At least one of the imaging 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 or not a pedestrian is present in the image captured by the imaging units 12101 to 12104. The recognition of such a pedestrian is performed, for example, by a procedure of extracting feature points in the image captured by the imaging units 12101 to 12104 as infrared cameras, and a procedure of performing pattern matching processing on a series of feature points that indicate the contour of an object to determine whether or not it is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the image captured by the imaging units 12101 to 12104 and recognizes a pedestrian, the audio/image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio/image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating a pedestrian at a desired position.

Above, an example of a mobile object control system to which the technology of the present disclosure can be applied has been described. Of the configurations described above, the technology of the present disclosure can be applied to the imaging unit 12031. Specifically, the light detection device according to the above embodiment and its modified example (e.g., light detection device 1) can be applied to the imaging unit 12031. By applying the technology of the present disclosure to the imaging unit 12031, a high-definition captured image with little noise can be obtained, thereby enabling high-precision control to be performed using the captured image in the mobile object control system.

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 the embodiments, etc.). However, the present disclosure is not limited to the above embodiments, etc., and various modifications are possible. For example, the present disclosure is not limited to back-illuminated image sensors, and can also be applied to front-illuminated image sensors.

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 it is also possible to obtain a black and white visible light image without providing a CF 53.

Furthermore, the imaging device of 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.

In addition, in the above embodiments, a solid-state imaging device that converts the amount of incident light focused on the 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 are described as examples, but 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 an electric charge according to the amount of received light through photoelectric conversion. The output signal may be an image information signal or a ranging information signal.

Furthermore, in the above embodiment, the photoelectric conversion unit 10 as the second photoelectric conversion unit is an iTOF sensor, but the present disclosure is not limited to this. In other words, the second photoelectric conversion unit is not limited to detecting light having a wavelength in the infrared light range, and may detect wavelength light in other wavelength ranges. Also, if the photoelectric conversion unit 10 is not an iTOF sensor, only one transfer transistor (TG) may be provided.

Furthermore, the materials constituting each component of the photoelectric conversion element disclosed herein are not limited to the materials listed in the above embodiments. 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.

Note that the effects described in this specification are merely examples and are not limiting, and other effects may also be present.

In addition, the present technology can also be configured as follows. According to the present technology having the following configuration,
(1)
a semiconductor substrate having opposing first and second surfaces;
a first photoelectric conversion unit provided on a 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 and configured to accumulate signal charges generated in the first photoelectric conversion portion;
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, the first through electrode electrically connecting the first photoelectric conversion unit and the first floating diffusion layer;
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 at least a portion of a thickness thinner than a thickness of the first insulating film, and a second penetrating 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.
(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 first insulating film has a thickness larger than that of the second insulating film.
(4)
The optical detection device according to any one of (1) to (3), wherein a diameter of the first conductor is smaller than a diameter of the second conductor.
(5)
The photodetector according to any one of (1) to (4), wherein the first through electrode has a different diameter 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)
a first partition wall surrounding the first through electrode and a second partition wall surrounding the second through electrode,
The photodetector according to any one of (1) to (10), wherein the second partition has a thickness larger than that of the first partition.
(12)
The photodetector according to (11), wherein the first partition and the second partition are made of a metal material or a conductive material having a light-shielding property.
(13)
The photodetection device described in any one of (1) to (12), further comprising a second photoelectric conversion unit provided within the semiconductor substrate overlapping the first photoelectric conversion unit in a planar view, detecting light in a second wavelength range and performing photoelectric conversion.
(14)
the semiconductor substrate includes a plurality of pixels arranged in a matrix;
the second photoelectric conversion unit is provided for each pixel,
The photodetector according to (13), wherein the first through electrode and the second through electrode are provided at a boundary between adjacent pixels.
(15)
The pixel has a substantially square shape,
The photodetector according to (14), wherein the first through electrodes are provided at four corners of the pixel.
(16)
14. The optical detection device 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 photodetection device described in any one of (13) to (16), further comprising 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)
a second floating diffusion layer provided on the second surface of the semiconductor substrate and configured to accumulate signal charges generated in the third photoelectric conversion unit;
a third through electrode electrically connecting the third photoelectric conversion unit and the second floating diffusion layer,
The photodetector according to (17), wherein a capacitance per length of the first through electrode is smaller than a capacitance per length of the third through electrode.
(19)
a semiconductor substrate having opposing first and second surfaces;
a first photoelectric conversion unit provided on a 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 and configured to accumulate signal charges generated in the first photoelectric conversion portion;
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;
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, and a second penetrating 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.

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.

Those skilled in the art may conceive of various modifications, combinations, subcombinations, and variations depending on design requirements and other factors, and it is understood that these are within the scope of the appended claims and their equivalents.

Claims (19)

a semiconductor substrate having opposing first and second surfaces;
a first photoelectric conversion unit provided on a 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 and configured to accumulate signal charges generated in the first photoelectric conversion portion;
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, the first through electrode electrically connecting the first photoelectric conversion unit and the first floating diffusion layer;
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 at least a portion of a thickness thinner than a thickness of the first insulating film, and a second penetrating 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. The optical detection device of claim 1, wherein the diameter of the first through electrode is greater than the diameter of the second through electrode. The photodetector according to claim 1, wherein the thickness of the first insulating film is greater than the thickness of the second insulating film. The optical detection device of claim 1, wherein the diameter of the first conductor is smaller than the diameter of the second conductor. The optical detection device of claim 1, wherein the first through electrode has a different diameter on the first surface side and the second surface side. The optical detection device of claim 1, wherein the first through electrode has a tapered cross-sectional shape. The photodetector according to claim 1, wherein the first through-hole electrode and the second through-hole electrode have different planar shapes. The optical detection device of claim 1, wherein the first through electrode has a circular or polygonal planar shape. The light detection device of claim 1, wherein the conductor is made of a metal material or a conductive material. The photodetector device of claim 1, wherein the insulating film is made of a dielectric material. a first partition wall surrounding the first through electrode and a second partition wall surrounding the second through electrode,
The photodetector according to claim 1 , wherein the second partition has a thickness greater than a thickness of the first partition. 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. The photodetector according to claim 1, further comprising a second photoelectric conversion section provided in the semiconductor substrate that overlaps with the first photoelectric conversion section in a plan view and detects light in a second wavelength range and performs photoelectric conversion. the semiconductor substrate includes a plurality of pixels arranged in a matrix;
the second photoelectric conversion unit is provided for each pixel,
The photodetector according to claim 13 , wherein the first through electrode and the second through electrode are provided in a boundary portion between adjacent pixels. The pixel has a substantially square shape,
The photodetector according to claim 14 , wherein the first through electrodes are provided at four corners of the pixel. 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. 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. a second floating diffusion layer provided on the second surface of the semiconductor substrate and configured to accumulate signal charges generated in the third photoelectric conversion unit;
a third through electrode electrically connecting the third photoelectric conversion unit and the second floating diffusion layer,
The photodetector according to claim 17 , wherein a capacitance per length of the first through electrode is smaller than a capacitance per length of the third through electrode. a semiconductor substrate having opposing first and second surfaces;
a first photoelectric conversion unit provided on a 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 and configured to accumulate signal charges generated in the first photoelectric conversion portion;
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;
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, and a second penetrating 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.

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