Photodetection device and electronic apparatus

Abstract

A photodetection device according to an embodiment of the present disclosure is provided with a photodetector including a photoelectric conversion layer, a first electrode, and a second electrode. The photoelectric conversion layer has a first surface and a second surface that face each other. The first electrode is disposed on a first surface side of the photoelectric conversion layer. The second electrode is disposed on a second surface side of the photoelectric conversion layer and extends to at least a portion of a side surface between the first surface and the second surface of the photoelectric conversion layer.

Description

Photodetector and electronic equipment

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

[0002] For example, Patent Document 1 discloses an image sensor having a structure in which a first electrode, an organic photoelectric conversion layer, and a second electrode are stacked in that order, and a charge injection blocking layer and an aggregation suppression layer or diffusion prevention layer are formed between the first electrode and the organic photoelectric conversion layer.

[0003] Japanese Patent Publication No. 2018-098438

[0004] By the way, in photodetectors using quantum dots, there is a need to improve the efficiency of charge extraction.

[0005] It is desirable to provide a photodetector and electronic device capable of improving the efficiency of charge extraction.

[0006] A photodetector according to one embodiment of the present disclosure comprises a photoelectric conversion layer having opposing first and second surfaces, a first electrode provided on the first surface side of the photoelectric conversion layer, and a second electrode provided on the second surface side of the photoelectric conversion layer and extending to at least a portion of the side surface between the first and second surfaces of the photoelectric conversion layer.

[0007] An electronic device according to one embodiment of the present disclosure includes an optical system and a light detection device according to the above embodiment, which receives light transmitted through the optical system.

[0008] In one embodiment of the present disclosure, a photodetector and an electronic device, of which a first electrode and a second electrode are positioned opposite each other with a photoelectric conversion layer in between, the second electrode is made to extend to at least a portion of the side surface of the photoelectric conversion layer. This reduces the distance between the first electrode and the second electrode.

[0009] Figure 1 is a block diagram showing the overall configuration of a photodetector according to an embodiment of the present disclosure. Figure 2 is an equivalent circuit diagram of a unit pixel of the photodetector shown in Figure 1. Figure 3 is a schematic cross-sectional diagram showing an example of the configuration of the photodetector shown in Figure 1. Figure 4 is a schematic plan view showing an example of the configuration of the photodetector shown in Figure 1. Figure 5 is a schematic cross-sectional diagram showing an example of the detailed configuration of a unit pixel of the photodetector shown in Figure 1. Figure 6A is a schematic cross-sectional diagram showing an example of a method for manufacturing the photodetector shown in Figure 3. Figure 6B is a schematic cross-sectional diagram showing the process following Figure 6A. Figure 6C is a schematic cross-sectional diagram showing the process following Figure 6B. Figure 6D is a schematic cross-sectional diagram showing the process following Figure 6C. Figure 6E is a schematic cross-sectional diagram showing the process following Figure 6D. Figure 7A is a schematic cross-sectional diagram showing an example of a method for manufacturing the photodetector shown in Figure 3. Figure 7B is a schematic cross-sectional diagram showing the process following Figure 7A. Figure 7C is a schematic cross-sectional diagram showing the process following Figure 7B. Figure 7D is a schematic cross-sectional diagram showing the process following Figure 7C. Figure 7E is a schematic cross-sectional view showing the process following Figure 7D. Figure 8 is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 1 of the present disclosure. Figure 9 is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 2 of the present disclosure. Figure 10 is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 3 of the present disclosure. Figure 11 is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 4 of the present disclosure. Figure 12 is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 5 of the present disclosure. Figure 13 is a schematic plan view showing an example of the configuration of the photodetector shown in Figure 12. Figure 14 is a schematic plan view showing another example of the configuration of the photodetector shown in Figure 12. Figure 15 is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 6 of the present disclosure. Figure 16 is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 7 of the present disclosure. Figure 17 is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 8 of the present disclosure. Figure 18 is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 9 of this disclosure. Figure 19 is a schematic plan view showing an example of the configuration of the photodetector shown in Figure 18. Figure 20 is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 10 of this disclosure. Figure 21 is a block diagram showing an example of the configuration of an electronic device using the photodetector shown in Figure 1.Figure 22A is a schematic diagram showing an example of the overall configuration of a photodetection system using the photodetector shown in Figure 1. Figure 22B is a diagram showing an example of the circuit configuration of the photodetection system shown in Figure 22A. Figure 23 is a diagram showing an example of the schematic configuration of an endoscopic surgery system. Figure 24 is a block diagram showing an example of the functional configuration of a camera head and a CCU. Figure 25 is a block diagram showing an example of the schematic configuration of a vehicle control system. Figure 26 is an explanatory diagram showing an example of the installation location of the external information detection unit and the imaging unit.

[0010] The embodiments described below will be explained in detail with reference to the drawings. The following description is one specific example of the present disclosure, and the present disclosure is not limited to the following embodiments. Furthermore, the present disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc., of each component shown in each figure. The order of explanation is as follows: 1. Embodiment (Example of a photodetector in which the upper electrode extends to the side surface of the photoelectric conversion layer) 2. Modifications 2-1. Modification 1 (Another example of the configuration of a photodetector) 2-2. Modification 2 (Another example of the configuration of a photodetector) 2-3. Modification 3 (Another example of the configuration of a photodetector) 2-4. Modification 4 (Another example of the configuration of a photodetector) 2-5. Modification 5 (Another example of the configuration of a photodetector) 2-6. Modification 6 (Another example of the configuration of a photodetector) 2-7. Modification 7 (Another example of the configuration of a photodetector) 2-8. Modification 8 (Another example of the configuration of a photodetector) 2-9. Modification 9 (Another example of the configuration of a photodetector) 2-10. Modification 10 (Another example of the configuration of the photodetector) 3. Application Examples 4. Application Examples

[0011] <1. Embodiments> Figure 1 is a block diagram showing an example of the schematic configuration of a light detection device (light detection device 1) according to one embodiment of the present disclosure. The light detection device 1 is a device capable of detecting incident light, and is, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor used in electronic devices such as digital still cameras and video cameras.

[0012] [Overall Configuration of the Light Detection Device] The light detection device 1, for example, captures incident light (image light) from a subject via an optical lens system (not shown), converts the amount of light of the incident light imaged on the imaging surface into an electrical signal on a pixel-by-pixel basis, and outputs it as a pixel signal. The light detection device 1 has a pixel section 100A as an imaging area on a semiconductor substrate 20, and in the area surrounding this pixel section 100A, for example, a vertical drive circuit 111, a column signal processing circuit 112, a horizontal drive circuit 113, an output circuit 114, a control circuit 115, and input / output terminals 116.

[0013] The pixel section 100A has, for example, a plurality of unit pixels P arranged in a matrix in two dimensions. For example, each pixel row of these unit pixels P is wired with a pixel drive line Lread (specifically, a row selection line and a reset control line), and each pixel column is wired with a vertical signal line Lsig. The pixel drive line Lread transmits a drive signal for reading signals from the unit pixels P. One end of the pixel drive line Lread is connected to the output terminal corresponding to each row of the vertical drive circuit 111.

[0014] The vertical drive circuit 111 is a pixel drive unit composed of a shift register, an address decoder, etc., which drives each unit pixel P of the pixel unit 100A, for example, in row units. The signals output from each unit pixel P of the pixel row selected and scanned by the vertical drive circuit 111 are supplied to the column signal processing circuit 112 through each of the vertical signal lines Lsig. The column signal processing circuit 112 is composed of amplifiers, horizontal selection switches, etc., provided for each vertical signal line Lsig.

[0015] The horizontal drive circuit 113 is composed of a shift register, an address decoder, etc., and sequentially drives each horizontal selection switch of the column signal processing circuit 112 while scanning it. Through this selection scanning by the horizontal drive circuit 113, the signals of each pixel transmitted through each of the vertical signal lines Lsig are sequentially output to the horizontal signal line 121 and transmitted to the outside of the semiconductor substrate 20 through the horizontal signal line 121.

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

[0017] The circuit portion including the vertical drive circuit 111, the column signal processing circuit 112, the horizontal drive circuit 113, the horizontal signal lines 121, and the output circuit 114 may be formed directly on the semiconductor substrate 20, or may be disposed in an external control IC. Further, those circuit portions may be formed on another substrate connected by a cable or the like.

[0018] The control circuit 115 receives a clock given from outside the semiconductor substrate 20, data for instructing an operation mode, etc., and outputs data such as internal information of the photodetection device 1. The control circuit 115 further has a timing generator that generates various timing signals, and performs drive control of peripheral circuits such as the vertical drive circuit 111, the column signal processing circuit 112, and the horizontal drive circuit 113 based on the various timing signals generated by the timing generator.

[0019] The input / output terminal 116 exchanges signals with the outside.

[0020] [Circuit Configuration of Unit Pixel] FIG. 2 shows an example of the configuration of the readout circuit of the unit pixel P of the photodetection device 1. The unit pixel P has a photodetection element 11 and a readout circuit 120. The photodetection element 11 is configured to receive light and generate a signal. The readout circuit 120 is configured to be able to output a signal based on the charge that has been photoelectrically converted.

[0021] The photodetector 11 is configured to generate charges by photoelectric conversion. The photodetector 11 includes, for example, a lower electrode 12, a photoelectric conversion layer 13, and an upper electrode 14, details of which will be described later. The photodetector 11 converts incident light into charges in the photoelectric conversion layer 13. The photodetector 11 performs photoelectric conversion to generate charges corresponding to the amount of received light. The charges photoelectrically converted and accumulated in the photodetector 11 are transferred by the lower electrode 12 to the floating diffusion FD of the readout circuit 120.

[0022] As an example, the readout circuit 120 includes a floating diffusion FD, an amplification transistor AMP, a selection transistor SEL, and a reset transistor RST. The amplification transistor AMP, the selection transistor SEL, and the reset transistor RST are each MOS transistors (MOSFETs) having gate, source, and drain terminals.

[0023] The amplification transistor AMP, the selection transistor SEL, and the reset transistor RST are each composed of, for example, NMOS transistors. Note that each transistor of the unit pixel P may be composed of PMOS transistors.

[0024] The floating diffusion FD is a charge storage unit and is configured to store the transferred charges. The floating diffusion FD can store the charges photoelectrically converted by the photodetector 11. The floating diffusion FD can also be said to be a charge holding unit that can hold the transferred charges. The floating diffusion FD stores the transferred charges and converts them into a voltage corresponding to the capacitance of the floating diffusion FD.

[0025] The amplification transistor AMP is configured to generate and output a signal based on the charges stored in the floating diffusion FD. The gate of the amplification transistor AMP is electrically connected to the floating diffusion FD, and the voltage converted by the floating diffusion FD is input thereto.

[0026] The drain of the amplification transistor AMP is connected to a power line to which the power supply voltage VDD is supplied, and the source of the amplification transistor AMP is connected to the vertical signal line VSL via a selection transistor SEL. The amplification transistor AMP is an amplification transistor that can generate a signal based on the charge stored in the floating diffusion FD, i.e., a signal based on the voltage of the floating diffusion FD, and output it to the vertical signal line VSL.

[0027] The selection transistor SEL is configured to control the output of the signal for a unit pixel. The selection transistor SEL is controlled by the signal SSEL and is configured to output the signal from the amplification transistor AMP to the vertical signal line VSL. The selection transistor SEL can control the output timing of the signal for a unit pixel. The selection transistor SEL may be placed between the power line to which the power supply voltage VDD is supplied and the amplification transistor AMP. The selection transistor SEL may also be omitted if necessary.

[0028] The reset transistor RST is configured to reset the voltage of the floating diffusion FD. The reset transistor RST is electrically connected to a power line to which the power supply voltage VDD is supplied and is configured to reset the charge of a unit pixel P. The reset transistor RST is controlled by the signal SRST and can reset the charge accumulated in the floating diffusion FD and reset the voltage of the floating diffusion FD.

[0029] The configuration of the readout circuit 120 may be modified as appropriate. For example, it may be configured to allow the conversion efficiency (gain) when converting electric charge to voltage to be changed. For instance, the readout circuit 120 may include a switching transistor or a capacitive element used to set the conversion efficiency.

[0030] The vertical drive circuit 111 (see Figure 1) supplies control signals to the gates of the selection transistor SEL, reset transistor RST, etc., of each unit pixel P via the pixel drive line Lread described above, and sets the transistors to an ON state (conducting state) or an OFF state (non-conducting state). The multiple pixel drive lines Lread of the light detection device 1 include wiring that transmits the signal SSEL which controls the selection transistor SEL, and wiring that transmits the signal SRST which controls the reset transistor RST.

[0031] The selection transistor SEL, reset transistor RST, etc., are switched on and off by the vertical drive circuit 111. The vertical drive circuit 111 controls the readout circuit 120 for each unit pixel P, causing each unit pixel P to output a unit pixel signal to the vertical signal line VSL. The vertical drive circuit 111 can control the reading of the unit pixel signal from each unit pixel P to the vertical signal line VSL.

[0032] [Unit Pixel Configuration] Figure 3 schematically shows an example of the cross-sectional configuration of the light detection device 1 shown in Figure 1. Figure 4 schematically shows an example of the planar configuration of the light detection device 1 shown in Figure 1.

[0033] The photodetector 1 has, for example, a photoelectric conversion unit (photodetector element 11) on the light incident side S1 of the semiconductor substrate 20 (see Figure 5) that absorbs light corresponding to some or all of the wavelengths in a selective wavelength range (for example, near-infrared (NIR) and short-wave infrared (SWIR) from 700 nm to less than 1600 nm) to generate excitons (electron-hole pairs). The photodetector 1 includes, for example, a light receiving unit 10, a semiconductor substrate 20, a multilayer wiring layer 30, and an optical layer 40. The light receiving unit 10, the semiconductor substrate 20, the multilayer wiring layer 30, and the optical layer 40 are stacked on top of each other. In the photodetector 1, the semiconductor substrate 20 is located on the opposite side of the light incident side S1 of the light receiving unit 10, and the multilayer wiring layer 30 is located between the light receiving unit 10 and the semiconductor substrate 20. The optical layer 40 is located on the light incident side S1 of the light receiving unit 10.

[0034] The light-receiving unit 10 has a plurality of photodetectors 11. The plurality of photodetectors 11 are provided for each unit pixel P, and are arranged in a matrix in a two-dimensional manner in the pixel unit 100A, as shown in Figure 4, for example.

[0035] As described above, the photodetector 11 has a lower electrode 12, a photoelectric conversion layer 13, and an upper electrode 14. The photoelectric conversion layer 13 has a pair of opposing surfaces (a first surface 13S1 and a second surface 13S2), with the lower electrode 12 positioned on the first surface 13S1 side and the upper electrode 14 positioned on the second surface 13S2 side. The photodetector 11 further has buffer layers 15 and 16. The buffer layer 15 is positioned between the lower electrode 12 and the photoelectric conversion layer 13. The buffer layer 15 is positioned between the upper electrode 14 and the photoelectric conversion layer 13. In this embodiment, the upper electrode 14 positioned on the second surface 13S2 side of the photoelectric conversion layer 13 further extends to the side surface 13S3 of the photoelectric conversion layer 13, including the buffer layers 15 and 16.

[0036] Here, the photodetector 11 corresponds to a specific example of the "photodetector" as one embodiment of the present disclosure. The lower electrode 12 corresponds to a specific example of the "first electrode" as one embodiment of the present disclosure. The photoelectric conversion layer 13 corresponds to a specific example of the "photoelectric conversion layer" as one embodiment of the present disclosure. The upper electrode 14 corresponds to a specific example of the "second electrode" as one embodiment of the present disclosure.

[0037] In the photodetector element 11, for example, electrons from the electron-hole pairs generated by photoelectric conversion are read out as signal charges from the lower electrode 12 side. Below, the configuration and materials of each part will be explained using the case where electrons are read out as signal charges from the lower electrode 12 side as an example.

[0038] The lower electrode 12 is composed of, for example, a light-transmitting conductive film. The constituent material of the lower electrode 12 is, for example, In, which has tin (Sn) added as a dopant. ２ O ３ Indium tin oxide (ITO) is one example. In addition to the above, dopant-doped tin oxide (SnO) can also be used as a constituent material for the lower electrode 12. ２Examples of such materials include ATO with Sb added as a dopant, and FTO with F added as a dopant. Further, zinc oxide (ZnO) or a zinc oxide-based material with a dopant added may be used. Examples of ZnO-based materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, boron zinc oxide with boron (B) added, and indium zinc oxide (IZO) with indium (In) added. Additionally, zinc oxide with indium and gallium added as dopants (IGZO, In-GaZnO ４ ), may be used. In addition, examples of the constituent material of the lower electrode 12 include CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３ or TiO ２ etc., and spinel oxides or oxides having a YbFe ２ O ４ structure may also be used.

[0039] Also, when the lower electrode 12 does not require light transmissibility, a single metal or alloy having a low work function (e.g., φ = 3.5 eV to 4.5 eV) can be used. Specifically, alkali metals (e.g., lithium (Li), sodium (Na), potassium (K), etc.) and their fluorides or oxides, alkaline earth metals (e.g., magnesium (Mg), calcium (Ca), etc.) and their fluorides or oxides can be mentioned. In addition, aluminum (Al), Al-Si-Cu alloy, zinc (Zn), tin (Sn), thallium (Tl), Na-K alloy, Al-Li alloy, Mg-Ag alloy, indium (In), rare earth metals such as ytterbium (Yb), or their alloys can be mentioned.

[0040] Furthermore, the materials constituting the lower electrode 12 include metals such as platinum (Pt), gold (Au), palladium (Pd), chromium (Cr), nickel (Ni), aluminum (Al), silver (Ag), tantalum (Ta), tungsten (W), copper (Cu), titanium (Ti), indium (In), tin (Sn), iron (Fe), cobalt (Co), and molybdenum (Mo), or alloys containing these metal elements, or conductive particles made from these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductor materials, carbon nanotubes, graphene, and other conductive materials. In addition, organic materials (conductive polymers) such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid [PEDOT / PSS] can be used as materials constituting the lower electrode 12. Alternatively, the above materials may be mixed with a binder (polymer) to form a paste or ink, which can then be cured and used as an electrode.

[0041] The lower electrode 12 can be formed as a single layer or a multilayer film made of the above material. The thickness of the lower electrode 12 in the stacking direction (hereinafter simply referred to as thickness) is, for example, 20 nm to 200 nm, and preferably 30 nm to 150 nm.

[0042] The photoelectric conversion layer 13 converts light energy into electrical energy, and for example, absorbs, for example, 60% or more of light in wavelength ranges such as near-infrared (NIR) and short-wave infrared (SWIR) to separate the charges. The photoelectric conversion layer 13 is composed of a plurality of quantum dots. The quantum dots correspond to one specific example of a "nanoparticle aggregate" as one embodiment of the present disclosure. Specific constituent materials of the photoelectric conversion layer 13 include nanoparticles such as lead sulfide (PbS), lead selenide (PbSe), lead telluride (PbTe), indium phosphide (InP), indium arsenide (InAs), indium antimonide (InSb), cadmium sulfide (CdS), cadmium selenide (CdSe), or cadmium telluride (CdTe).

[0043] The photoelectric conversion layer 13 may be configured to receive light in the visible light region and generate an electric charge. The photoelectric conversion layer 13 may be made of an inorganic material or an organic material.

[0044] The photoelectric conversion layer 13 may be a photoelectric conversion film made of an organic material. Alternatively, the photoelectric conversion layer 13 may be a photoelectric conversion film made of an inorganic material. The photoelectric conversion layer 13 may be composed of, for example, an organic semiconductor film or an amorphous silicon film. The constituent material of the photoelectric conversion layer 13 may be selected, for example, according to the wavelength range of the incident light to be measured.

[0045] The thickness of the photoelectric conversion layer 13 is, for example, 10 nm to 300 nm, and preferably 30 nm to 150 nm.

[0046] The upper electrode 14, like the lower electrode 12, is composed of, for example, a light-transmitting conductive film. In particular, it is preferable that the upper electrode 14 has a transmittance of 50% or more and 100% or less for light included in wavelength ranges such as near-infrared (NIR) and short-wave infrared (SWIR). Furthermore, it is preferable that the resistivity of the upper electrode 14 is 0 mΩ·m or more and 3.8 mΩ·m or less. Examples of constituent materials for the upper electrode 14 include oxide semiconductor materials. Specifically, as a constituent material for the upper electrode 14, for example, In(Sn) dopant is added. ２ O ３ Indium tin oxide (ITO) is one example. The crystallinity of the ITO thin film may be high or low (approaching amorphous). In addition to the above, dopant-doped tin oxide (SnO) can also be used as a constituent material for the upper electrode 14. ２Examples of ZnO-based materials include ATO with Sb added as a dopant, and FTO with fluorine added as a dopant. Alternatively, zinc oxide (ZnO) or zinc oxide-based materials with added dopants may be used. Examples of ZnO-based materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, boron zinc oxide with boron (B) added, and indium zinc oxide (IZO) with indium (In) added. Furthermore, zinc oxide (IGZO, In-GaZnO) with indium and gallium added as dopants may also be used. ４ ) may be used. In addition, CuI, InSbO may be used as the constituent material of the upper electrode 14. ４ , ZnMgO, CuInO ２ MgIN ２ O ４ , CdO, ZnSnO ３ or TiO ２ You may also use spinel-type oxides or YbFe ２ O ４ Oxides having a specific structure may also be used.

[0047] The upper electrode 14 can be formed as a single layer or a multilayer film made of the above material. The thickness of the upper electrode 14 is, for example, 10 nm to 300 nm, preferably 10 nm to 100 nm.

[0048] Other layers may be provided between the lower electrode 12 and the upper electrode 14. For example, buffer layers 15 and 16 may be provided between the lower electrode 12 and the photoelectric conversion layer 13, and between the upper electrode 14 and the photoelectric conversion layer 13, respectively, as described above.

[0049] The buffer layer 15 is a so-called electrical blocking layer that selectively transports electrons from the charge generated in the photoelectric conversion layer 13 to the lower electrode 12 and inhibits the injection of holes from the lower electrode 12. The buffer layer 15 can be formed using an organic material, an oxide semiconductor material, or semiconductor nanoparticles. As the organic material, n-type semiconductors are preferred, and examples include organometallic dyes formed as complexes of transition metal ions such as zinc(II) phthalocyanine and organic materials. Other examples of n-type semiconductors include fullerenes or their derivatives, ITIC derivatives and non-fullerene acceptors such as BTP derivatives. As oxide semiconductor materials and semiconductor nanoparticles, for example, titanium dioxide (TiO2) ２ ), zinc oxide, zinc sulfide (ZnS), SrTiO ３ niobium oxide (Nb ２ O ５ ), tungsten oxide (WO ３ ), indium oxide (In ２ O ３ ), CuTiO ３ , tin oxide (SnO ２ ), InGaZnO4, InTiO ２ and β-Ga ２ O ３ Examples of inorganic materials include the following.

[0050] The buffer layer 15 is a so-called electron blocking layer that selectively transports holes from the charge generated in the photoelectric conversion layer 13 to the upper electrode 14 and inhibits electron injection from the upper electrode 14. The buffer layer 15 can be formed using an organic material, an oxide semiconductor material, or semiconductor nanoparticles. Examples of organic materials include P3HT (poly(3-hexylthiophene-2,5-diyl)), SPIRO-OMeTAD, 2T-NATA, PTB7, PBTB-T, V886, PTB7-Th, Poly-TPD, and PBDB-T-2F. Examples of oxide semiconductor materials and semiconductor nanoparticles include nickel oxide, compound semiconductors of groups I-V, I-III-VI, or I-II-III-VI. Examples of semiconductor nanoparticles of groups I-V include Ag. ２ S and Ag ２Includes Se. Semiconductor nanoparticles of the I-III-VI groups include, for example, AgInS. ２ AgInSe ２ AgInTe ２ CuInS ２ CuInSe ２ and CuInTe ２ This includes semiconductor nanoparticles of groups I-III-III-VI, such as ZnCuInS and ZnCuInSe.

[0051] In addition to the electron blocking layer, the buffer layer 15 may also include a so-called work function adjustment layer. The work function adjustment layer has an electron affinity or work function greater than the work function of the upper electrode 14. The work function adjustment layer can be formed using an organic material, an oxide semiconductor material, or semiconductor nanoparticles. Examples of organic materials include dipyradino[2,3-f:2',3'v-h]quinoxaline-2,3,6,7,10,11-hexacarbonite (HAT-CN), PEDOT / PSS, and polyaniline. Examples of oxide semiconductor materials and semiconductor nanoparticles include MoO ３ RuO ４ , V １ O ５ and WO ３ These are some examples.

[0052] In the photodetector 1, light incident on the photodetector element 11 from the upper electrode 14 side is absorbed in the photoelectric conversion layer 13. The resulting excitons undergo exciton separation and dissociate into electrons and holes. The charges (electrons and holes) generated here are transported to different electrodes by diffusion due to the difference in charge concentration and by the internal electric field due to the difference in work functions between the anode (e.g., upper electrode 14) and the cathode (e.g., lower electrode 12), and are detected as a photocurrent. The transport direction of electrons and holes is controlled by applying a potential between the lower electrode 12 and the upper electrode 14.

[0053] In the photodetector 1, the upper electrode 14 extends from the second surface 13S2 side of the photoelectric conversion layer 13 to the side surface 13S3 of the photoelectric conversion layer 13, including the buffer layers 15 and 16, as described above. Specifically, as shown in Figures 3 and 4, for example, the upper electrode 14 is formed continuously in the XY plane direction as a common electrode for a plurality of unit pixels P, and extends in the Z axis direction so as to surround the side surface 13S3 of the photoelectric conversion layer 13 provided for each unit pixel P. As a result, in the photodetector 1, the distance between the lower electrode 12 and the upper electrode 14 is reduced, which prevents deactivation due to recombination of charge (holes and electrons).

[0054] Furthermore, the upper electrode 14, which extends in the Z-axis direction, is in contact with the surface of the multilayer wiring layer 30 into which the lower electrode 12 is embedded, as shown in Figure 3, for example. In other words, the upper electrode 14 separates the photoelectric conversion layer 13, which includes buffer layers 15 and 16 provided between the lower electrode 12 and the upper electrode 14, for each unit pixel P. As a result, electrical color mixing between adjacent unit pixels P is prevented in the photodetector 1. In addition, peeling due to film shrinkage of the photoelectric conversion layer 13, which includes buffer layers 15 and 16, is reduced in the photodetector 1.

[0055] In the photodetector 1, the photoelectric conversion layer 13 and buffer layers 15, 16 provided between the lower electrode 12 and the upper electrode 14 have a higher refractive index than the upper electrode 14. For example, the photoelectric conversion layer 13 is made of an aggregate of nanoparticles (quantum dots) such as PbS, and its refractive index is, for example, n = 2.1. On the other hand, the upper electrode 14 is made of a light-transmitting oxide semiconductor material such as ITO, and its refractive index varies depending on its crystallinity, but is, for example, n = 1.4 to 1.8. In other words, the upper electrode 14 extending between adjacent photodetectors 11 has a lower refractive index than the photoelectric conversion layer 13 and buffer layers 15, 16. Therefore, the upper electrode 14 extending between adjacent photodetectors 11 functions as a waveguide. As a result, color mixing between adjacent unit pixels P is suppressed in the photodetector 1.

[0056] The semiconductor substrate 20 is made of, for example, a silicon (Si) substrate. The semiconductor substrate 20 can also be called a semiconductor layer. The semiconductor substrate 20 may be an SOI (Silicon On Insulator) substrate, a SiGe (silicon germanium) substrate, a SiC (silicon carbide) substrate, or it may be formed using other semiconductor materials.

[0057] The multilayer wiring layer 30 includes, for example, a conductive film and an insulating film, and has a plurality of wirings and vias. The multilayer wiring layer 30 is laminated on the semiconductor substrate 20. The multilayer wiring layer 30 has a configuration in which a plurality of wirings are laminated with insulating films in between. The multilayer wiring layer 30 includes, for example, interlayer insulating layers 31 and 32. A lower electrode 12 is embedded in the surface of the interlayer insulating layer 31, which is located on the light-receiving unit 10 side, that faces the light-receiving unit 10. An electrode 34 is embedded in the surface of the interlayer insulating layer 32, which is located on the semiconductor substrate 20 side, that faces the semiconductor substrate 20. The lower electrode 12 and the electrode 34 are electrically connected by wiring 33. An insulating layer 35 is further provided between the semiconductor substrate 20 and the interlayer insulating layer 32.

[0058] The interlayer insulating layers 31, 32 and insulating layer 35 are formed using, for example, silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), etc.

[0059] The wiring 33 is formed using a metallic material such as aluminum (Al), copper (Cu), or tungsten (W). The wiring 33 may also be made using polysilicon (Poly-Si) or other conductive materials. The electrode 34 is formed using a metallic material such as copper (Cu) or aluminum (Al).

[0060] The semiconductor substrate 20 and the multilayer wiring layer 30 are provided with, for example, the readout circuit 120 described above for each unit pixel P or for each of multiple unit pixels P. The vertical drive circuit 111, column signal processing circuit 112, horizontal drive circuit 113, output circuit 114, and control circuit 115 described above may be provided on the semiconductor substrate 20 and the multilayer wiring layer 30, or on a substrate separate from the semiconductor substrate 20. Note that the semiconductor substrate 20 and part or all of the multilayer wiring layer 30 together can also be referred to as the semiconductor substrate 20.

[0061] Figure 5 schematically shows an example of a detailed cross-sectional configuration of a unit pixel P of the photodetector 1. The photodetector 1 includes a semiconductor substrate 20 as shown in Figure 5.

[0062] As described above, the semiconductor substrate 20 is provided with a readout circuit 120. The lower electrode 12 of the photodetector element 11 is electrically connected to the floating diffusion FD and the gate portion of the amplification transistor AMP. The photodetector element 11 is positioned above the semiconductor substrate 20. Here, the surface 20S on the light incident surface side of the semiconductor substrate 20 is considered the upper side, and the opposite side of surface 20S is considered the lower side.

[0063] The lower electrode 12 of the photodetector element 11 is embedded in the upper surface of the interlayer insulating layer 31 of the multilayer wiring layer 30. A buffer layer 15, a photoelectric conversion layer 13, a buffer layer 16, and an upper electrode 14 are formed on the lower electrode 12 in this order. The upper electrode 14 extends from the buffer layer 16 to the sides of the photoelectric conversion layer 13 and buffer layers 15 and 16.

[0064] On the surface 20S of the semiconductor substrate 20, an element isolation region 24 and an oxide film 25 are formed. Furthermore, on the surface 20S of the semiconductor substrate 20, a reset transistor RST, an amplification transistor AMP, a selection transistor SEL, a floating diffusion FD, and other components of the readout circuit 120 are provided.

[0065] The reset transistor RST has a reset gate 21, a channel formation region 21A, and source / drain regions 21B and 21C. The source / drain region 21C of the reset transistor RST also serves as a floating diffusion FD. The other source / drain region 21B is electrically connected to a power line to which the power supply voltage VDD is supplied.

[0066] The lower electrode 12 of the photodetector element 11 is electrically connected to one source / drain region 21C (floating diffusion FD) of the reset transistor RST via wiring 33, electrode 34, and wiring 36.

[0067] The amplification transistor AMP has an amplifier gate 22, a channel formation region 22A, and source / drain regions 22B and 22C. The amplifier gate 22 is connected via wiring 36 to the lower electrode 12 and one of the source / drain regions 21C (floating diffusion FD) of the reset transistor RST. One of the source / drain regions 22B shares a region with the other source / drain region 21B that constitutes the reset transistor RST and is connected to the power line to which the power supply voltage VDD is supplied.

[0068] The selection transistor SEL has a selection gate 23, a channel formation region 23A, and source / drain regions 23B and 23C. One source / drain region 23B shares a region with the other source / drain region 22C that constitutes the amplification transistor AMP, and the other source / drain region 23C is connected to the vertical signal line VSL.

[0069] The element isolation region 24 has an STI (Shallow Trench Isolation) structure and is composed of, for example, silicon oxide.

[0070] The oxide film 25 may be a film having a positive fixed charge or a film having a negative fixed charge. Examples of materials for a film having a negative fixed charge include hafnium oxide, aluminum oxide, zirconium oxide, tantalum oxide, and titanium oxide. Other materials include lanthanum oxide, praseodymium oxide, cerium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, thulium oxide, ytterbium oxide, lutetium oxide, and yttrium oxide. The oxide film 25 may also be an aluminum nitride film, a hafnium oxynitride film, or an aluminum oxynitride film.

[0071] The reset gate 21, amplifier gate 22, selection gate 23, and wiring 36 are formed using, for example, doped silicon material such as PDAS (Phosphorus Doped Amorphous Silicon) or metallic material such as aluminum (Al), tungsten (W), titanium (Ti), cobalt (Co), hafnium (Hf), or tantalum (Ta).

[0072] The optical layer 40 includes, for example, a protective layer 41 and an on-chip lens 42.

[0073] The protective layer 41 is a passivation layer (protective film). The protective layer 41 is, for example, amorphous silicon (a-Si), silicon nitride (SiN), aluminum oxide (Al ２ O ３ ), is composed of resin material, etc. The protective layer 41 may be composed of other insulating materials. The protective layer 41 can also be called a planarization layer (planarization film).

[0074] The on-chip lens 42 corresponds to a specific example of the "first lens" as one embodiment of the present disclosure. The on-chip lens 42 is a lens that focuses light and guides the light incident from the light incident side S1 to the light receiving unit 10 side. The on-chip lens 42 is provided, for example, above the light receiving unit 10 for each unit pixel P or for each of a plurality of unit pixels P. Light from the subject to be measured is incident on the on-chip lens 42 through an optical system such as an imaging lens. The photodetector element 11 of the unit pixel P converts the light incident via the on-chip lens 42 into photoelectric power.

[0075] The on-chip lens 42 is constructed using, for example, amorphous silicon (a-Si). In this case, it is possible to efficiently focus the incident infrared light onto the photodetector element 11. The on-chip lens 42 may also be constructed using silicon nitride (SiN) or a resin material. The on-chip lens 42 may also be formed using another material having a refractive index higher than that of the protective layer 41.

[0076] The light detection device 1 may have a color filter that selectively transmits light. The color filter is configured to selectively transmit light in a specific wavelength range from the incident light. The color filter may be an RGB color filter, a complementary color filter, an infrared light transmitting filter, etc., and is provided above the light receiving unit 10. For example, the color filter may be provided between the on-chip lens 42 and the protective layer 41, or within the protective layer 41, for each unit pixel P or for each of a plurality of unit pixels P.

[0077] [Manufacturing Method for Photodetector] The photodetector 1 can be manufactured, for example, as follows. Figures 6A to 6E illustrate an example of the manufacturing method for the photodetector 1.

[0078] First, as shown in Figure 6A, a buffer layer 15, a photoelectric conversion layer 13, and a buffer layer 16 are formed in order on a multilayer wiring layer 30 in which a plurality of lower electrodes 12 are embedded on the surface.

[0079] Next, as shown in Figure 6B, a resist film 51 is formed on the buffer layer 16 in a predetermined pattern by photolithography. Subsequently, as shown in Figure 6C, the buffer layer 16, the photoelectric conversion layer 13, and the buffer layer 15 are selectively removed, for example by dry etching, to separate them into, for example, individual pixels P.

[0080] Next, as shown in Figure 6D, the upper electrode 14 is formed on the buffer layer 16 and the selectively removed portion using, for example, chemical vapor deposition (CVD) or sputtering.

[0081] Next, as shown in Figure 6E, a protective layer 41 is formed on the upper electrode 14, and then the surface of the protective layer 41 is flattened by chemical mechanical polishing (CMP). After that, an on-chip lens 42 is formed on the protective layer 41. With these steps, the photodetector shown in Figure 1 is completed.

[0082] Figures 7A to 7E illustrate other examples of the manufacturing method for the light detection device 1.

[0083] First, as shown in Figure 7A, a buffer layer 15, a photoelectric conversion layer 13, a buffer layer 16, and an upper electrode 14 are formed in order on a multilayer wiring layer 30 in which a plurality of lower electrodes 12 are embedded on the surface.

[0084] Next, as shown in Figure 7B, a resist film 51 is formed on the upper electrode 14 in a predetermined pattern by photolithography. Subsequently, as shown in Figure 7C, the upper electrode 14, buffer layer 16, photoelectric conversion layer 13, and buffer layer 15 are selectively removed, for example by dry etching, to separate them into, for example, individual pixels P.

[0085] Next, as shown in Figure 7D, the upper electrode 14 is further formed on the selectively removed portion using, for example, chemical vapor deposition (CVD) or sputtering.

[0086] Next, as shown in Figure 7E, a protective layer 41 is formed on the upper electrode 14, and then the surface of the protective layer 41 is flattened by chemical mechanical polishing (CMP). After that, an on-chip lens 42 is formed on the protective layer 41. With these steps, the photodetector shown in Figure 1 is completed.

[0087] Note that the manufacturing method described above is merely one example, and other manufacturing methods may be used. [Effects] In the photodetector 1 of this embodiment, the upper electrode 14, which is located on the second surface 13S2 side of the photoelectric conversion layer 13, is extended to the side surface 13S3 of the photoelectric conversion layer 13. This reduces the distance between the lower electrode 12 and the upper electrode 14. This will be explained below.

[0088] In image sensors having a structure in which the first electrode, organic photoelectric conversion layer, and second electrode are stacked in that order, as described above, a structure is employed in which adjacent pixels are separated by trenches (grooves). For example, insulating material is embedded in the grooves.

[0089] In an image sensor with this configuration, the charges (holes and electrons) generated near the separation structure are far from the upper and lower electrodes. Therefore, there is a concern that the holes and electrons, once separated, will recombine and become inactive before reaching the electrodes.

[0090] Furthermore, in recent years, the development of photodetectors using quantum dots in the photoelectric conversion layer has been progressing, but the low external quantum efficiency (EQE) of the photoelectric conversion layer made of quantum dots (quantum dot layer) is a challenge. EQE can be increased by making the quantum dot layer thicker, but if it is made too thick, regions (non-depletion regions) will be created where the generated charges (holes and electrons) become inactive and cannot be extracted, thus lowering the EQE.

[0091] In contrast, in this embodiment, as described above, the upper electrode 14, which is positioned on the second surface 13S2 side of the photoelectric conversion layer 13, is extended to the side surface 13S3 of the photoelectric conversion layer 13, thereby reducing the distance between the lower electrode 12 and the upper electrode 14. This allows the generated charge (holes and electrons) to be removed before it is deactivated by recombination.

[0092] As a result of the above, the photodetector 1 of this embodiment makes it possible to improve the charge extraction efficiency.

[0093] Furthermore, in the photodetector 1 of this embodiment, the photoelectric conversion layer 13 is separated for each unit pixel P, making it possible to prevent electrical color mixing between adjacent unit pixels P. Moreover, in the photodetector 1 of this embodiment, since the photoelectric conversion layer 13 is separated for each unit pixel P, it is possible to reduce peeling of the photoelectric conversion layer 13 due to film shrinkage.

[0094] Furthermore, in the photodetector 1 of this embodiment, an upper electrode 14 having a lower refractive index than the photoelectric conversion layer 13 and buffer layers 15 and 16 is extended to the side surface of the photodetector element 11 provided for each unit pixel P. As a result, the upper electrode 14 extending between adjacent photodetector elements 11 functions as a waveguide. Therefore, the photodetector 1 makes it possible to suppress color mixing between adjacent unit pixels P.

[0095] Furthermore, in the photodetector 1 of this embodiment, the upper electrode 14 separates adjacent photodetectors 11, thus reducing the number of manufacturing steps compared to the case where they are separated by grooves embedded with insulating material, as described above.

[0096] Next, modifications 1 to 10 of the present disclosure, application examples, and application examples will be described. Note that components corresponding to the above embodiments are denoted by the same reference numerals and their descriptions are omitted.

[0097] <2. Modifications> (2-1. Modification 1) Figure 8 schematically shows an example of a cross-sectional configuration of a light detection device (light detection device 1A) according to Modification 1 of the present disclosure. The light detection device 1A is a device capable of detecting incident light, similar to the light detection device 1 of the above embodiment, and is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0098] In the above embodiment, an example was shown in which the upper electrode 14 between adjacent photodetectors 11 extends to the surface of the multilayer wiring layer 30, but the invention is not limited to this. In this modified example, the photodetector 1A has an insulating film 17 between the upper electrode 14 extending to the side surface of adjacent photodetectors 11 and the multilayer wiring layer 30. Except for this point, the photodetector 1A has substantially the same configuration as the photodetector 1 of the above embodiment.

[0099] Even with this configuration, the modified photodetector 1A can achieve the same effects as the embodiment described above.

[0100] (2-2. Modification 2) Figure 9 schematically shows an example of a cross-sectional configuration of a photodetector (photodetector 1B) according to Modification 2 of the present disclosure. The photodetector 1B is a device capable of detecting incident light, similar to the photodetector 1 of the above embodiment, and is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0101] In the above embodiment, an example was shown in which the side surface 13S3 of the photoelectric conversion layer 13, including the buffer layers 15 and 16 to which the upper electrode 14 extends, forms a surface perpendicular to the XY plane direction, but the invention is not limited to this. In this modified example, the photodetector 1B has a side surface 13S3 of the photoelectric conversion layer 13, including the buffer layers 15 and 16, which is an inclined surface that extends from the second surface 13S2 side toward the first surface 13S1 side, and the upper electrode 14 extends along this inclined surface. Except for this point, the photodetector 1B has substantially the same configuration as the photodetector 1 of the above embodiment.

[0102] Even with this configuration, the modified photodetector 1B can achieve the same effects as the embodiment described above.

[0103] Furthermore, in the modified photodetector 1B, as described above, the side surface 13S3 of the photoelectric conversion layer 13 including the buffer layers 15 and 16 is made inclined, which facilitates the embedding of the upper electrode 14 between adjacent photodetectors 11.

[0104] (2-3. Modification 3) Figure 10 schematically shows an example of a cross-sectional configuration of a photodetector (photodetector 1C) according to Modification 3 of the present disclosure. The photodetector 1C is a device capable of detecting incident light, similar to the photodetector 1 of the above embodiment, and is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0105] In the above embodiment, an example was shown in which the photoelectric conversion layer 13 is separated for each unit pixel P by the upper electrode 14, but the invention is not limited to this. In this modified example, the photodetector 1C has an upper electrode 14 extending from the side surface of the photoelectric conversion layer 13, with its end located within the photoelectric conversion layer 13, and a buffer layer 15 and a part of the photoelectric conversion layer 13 are continuous between adjacent photodetector elements 11. Except for this point, the photodetector 1C has substantially the same configuration as the photodetector 1 of the above embodiment.

[0106] Even with this configuration, the modified photodetector 1C can achieve the same effects as the embodiment described above.

[0107] (2-4. Modification 4) Figure 11 schematically shows an example of the cross-sectional configuration of a photodetector (photodetector 1D) according to Modification 4 of the present disclosure. The photodetector 1D is a device capable of detecting incident light, similar to the photodetector 1 of the above embodiment, and is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0108] In the above embodiment, an example was shown in which the upper electrode 14 between adjacent photodetectors 11 extends to the surface of the multilayer wiring layer 30, but the invention is not limited to this. In this modified photodetector device 1D, the upper electrode 14 extends into the interlayer insulating layer 31 of the multilayer wiring layer 30 in which the lower electrode 12 is embedded. Except for this point, the photodetector device 1D has substantially the same configuration as the photodetector device 1 of the above embodiment.

[0109] Here, the interlayer insulating layer 31 corresponds to a specific example of the "first insulating layer" as one embodiment of the present disclosure.

[0110] Even with this configuration, the modified photodetector 1D can obtain the same effects as in the above embodiment.

[0111] (2-5. Modification 5) Figure 12 schematically shows an example of a cross-sectional configuration of the photodetector (photodetector 1E) according to Modification 5 of the present disclosure. Figure 13 schematically shows an example of a planar configuration of the photodetector 1E shown in Figure 12. Figure 14 schematically shows another example of a planar configuration of the photodetector 1E shown in Figure 12. The photodetector 1E is a device capable of detecting incident light, similar to the photodetector 1 of the above embodiment, and is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0112] In this modified example, the photodetector 1E has an upper electrode 14 that extends to the side surface of adjacent photodetector elements 11, and a light-shielding portion 18A that extends to the side surface of adjacent photodetector elements 11 is enclosed within the upper electrode 14 that extends to the side surface of adjacent photodetector elements 11. Except for this point, the photodetector 1E has substantially the same configuration as the photodetector 1 of the above embodiment.

[0113] The light-shielding portion 18A corresponds to a specific example of a "light-shielding film" and a "conductive film" as one embodiment of the present disclosure. The light-shielding portion 18A is provided in a grid pattern surrounding the photoelectric conversion layer 13 provided for each unit pixel P, as shown in Figure 13, for example. Alternatively, the light-shielding portion 18A may be provided discretely around the photoelectric conversion layer 13, as shown in Figure 4, for example. Examples of materials constituting the light-shielding portion 18A include tungsten (W), aluminum (Al), copper (Cu), or aluminum-copper alloys.

[0114] Even with this configuration, the modified photodetector 1E can obtain the same effects as in the above embodiment.

[0115] Furthermore, in this modified photodetector 1E, the light-shielding portion 18A is arranged between adjacent photodetectors 11 together with the upper electrode 14, thereby further suppressing color mixing between adjacent unit pixels P.

[0116] (2-6. Modification 6) Figure 15 schematically shows an example of a cross-sectional configuration of a photodetector (photodetector 1F) according to Modification 6 of the present disclosure. The photodetector 1F is a device capable of detecting incident light, similar to the photodetector 1 of the above embodiment, and is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0117] In the above modified example 5, an example is shown in which a light-shielding portion 18A extending from the side surface of adjacent photodetector elements 11 is enclosed within an upper electrode 14 extending from the side surface of adjacent photodetector elements 11, but the invention is not limited to this. In this modified example, the photodetector 1F has an insulating portion 18B extending from the side surface of adjacent photodetector elements 11 enclosed within an upper electrode 14 extending from the side surface of adjacent photodetector elements 11. Except for this point, the photodetector 1F has substantially the same configuration as the photodetector 1 of the above embodiment.

[0118] The insulating portion 18B corresponds to a specific example of an "insulating film" as one embodiment of the present disclosure. The insulating portion 18B may be provided in a grid pattern (see Figure 13) surrounding the photoelectric conversion layer 13 provided for each unit pixel P, as in the modified example 5 above, or it may be provided discretely around the photoelectric conversion layer 13 (see Figure 14). Examples of materials constituting the insulating portion 18B include silicon oxide (SiO), silicon nitride (SiN), or silicon oxynitride (SiON). In addition, the insulating portion 18B may be formed as a void.

[0119] Even with this configuration, the photodetector 1F of this modified example can obtain the same effects as in the above embodiment.

[0120] (2-7. Modification 7) Figure 16 schematically shows an example of a cross-sectional configuration of a photodetector (photodetector 1G) according to Modification 7 of the present disclosure. The photodetector 1G is a device capable of detecting incident light, similar to the photodetector 1 of the above embodiment, and is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0121] In the above embodiment, an example was shown in which the side surface 13S3 of the photoelectric conversion layer 13 is surrounded by the upper electrode 14, but the invention is not limited to this. In this modified example, the photodetector 1G has a buffer layer 16 provided on the photoelectric conversion layer 13 that extends to the side surface 13S3 of the photoelectric conversion layer 13. Except for this point, the photodetector 1G has substantially the same configuration as the photodetector 1 of the above embodiment.

[0122] Here, the buffer layer 16 corresponds to a specific example of the "first buffer layer" as one embodiment of the present disclosure. As described above, the buffer layer 16 extends along the side surface 13S3 of the photoelectric conversion layer 13, and its end is in contact with the buffer layer 15 provided on the first surface 13S1 side of the photoelectric conversion layer 13. Here, the buffer layer 15 corresponds to a specific example of the "second buffer layer" as one embodiment of the present disclosure.

[0123] Even with this configuration, the modified photodetector 1G can obtain the same effects as in the above embodiment.

[0124] Furthermore, in this modified example, as described above, the buffer layer 16 is extended to the side surface 13S3 of the photoelectric conversion layer 13, and the buffer layer 16 is interposed between the side surface 13S3 of the photoelectric conversion layer 13 and the upper electrode 14. As a result, compared to the case where the upper electrode 14 extends directly to the side surface 13S3 of the photoelectric conversion layer 13, the generation of dark current is suppressed.

[0125] (2-8. Modification 8) Figure 17 schematically shows an example of a cross-sectional configuration of a light detection device (light detection device 1H) according to Modification 8 of the present disclosure. The light detection device 1H is a device capable of detecting incident light, similar to the light detection device 1 of the above embodiment, and is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0126] In this modified example, the photodetector 1H has an uneven structure X formed on the side surface 13S3 of the photoelectric conversion layer 13, which includes buffer layers 15 and 16, and similarly, a metal film 19 extending to the side surface of adjacent photodetector elements 11 is embedded in the upper electrode 14 that extends to the side surface of adjacent photodetector elements 11. Except for this point, the photodetector 1H has substantially the same configuration as the photodetector 1 of the above embodiment.

[0127] The uneven structure X corresponds to one specific example of the "uneven structure" as one embodiment of the present disclosure. The pitch (p) of the uneven structure X is, for example, 5 nm or more and 10 nm or less. This uneven structure X can be formed by repeatedly etching and depositing the side surface 13S3 of the photoelectric conversion layer 13, which includes buffer layers 15 and 16.

[0128] The metal film 19 corresponds to a specific example of a "conductive film" as one embodiment of the present disclosure. The metal film 19 may be provided in a grid pattern (see Figure 13) surrounding the photoelectric conversion layer 13 provided for each unit pixel P, as in the modified example 5 above, or it may be provided discretely around the photoelectric conversion layer 13 (see Figure 14). Examples of materials constituting the metal film 19 include tungsten (W), aluminum (Al), copper (Cu), or aluminum-copper alloys.

[0129] Even with this configuration, the photodetector 1H of this modified example can obtain the same effects as in the above embodiment.

[0130] Furthermore, in this modified example, as described above, an uneven structure X is formed on the side surface 13S3 of the photoelectric conversion layer 13, which includes the buffer layers 15 and 16. This increases the surface area of ​​the side surface 13S3 of the photoelectric conversion layer 13, making it possible to absorb more charge at the upper electrode 14.

[0131] (2-9. Modification 9) Figure 18 schematically shows an example of the cross-sectional configuration of the photodetector (photodetector 1I) according to Modification 9 of the present disclosure. Figure 19 schematically shows an example of the planar configuration of the photodetector 1I shown in Figure 18. The photodetector 1I is a device capable of detecting incident light, similar to the photodetector 1 of the above embodiment, and is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0132] In this modified example, the photodetector 1I has a light-shielding film 44 on the light-receiving section 10, for example, with an aperture 44H for each unit pixel P via an insulating layer 43. Except for this point, the photodetector 1I has substantially the same configuration as the photodetector 1 of the above embodiment.

[0133] The light-shielding film 44 corresponds to one specific example of the "light-shielding portion" as one embodiment of the present disclosure. As shown in Figure 18, the light-shielding film 44 is provided on the optical layer 40 and has an aperture 44H for each unit pixel P. The aperture 44H is filled with, for example, a protective layer 41. The light-shielding film 44 has a configuration in which a reflective member that reflects incident light and an absorbing member that absorbs incident light are laminated from the light-receiving portion 10 side.

[0134] The reflective member reflects the light that has passed through the aperture 44H from the on-chip lens 42 and has been reflected by the photodetector 11 before becoming incident. Examples of materials for the reflective member include metallic materials such as aluminum (Al) and tantalum (Ta). The reflective member reflects the incident light that has passed through the aperture 44H and been reflected by the photodetector 11 back towards the photodetector 11. The reflective member may also be formed using other materials with a low refractive index.

[0135] The absorbing member is made of a light-absorbing material and absorbs incident light. Examples of materials for the absorbing member include tungsten (W) and black filters. The absorbing member absorbs unwanted light incident around the aperture 44H. The absorbing member may also be formed using other light-absorbing metallic materials or constructed using other color filters.

[0136] The aperture 44H corresponds to one specific example of an "aperture" as one embodiment of the present disclosure, and is an aperture (hole) into which light from the on-chip lens 42 enters. The aperture 44H may have a rectangular shape (e.g., a square) in a plan view, as shown in Figure 19, for example. Alternatively, the aperture 44H may have a circular shape in a plan view. The shape of the aperture 44H can be changed as appropriate, and may be rectangular, elliptical, or other shapes.

[0137] Even with this configuration, the modified photodetector 1I can achieve the same effects as in the above embodiment.

[0138] Furthermore, in this modified example, a light-shielding film 44 is provided on the light-receiving section 10, for example, having an aperture 44H for each unit pixel P, and having a reflective member and an absorbing member stacked in that order from the light-receiving section 10 side. As a result, for example, the light reflected by the lower electrode 12 is reflected by the side surface 13S3 of the photoelectric conversion layer 13 including the buffer layers 15 and 16, and the light-shielding film 44, thereby increasing the optical path length of the incident light. This makes it possible to increase the amount of light absorbed by the photoelectric conversion layer 13.

[0139] (2-10. Modification 10) Figure 20 schematically shows an example of a cross-sectional configuration of a photodetector (photodetector 1J) according to Modification 10 of the present disclosure. The photodetector 1J is a device capable of detecting incident light, similar to the photodetector 1 of the above embodiment, and is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0140] In this modified example, the photodetector 1J has an inner lens 45 further provided between the protective layer 41 and the on-chip lens 42. Except for this point, the photodetector 1J has substantially the same configuration as the photodetector 1 of the above embodiment.

[0141] Here, the protective layer 41 corresponds to a specific example of the "second insulating layer" as one embodiment of the present disclosure. The inner lens 45 corresponds to a specific example of the "second lens" as one embodiment of the present disclosure.

[0142] The inner lens 45, like the on-chip lens 42, is a lens that focuses light and guides the light incident from the light incident side S1 to the light-receiving unit 10. The inner lens 45 is provided, for example, above the light-receiving unit 10 for each unit pixel P or for each of multiple unit pixels P. Light from the subject to be measured is incident on the inner lens 45 via the optical system such as the imaging lens and the on-chip lens 42.

[0143] The inner lens 45 is, for example, a concave lens and is formed using a material that has a refractive index higher than that of the protective layer 41 and a refractive index lower than that of the on-chip lens 42. Examples of such materials include silicon nitride (SiN).

[0144] Even with this configuration, the modified photodetector 1J can achieve the same effects as the embodiment described above.

[0145] <5. Application Examples> (Application Example 1) The above-mentioned light detection device (e.g., light detection device 1) can be applied to various electronic devices such as imaging systems such as digital still cameras and digital video cameras, mobile phones equipped with imaging functions, or other devices equipped with imaging functions.

[0146] Figure 21 is a block diagram showing an example of the configuration of the electronic device 1000.

[0147] As shown in Figure 21, the electronic device 1000 includes an optical system 1001, a light detection device 1, and a DSP (Digital Signal Processor) 1002. The DSP 1002, memory 1003, display device 1004, recording device 1005, operating system 1006, and power supply system 1007 are connected via a bus 1008, and it is capable of capturing still and moving images.

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

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

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

[0151] (Application Example 2) Figure 22A schematically shows an example of the overall configuration of a photodetection system 2000 equipped with a photodetector (for example, photodetector 1). Figure 22B shows an example of the circuit configuration of the photodetection system 2000. The photodetection system 2000 includes a light-emitting device 2001 as a light source that emits infrared light L2, and a photodetector 2002 as a light-receiving device. As the photodetector 2002, for example, the photodetector 1 described above can be used. The photodetection system 2000 may further include a system control unit 2003, a light source drive unit 2004, a sensor control unit 2005, a light source side optical system 2006, and a camera side optical system 2007.

[0152] The photodetector 2002 can detect light L1 and light L2. Light L1 is light reflected from ambient light from the outside by the subject (object to be measured) 2100 (Figure 22A). Light L2 is light that has been emitted by the light-emitting device 2001 and then reflected by the subject 2100. Light L1 is, for example, visible light, and light L2 is, for example, infrared light. Light L1 is detectable in the photoelectric conversion unit of the photodetector 2002, and light L2 is detectable in the photoelectric conversion region of the photodetector 2002. Image information of the subject 2100 can be obtained from light L1, and distance information between the subject 2100 and the photodetector system 2000 can be obtained from light L2. The photodetector system 2000 can be mounted on, for example, electronic devices such as smartphones or mobile devices such as cars. The light-emitting device 2001 can be, for example, a semiconductor laser, a surface-emitting semiconductor laser, or a vertical-cavity surface-emitting laser (VCSEL). As a detection method for the light L2 emitted from the light-emitting device 2001 by the photodetector 2002, for example, the iTOF method can be used, but is not limited to this. In the iTOF method, the photoelectric conversion unit can measure the distance to the subject 2100 by, for example, the time-of-flight (TOF). As a detection method for the light L2 emitted from the light-emitting device 2001 by the photodetector 2002, for example, the structured light method or the stereo vision method can also be used. For example, in the structured light method, the distance between the photodetector 2000 and the subject 2100 can be measured by projecting a predetermined pattern of light onto the subject 2100 and analyzing the degree of distortion of the pattern. In the stereo vision method, for example, the distance between the photodetector 2000 and the subject can be measured by using two or more cameras to acquire two or more images of the subject 2100 from two or more different viewpoints. Furthermore, the light-emitting device 2001 and the light-detecting device 2002 can be synchronously controlled by the system control unit 2003.

[0153] <4. Application Examples> (Application Example to Endoscopic Surgical Systems) The technology disclosed herein (this technology) can be applied to various products. For example, the technology disclosed herein may be applied to an endoscopic surgical system.

[0154] Figure 23 is a diagram showing an example of a schematic configuration of an endoscopic surgical system to which the technology described herein (the technology) may be applied.

[0155] Figure 23 illustrates a surgeon (physician) 11131 performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgical system 11000. As shown in the figure, the endoscopic surgical system 11000 consists of an endoscope 11100, other surgical instruments 11110 such as an insufflation tube 11111 and an energy treatment device 11112, a support arm device 11120 for supporting the endoscope 11100, and a cart 11200 equipped with various devices for endoscopic surgery.

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

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

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

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

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

[0161] The light source device 11203 is composed of a light source such as an LED (light-emitting diode) and supplies illumination light to the endoscope 11100 when photographing the surgical area, etc.

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

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

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

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

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

[0167] Figure 24 is a block diagram showing an example of the functional configuration of the camera head 11102 and CCU 11201 shown in Figure 23.

[0168] The camera head 11102 includes a lens unit 11401, an imaging unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. The CCU 11201 includes a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are connected to each other via a transmission cable 11400 so that they can communicate with each other.

[0169] The lens unit 11401 is an optical system provided at the connection point with the lens barrel 11101. Observation light taken in from the tip of the lens barrel 11101 is guided to the camera head 11102 and then incident on the lens unit 11401. The lens unit 11401 is composed of a combination of multiple lenses, including a zoom lens and a focus lens.

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

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

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

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

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

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

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

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

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

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

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

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

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

[0183] In the illustrated example, communication was performed via a wired connection using a transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may be performed wirelessly.

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

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

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

[0187] Figure 25 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology described herein may be applied.

[0188] The vehicle control system 12000 comprises a plurality of electronic control units connected via a communication network 12001. In the example shown in Figure 25, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. The functional configuration of the integrated control unit 12050 is shown in the figure, which includes a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface 12053.

[0189] The drivetrain control unit 12010 controls the operation of devices related to the vehicle's drivetrain according to various programs. For example, the drivetrain control unit 12010 functions as a control device for a drivetrain generating device that generates driving force for the vehicle, such as an internal combustion engine or a drive motor; a drivetrain transmission mechanism that transmits driving force to the wheels; a steering mechanism that adjusts the steering angle of the vehicle; and a braking device that generates braking force for the vehicle.

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

[0191] The external information detection unit 12030 detects information from outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the external information detection unit 12030. The external information detection unit 12030 causes the imaging unit 12031 to capture images of the outside of the vehicle and receives the captured images. Based on the received images, the external information detection unit 12030 may perform object detection processing such as detecting people, cars, obstacles, signs, or characters on the road surface, or distance detection processing.

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

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

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

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

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

[0197] The audio-image output unit 12052 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying information to the vehicle's occupants or to those outside the vehicle. In the example shown in Figure 25, the output devices include an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an onboard display and a head-up display.

[0198] Figure 26 shows an example of the installation position of the imaging unit 12031.

[0199] In Figure 26, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

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

[0201] Figure 26 shows an example of the imaging range of imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of imaging unit 12101 located on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of imaging units 12102 and 12103 located on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of imaging unit 12104 located on the rear bumper or back door. For example, by superimposing the image data captured by imaging units 12101 to 12104, an overhead view image of the vehicle 12100 can be obtained.

[0202] At least one of the imaging units 12101 to 12104 may have a function for acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera consisting of multiple image sensors, or an image sensor having pixels for phase difference detection.

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

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

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

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

[0207] The present technology has been described above with reference to embodiments, modifications 1 to 10, application examples, and application examples. However, the contents of this disclosure are not limited to the above embodiments, and various modifications are possible.

[0208] For example, in the above embodiment, an example was shown in which electrons are read out as signal charge from the lower electrode 12 side, but the invention is not limited to this, and holes may also be read out as signal charge from the lower electrode 12 side. In that case, the stacking order of each layer of the photodetector element 11 shown in Figure 3 will be reversed. That is, the layers will be stacked in order from the upper electrode 14 side toward the light incident side S1. Furthermore, the lower electrode 12 will extend to the side surface of the photoelectric conversion layer 13. In addition, the signal charge may be read out from the upper electrode 14 side.

[0209] Furthermore, the above-described modifications 1 to 10 can be combined with each other. For example, by combining modifications 8 and 9, a light-shielding film 44 having an opening 44H may be placed above a photodetector 11 having an uneven structure X on the side surface 13S3 of the photoelectric conversion layer 13 including buffer layers 15 and 16.

[0210] Furthermore, in the photodetector 1 and others mentioned in this disclosure, the semiconductor substrate 20 may be provided with one or more photoelectric conversion units (inorganic photodiodes) that detect light in a wavelength range different from that of the photodetector element 11.

[0211] Furthermore, although the above embodiments illustrate the configuration of a surface-illuminated photodetector, the contents of this disclosure are also applicable to back-illuminated photodetectors.

[0212] Furthermore, the light detection device 1 and electronic device 1000 of this disclosure do not need to be equipped with all of the components described in the above embodiments, and conversely, they may be equipped with other components. For example, the electronic device 1000 may be provided with a shutter for controlling the incidence of light to the light detection device 1, or it may be equipped with an optical cut filter depending on the purpose of the electronic device 1000.

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

[0214] Furthermore, this technology can also be configured as follows. According to the following configurations of this technology, the distance between the first electrode and the second electrode, which are positioned opposite each other with a photoelectric conversion layer in between, is reduced, thereby preventing deactivation due to recombination of charges (holes and electrons) and improving the efficiency of charge extraction. (1) A photodetector comprising a photodetector element having a photoelectric conversion layer having opposing first and second surfaces, a first electrode provided on the first surface side of the photoelectric conversion layer, and a second electrode provided on the second surface side of the photoelectric conversion layer and extending to at least a part of the side surface between the first and second surfaces of the photoelectric conversion layer. (2) The photodetector according to (1), wherein the photoelectric conversion layer has a higher refractive index than the second electrode. (3) The photodetector according to (1) or (2), wherein the side surface of the photoelectric conversion layer has an inclined surface that extends from the second surface side toward the first surface side. (4) The photodetector according to any one of (1) to (3), wherein the photoelectric conversion layer is continuous between adjacent photodetectors. (5) The photodetector according to any one of (1) to (4), further comprising a first insulating layer on the first surface side of the photoelectric conversion layer in which the first electrode is embedded, and the second electrode extends between adjacent photodetectors and a portion of it is embedded in the first insulating layer. (6) The photodetector according to any one of (1) to (5), wherein the second electrode contains a light-shielding film that extends between adjacent photodetectors. (7) The photodetector according to any one of (1) to (6), wherein the second electrode contains an insulating film that extends between adjacent photodetectors. (8) The photodetector according to any one of (1) to (7), further comprising a first buffer layer between the photoelectric conversion layer and the second electrode, wherein the first buffer layer extends to the second surface and the side surface of the photoelectric conversion layer. (9) The photodetector according to (8), further comprising a second buffer layer between the photoelectric conversion layer and the first electrode, wherein the first buffer layer and the second buffer layer are in contact with each other. (10) The photodetector according to any one of (1) to (9), wherein the photoelectric conversion layer has an uneven structure on its side surface.(11) The photodetector according to any one of (1) to (10), wherein the second electrode contains a conductive film extending between adjacent photodetectors. (12) The photodetector according to (11), wherein the conductive film comprises tungsten, aluminum, copper, or an aluminum-copper alloy. (13) The photodetector according to any one of (1) to (12), further comprising a light-shielding portion provided on the second surface side of the photoelectric conversion layer between the second electrodes, wherein the light-shielding portion has an opening into which light is incident above the photoelectric conversion layer. (14) The photodetector according to any one of (1) to (13), wherein the photoelectric conversion layer comprises an organic material, an amorphous silicon film, an organic semiconductor film, or an aggregate of nanoparticles. (15) The photodetector according to (14), wherein the nanoparticles include lead sulfide, lead selenide, lead telluride, indium phosphide, indium arsenide, indium antimonide, cadmium sulfide, cadmium selenide, or cadmium telluride. (16) The photodetector according to any one of (1) to (15), wherein the second electrode includes a light-transmitting oxide semiconductor material. (17) The photodetector according to (16), wherein the oxide semiconductor material is indium tin oxide or indium zinc oxide. (18) The photodetector according to any one of (1) to (17), further comprising: a second insulating layer covering the light incident side of the photodetector; a first lens disposed on the light incident side of the photodetector with the second insulating layer in between; and a second lens disposed between the second insulating layer and the first lens, wherein the first lens has a higher refractive index than the second lens, and the second lens has a higher refractive index than the second insulating layer. (19) An electronic device comprising: an optical system; and a photodetector that receives light transmitted through the optical system, wherein the photodetector has a photodetector element comprising: a photoelectric conversion layer having opposing first and second surfaces; a first electrode provided on the first surface side of the photoelectric conversion layer; and a second electrode provided on the second surface side of the photoelectric conversion layer and extending to at least a part of the side surface between the first and second surfaces of the photoelectric conversion layer.

[0215] This application claims priority based on Japanese Patent Application No. 2024-221597, filed with the Japan Patent Office on 18 December 2024, and all contents of that application are incorporated herein by reference.

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

Claims

1. A photodetector comprising a photodetector element having a photoelectric conversion layer having opposing first and second surfaces, a first electrode provided on the first surface side of the photoelectric conversion layer, and a second electrode provided on the second surface side of the photoelectric conversion layer and extending to at least a portion of the side surface between the first and second surfaces of the photoelectric conversion layer.

2. The photodetector according to claim 1, wherein the photoelectric conversion layer has a higher refractive index than the second electrode.

3. The photodetector according to claim 1, wherein the side surface of the photoelectric conversion layer has an inclined surface that extends from the second surface side toward the first surface side.

4. The photodetector according to claim 1, wherein the photoelectric conversion layer is continuous between adjacent photodetectors.

5. The photodetector according to claim 1, further comprising a first insulating layer on the first surface side of the photoelectric conversion layer in which the first electrode is embedded, wherein the second electrode extends between adjacent photodetectors and a portion of it is embedded in the first insulating layer.

6. The photodetector according to claim 1, wherein the second electrode contains a light-shielding film that extends between adjacent photodetectors.

7. The photodetector according to claim 1, wherein the second electrode contains an insulating film extending between adjacent photodetectors.

8. The photodetector according to claim 1, further comprising a first buffer layer between the photoelectric conversion layer and the second electrode, wherein the first buffer layer extends to the second surface and the side surface of the photoelectric conversion layer.

9. The photodetector according to claim 8, further comprising a second buffer layer between the photoelectric conversion layer and the first electrode, wherein the first buffer layer and the second buffer layer are in contact with each other.

10. The photodetector according to claim 1, wherein the photoelectric conversion layer has an uneven surface structure on its side surface.

11. The photodetector according to claim 1, wherein the second electrode contains a conductive film extending between adjacent photodetectors.

12. The photodetector according to claim 11, wherein the conductive film comprises tungsten, aluminum, copper, or an aluminum-copper alloy.

13. The photodetector according to claim 1, further comprising a light-shielding portion provided on the second surface side of the photoelectric conversion layer between the second electrodes, wherein the light-shielding portion has an opening into which light enters above the photoelectric conversion layer.

14. The photodetector according to claim 1, wherein the photoelectric conversion layer comprises an organic material, an amorphous silicon film, an organic semiconductor film, or an aggregate of nanoparticles.

15. The photodetector according to claim 14, wherein the nanoparticles include lead sulfide, lead selenide, lead telluride, indium phosphide, indium arsenide, indium antimonide, cadmium sulfide, cadmium selenide, or cadmium telluride.

16. The photodetector according to claim 1, wherein the second electrode comprises a light-transmitting oxide semiconductor material.

17. The photodetector according to claim 16, wherein the oxide semiconductor material is indium tin oxide or indium zinc oxide.

18. The photodetector according to claim 1, further comprising: a second insulating layer covering the light incident side of the photodetector; a first lens disposed on the light incident side of the photodetector with the second insulating layer in between; and a second lens disposed between the second insulating layer and the first lens, wherein the first lens has a higher refractive index than the second lens, and the second lens has a higher refractive index than the second insulating layer.

19. An electronic device comprising an optical system and a photodetector that receives light transmitted through the optical system, wherein the photodetector has a photodetector element comprising a photoelectric conversion layer having opposing first and second surfaces, a first electrode provided on the first surface side of the photoelectric conversion layer, and a second electrode provided on the second surface side of the photoelectric conversion layer and extending to at least a portion of the side surface between the first and second surfaces of the photoelectric conversion layer.

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