Light detection device and distance measuring device

Abstract

The invention provides a light detection device with high light detection performance. The light detection device includes: a first light detection unit capable of detecting light of a first wavelength range; a second light detection unit stacked with the first light detection unit and capable of detecting light of a second wavelength range different from the light of the first wavelength range; and one or more optical elements disposed between the first light detection unit and the second light detection unit, converging light of the second wavelength range that has passed through the first light detection unit, and guiding the converged light to the second light detection unit.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a light detection device having, for example, a structure in which two light detection units are stacked, and a distance measuring device including the light detection device. BACKGROUND

[0002] For example, a light detection device configured to simultaneously acquire both visible light and infrared light to measure a distance to an object has been proposed (for example, refer to Patent Literature 1). LIST OF CITATIONS PATENT LITERATURE

[0003] Patent Literature 1: Japanese Laid-Open Patent Application No. 2017-112169 SUMMARY

[0004] Now, for such a light detection device, there is a demand for improving light detection performance.

[0005] Therefore, a light detection device having high light detection performance is desired.

[0006] A light detection device according to an embodiment of the present disclosure includes: a first light detection unit configured to detect light of a first wavelength range; a second light detection unit stacked with the first light detection unit and configured to detect light of a second wavelength range different from the light of the first wavelength range; and one or more optical elements disposed between the first light detection unit and the second light detection unit, converging the light of the second wavelength range that has transmitted through the first light detection unit, and guiding the converged light to the second light detection unit.

[0007] In the light detection device according to the embodiment of the present disclosure, one or more optical elements are disposed between the first light detection unit and the second light detection unit. The one or more optical elements converge the light of the second wavelength range that has transmitted through the first light detection unit, and guide the converged light to the second light detection unit. Therefore, the light of the first wavelength range that has transmitted through the first light detection unit does not leak to a peripheral region, but is incident to a predetermined second light detection unit corresponding to the first light detection unit. BRIEF DESCRIPTION OF DRAWINGS

[0008] FIG. 1A is a schematic configuration view that shows an example of a light detection device according to a first embodiment of the present disclosure. FIG. 1B is a schematic view that FIG. 1A is an explanatory view of a configuration example of a pixel unit shown. FIG. 2 is a vertical sectional view that shows FIG. 1A is a vertical sectional view that shows a configuration example of a light detection device shown. FIG. 3A is a schematic cross-sectional view showing a first configuration example of a horizontal cross section of the light detection device. FIG. 2 is a schematic cross-sectional view showing a first configuration example of a horizontal cross section of the light detection device. FIG. 3B is a schematic cross-sectional view showing a second configuration example of a horizontal cross section of the light detection device. FIG. 2 is a schematic cross-sectional view showing a second configuration example of a horizontal cross section of the light detection device. FIG. 3C is a schematic cross-sectional view showing a third configuration example of a horizontal cross section of the light detection device. FIG. 2 is a schematic cross-sectional view showing a third configuration example of a horizontal cross section of the light detection device. FIG. 3D is a schematic cross-sectional view showing a fourth configuration example of a horizontal cross section of the light detection device. FIG. 2 is a schematic cross-sectional view showing a fourth configuration example of a horizontal cross section of the light detection device. FIG. 4 is a vertical cross-sectional view showing a configuration example of the light detection device according to the reference example. FIG. 5A is a schematic cross-sectional view showing a first configuration example of a horizontal cross section of the light detection device. FIG. 4 is a schematic cross-sectional view showing a first configuration example of a horizontal cross section of the light detection device. FIG. 5B is a schematic cross-sectional view showing a second configuration example of a horizontal cross section of the light detection device. FIG. 4 is a schematic cross-sectional view showing a second configuration example of a horizontal cross section of the light detection device. FIG. 5C is a schematic cross-sectional view showing a third configuration example of a horizontal cross section of the light detection device. FIG. 4 is a schematic cross-sectional view showing a third configuration example of a horizontal cross section of the light detection device. FIG. 5D is a schematic cross-sectional view showing a fourth configuration example of a horizontal cross section of the light detection device. FIG. 4 is a schematic cross-sectional view showing a fourth configuration example of a horizontal cross section of the light detection device. FIG. 6 is a vertical cross-sectional view showing a second configuration example of the light detection device. FIG. 1A is a vertical cross-sectional view showing a second configuration example of the light detection device. FIG. 7 is a vertical cross-sectional view showing a first modification example of the light detection device. FIG. 1A is a vertical cross-sectional view showing a first modification example of the light detection device. FIG. 8 is a vertical cross-sectional view showing a second modification example of the light detection device. FIG. 1A is a vertical cross-sectional view showing a second modification example of the light detection device. FIG. 9 is a vertical cross-sectional view showing a third modification example of the light detection device. FIG. 1A is a vertical cross-sectional view showing a third modification example of the light detection device. FIG. 10 is a vertical cross-sectional view showing a fourth modification example of the light detection device. FIG. 1A is a vertical cross-sectional view showing a fourth modification example of the light detection device. FIG. 11 is a first vertical cross-sectional view showing a configuration example of the light detection device according to the second embodiment of the present disclosure. FIG. 12 is a schematic plan view showing a plan configuration example of the superlens. FIG. 11 FIG. 13 is a second vertical sectional view showing a configuration example of a light detection device according to a second embodiment of the present disclosure. FIG. 14 is a vertical sectional view showing a first modification example of the light detection device. FIG. 11 FIG. 15 is a functional block diagram showing an example of an electronic device (a distance measuring device) using the light detection device shown in FIG. 1 or the like. FIG. 16 is a block diagram showing an example of a schematic configuration of a vehicle control system. FIG. 17 is a diagram for assisting in explaining an example of mounting positions of an outside-vehicle information detection section and an imaging section. DETAILED DESCRIPTION

[0009] Hereinafter, some embodiments of the present disclosure will be explained in detail with reference to the attached drawings. The following explanation is a specific example of the present disclosure, but the present disclosure is not limited to the following aspects. Furthermore, the present disclosure is not limited to the arrangement, size, and size ratio of the constituent elements shown in the drawings, and the like. Note that, for example, the explanation is made in the following order. 0. BACKGROUND 1. First Embodiment A first example of a light detection device includes a first light detection unit that obtains visible light image information, and a second light detection unit that is a direct TOF (dTOF) sensor, receives infrared light, and obtains distance information. 1-1. Configuration 1-2. Effects and Advantages 1-3. Modification 2. Second Embodiment A second example of a light detection device includes a first light detection unit that obtains visible light image information, and a second light detection unit that is a dTOF sensor, receives infrared light, and obtains distance information. 2-1. Configuration 2-2. Effects and Advantages 2-3. Modification 3. Application Example 4. Application Example

[0010] <0. BACKGROUND> ​​First, the background that led to the technology of the present disclosure will be described. As described above, a light detection device configured to simultaneously detect light of a plurality of different wavelength ranges (e.g., visible light and infrared light) has been proposed. For example, in such a light detection device, a first light detection unit and a second light detection unit are stacked. The first light detection unit is configured to detect visible light, and the second light detection unit is configured to detect infrared light. The light detection device allows the first light detection unit to detect visible light while allowing the second light detection unit to detect infrared light that has passed through the first light detection unit. With such a configuration, compared to a case where the first light detection unit and the second light detection unit are arranged in an in-plane direction, it is possible to improve resolution.

[0011] However, in such a stacked structure, light traveling in a stacking direction is diffused or diffracted when reaching the second light detection unit after passing through the first light detection unit. This sometimes causes a part of the light to not be incident on the second light detection unit, but to become leakage light that leaks to a peripheral area. In addition, a part of obliquely incident light that is obliquely incident on the first light detection unit and passes through the first light detection unit sometimes does not be incident on the second light detection unit corresponding to the first light detection unit, but becomes leakage light that leaks to a peripheral area. In addition, or when the relative positions of the first light detection unit and the second light detection unit in the in-plane direction deviate due to manufacturing errors or the like, similar leakage light is generated.

[0012] When such leakage light is generated, the amount of light incident on the second light detection unit decreases, causing the detection sensitivity of the second light detection unit to decrease. In addition, such leakage light incident on light detection units of other pixels in the periphery causes so-called crosstalk.

[0013] Therefore, in view of such circumstances, the present applicant proposes a new light detection device that has good light detection performance such as high light detection sensitivity and high resolution, while suppressing the occurrence of crosstalk, hereinafter.

[0014] <1. First Embodiment> <1-1. Configuration> <Overall Configuration Example> FIG. 1AAn overall configuration example of a light detecting device 1 according to an embodiment of the present disclosure is shown. The light detecting device 1 is, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The light detecting device 1 receives incident light (image light) from an object through, for example, an optical lens system, converts the incident light, which is condensed on an imaging surface, into an electric signal in units of pixels, and outputs the electric signal as a pixel signal. The light detecting device 1 includes, for example, a pixel unit 100 as an imaging region on a semiconductor substrate 21, 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. The vertical drive circuit 111, the column signal processing circuit 112, the horizontal drive circuit 113, the output circuit 114, the control circuit 115, and the input / output terminal 116 are arranged in a peripheral region of the pixel unit 100.

[0015] FIG. 1B A configuration example of the pixel unit is schematically shown. As shown in FIG. 1B the pixel unit 100 includes, for example, an effective region 100R1 and a peripheral region 100R2. The effective region 100R1 includes a plurality of pixels P arranged two-dimensionally in a matrix shape. The peripheral region 100R2 is located around the effective region 100R1. In the effective region 100R1 of the pixel unit 100, for example, a plurality of pixel rows and a plurality of pixel columns are provided. The plurality of pixel rows each include a plurality of pixels P arranged in a horizontal direction (lateral direction on the paper). The plurality of pixel columns each include a plurality of pixels P arranged in a vertical direction (longitudinal direction on the paper). In the pixel unit 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 pixel P. The ends of the plurality of pixel drive lines Lread are connected to each output terminal of the vertical drive circuit 111 corresponding to each pixel row.

[0016] The vertical drive circuit 111 includes a shift register or an address decoder, and the like, and functions as a pixel drive unit that drives each pixel P in the pixel unit 100, for example, in units of pixel rows. Signals output from each pixel P of the pixel row selected and scanned by the vertical drive circuit 111 are supplied to the column signal processing circuit 112 through each vertical signal line Lsig.

[0017] The column signal processing circuit 112 includes an amplifier and a horizontal selection switch, and the like, provided for each vertical signal line Lsig.

[0018] The horizontal drive circuit 113 includes a shift register or an address decoder, and the like, and scans and sequentially drives the horizontal selection switches of the column signal processing circuit 112. The signals of the respective pixels P transmitted through the vertical signal lines Lsig are sequentially output to the horizontal signal line 121 by the selection and scanning of the horizontal drive circuit 113, and are transmitted to the outside of the semiconductor substrate 21 through the horizontal signal line 121.

[0019] The output circuit 114 performs signal processing on the signals sequentially supplied from the respective column signal processing circuits 112 through the horizontal signal line 121, and outputs the resultant signals. For example, the output circuit 114 can perform only buffering, or can perform black level adjustment, column bias correction, and various types of digital signal processing, and the like.

[0020] The circuit portions including the vertical drive circuit 111, the column signal processing circuit 112, the horizontal drive circuit 113, the horizontal signal line 121, and the output circuit 114 can be directly formed on the semiconductor substrate 21, or can be arranged in an external control IC. Further, these circuit portions can be formed on other substrates connected through a cable or the like.

[0021] The control circuit 115 receives a clock and data indicating an operation mode, and the like, supplied from the outside of the semiconductor substrate 21. Further, the control circuit 115 also outputs data such as internal information on the pixels P as an imaging element. The control circuit 115 also includes a timing generator that generates various types of timing signals. The control circuit 115 performs drive control on the peripheral circuits such as the vertical drive circuit 111, the column signal processing circuit 112, and the horizontal drive circuit 113, based on the various types of timing signals generated by the timing generator.

[0022] The input / output terminal 116 exchanges signals with the outside.

[0023] <Example of cross-sectional configuration of pixel unit 100> FIG. 2 An example of a vertical cross-sectional configuration along the thickness direction of a portion of the pixel unit 100 is schematically shown. As an example, FIG. 2 A pixel P1 and a pixel P2 that are some of the plurality of pixels P arranged in the pixel unit 100 in a matrix shape are shown. In FIG. 2 In the present embodiment, the thickness direction (stacking direction) of the pixel P1 and the pixel P2 is defined as the Z-axis direction. A planar direction parallel to a stacking plane orthogonal to the Z-axis direction is defined as the X-axis direction and the Y-axis direction. Note that the X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal to each other.

[0024] As FIG. 2As shown, the pixel unit 100 is a so-called longitudinal light-splitting type image pickup element. That is, the pixel unit 100 has a structure in which the first light detection unit 10 and the second light detection unit 20 are stacked in the Z-axis direction (i.e., the thickness direction). The first light detection unit 10 is configured to detect light in a first wavelength range. The second light detection unit 20 is configured to detect light in a second wavelength range. Here, the light in the first wavelength range is, for example, visible light, and the light in the second wavelength range is infrared light having a longer wavelength than the visible light. The pixel unit 100 further includes an intermediate layer 50, an intermediate layer 40, and a multilayer wiring substrate 30. The intermediate layer 40 is provided between the first light detection unit 10 and the second light detection unit 20 in the Z-axis direction. The intermediate layer 50 is provided between the second light detection unit 20 and the intermediate layer 40 in the Z-axis direction. The multilayer wiring substrate 30 is provided on the side opposite to the first light detection unit 10 when viewed from the second light detection unit 20. A black filter can be provided in the peripheral region 100R2. Further, the second light detection unit 20 includes, for example, a plurality of color filters 14 and on-chip lenses (OCLs) 15 provided corresponding to each of the plurality of color filters 14. Note that an antireflection film can be provided to cover the on-chip lenses 15. The plurality of color filters 14 include, for example, a color filter that mainly transmits red light, a color filter that mainly transmits green light, and a color filter that mainly transmits blue light. Note that the pixel P1 of the present embodiment includes each of the red, green, and blue color filters 14, and is such that the first light detection unit 10 receives each of the red, green, and blue light to obtain a color visible light image.

[0025] <Second light detection unit 20> <Second light detection unit 20> The second light detecting unit 20 is a direct TOF (dTOF) sensor that acquires a distance image (distance information) by, for example, light Time-of-Flight (TOF). The second light detecting unit 20 has a stacked structure in which, for example, an insulating layer Z1 and a semiconductor substrate 21 are stacked in order in a direction from the multilayer wiring substrate 30 toward the intermediate layer 50. A wiring group W21 is buried in the insulating layer Z1. The insulating layer Z1 includes an inorganic insulating material such as silicon oxide (SiO2) or aluminum oxide. More specifically, the insulating layer Z1 can include a single layer film containing one of inorganic insulating materials such as silicon oxide (SiOx), silicon nitride (SiNx), and silicon oxynitride (SiON), or a laminated film containing two or more of these inorganic insulating materials. Further, as a material constituting the insulating layer Z1, an organic insulating material such as polymethyl methacrylate (PMMA), polyvinyl phenol (PVP), polyvinyl alcohol (PVA), polyimide, polycarbonate (PC), polyethylene terephthalate (PET), polystyrene, N-2(aminoethyl) 3-aminopropyl trimethoxysilane (AEAPTMS), 3-mercaptopropyl trimethoxysilane (MPTMS), tetraethoxysilane (TEOS), or octadecyltrichlorosilane (OTS) or the like can be used. In the semiconductor substrate 21, a photoelectric conversion region 22, a fixed charge layer 23, a first contact layer 24, a second contact layer 25, and a pixel inter-region light shielding wall 26 are buried. However, the upper edge of the pixel inter-region light shielding wall 26 can protrude from the back surface 21B (to be described later) of the semiconductor substrate 21 toward the first light detecting unit 10. Examples of the constituent material of the wiring group W21 include a highly conductive non-magnetic material such as Cu (copper). Further, the second light detecting unit 20 includes a unit pixel region 20P (20P1 and 20P2) provided at a position corresponding to each of the plurality of pixels P.

[0026] The semiconductor substrate 21 is, for example, an n-type silicon (Si) substrate including a front surface 21A and a back surface 21B. The semiconductor substrate 21 includes a p-well (p) in a predetermined region. The front surface 21A faces the multilayer wiring substrate 30. The back surface 21B is a surface facing the intermediate layer 50. The back surface 21B preferably has a fine uneven structure. This is because the fine uneven structure can effectively restrict infrared light incident to the semiconductor substrate 21 inside the semiconductor substrate 21. Note that the front surface 21A can also have a similar fine uneven structure.

[0027] For example, the photoelectric conversion region 22 converts incident light into an electric signal through photoelectric conversion, and outputs the electric signal. The photoelectric conversion region 22 converts incident light (photons) into an electric signal through photoelectric conversion, and outputs a pulse corresponding to the incidence of the photons. The photoelectric conversion region 22 is, for example, a SPAD (Single Photon Avalanche Diode) element. The SPAD element has, for example, the following characteristics: a large negative voltage is applied to a cathode to form an avalanche multiplication region (depletion layer), and an electron generated in response to the incidence of one photon causes avalanche multiplication, thereby flowing a large current. The photoelectric conversion region 22 detects light having a wavelength in particular the infrared light range among light from an object, converts the light into an electric signal, and outputs the electric signal. The light detection device 1 includes the photoelectric conversion region 22 for each unit pixel region 20P.

[0028] The photoelectric conversion region 22 includes a light-receiving unit 22A and a multiplication unit 22B. The light-receiving unit 22A has a photoelectric conversion function of absorbing light incident from the back surface 21B side of the semiconductor substrate 21 and converting a photon into an electric charge. The light-receiving unit 22A includes, for example, an n-type semiconductor region (n) whose impurity concentration is controlled to be n-type. An electric charge (in this case, an electron) generated in the light-receiving unit 22A is transported to the multiplication unit 22B by a potential gradient.

[0029] The multiplication unit 22B performs avalanche multiplication on the electric charge (electron) generated in the light-receiving unit 22A. The multiplication unit 22B has, for example, a stacked structure of a p-type semiconductor region (p+) 22BX and an n-type semiconductor region (n+) 22BY. The p-type semiconductor region (p+) 22BX has a higher impurity concentration than that of a p-well (p) of the semiconductor substrate 21. The n-type semiconductor region (n+) 22BY has a higher impurity concentration than that of the n-type semiconductor region (n) of the light-receiving unit 22A. In the photoelectric conversion region 22, an avalanche multiplication region is formed at a junction between the p-type semiconductor region (p+) 22BX and the n-type semiconductor region (n+) 22BY. This avalanche multiplication region is a high electric field region (depletion layer) formed at an interface between the p-type semiconductor region (p+) 22BX and the n-type semiconductor region (n+) 22BY by a large negative voltage applied to a cathode. In this avalanche multiplication region, an electron (e-) generated in one photon incident to the photoelectric conversion region 22 is multiplied.

[0030] A fixed charge layer 23 is provided to cover the back surface 21B and the like of the semiconductor substrate 21. The fixed charge layer 23 includes, for example, a negative fixed charge to suppress generation of dark current caused by an interface level of the back surface 21B as a light-receiving surface of the semiconductor substrate 21. An electric field induced by the fixed charge layer 23 forms a hole accumulation layer near the back surface 21B of the semiconductor substrate 21. This hole accumulation layer contributes to suppression of generation of electrons from the back surface 21B. Note that the fixed charge layer 23 also includes a portion extending along the Z-axis direction between the inter-pixel region light-blocking wall 26 and the photoelectric conversion region 22. The fixed charge layer 23 is preferably formed using an insulating material. Specifically, examples of the constituent material of the fixed charge layer 23 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 (EuOx), 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), and the like.

[0031] A first contact layer 24 and a second contact layer 25 are respectively provided near the front surface 21A of the semiconductor substrate 21. The first contact layer 24 includes an n-type semiconductor region (n++) electrically connected to an n-type semiconductor region (n+) 22BY constituting a multiplication unit 22B. The second contact layer 25 includes a p-type semiconductor region (p++) electrically connected to an n-type semiconductor region (n) constituting a light-receiving unit 22A. For example, as shown in FIG. 2A, the second contact layer 25 is provided to surround the light-receiving unit 22A along the inter-pixel region light-blocking wall 26. A bias voltage is applied to the second contact layer 25 as an anode of the photoelectric conversion region 22. The first contact layer 24 is a cathode of the photoelectric conversion region 22 and is connected, for example, to a quenching resistance element. FIG. 2 A first contact layer 24 and a second contact layer 25 are respectively provided near the front surface 21A of the semiconductor substrate 21. The first contact layer 24 includes an n-type semiconductor region (n++) electrically connected to an n-type semiconductor region (n+) 22BY constituting a multiplication unit 22B. The second contact layer 25 includes a p-type semiconductor region (p++) electrically connected to an n-type semiconductor region (n) constituting a light-receiving unit 22A. For example, as shown in FIG. 2A, the second contact layer 25 is provided to surround the light-receiving unit 22A along the inter-pixel region light-blocking wall 26. A bias voltage is applied to the second contact layer 25 as an anode of the photoelectric conversion region 22. The first contact layer 24 is a cathode of the photoelectric conversion region 22 and is connected, for example, to a quenching resistance element.

[0032] The inter-pixel region light-blocking wall 26 is provided at a boundary portion between adjacent pixels P in the XY plane. The inter-pixel region light-blocking wall 26 is provided to surround the photoelectric conversion region 22 of each pixel P. By providing the inter-pixel region light-blocking wall 26 at the boundary portion between adjacent pixels P, it is possible to suppress unnecessary light from obliquely incident into the photoelectric conversion region 22 of the adjacent pixel P, thereby preventing color mixing.

[0033] The inter-pixel region light-shielding wall 26 includes, for example, a material containing at least one of a metal element, a metal alloy, a metal nitride, and a metal silicide having light-shielding properties. More specifically, examples of the material constituting the inter-pixel region light-shielding wall 26 include 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), and a tungsten silicide compound. Note that the material constituting the inter-pixel region light-shielding wall 26 is not limited to a metal material. The inter-pixel region light-shielding wall 26 can be formed using graphite. Furthermore, the inter-pixel region light-shielding wall 26 is not limited to a conductive material, but can include a non-conductive material having light-shielding properties such as an organic material. An insulating layer can be provided outside the inter-pixel region light-shielding wall 26, that is, between the inter-pixel region light-shielding wall 26 and the fixed charge layer 23. Alternatively, a gap can be provided between the inter-pixel region light-shielding wall 26 and the fixed charge layer 23 to provide insulation between the inter-pixel region light-shielding wall 26 and the fixed charge layer 23.

[0034] <Multi-layer wiring substrate 30> The multi-layer wiring substrate 30 is a logic circuit substrate having an insulating layer Z6 stacked on a semiconductor substrate 31 such as silicon. In the insulating layer Z6, a wiring group 32 constituting a readout circuit is buried. The readout circuit performs readout of signal charges from the first light detection unit 10 and the second light detection unit 20. A metal terminal of the wiring group 32 exposed in a back surface Z6B of the insulating layer Z6 is directly bonded to a metal terminal of a wiring group W21 exposed in a front surface Z1A of the insulating layer Z1 of the second light detection unit 20. As for the material constituting the insulating layer Z6, for example, the same material as the material constituting the insulating layer Z1 or the like can be applied. Examples of the material constituting the wiring group 32 include a highly conductive non-magnetic material such as Cu (copper).

[0035] <Intermediate layer 50> The intermediate layer 50 has a stacked structure in which an insulating layer Z2, a passivation film P1, and an insulating layer Z3 are sequentially stacked in a direction from the second light detection unit 20 toward the intermediate layer 40. In the insulating layer Z2, a light-shielding layer 51 and a light waveguide 52 are buried. As for the materials constituting the insulating layers Z2 and Z3, for example, the same material as the material constituting the insulating layer Z1 can be applied. The passivation film P1 can include an inorganic insulating material such as silicon nitride (Si3N4).

[0036] The light-shielding layer 51 is provided at a position overlapping with the inter-pixel region light-shielding wall 26 in the Z-axis direction. The light-shielding layer 51 can suppress unnecessary light from obliquely incident into the photoelectric conversion region 22 of the adjacent pixel P, thereby preventing color mixing. As for the material constituting the light-shielding layer 51, the same material as the inter-pixel region light-shielding wall 26 can be applied.

[0037] The optical waveguide 52 is a metal waveguide provided in a layer level between the first light detecting unit 10 and the second light detecting unit 20. The optical waveguide 52 guides light that has transmitted through the first light detecting unit 10 toward the photoelectric conversion region 22 of the second light detecting unit 20. The optical waveguide 52 is annularly provided in the XY plane along an outer edge of the photoelectric conversion region 22 of each unit pixel region 20P (20P1 or 20P2). The optical waveguide 52 penetrates the insulating layer Z2 in the Z-axis direction. For example, the width of the optical waveguide 52 orthogonal to the Z-axis direction gradually narrows as it gets closer to the second light detecting unit 20 from the passivation film P1. The optical waveguide 52 can include, for example, Al (aluminum) simple substance or a metal containing Al.

[0038] The second light detecting unit 20 and the intermediate layer 50 further include a connection unit W22 and a connection unit W23. Each of the connection unit W22 and the connection unit W23 extends in the Z-axis direction to penetrate the insulating layer Z1, the semiconductor substrate 21, the insulating layer Z2, the passivation film P1, and the insulating layer Z3 from the wiring group W21 provided in the insulating layer Z1 to the back surface of the insulating layer Z3 facing the intermediate layer 40.

[0039] <Intermediate layer 40> The intermediate layer 40 has a stacked structure in which, for example, the insulating layer Z4, the passivation film P2, and the insulating layer Z5 are sequentially stacked in a direction from the intermediate layer 50 toward the first light detecting unit 10. In the insulating layer Z5, the condenser lens 41 and the wiring groups W41, W42, and W43 are buried. As a constituent material of the insulating layers Z4 and Z5, for example, the same material as that of the constituent material of the insulating layer Z1 or the like can be applied. For example, one condenser lens 41 is provided for each pixel P. The condenser lens 41 includes, for example, a resin material configured to transmit light of the second wavelength range (for example, infrared light) that has transmitted through the first light detecting unit 10. The condenser lens 41 is an optical element that condenses light of the second wavelength range (for example, infrared light) that has transmitted through the first light detecting unit 10 and guides the condensed light to the second light detecting unit 20. That is, the condenser lens 41 is a positive lens having a positive refractive power with respect to light of the second wavelength range. Note that the condenser lens 41 can also have a positive refractive power with respect to light of the first wavelength range (for example, visible light).

[0040] The wiring group W41 is connected to the lower electrode 11 of the first light detecting unit 10 described later. The wiring group W41 is connected to a part of the wiring group W42. At an interface between the intermediate layer 40 and the intermediate layer 50, the wiring group W42 is connected to the connection unit W22. The wiring group W43 is connected to the upper electrode 13 of the first light detecting unit 10 described later. The wiring group W43 is connected to the connection unit W23 at the interface between the intermediate layer 40 and the intermediate layer 50.

[0041] At least one of the intermediate layer 40 and the intermediate layer 50 can further include a predetermined optical filter. The optical filter has a transmission band of a second wavelength range in which photoelectric conversion is performed in the photoelectric conversion region 22. That is, the optical filter more easily transmits light having a wavelength of the second wavelength range than light having a wavelength of the first wavelength range. Specifically, the optical filter can include, for example, an organic material, and absorb at least a part of light having a wavelength of a visible light range while selectively transmitting light of an infrared light range. The optical filter includes an organic material such as a phthalocyanine derivative or the like.

[0042] <First light detection unit 10> The first light detection unit 10 includes unit pixel regions 10P (10P1 and 10P2) provided at positions corresponding to respective pixels of the plurality of pixels P. Each unit pixel region 10P (10P1 and 10P2) includes a plurality of sub-pixel regions 10SP. In the present embodiment, as shown in FIG. 3A Each unit pixel region 10P (10P1 and 10P2) includes four sub-pixel regions 10SP1 to 10SP4, respectively. FIG. 3A An example of the configuration of a horizontal section of the pixel P at a height position Lv1 in the Z-axis direction is schematically shown in FIG. 2 That is, an example of the configuration of a horizontal section of the pixel P at a height position Lv1 in the Z-axis direction is schematically shown in FIG. 3A An example of the configuration of a horizontal section of the OCL 15 is shown. Note that, in FIG. 3A In the drawing, the reference sign LF represents the spread of a light flux of light from the outside that has been incident on the OCL 15.

[0043] The first light detection unit 10 includes, for each sub-pixel region 10SP, a lower electrode 11, a photoelectric conversion region 12, an upper electrode 13, a color filter 14, and an OCL 15, which are stacked in order from, for example, a position close to the second light detection unit 20. An inter-pixel light-shielding unit 16 is provided between the sub-pixel regions 10SP. The inter-pixel light-shielding unit 16 shields light of the first wavelength range. The lower electrode 11, the photoelectric conversion region 12, and the upper electrode 13 are buried in a semiconductor substrate 17.

[0044] The lower electrode 11 and the upper electrode 13 include a light-transmissive conductive film. For example, the lower electrode 11 and the upper electrode 13 include ITO (indium tin oxide). However, as a material constituting the lower electrode 11 and the upper electrode 13, a tin oxide (SnOx) -based material to which a dopant is added, or a zinc oxide (ZnO) -based material obtained by adding a dopant to zinc oxide can be used in addition to ITO. Examples of the zinc oxide-based material include aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), and indium-doped zinc oxide (IZO). In addition, as a material constituting the lower electrode 11 and the upper electrode 13, CuI, InSbO4, ZnMgO, CuInO2, MgIn2O4, CdO, ZnSnO3, or TiO2, or the like can be used. In addition, a spinel oxide or an oxide having a YbFe2O4 structure can be used.

[0045] The photoelectric conversion region 12 converts light energy into electric energy. The photoelectric conversion region 12 includes, for example, two or more kinds of organic materials that function as a p-type semiconductor and an n-type semiconductor. The p-type semiconductor functions as an electron donor (donor), and the n-type semiconductor functions as an electron acceptor (acceptor). The photoelectric conversion region 12 has a bulk heterojunction structure in the layer. The bulk heterojunction structure is a p / n junction interface formed by mixing the p-type semiconductor and the n-type semiconductor together. Excitons generated when light is absorbed are separated into an electron and a hole at the p / n junction interface.

[0046] In addition to the p-type semiconductor and the n-type semiconductor, the photoelectric conversion region 12 can include a so-called dye material that performs photoelectric conversion on light of a predetermined wavelength band while transmitting light of other wavelength bands. The p-type semiconductor, the n-type semiconductor, and the dye material preferably have different maximum absorption wavelengths from each other. This makes it possible to absorb a wide range of wavelengths in the visible light range.

[0047] The photoelectric conversion region 12 can be formed by, for example, mixing the various kinds of organic semiconductor materials described above and using a spin coating technique. In addition, for example, the photoelectric conversion region 12 can be formed using a vacuum deposition method or a printing technique, or the like.

[0048] The photoelectric conversion region 12 detects part or all of light in the first wavelength range. In addition, it is desirable that the photoelectric conversion region 12 have no sensitivity to light in the second wavelength range.

[0049] Light incident to the side where the upper electrode 13 is arranged is absorbed by the photoelectric conversion region 12. Excitons (electron-hole pairs) generated thereby move to the interface between the electron donor and the electron acceptor constituting the photoelectric conversion region 12, and exciton separation, or dissociation into an electron and a hole, is caused. The electric charges (i.e., the electron and the hole) generated here are transported to the upper electrode 13 or the lower electrode 11 by diffusion due to a carrier concentration difference or an internal electric field due to a potential difference between the upper electrode 13 and the lower electrode 11, and are detected as a photoelectric current.

[0050] <1-2. Effects and advantages> The light detection device 1 of the present embodiment includes a first light detection unit 10 and a second light detection unit 20. The first light detection unit 10 is configured to detect light of a first wavelength range. The second light detection unit 20 is stacked with the first light detection unit 10, and is configured to detect light of a second wavelength range different from the light of the first wavelength range. The light detection device 1 further includes a condenser lens 41 as an optical element between the first light detection unit 10 and the second light detection unit 20. The condenser lens 41 condenses the light of the second wavelength range that has passed through the first light detection unit 10, and guides the condensed light to the second light detection unit 20. As described above, because the condenser lens 41 is disposed at a predetermined position, in the light detection device 1, the light of the first wavelength range that has passed through the first light detection unit 10 of a certain pixel P is incident to the second light detection unit 20 where the light should originally be incident, without leaking to the second light detection unit 20 of other pixels P in the periphery. Therefore, it is possible to prevent a decrease in detection sensitivity, and it is possible to suppress occurrence of so-called crosstalk.

[0051] Therefore, according to the light detection device 1 of the present embodiment, by stacking the first light detection unit 10 and the second light detection unit 20, it is possible to achieve high integration in the XY plane, and it is possible to improve resolution. In addition, the light detection device 1 of the present embodiment can exhibit better light detection performance.

[0052] Here, in addition to FIG. 2 and FIG. 3A , a description is made of FIG. 3B to FIG. 3D the behavior of light incident to the light detection device 1. FIG. 3B to FIG. 3D A configuration example of a horizontal cross section of the pixel P at each height position Lv2 to Lv4 of the light detection device 1 shown in FIG. 2 is schematically shown. FIG. 3B A horizontal cross section of the insulating layer Z4 of the intermediate layer 40 is shown. FIG. 3C A horizontal cross section of the insulating layer Z2 of the intermediate layer 50 is shown. In addition, FIG. 3D A horizontal cross section of the semiconductor substrate 21 provided with the photoelectric conversion region 22 is shown.

[0053] AsFIG. 3A As shown, the light beam incident on OCL 15 covers almost the entire area of ​​pixel P1. In the light incident on OCL 15, light in the first wavelength range undergoes photoelectric conversion when it passes through the first light detection unit 10 provided for each sub-pixel region 10SP. Subsequently, the light that has passed through the first light detection unit 10 enters the intermediate layer 40 and is converged by the condenser lens 41. Therefore, as... FIG. 3B As shown, the area occupied by beam LF in the horizontal cross-section at height position Lv2 is smaller than the area occupied by beam LF in the horizontal cross-section at height position Lv1. As the light travels further, as... FIG. 3C As shown, the area occupied by the light beam LF in the horizontal cross-section at height position Lv3 becomes even smaller than the area occupied by the light beam LF in the horizontal cross-section at height position Lv2. In the horizontal cross-section at height position Lv3, the area occupied by the light beam LF is much smaller than the opening area of ​​the optical waveguide 52. Subsequently, when the light travels from height position Lv3 to height position Lv4, the light beam LF thickens slightly, causing the area occupied by the light beam LF in the horizontal cross-section at height position Lv4 to become larger than the area occupied by the light beam LF in the horizontal cross-section at height position Lv3. However, the area occupied by the light beam LF in the horizontal cross-section at height position Lv4 can be suppressed to be much smaller than the area occupied by the photoelectric conversion region 22 in the same horizontal cross-section at height position Lv4. Therefore, it is possible to prevent light that has passed through the first photodetector unit 10 of pixel P from accidentally incidenting into the second photodetector unit 20 of other surrounding pixels P.

[0054] However, as FIG. 4 As shown in the light detection device 101 as a reference example, when no optical element with a focusing effect, such as a condenser lens 41, is provided between the first light detection unit 10 and the second light detection unit 20, the light spot incident on the light detection device 101 gradually increases as it travels in the Z-axis direction. Except that the light detection device 101 does not have a condenser lens 41, the light detection device 101 has the same structure as the light detection device 1. FIG. 5A to FIG. 5D Schematic illustration in FIG. 4 Example of the construction of the horizontal cross-section of pixel P at each height position Lv1 to Lv4 of the light detection device 101 shown. FIG. 5A As shown, the light beam incident on OCL 15 covers almost the entire area of ​​pixel P1. The light incident on OCL 15 passes through the first light detection unit 10 and then enters the intermediate layer 40. However, since there is no focusing lens, the light diffuses as it travels in the Z-axis direction. Therefore, as... FIG. 5B As shown, the area occupied by beam LF in the horizontal cross-section at height Lv2 is greater than the area occupied by beam LF in the horizontal cross-section at height Lv1. As the light travels further, as...FIG. 5C As shown, the occupied area of the light beam LF in the horizontal cross section at the height position Lv3 becomes even larger than the occupied area of the light beam LF in the horizontal cross section at the height position Lv2. In the horizontal cross section at the height position Lv3, the occupied area of the light beam LF is even larger than the opening area of the optical waveguide 52. Thereafter, when the light travels from the height position Lv3 to the height position Lv4, the light beam LF becomes thicker, resulting in that the occupied area of the light beam LF in the horizontal cross section at the height position Lv4 becomes even larger than the occupied area of the light beam LF in the horizontal cross section at the height position Lv3. Thus, the occupied area of the light beam LF in the horizontal cross section at the height position Lv4 is eventually larger than the occupied area of the photoelectric conversion region 12 in the horizontal cross section at the same height position Lv4. Therefore, the light that has transmitted through the first light detecting element 10 of the pixel P eventually accidentally incident to the second light detecting element 20 of the other pixel P in the periphery.

[0055] In contrast, in the light detecting device 1 of the present embodiment, the light that has transmitted through the first light detecting element 10 of one pixel P is converged by the condenser lens 41. Thus, it is possible to deliver the light to the second light detecting element 20 of the pixel P without causing the light to be incident to the second light detecting element 20 of the other pixel P. This results in that a sufficient amount of light of the second wavelength range is incident to the unit pixel region 10P of each pixel, while avoiding unnecessary light from being incident to the unit pixel region 10P of each pixel P.

[0056] Thus, for example, as shown in the light detecting device 1-1, even when the center position of the unit pixel region 10P (10P1 and 10P2) deviates from the center position of the unit pixel region 20P (20P1 and 20P2) corresponding thereto in the XY plane direction due to a manufacturing error or the like, it is possible to avoid occurrence of so-called crosstalk. FIG. 6

[0057] Further, in the light detecting device 1 of the present embodiment, the optical waveguide 52 is provided in the intermediate layer 50 along the outer edge of the second light detecting element 20. Thus, it is possible to guide the light accidentally shot toward the adjacent pixel P toward the second light detecting element 20 where the light is originally supposed to be incident due to accidental reflection or the like. Thus, it is possible to further reduce occurrence of crosstalk.

[0058] <1-3. Modification> <Modification 1-1> FIG. 7 is a sectional view showing a configuration example of a vertical cross section of a light detecting device 1A as a first modification of the above-described first embodiment. In the light detecting device 1 of the above-described first embodiment, the optical waveguide 52 penetrates the insulating layer Z2 in the Z-axis direction. In contrast, in the light detecting device 1A of the present modification, the optical waveguide 52 is provided in the intermediate layer 50 in the Z-axis direction. Thus, the light that has transmitted through the first light detecting element 10 of one pixel P is guided toward the second light detecting element 20 of the pixel P without causing the light to be incident to the second light detecting element 20 of the other pixel P. This results in that a sufficient amount of light of the second wavelength range is incident to the unit pixel region 10P of each pixel, while avoiding unnecessary light from being incident to the unit pixel region 10P of each pixel P. FIG. 7 ​In the light detecting device 1A, the optical waveguide 52 penetrates not only the insulating layer Z2 but also the passivation film P1 provided on the insulating layer Z2. Other than this, the configuration of the light detecting device 1A is substantially the same as that of the light detecting device 1. In the light detecting device 1A having such a configuration, it is possible to more effectively prevent light that should have been incident on the first light detecting element 10 of the predetermined pixel P from being incident on the second light detecting element 20 of the other pixel P.

[0059] <Modification Example 1-2> FIG. 8 is a sectional view illustrating a configuration example of a vertical section of a light detecting device 1B as a second modification example of the above-described first embodiment. In the light detecting device 1B, FIG. 8 In the light detecting device 1B, the portion of the insulating layer Z2 surrounded by the optical waveguide 52 along the XY plane is replaced with a high refractive index material 53. The high refractive index material 53 has, for example, a higher refractive index than the refractive index of the insulating layer Z2 and the refractive index of the passivation film P1 for light of the second wavelength range. Other than this, the configuration of the light detecting device 1B is substantially the same as that of the light detecting device 1. In the light detecting device 1B having such a configuration, since the high refractive index material 53 is provided, the physical wavelength of light passing through the high refractive index material 53 is shortened. Thus, it is possible to hinder the light that has transmitted through the first light detecting element 10 from spreading to the periphery, making it possible to more efficiently deliver light of the second wavelength range to the second light detecting element 20.

[0060] <Modification Example 1-3> FIG. 9 is a sectional view illustrating a configuration example of a vertical section of a light detecting device 1C as a third modification example of the above-described first embodiment. In the light detecting device 1 of the first embodiment, the width of the optical waveguide 52 orthogonal to the Z-axis direction gradually narrows as it gets closer to the second light detecting element 20 along the optical waveguide 52 in the Z-axis direction from the passivation film P1. In contrast, in the light detecting device 1C, FIG. 9 In the light detecting device 1C, the width of the optical waveguide 52 orthogonal to the Z-axis direction is substantially constant. Other than this, the configuration of the light detecting device 1B is substantially the same as that of the light detecting device 1. Note that the optical waveguide 52 can be electrically connected to the light-shielding layer 51 and the inter-pixel region light-shielding wall 26, and can have the same potential as the second contact layer 25 as an anode.

[0061] <Modification Example 1-4> FIG. 10 is a sectional view illustrating a configuration example of a vertical section of a light detecting device 1D as a fourth modification example of the above-described first embodiment. In the light detecting device 1D, FIG. 10In the light detection device 1D, the optical waveguide 52 is also provided at a position overlapping the inter-pixel region light shielding wall 26 in the Z-axis direction. That is, the light shielding layer 51 is replaced with the optical waveguide 52. Other than this, the configuration of the light detection device 1D is substantially the same as that of the light detection device 1. The light detection device 1D is simplified in terms of configuration as compared with the light detection device 1.

[0062] <2. Second Embodiment> <2-1. Configuration> FIG. 11 An example of a cross-sectional configuration of a light detection device 2 according to a second embodiment of the present disclosure is schematically shown. In the light detection device 1 according to the above-described first embodiment, the light from the first light detection unit 10 is converged using the condenser lens 41, and the converged light is guided to the second light detection unit 20. In contrast, the light detection device 2 of the present embodiment includes superlenses 61 and 62 using super surface technology instead of the condenser lens 41. Further, the light detection device 2 includes an optical filter 54 buried in the insulating layer Z2 of the intermediate layer 50. Further, in the light detection device 2, the unit pixel region 10P corresponding to one pixel P includes a total of sixteen sub-pixel regions 10SP arranged in a 4 x 4 array in both the X-axis direction and the Y-axis direction. Other than this, the configuration of the light detection device 2 is substantially the same as that of the light detection device 1. Note that, FIG. 11 Only one pixel P (in particular, a pixel Pctr close to the center) in the effective region 100R1 within the pixel unit 100 of the light detection device 2 is shown so that the structure of the superlens 61 is more easily seen, and the illustration of the peripheral region 100R2 is omitted. Further, in FIG. 11 In the intermediate layer 40, the illustration of the multilayer wiring substrate 30 is omitted.

[0063] As shown in FIG. 11 In the light detection device 2, as an optical element, the superlens 61 is provided. The superlens 61 is buried in the insulating layer Z5 of the intermediate layer 40. The superlens 61 has a plurality of structures 61A having a size equal to or smaller than the wavelength of light (for example, infrared light) in the second wavelength range that the second light detection unit 20 can detect. Specifically, each of the plurality of structures 61A has a width and a height equal to or smaller than the wavelength of light in the second wavelength range. The width used herein refers to the size in the XY plane direction orthogonal to the Z-axis, and the height used herein refers to the length in the Z-axis direction. The plurality of structures 61A are regularly distributed in substantially the entire region of each unit pixel region 10P. The plurality of structures 61A are dielectric waveguides including a dielectric material such as silicon oxide (SiOx).

[0064] FIG. 12is a schematic view showing the shape, size, and arrangement position of the plurality of structures 61A in the XY plane in a portion of the superlens 61 corresponding to each sub-pixel region 10SP. As shown in FIG. 12 the plurality of structures 61A are regularly arranged at a substantially constant pitch with respect to each other in the XY plane direction orthogonal to the direction in which the first light detection unit 10 and the second light detection unit 20 overlap (Z-axis direction). For example, the plurality of structures 61A are thickest near the center of each sub-pixel region 10SP, and gradually become thinner as they approach the peripheral region of each sub-pixel region 10SP.

[0065] In the light detection device 2, as the optical element, a superlens 62 is also provided in the intermediate layer 50. The superlens 62 is buried in the insulating layer Z2. That is, in the light detection device 2, the superlens 61 and the superlens 62 as the plurality of optical elements are stacked with each other. Like the superlens 61, the superlens 62 has a plurality of structures 62A having a size equal to or smaller than the wavelength of light (for example, infrared light) in the second wavelength range that the second light detection unit 20 can detect. Specifically, each of the plurality of structures 62A has a width and a height equal to or smaller than the wavelength of light in the second wavelength range. However, the arrangement position, size, and shape of the plurality of structures 61A are not limited to those shown in FIG. 11 and FIG. 12 but can be designed arbitrarily.

[0066] The plurality of structures 62A are regularly distributed in substantially the entire region of each unit pixel region 20P. For example, the plurality of structures 62A are thickest near the center of each unit pixel region 20P, and gradually become thinner as they approach the peripheral region of each sub-pixel region 20SP. However, the arrangement position, size, and shape of the plurality of structures 62A are not limited to those shown in FIG. 11 but can be designed arbitrarily.

[0067] The optical filter 54 buried in the insulating layer Z2 of the intermediate layer 50 suppresses the transmission of light (for example, visible light) in the first wavelength range, and selectively transmits light (for example, infrared light) in the second wavelength range.

[0068] Further, FIG. 11 shows a configuration example of the vertical cross section of the pixel Pctr near the center of the effective region 100R1 of the pixel unit 100. Meanwhile, FIG. 13 shows a configuration example of the vertical cross section of the pixel Pper in the peripheral region of the effective region 100R1 of the pixel unit 100 of the light detection device 2. As shown in FIG. 11As shown, light L from the object is incident on a pixel Pctr in the vicinity of the center of the effective region 100R1 substantially in parallel to the Z-axis direction, that is, perpendicularly to the XY plane as the light-receiving surface. Meanwhile, light L from the object is incident on a pixel Pper shown in the figure in a direction inclined with respect to the Z-axis direction. That is, light L is incident obliquely on the XY plane as the light-receiving surface. FIG. 13

[0069] Therefore, in the pixel Pper, the positions of the color filter 14 and the OCL 15 in the XY plane deviate from the positions of the photoelectric conversion region 12 of the color filter 14 and the OCL 15 in the XY plane according to the assumed inclination angle of light L. In this way, light that has been incident on the OCL 15 of a certain sub-pixel region 10SP is incident on the photoelectric conversion region 12 of the sub-pixel region 10SP through the color filter 14 of the sub-pixel region 10SP. Among the light incident on the photoelectric conversion region 12, the component of light of the first wavelength range is photoelectrically converted, and the component of light of the second wavelength range is transmitted. The light of the second wavelength range that has transmitted through the photoelectric conversion region 12 is deflected toward the vertical direction while being condensed by the superlens 61, after which the deflected light is condensed by the superlens 62 and is incident on the photoelectric conversion region 22 of the second light detection unit 20.

[0070] <2-2. Effects and advantages> As described above, in the light detection device 2 of the present embodiment, the superlenses 61 and 62 as optical elements are provided between the first light detection unit 10 and the second light detection unit 20. The superlenses 61 and 62 condense light of the second wavelength range that has transmitted through the first light detection unit 10 and guide the condensed light to the second light detection unit 20. Therefore, in the light detection device 2, light of the first wavelength range that has transmitted through the first light detection unit 10 of a certain pixel P is incident on the second light detection unit 20 where the light should have been incident originally, without leaking to the second light detection unit 20 of other pixels P in the periphery. Therefore, according to the light detection device 2, similar effects to those of the light detection device of the first embodiment described above can be expected.

[0071] <2-3. Modified examples> <Modified example 2-1>

[0072] FIG. 14 is a sectional view showing a configuration example of a vertical section of a light detection device 2A as a first modified example of the second embodiment described above. In the light detection device 2 of the second embodiment described above, the photoelectric conversion region 12 and the like are provided in the entire region corresponding to one pixel P. In contrast, in the light detection device 2A of the first modified example, the photoelectric conversion region 12 and the like are provided in the entire region corresponding to one pixel P, but the color filter 14 is not provided in the entire region corresponding to one pixel P. FIG. 14 ​In the light detection device 2A, the sub-pixel regions 10SP2 and 10SP3 exist in a part of the region corresponding to one pixel P. The sub-pixel regions 10SP2 and 10SP3 do not have the lower electrode 11 and the photoelectric conversion region 12. Therefore, in the sub-pixel regions 10SP2 and 10SP3 without the lower electrode 11 and the photoelectric conversion region 12, the visible light in the light L from the object directly enters the second light detection unit 20 through the superlenses 61 and 62 and the optical filter 54, etc., without being subjected to photoelectric conversion. Such sub-pixel regions 10SP2 and 10SP3 without the photoelectric conversion region 12, etc., are used for, for example, pupil correction.

[0073] <3. Application example> FIG. 15 A schematic configuration example of a distance image device 1000 that is an electronic device including the light detection device of the present disclosure (for example, the light detection device 1) is shown. The distance image device 1000 is a specific example that functions as the "distance measuring device" of the present disclosure.

[0074] The distance image device 1000 includes, for example, a light source device 1100, an optical system 1200, the light detection device 1, an image processing circuit 1300, a monitor 1400, and a memory 1500.

[0075] The distance image device 1000 is configured to acquire a distance image corresponding to a distance to an irradiation target 2000 by receiving light (modulated light or pulsed light) projected from the light source device 1100 toward the irradiation target 2000 and reflected from the surface of the irradiation target 2000.

[0076] The optical system 1200 includes one or more lenses. The optical system 1200 guides image light (incident light) from the irradiation target 2000 to the light detection device 1 to form an image on a light-receiving surface (sensor unit) of the light detection device 1.

[0077] The image processing circuit 1300 performs image processing based on a distance signal supplied from the light detection device 1 to construct a distance image. The distance image (image data) obtained by the image processing is supplied to the monitor 1400 and displayed, or supplied to the memory 1500 and stored (recorded).

[0078] In the distance image device 1000 thus configured, the application of the above-described light detection device (for example, the light detection device 1) makes it possible to calculate a distance to the irradiation target 2000 based on only a light-receiving signal from a unit pixel P having high stability, and to generate a distance image with high precision. That is, the distance image device 1000 can acquire a more accurate distance image.

[0079] <4. Application example> (Application example of a mobile body) The technology disclosed herein can be applied to a variety of products. For example, the technology disclosed herein can be implemented as a device that can be installed on any type of mobile body such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, ships, robots, construction machinery, and agricultural machinery (tractors).

[0080] FIG. 16 This is a block diagram illustrating a schematic construction example of a vehicle control system, which is an example of a mobile body control system to which the technology according to the embodiments of this disclosure can be applied.

[0081] The vehicle control system 12000 includes multiple electronic control units interconnected via a communication network 12001. FIG. 16 In the example shown, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and a comprehensive control unit 12050. Furthermore, as part of the functional structure of the comprehensive control unit 12050, a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface (I / F) 12053 are shown.

[0082] The drive system control unit 12010 controls the operation of devices related to the vehicle's drive system according to various types of programs. For example, the drive system control unit 12010 is used as a control device for devices such as an internal combustion engine or drive motor for generating vehicle driving force, a drive force transmission mechanism for transmitting driving force to the wheels, a steering mechanism for adjusting the vehicle's steering angle, and a braking device for generating vehicle braking force.

[0083] The body system control unit 12020 controls the operation of various types of devices installed on the vehicle body according to various types of programs. For example, the body system control unit 12020 is used as a control device for keyless entry systems, smart key systems, power windows, or various lights such as headlights, reversing lights, brake lights, turn signals, or fog lights. In this case, radio waves or signals of various types of switches sent from a keyless entry device can be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signal inputs and controls the vehicle's door locks, power windows, lights, etc.

[0084] The vehicle exterior information detection unit 12030 detects information outside the vehicle including the vehicle control system 12000. For example, the vehicle exterior information detection unit 12030 is connected with an imaging section 12031. The vehicle exterior information detection unit 12030 causes the imaging section 12031 to image an image of the outside of the vehicle, and receives the imaged image. Based on the received image, the vehicle exterior information detection unit 12030 can perform a detection process of an object such as a person, a vehicle, an obstacle, a sign, or a character on a road surface, or can perform a detection process of a distance to the above object.

[0085] The imaging section 12031 is an optical sensor that receives light and outputs an electric signal corresponding to a light quantity of the received light. The imaging section 12031 can output the electric signal as an image, or can output the electric signal as ranging information. In addition, the light received by the imaging section 12031 can be visible light, or can be invisible light such as infrared rays.

[0086] The vehicle interior information detection unit 12040 detects information inside the vehicle. The vehicle interior information detection unit 12040 is connected with, for example, a driver state detection section 12041 that detects a state of a driver. The driver state detection section 12041 includes, for example, a camera that images the driver. Based on detection information input from the driver state detection section 12041, the vehicle interior information detection unit 12040 can calculate a degree of fatigue of the driver or a degree of concentration of the driver, or can determine whether the driver is dozing off.

[0087] The microcomputer 12051 can calculate a control target value of a driving force generation device, a steering mechanism, or a braking device based on information outside or inside the vehicle obtained by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, and output a control command to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing an advanced driver assistance system (ADAS) function including collision avoidance or impact mitigation of the vehicle, follow-up driving based on an inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, or vehicle lane departure warning, or the like.

[0088] In addition, by controlling the driving force generation device, the steering mechanism, or the braking device, or the like, based on information outside or inside the vehicle obtained by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, the microcomputer 12051 can perform cooperative control aimed at realizing automatic driving or the like that enables the vehicle to travel autonomously without depending on an operation of the driver.

[0089] In addition, the microcomputer 12051 can output a control command to the body system control unit 12020 on the basis of information outside the vehicle obtained by the outside information detection unit 12030. For example, the microcomputer 12051 can perform cooperative control intended to prevent glare by controlling the headlamp to change from high beam to low beam, for example, in accordance with the position of a preceding vehicle or an oncoming vehicle detected by the outside information detection unit 12030.

[0090] The sound / image output section 12052 transmits an output signal of at least one of sound and image to an output device capable of visually or aurally notifying information to the occupant of the vehicle or outside the vehicle. In FIG. 16 In the example, as the output device, an audio speaker 12061, a display section 12062, and an instrument panel 12063 are shown. The display section 12062 can include at least one of a vehicle-mounted display and a head-up display, for example.

[0091] FIG. 17 FIG. 36 is a diagram showing an example of a mounting position of the imaging section 12031.

[0092] In FIG. 36, the imaging section 12031 includes imaging sections 12101, 12102, 12103, 12104, and 12105.

[0093] The imaging sections 12101, 12102, 12103, 12104, and 12105 are provided at positions of the front nose, the side mirrors, the rear bumper, and the rear door of the vehicle 12100, for example, and at a position of the upper portion of the windshield inside the cabin, for example. The imaging section 12101 provided at the front nose and the imaging section 12105 provided at the upper portion of the windshield inside the cabin mainly obtain images of the front of the vehicle 12100. The imaging sections 12102 and 12103 provided at the side mirrors mainly obtain images of the sides of the vehicle 12100. The imaging section 12104 provided at the rear bumper or the rear door mainly obtains images of the rear of the vehicle 12100. The imaging section 12105 provided at the upper portion of the windshield inside the cabin is mainly used to detect a preceding vehicle, a pedestrian, an obstacle, a traffic signal, a traffic sign, or a lane, and the like.

[0094] Incidentally, FIG. 17 An example of the imaging range of the imaging sections 12101 to 12104 is shown. The imaging range 12111 indicates the imaging range of the imaging section 12101 provided at the front nose. The imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging sections 12102 and 12103 provided at the side mirrors, respectively. The imaging range 12114 indicates the imaging range of the imaging section 12104 provided at the rear bumper or the rear door. For example, by superimposing the image data imaged by the imaging sections 12101 to 12104, an overhead view image of the vehicle 12100 viewed from above is obtained.

[0095] At least one of the imaging sections 12101 to 12104 can have a function of obtaining distance information. For example, at least one of the imaging sections 12101 to 12104 can be a stereo camera composed of a plurality of imaging elements, or can be an imaging element having pixels for phase difference detection.

[0096] For example, based on the distance information obtained from the imaging sections 12101 to 12104, the microcomputer 12051 can determine the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the temporal change of the distance (relative speed with respect to the vehicle 12100), and thus extract the closest three-dimensional object as a preceding vehicle, in particular, the three-dimensional object present on the travel path of the vehicle 12100 and traveling in substantially the same direction as the vehicle 12100 at a predetermined speed (for example, equal to or greater than 0 km / h). Further, the microcomputer 12051 can set in advance the inter-vehicle distance to the front to be maintained by the preceding vehicle, and perform automatic brake control (including follow-up stop control) or automatic acceleration control (including follow-up start control), and the like. Thus, cooperative control aimed at autonomous travel of the vehicle independently of the operation of the driver, or the like, such as automatic driving, can be performed.

[0097] For example, based on the distance information obtained from the imaging sections 12101 to 12104, the microcomputer 12051 can classify three-dimensional object data of three-dimensional objects into three-dimensional object data of two-wheeled vehicles, standard vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects, extract the classified three-dimensional object data, and use the extracted three-dimensional object data to automatically avoid obstacles. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 as obstacles that the driver of the vehicle 12100 can visually recognize and obstacles that the driver of the vehicle 12100 is difficult to visually recognize. Then, the microcomputer 12051 determines a collision risk indicating the degree of danger of collision with each obstacle. In the case where the collision risk is equal to or higher than a set value and thus there is a possibility of collision, the microcomputer 12051 outputs a warning to the driver via the audio speaker 12061 or the display section 12062, and performs forced deceleration or evasive steering via the drive system control unit 12010. Thus, the microcomputer 12051 can assist the driver to avoid collision.

[0098] At least one of the imaging sections 12101 to 12104 can be an infrared camera that detects infrared rays. The microcomputer 12051 can recognize a pedestrian, for example, by determining whether or not a pedestrian is present in an imaging image of the imaging section 12101 to 12104. Such recognition of a pedestrian is performed, for example, by a step of extracting a feature point in an imaging image of the imaging section 12101 to 12104 that is an infrared camera, and a step of determining whether or not it is a pedestrian by performing pattern matching processing on a series of feature points that represent the outline of an object. If the microcomputer 12051 determines that a pedestrian is present in an imaging image of the imaging section 12101 to 12104 and thus recognizes a pedestrian, the sound / image output section 12052 controls the display section 12062 so that a square outline for emphasis is displayed in a manner superimposed on the recognized pedestrian. The sound / image output section 12052 can also control the display section 12062 so that an icon or the like that represents a pedestrian is displayed at a desired position.

[0099] Although some embodiments and modifications, as well as applicable cases and application examples, have been described above, the present disclosure is by no means limited to the above-described embodiments and the like, and various modifications can be made. For example, the light detection device according to the present disclosure does not necessarily include all the constituent elements described in the above-described embodiments and the like. Furthermore, conversely, the light detection device according to the present disclosure can include other layers.

[0100] For example, in the first embodiment and the second embodiment, a case in which the first light detection unit detects visible light and the second light detection unit detects infrared light is exemplified, but the present disclosure is not limited thereto. The wavelength range of light detected by the first light detection unit and the second light detection unit can be set to an arbitrary value.

[0101] In addition, in the first embodiment and the second embodiment, a case in which the second light detection unit includes a SPAD element is exemplified. However, the present disclosure is not limited thereto. The second light detection unit can include a photoelectric conversion element including, for example, a PIN (positive intrinsic negative) photodiode (PD).

[0102] Furthermore, in the light detection device according to the present disclosure, an indirect TOF (iTOF) sensor can be employed as the second light detection unit.

[0103] Furthermore, in the above-described first embodiment and the second embodiment, a case in which the first light detection unit includes a photoelectric conversion region containing an organic semiconductor material is exemplified. However, the present disclosure is not limited thereto. For example, the first light detection unit can include a photoelectric conversion region containing an inorganic semiconductor material such as Si (silicon) or the like.

[0104] In the light detection device according to the embodiment of the present disclosure, one or more optical elements are provided between the first light detection unit and the second light detection unit. The one or more optical elements converge light of the second wavelength range that has transmitted through the first light detection unit, and guide the converged light to the second light detection unit. Thus, the light detection device of the present embodiment can exhibit better light detection performance while improving resolution. Note that the effects described in the above embodiments and the like are illustrative. The effects can be other effects, or the effects can include other effects.

[0105] The present disclosure can have the following configuration.

[0106] <1> A light detection device includes: a first light detection unit configured to detect light of a first wavelength range; a second light detection unit stacked with the first light detection unit and configured to detect light of a second wavelength range different from the light of the first wavelength range; and one or more optical elements provided between the first light detection unit and the second light detection unit, converging the light of the second wavelength range that has transmitted through the first light detection unit, and guiding the converged light to the second light detection unit. <2> The light detection device according to <1> described above, in which the light of the second wavelength range has a longer wavelength than the light of the first wavelength range. <3> The light detection device according to <1> or <2> described above, in which the light of the first wavelength range is visible light, and the light of the second wavelength range is infrared light. <4> The light detection device according to any one of <1> to <3> described above, in which the optical element refracts the light of the second wavelength range. <5> The light detection device according to any one of <1> to <4> described above, in which the optical element includes a plurality of structures having a size equal to or smaller than a wavelength of the light of the second wavelength range. <6> The light detection device according to <5> described above, in which each of the plurality of structures is a dielectric waveguide. <7> The light detection device according to <5> or <6> described above, in which Each of the plurality of structures has a width and a height equal to or smaller than a wavelength of light of the second wavelength range. <8> The light detection device according to any one of <5> to <7> above, wherein The plurality of structures are arranged at a substantially constant pitch in a planar direction orthogonal to a direction in which the first light detection unit and the second light detection unit overlap. <9> The light detection device according to any one of <1> to <4> above, wherein The optical element includes a condenser lens. <10> The light detection device according to <9> above, further comprising: A metal waveguide provided between the first light detection unit and the second light detection unit. <11> The light detection device according to <10> above, wherein The metal waveguide is provided along an outer edge of the second light detection unit in a plan view. <12> The light detection device according to <10> or <11> above, wherein The metal waveguide includes a metal containing aluminum (Al). <13> The light detection device according to any one of <1> to <4> above, wherein The optical element includes a metal waveguide. <14> The light detection device according to any one of <1> to <4> above, further comprising: A high refractive index material layer between the optical element and the second light detection unit. <15> The light detection device according to any one of <1> to <14> above, wherein The plurality of optical elements are stacked with each other. <16> The light detection device according to any one of <1> to <155> above, wherein The second light detection unit includes: A light-receiving unit that generates a carrier corresponding to an amount of received light through photoelectric conversion; and A multiplication unit having a stacked structure of a first conductive region and a second conductive region, and performing avalanche multiplication of the carrier generated in the light-receiving unit. <17> A distance measuring device includes: an optical system; a light detection device; and a signal processing circuit that calculates a distance to a measurement object based on an output signal of the light detection device, the light detection device includes: a first light detection unit configured to detect light of a first wavelength range; a second light detection unit stacked with the first light detection unit and configured to detect light of a second wavelength range different from the light of the first wavelength range; and an optical element disposed between the first light detection unit and the second light detection unit, converges light that has passed through the first light detection unit, and guides the converged light to the second light detection unit.

[0107] This application claims priority to Japanese Patent Application No. 2023-074996, filed April 28, 2023, to the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0108] Those skilled in the art will understand that various modifications, combinations, sub-combinations, and alterations can occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.

Claims

1. A light detecting device, comprising: a first light detecting unit configured to detect light of a first wavelength range; a second light detecting unit stacked with the first light detecting unit and configured to detect light of a second wavelength range different from the light of the first wavelength range; and one or more optical elements disposed between the first light detecting unit and the second light detecting unit, converging the light of the second wavelength range that has transmitted through the first light detecting unit, and guiding the converged light to the second light detecting unit.

2. The light detecting device according to claim 1, wherein the light of the second wavelength range has a longer wavelength than the light of the first wavelength range.

3. The light detecting device according to claim 1, wherein the light of the first wavelength range is visible light, and the light of the second wavelength range is infrared light.

4. The light detecting device according to claim 1, wherein the optical elements refract the light of the second wavelength range.

5. The light detecting device according to claim 1, wherein the optical elements include a plurality of structures having a size equal to or smaller than a wavelength of the light of the second wavelength range.

6. The light detecting device according to claim 5, wherein each of the plurality of structures is a dielectric waveguide.

7. The light detecting device according to claim 5, wherein each of the plurality of structures has a width and a height equal to or smaller than the wavelength of the light of the second wavelength range.

8. The light detecting device according to claim 5, wherein the plurality of structures are arranged at a substantially constant pitch in a planar direction orthogonal to a direction in which the first light detecting unit and the second light detecting unit overlap.

9. The light detecting device according to claim 1, wherein the optical elements include a condenser lens.

10. The light detecting device according to claim 9, further comprising: a metal waveguide disposed between the first light detecting unit and the second light detecting unit.

11. The light detecting device according to claim 10, wherein the metal waveguide is disposed along an outer edge of the second light detecting unit in a plan view.

12. The light detecting device according to claim 10, wherein the metal waveguide includes a metal containing aluminum (Al).

13. The light detecting device according to claim 1, wherein the optical elements include a metal waveguide.

14. The light detecting device according to claim 1, further comprising: a high refractive index material layer between the optical elements and the second light detecting unit.

15. The light detecting device according to claim 1, wherein a plurality of the optical elements are stacked with each other.

16. The light detecting device according to claim 1, wherein the second light detecting unit includes: a light receiving unit that generates a carrier corresponding to an amount of received light through photoelectric conversion; and a multiplication unit having a stacked structure of a first conductive region and a second conductive region, and performing avalanche multiplication of the carrier generated in the light receiving unit.

17. A distance measuring device, comprising: an optical system; a light detecting device; and a control unit configured to control the light detecting device. signal processing circuitry that calculates a distance to a measurement object based on an output signal of the light detection device, the light detection device includes: a first light detection unit configured to detect light of a first wavelength range; a second light detection unit stacked with the first light detection unit and configured to detect light of a second wavelength range different from the light of the first wavelength range; and an optical element disposed between the first light detection unit and the second light detection unit, converges light that has passed through the first light detection unit, and guides the converged light to the second light detection unit.

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