Light detection device and electronic equipment

Abstract

A first light detection device of an embodiment according to the present disclosure is provided with: a photoelectric conversion layer; a first electrode electrically connected to the photoelectric conversion layer; a second electrode arranged facing the first electrode with the photoelectric conversion layer therebetween; and a first intermediate layer provided between the first electrode and the photoelectric conversion layer, at least outside the first electrode in a planar view, and having a higher charge mobility in the in-plane direction than the photoelectric conversion layer, among the in-plane direction and the stacking direction perpendicular to the in-plane direction.

Description

Photodetector and electronic equipment

[0001] The present disclosure relates to, for example, photodetection devices and electronic devices using organic materials.

[0002] For example, Patent Document 1 discloses an imaging element in which an oxide semiconductor layer and an oxide film are stacked between a first electrode and a photoelectric conversion layer made of an organic material from the first electrode side.

[0003] International Publication No. 2020 / 017330

[0004] Incidentally, for example, in a photodetector used in an image sensor or the like, there is a demand for improved photodetection characteristics.

[0005] It is desirable to provide a photodetector device and electronic equipment that can improve the photodetection characteristics.

[0006] A first photodetector according to one embodiment of the present disclosure comprises a photoelectric conversion layer, a first electrode electrically connected to the photoelectric conversion layer, a second electrode arranged opposite the first electrode with the photoelectric conversion layer in between, and a first intermediate layer disposed between the first electrode and the photoelectric conversion layer, at least outside the first electrode in a planar view, and having a higher charge mobility in the in-plane direction than the photoelectric conversion layer in the in-plane direction and in a stacking direction perpendicular to the in-plane direction.

[0007] An electronic device according to an embodiment of the present disclosure includes the photodetector according to the embodiment of the present disclosure.

[0008] A second photodetector device according to one embodiment of the present disclosure includes a first electrode and a third electrode arranged in parallel, a second electrode arranged opposite the first and third electrodes, and a photoelectric conversion layer provided between the first and third electrodes and the second electrode, wherein the third electrode is electrically insulated from the photoelectric conversion layer, and the electric field applied to the photoelectric conversion layer above the third electrode is weaker than the electric field applied to the photoelectric conversion layer above the first electrode.

[0009] In the first and second photodetector devices and the electronic device according to the embodiment of the present disclosure, a first intermediate layer having a higher charge mobility in the in-plane direction than the photoelectric conversion layer is provided between the first electrode and the photoelectric conversion layer and outside the first electrode electrically connected to the photoelectric conversion layer in a plan view, out of the in-plane direction and the stacking direction orthogonal to the in-plane direction, thereby facilitating transport of charges present outside the first electrode toward the first electrode.

[0010] FIG. 1 is a cross-sectional view schematically illustrating an example of a configuration of a photodetector according to an embodiment of the present disclosure. FIG. 2 is a plan view schematically illustrating an example of a pixel configuration of the photodetector shown in FIG. 1. FIG. 3 is a cross-sectional view schematically illustrating an example of a configuration of a photoelectric conversion unit shown in FIG. 1. FIG. 4 is a diagram illustrating the energy levels of each layer constituting the photoelectric conversion unit shown in FIG. 3. FIG. 5 is an equivalent circuit diagram of the photodetector shown in FIG. 1. FIG. 6 is a schematic diagram illustrating the arrangement of transistors constituting the lower electrode and control unit of the photodetector shown in FIG. 1. FIG. 7 is a cross-sectional view for explaining a method of manufacturing the photodetector shown in FIG. 1. FIG. 8 is a cross-sectional view illustrating a process subsequent to FIG. 7. FIG. 9 is a cross-sectional view illustrating a process subsequent to FIG. 8. FIG. 10 is a cross-sectional view illustrating a process subsequent to FIG. 9. FIG. 11 is a cross-sectional view illustrating a process subsequent to FIG. 10. FIG. 12 is a cross-sectional view illustrating a process subsequent to FIG. 11. FIG. 13 is a timing chart illustrating an example of operation of the photodetector shown in FIG. 1. FIG. 14 is a diagram illustrating a cross-sectional configuration of a photoelectric conversion unit (A) and the potential of each unit (B) as a comparative example. FIG. 15 is a cross-sectional schematic diagram illustrating an example of the configuration of a photoelectric conversion unit according to Modification 1 of the present disclosure. FIG. 16 is a diagram illustrating the energy levels of each layer constituting the photoelectric conversion unit shown in FIG. 15 . FIG. 17 is a cross-sectional schematic diagram illustrating an example of the configuration of a photodetector according to Modification 2 of the present disclosure. FIG. 18 is a plan view schematic illustrating an example of the pixel configuration of the photodetector shown in FIG. 17 . FIG. 19 is a cross-sectional schematic diagram illustrating an example of the configuration of the photoelectric conversion unit shown in FIG. 17 . FIG. 20 is a diagram illustrating the energy levels of each layer above a shield electrode constituting the photoelectric conversion unit shown in FIG. 19 . FIG. 21 is a cross-sectional schematic diagram illustrating an example of the configuration of a photoelectric conversion unit according to Modification 3 of the present disclosure. FIG. 22 is a diagram illustrating the energy levels of each layer above a shield electrode constituting the photoelectric conversion unit shown in FIG. 21 . FIG. 23 is a cross-sectional schematic diagram illustrating an example of the configuration of a photodetector according to Modification 4 of the present disclosure. FIG. 24A is a cross-sectional schematic diagram illustrating an example of the configuration of a photodetector according to Modification 5 of the present disclosure. Fig. 24B is a schematic plan view of the photodetector shown in Fig. 24A. Fig. 25A is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 6 of the present disclosure. Fig. 25B is a schematic plan view of the photodetector shown in Fig. 25A. Fig. 26 is a schematic cross-sectional view illustrating another example of the configuration of a photodetector according to Modification 2 of another modification of the present disclosure.FIG. 27A is a cross-sectional schematic diagram illustrating another example of the configuration of a photodetector element of Modification 3 according to another modification of the present disclosure. FIG. 27B is a schematic diagram illustrating a planar configuration of the photodetector element illustrated in FIG. 31A. FIG. 28A is a cross-sectional schematic diagram illustrating another example of the configuration of a photodetector element of Modification 4 according to another modification of the present disclosure. FIG. 28B is a schematic diagram illustrating a planar configuration of the photodetector element illustrated in FIG. 28A. FIG. 29 is a block diagram illustrating the overall configuration of a photodetector including the photodetector element illustrated in FIG. 1 etc. FIG. 30 is a block diagram illustrating an example of the configuration of an electronic device using the photodetector illustrated in FIG. 29. FIG. 31A is a schematic diagram illustrating an example of the overall configuration of a photodetection system using the photodetector illustrated in FIG. 29. FIG. 31B is a diagram illustrating an example of the circuit configuration of the photodetection system illustrated in FIG. 29A. FIG. 32 is a diagram illustrating an example of a schematic configuration of an endoscopic surgery system. FIG. 33 is a block diagram illustrating an example of the functional configuration of a camera head and a CCU. FIG. 34 is a block diagram illustrating an example of a schematic configuration of a vehicle control system. FIG. 35 is an explanatory diagram illustrating an example of the installation positions of an outside vehicle information detection unit and an imaging unit.

[0011] An embodiment of the present disclosure will be described in detail below with reference to the drawings. The following description is a specific example of the present disclosure, and the present disclosure is not limited to the following aspects. Furthermore, the present disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc. of each component shown in each drawing. The description will be given in the following order. 1. Embodiment (Example of a photodetector having a charge confinement layer between a shield electrode and a photoelectric conversion layer) 1-1. Configuration of a photodetector 1-2. Method for manufacturing a photodetector 1-3. Signal acquisition operation of a photodetector 1-4. Actions and effects 2. Modifications 2-1. Modification 1 (Another example of the configuration of the photoelectric conversion unit) 2-2. Modification 2 (Another example of the configuration of the photoelectric conversion unit) 2-3. Modification 3 (Another example of the configuration of the photoelectric conversion unit) 2-4. Modification 4 (An example of a photodetector that separates light using a color filter) 2-5. Modification 5 (Another example of a photodetector that separates light using a color filter) 2-6. Modification 6 (an example of a photodetector element in which a plurality of photoelectric conversion units are stacked) 3. Application example 4. Application example

[0012] 1. Embodiment FIG. 1 illustrates a cross-sectional configuration of a photodetector element (photodetector element 1) according to an embodiment of the present disclosure. FIG. 2 schematically illustrates an example of a planar configuration of the photodetector element 1 illustrated in FIG. 1, and FIG. 1 illustrates a cross section taken along line II in FIG. 2. FIG. 3 schematically illustrates an enlarged cross-sectional configuration of a main portion (photoelectric conversion unit 20) of the photodetector element 1 illustrated in FIG. 1. The photodetector element 1 constitutes, for example, a single pixel (unit pixel P) repeatedly arranged in an array in a pixel array section 100A of a photodetector device (e.g., photodetector device 100; see FIG. 29 ) as an imaging element such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor used in electronic devices such as digital still cameras and video cameras. In the pixel array section 100A, as illustrated in FIG. 2, a pixel unit 1a, each consisting of four unit pixels P arranged in two rows and two columns, serves as a repeating unit and is repeatedly arranged in an array consisting of row and column directions.

[0013] In the photodetector element 1 of this embodiment, a charge confinement layer 25 is provided between a lower electrode 21 including a readout electrode 21A, a charge storage electrode 21B, and a shield electrode 21C and a photoelectric conversion layer 26 in a photoelectric conversion unit 20 provided on a semiconductor substrate 30. The charge confinement layer 25 has a higher charge mobility in the XY plane direction than the photoelectric conversion layer 26, among the in-plane direction (XY plane direction) and the stacking direction (Z-axis direction) perpendicular to the XY plane direction. Specifically, the photoelectric conversion unit 20 is configured by stacking a lower electrode 21 including a readout electrode 21A, a charge storage electrode 21B, and a shield electrode 21C, an insulating layer 22, an oxide semiconductor layer 23, a protective layer 24, the charge confinement layer 25, the photoelectric conversion layer 26, and an upper electrode 27 in this order. The insulating layer 22 has an opening 22H above the read electrode 21A, and the read electrode 21A and the photoelectric conversion layer 26 are electrically connected via this opening 22H. The shield electrode 21C is provided between adjacent unit pixels P, and is electrically insulated from the photoelectric conversion layer 26 by the insulating layer 22.

[0014] Here, the readout electrode 21A corresponds to a specific example of a "first electrode" in an embodiment of the present disclosure. The upper electrode 27 corresponds to a specific example of a "second electrode" in an embodiment of the present disclosure. The shield electrode 21C corresponds to a specific example of a "third electrode" in an embodiment of the present disclosure. The charge storage electrode 21B corresponds to a specific example of a "fourth electrode" in an embodiment of the present disclosure. The charge confinement layer 25 corresponds to a specific example of a "storage electrode" in an embodiment of the present disclosure.

[0015] (1-1. Configuration of Photodetector) The photodetector 1 is, for example, a so-called vertical spectroscopic type in which one photoelectric conversion unit 20 and two photoelectric conversion regions 32B, 32R are stacked vertically. The photoelectric conversion unit 20 is provided on the back surface (first surface 30S1) side of the semiconductor substrate 30. The photoelectric conversion regions 32B, 32R are embedded in the semiconductor substrate 30 and stacked in the thickness direction of the semiconductor substrate 30.

[0016] The photoelectric conversion unit 20 and the photoelectric conversion regions 32B and 32R selectively detect light in different wavelength ranges and perform photoelectric conversion. For example, the photoelectric conversion unit 20 acquires a green (G) color signal. The photoelectric conversion regions 32B and 32R acquire blue (B) and red (R) color signals, respectively, due to differences in absorption coefficients. This allows the photodetector 1 to acquire multiple types of color signals in one pixel without using color filters.

[0017] In this embodiment, a case where electrons, among pairs of electrons and holes (excitons) generated by photoelectric conversion, are read out as signal charges (when an n-type semiconductor region is used as the photoelectric conversion layer) will be described. In addition, in the figures, a "+ (plus)" attached to "p" and "n" indicates that the p-type or n-type impurity concentration is high.

[0018] The surface (second surface 30S2) of the semiconductor substrate 30 is provided with, for example, floating diffusions FD1 (region 36B within the semiconductor substrate 30), FD2 (region 37C within the semiconductor substrate 30), and FD3 (region 38C within the semiconductor substrate 30), transfer transistors Tr2 and Tr3, an amplifier transistor (modulation element) AMP, a reset transistor RST, and a selection transistor SEL. The second surface 30S2 of the semiconductor substrate 30 is further provided with a multilayer wiring layer 40 via a gate insulating layer 33. The multilayer wiring layer 40 has, for example, a configuration in which wiring layers 41, 42, and 43 are stacked within an insulating layer 44. A vertical drive circuit 111, a column signal processing circuit 112, a horizontal drive circuit 113, an output circuit 114, a control circuit 115, an input / output terminal 116, and the like, which will be described later, are provided in the peripheral portion of the semiconductor substrate 30, i.e., the peripheral region around the pixel array section 100A.

[0019] In the drawings, the first surface 30S1 side of the semiconductor substrate 30 is represented as a light incident side S1, and the second surface 30S2 side is represented as a wiring layer side S2.

[0020] The photoelectric conversion unit 20 includes an oxide semiconductor layer 23, a protective layer 24, a charge confinement layer 25, and a photoelectric conversion layer 26 formed using an organic material, stacked in this order from the lower electrode 21 side between an opposing lower electrode 21 and an upper electrode 27. The photoelectric conversion layer 26 is composed of a p-type semiconductor and an n-type semiconductor, and has a bulk heterojunction structure within the layer. The bulk heterojunction structure is a p / n junction surface formed by mixing a p-type semiconductor and an n-type semiconductor.

[0021] The photoelectric conversion unit 20 further includes an insulating layer 22 between the lower electrode 21 and the oxide semiconductor layer 23. The insulating layer 22 is provided, for example, over the entire surface of the pixel array unit 100A, and has an opening 22H on the read electrode 21A that constitutes the lower electrode 21. The read electrode 21A is electrically connected to the oxide semiconductor layer 23 through this opening 22H.

[0022] 1 shows an example in which the oxide semiconductor layer 23, the photoelectric conversion layer 26, and the upper electrode 27 are formed as a continuous layer common to a plurality of photodetector elements 1, but the present invention is not limited to this. The oxide semiconductor layer 23, the photoelectric conversion layer 26, and the upper electrode 27 may be formed separately for each photodetector element 1, for example.

[0023] Between the first surface 30S1 of the semiconductor substrate 30 and the lower electrode 21, for example, an insulating layer 28 and an interlayer insulating layer 29 are laminated. The insulating layer 28 is formed by laminating, in this order from the semiconductor substrate 30 side, a layer 28A having a fixed charge (fixed charge layer) and a dielectric layer 28B having insulating properties.

[0024] The photoelectric conversion regions 32B and 32R enable the vertical separation of light by utilizing the fact that the wavelength of light absorbed varies depending on the depth of incidence of the light in the semiconductor substrate 30 made of silicon, and each has a pn junction in a predetermined region of the semiconductor substrate 30.

[0025] A through electrode 34 is provided between the first surface 30S1 and the second surface 30S2 of the semiconductor substrate 30. The through electrode 34 is electrically connected to the readout electrode 21A, and the photoelectric conversion unit 20 is connected via the through electrode 34 to the gate Gamp of the amplifier transistor AMP and one source / drain region 36B of the reset transistor RST (reset transistor Tr1rst) that also serves as the floating diffusion FD1. This allows the photodetector element 1 to efficiently transfer carriers (electrons in this case) generated in the photoelectric conversion unit 20 provided on the first surface 30S1 side of the semiconductor substrate 30 to the second surface 30S2 side of the semiconductor substrate 30 via the through electrode 34, thereby improving its characteristics.

[0026] The lower end of the through electrode 34 is connected to a wiring (connection portion 41A) in the wiring layer 41, and the connection portion 41A and the gate Gamp of the amplifier transistor AMP are connected via a lower first contact 45. The connection portion 41A and the floating diffusion FD1 (region 36B) are connected via, for example, a lower second contact 46. The upper end of the through electrode 34 is connected to the read electrode 21A via, for example, a pad portion 39A and an upper first contact 39D.

[0027] A protective layer 51 is provided above the photoelectric conversion unit 20. Within the protective layer 51, for example, wiring 52 and a light-shielding film 53 that electrically connect the upper electrode 27 and the peripheral circuit unit around the pixel array unit 100A are provided. Optical members such as a planarization layer (not shown) and an on-chip lens 54 are further provided above the protective layer 51.

[0028] In the photodetector element 1 of this embodiment, light incident on the photoelectric conversion unit 20 from the light incident side S1 is absorbed by the photoelectric conversion layer 26. The excitons thus generated move to the interface between the electron donors and electron acceptors that make up the photoelectric conversion layer 26, where they undergo exciton dissociation, i.e., dissociation into electrons and holes. The carriers (electrons and holes) generated here are transported to different electrodes by diffusion due to differences in carrier concentration and an internal electric field due to the difference in work function between the anode (e.g., the upper electrode 27) and the cathode (e.g., the lower electrode 21), and are detected as photocurrent. The transport direction of the electrons and holes can also be controlled by applying a potential between the lower electrode 21 and the upper electrode 27.

[0029] The structure and materials of each part will be described in detail below.

[0030] The photoelectric conversion unit 20 is an organic photoelectric conversion element that absorbs, for example, green light corresponding to a part or all of a selective wavelength range (for example, 450 nm or more and 650 nm or less) and generates excitons.

[0031] The lower electrode 21 includes, for example, a read electrode 21A, a charge storage electrode 21B, and a shield electrode 21C arranged in parallel on the interlayer insulating layer 28.

[0032] The readout electrode 21A is for transferring carriers generated in the photoelectric conversion layer 26 to the floating diffusion FD1, and is provided for each pixel unit 1a, which includes, for example, four pixels arranged in two rows and two columns. The readout electrode 21A is electrically connected to the photoelectric conversion layer 26 via the oxide semiconductor layer 23, the protective layer 24, and the charge confinement layer 25, for example, in an opening 22H provided in the insulating layer 22. The readout electrode 21A is also connected to the floating diffusion FD1 via the upper first contact 39D, the pad portion 39A, the through electrode 34, the connection portion 41A, and the lower second contact 46.

[0033] The charge storage electrode 21B is provided for each unit pixel P to store, for example, electrons as signal charges in the oxide semiconductor layer 23 from among the carriers generated in the photoelectric conversion layer 26. The charge storage electrode 21B is electrically insulated from the photoelectric conversion layer 26 by an insulating layer 22. The charge storage electrode 21B is provided for each unit pixel P in an area that directly faces the light-receiving surfaces of the photoelectric conversion regions 32B, 32R formed in the semiconductor substrate 30 and covers these light-receiving surfaces. The charge storage electrode 21B is preferably larger than the readout electrode 21A, which allows it to store a larger number of carriers.

[0034] The shield electrode 21C, for example, prevents electrons stored above the charge storage electrode 21B from leaking to adjacent unit pixels P. The shield electrode 21C is provided around a pixel unit 1a, which includes four pixels arranged in a two-row by two-column configuration. The shield electrode 21C also extends between adjacent pixels in the row direction (Z-axis direction) and column direction (X-axis direction) within the pixel unit 1a. Potentials are applied individually to the readout electrode 21A, the charge storage electrode 21B, and the shield electrode 21C. For example, a fixed potential is applied to the shield electrode 21C. Similarly to the charge storage electrode 21B, the shield electrode 21C is electrically insulated from the photoelectric conversion layer 26 by an insulating layer 22. This prevents a decrease in external quantum efficiency (EQE) due to the absorption of electrons generated by photoelectric conversion by the shield electrode 21C. This prevents crosstalk between adjacent unit pixels P while improving the EQE.

[0035] The lower electrode 21, including the read electrode 21A, the charge storage electrode 21B, and the shield electrode 21C, is made of a light-transmitting conductive film, for example, ITO (indium tin oxide). In addition to ITO, the lower electrode 21 can also be made of tin oxide (SnO ２ Alternatively, a zinc oxide-based material obtained by adding a dopant to zinc oxide (ZnO) may be used. Examples of zinc oxide-based materials include aluminum zinc oxide (AZO) to which aluminum (Al) is added as a dopant, gallium zinc oxide (GZO) to which gallium (Ga) is added, and indium zinc oxide (IZO) to which indium (In) is added. Other examples include IGZO, ITZO, CuI, and InSbO. ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３ etc. may also be used.

[0036] The insulating layer 22 serves to electrically separate the charge storage electrode 21B and the shield electrode 21C from the oxide semiconductor layer 23. The insulating layer 22 is provided, for example, on the interlayer insulating layer 29 so as to cover the lower electrode 21. An opening 22H is provided in the insulating layer 22 above the read electrode 21A of the lower electrode 21, and the read electrode 21A and the oxide semiconductor layer 23 are electrically connected via this opening 22H. The insulating layer 22 is made of, for example, silicon oxide (SiO ｘ ), silicon nitride (SiN ｘ The insulating layer 22 is made of a single layer film made of one of silicon oxynitride (SiON) and silicon oxynitride (SiON), or a laminated film made of two or more of these materials. The thickness of the insulating layer 22 is, for example, 20 nm to 500 nm.

[0037] The oxide semiconductor layer 23 is provided to accumulate carriers (e.g., electrons) generated in the photoelectric conversion layer 26. As described above, the oxide semiconductor layer 23 is provided between the lower electrode 21 and the photoelectric conversion layer 26. Electrons generated in the photoelectric conversion layer 26 are accumulated near the interface between the insulating layer 22 and the oxide semiconductor layer 23 above the charge storage electrode 21B and transferred to the readout electrode 21A via the oxide semiconductor layer 23. The electrons accumulated above the charge storage electrode 21B are transferred to the readout electrode 21A by controlling the potential of the charge storage electrode 21B to generate a potential gradient, as will be described in detail later. The oxide semiconductor layer 23 may be formed as a single layer or a laminated film composed of multiple layers.

[0038] The oxide semiconductor layer 23 can be formed using, for example, the following materials. In the photodetector element 1, electrons among the carriers generated in the photoelectric conversion layer 26 are read out as signal charges. For this reason, the oxide semiconductor layer 23 can be formed using an n-type oxide semiconductor material. Specific examples include IGZO (In—Ga—Zn—O-based oxide semiconductor), ITZO (In—Sn—Zn—O-based oxide semiconductor), ZTO (Zn—Sn—O-based oxide semiconductor), IGZTO (In—Ga—Zn—Sn—O-based oxide semiconductor), GTO (Ga—Sn—O-based oxide semiconductor), and IGO (In—Ga—O-based oxide semiconductor). Other examples include AlZnO, GaZnO, InZnO, and the like, which are obtained by adding aluminum (Al), gallium (Ga), indium (In), or the like to the above-mentioned oxide semiconductors as dopants, as well as CuI and InSbO. ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, etc. can be used.

[0039] The protective layer 24 is intended to prevent oxygen from being released from the oxide semiconductor material constituting the oxide semiconductor layer 23 and to reduce the generation of traps at the interface between the oxide semiconductor layer 23 and the photoelectric conversion layer 26. Examples of materials constituting the protective layer 24 include TiO ２ , titanium silicide oxide (TiSiO), niobium oxide (Nb ２ O ５ ) and TaO ｘ The thickness of the protective layer 24 is effective if it is, for example, one atomic layer, and is preferably, for example, 0.5 nm to 10 nm.

[0040] The charge confinement layer 25 is intended to confine carriers (e.g., electrons) generated in the photoelectric conversion layer 26, for example, carriers generated within the layer of the photoelectric conversion layer 26 above the shield electrode 21C, within the layer, making it easier for them to be transported to the read electrode 21A side.

[0041] FIG. 4 shows an example of the relationship between the energy levels of the oxide semiconductor layer 23, protective layer 24, charge confinement layer 25, and photoelectric conversion layer 26 that constitute the photoelectric conversion unit 20. When the LUMO (Lowest Unoccupied Molecular Orbital) of the photoelectric conversion layer 26 is E0, the conduction band energy of the protective layer 24 is E1, the conduction band energy of the oxide semiconductor layer 23 is E2, and the LUMO of the charge confinement layer 25 is E4, it is preferable that at least |E4|≧|E0| be satisfied. It is also preferable that |E1|−|E4|≧−0.4 be satisfied, and it is even more preferable that |E2|−|E1|≧−0.4 be satisfied. The energy levels are defined as relative values, with the vacuum level being 0. In FIG. 4, the vacuum level is at the top of the vertical axis (not shown), and as you move downward, the negative values ​​become smaller and the absolute values ​​become larger.

[0042] The charge confinement layer 25 can be formed using, for example, the following materials. For example, the charge confinement layer 25 preferably has excellent charge mobility in the in-plane direction (XY plane direction) of the charge confinement layer 25 among the three-dimensional directions. Furthermore, the charge confinement layer 25 is preferably formed using, for example, a material that is edge-on oriented in the in-plane direction (XY plane direction) of the lower electrode 21. In the photodetector element 1 of this embodiment that reads out electrons as signal charges, the material that satisfies the above conditions is, for example, C, which is an n-type semiconductor material. ６０ Fullerene or C ６０ Examples of the charge confinement layer 25 include fullerene derivatives and perylene derivatives. The thickness of the charge confinement layer 25 is not particularly limited, but if it is too thin, the charge transport property decreases, and if it is too thick, the charge confinement performance decreases. Therefore, the thickness of the charge confinement layer 25 may be, for example, 3 nm or more, and the upper limit is, for example, 60 nm or less.

[0043] The energy levels of the layers 23, 24, 25, and 26 can be analyzed by a gas cluster ion beam ultraviolet photoelectron spectroscopy (GCIB-UPS). The presence or absence of orientation of the material molecules constituting the charge confinement layer 25 can be confirmed by X-ray diffraction (XRD).

[0044] 1 shows an example in which the charge confinement layer 25 is provided over the entire surface between the protective layer 24 and the photoelectric conversion layer 26, but the present invention is not limited to this. The charge confinement layer 25 may be selectively provided at least above the shield electrode 21C to which an electric field weaker than the electric field applied above the charge storage electrode 21B is applied. In other words, the charge confinement layer 25 may be selectively provided, for example, at least outside the charge storage electrode 21B in a plan view. This makes it easier for electrons generated in the photoelectric conversion layer 26 above the shield electrode 21C to be transported to the readout electrode 21A.

[0045] The photoelectric conversion layer 26 converts light energy into electrical energy. The photoelectric conversion layer 26 is configured, for example, by including two or more organic materials (p-type semiconductor materials or n-type semiconductor materials) that function as p-type or n-type semiconductors, respectively. The photoelectric conversion layer 26 has a junction surface (p / n junction surface) between a p-type semiconductor material and an n-type semiconductor material within the layer. The p-type semiconductor functions relatively as an electron donor, and the n-type semiconductor functions relatively as an electron acceptor. The photoelectric conversion layer 26 provides a site where excitons generated upon light absorption separate into electrons and holes. Specifically, the excitons separate into electrons and holes at the interface (p / n junction surface) between the electron donor and electron acceptor.

[0046] In addition to the p-type and n-type semiconductor materials, the photoelectric conversion layer 26 may also contain an organic material, a so-called dye material, that photoelectrically converts light in a predetermined wavelength range while transmitting light in other wavelength ranges. When the photoelectric conversion layer 26 is formed using three types of organic materials, i.e., a p-type semiconductor material, an n-type semiconductor material, and a dye material, the p-type and n-type semiconductor materials are preferably materials that are optically transparent in the visible range (e.g., 450 nm to 800 nm). The thickness of the photoelectric conversion layer 26 is, for example, 50 nm to 500 nm.

[0047] Examples of organic materials that can be used to form the photoelectric conversion layer 26 include quinacridone derivatives, naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, and fluoranthene derivatives. The photoelectric conversion layer 26 is formed by combining two or more of the above organic materials. Depending on the combination, the above organic materials function as p-type or n-type semiconductors.

[0048] The organic material constituting the photoelectric conversion layer 26 is not particularly limited. In addition to the above-mentioned organic materials, for example, polymers of phenylene vinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, diacetylene, and the like, or derivatives thereof, can be used. Alternatively, metal complex dyes, cyanine dyes, merocyanine dyes, phenylxanthene dyes, triphenylmethane dyes, rhodacyanine dyes, xanthene dyes, macrocyclic azaannulene dyes, azulene dyes, naphthoquinone dyes, anthraquinone dyes, condensed polycyclic aromatic compounds such as pyrene, linear compounds in which aromatic rings or heterocyclic compounds are condensed, quinoline having a squarylium group and a croconite methine group as a bonding chain, two nitrogen-containing heterocycles such as benzothiazole and benzoxazole, or cyanine-like dyes bonded by a squarylium group and a croconite methine group, can be used. Examples of the metal complex dye include dithiol metal complex dyes, metal phthalocyanine dyes, metal porphyrin dyes, and ruthenium complex dyes. Of these, ruthenium complex dyes are particularly preferred, but the invention is not limited to these.

[0049] The upper electrode 27 is made of a conductive film having optical transparency, similar to the lower electrode 21, and is made of, for example, ITO (indium tin oxide). In addition to ITO, the upper electrode 27 can also be made of a material such as tin oxide (SnO ２Alternatively, a zinc oxide-based material obtained by adding a dopant to zinc oxide (ZnO) may be used. Examples of zinc oxide-based materials include aluminum zinc oxide (AZO) to which aluminum (Al) is added as a dopant, gallium zinc oxide (GZO) to which gallium (Ga) is added, and indium zinc oxide (IZO) to which indium (In) is added. Other examples include IGZO, ITZO, CuI, and InSbO. ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３ The upper electrode 27 may be separated for each unit pixel P, or may be formed as an electrode common to all pixels P. The thickness of the upper electrode 27 is, for example, 10 nm to 200 nm.

[0050] In the photoelectric conversion unit 20, other layers may be provided between the lower electrode 21 and the photoelectric conversion layer 26 (for example, between the oxide semiconductor layer 23 and the photoelectric conversion layer 26) and between the photoelectric conversion layer 26 and the upper electrode 27. For example, the photoelectric conversion unit 20 may have, stacked in this order from the lower electrode 21 side, the oxide semiconductor layer 23, a buffer layer also serving as an electron blocking film, the photoelectric conversion layer 26, a buffer layer also serving as a hole blocking film, and a work function adjustment layer. In addition, the photoelectric conversion layer 26 may have a pin bulk heterostructure in which, for example, a p-type blocking layer, a layer including a p-type semiconductor and an n-type semiconductor (i-layer), and an n-type blocking layer are stacked.

[0051] The insulating layer 28 covers the first surface 30S1 of the semiconductor substrate 30, reduces the interface state density with the semiconductor substrate 30, and suppresses the generation of dark current from the interface with the semiconductor substrate 30. The insulating layer 28 also extends from the first surface 30S1 of the semiconductor substrate 30 to the side surface of an opening 34H (see FIG. 8 ) in which a through electrode 34 that penetrates the semiconductor substrate 30 is formed. The insulating layer 28 has, for example, a stacked structure of a fixed charge layer 28A and a dielectric layer 28B.

[0052] The fixed charge layer 28A may be a film having a positive fixed charge or a film having a negative fixed charge. The fixed charge layer 28A is preferably formed using a semiconductor material or a conductive material having a wider band gap than the semiconductor substrate 30. This makes it possible to suppress the generation of dark current at the interface of the semiconductor substrate 30. The fixed charge layer 28A may be formed using, for example, hafnium oxide (HfO ｘ ), aluminum oxide (AlO ｘ ), zirconium oxide (ZrO ｘ ), tantalum oxide (TaO ｘ ), titanium oxide (TiO ｘ ), lanthanum oxide (LaO ｘ ), praseodymium oxide (PrO ｘ ), cerium oxide (CeO ｘ ), neodymium oxide (NdO ｘ ), promethium oxide (PmO ｘ ), samarium oxide (SmO ｘ ), europium oxide (EuO ｘ ), gadolinium oxide (GdO ｘ ), terbium oxide (TbO ｘ ), dysprosium oxide (DyO ｘ ), holmium oxide (HoO ｘ ), thulium oxide (TmO ｘ ), ytterbium oxide (YbO ｘ ), lutetium oxide (LuO ｘ ), yttrium oxide (YO ｘ ), hafnium nitride (HfN ｘ ), aluminum nitride (AlN ｘ ), hafnium oxynitride (HfO ｘ N ｙ ) and aluminum oxynitride (AlO ｘ N ｙ ) etc.

[0053] The dielectric layer 28B is intended to prevent light reflection caused by the difference in refractive index between the semiconductor substrate 30 and the interlayer insulating layer 29. The constituent material of the dielectric layer 28B is preferably a material having a refractive index between the refractive index of the semiconductor substrate 30 and the refractive index of the interlayer insulating layer 29. Examples of constituent materials of the dielectric layer 28B include silicon oxide, TEOS, silicon nitride, and silicon oxynitride (SiON).

[0054] The interlayer insulating layer 29 is formed of, for example, a single layer film made of one of silicon oxide, silicon nitride, silicon oxynitride, etc., or a laminated film made of two or more of these materials.

[0055] The semiconductor substrate 30 is made of, for example, an n-type silicon (Si) substrate, and has a p-well 31 in a predetermined region.

[0056] The photoelectric conversion regions 32B and 32R are each composed of a photodiode (PD) having a pn junction in a predetermined region of the semiconductor substrate 30. They utilize the fact that different wavelengths of light are absorbed depending on the depth of incidence of light in the Si substrate to enable vertical light separation. The photoelectric conversion region 32B selectively detects, for example, blue light and accumulates signal charges corresponding to the blue color, and is located at a depth that allows efficient photoelectric conversion of the blue light. The photoelectric conversion region 32R selectively detects, for example, red light and accumulates signal charges corresponding to the red color, and is located at a depth that allows efficient photoelectric conversion of the red light. Note that blue (B) corresponds to a wavelength range of, for example, 450 nm to 495 nm, and red (R) corresponds to a wavelength range of, for example, 620 nm to 750 nm. Each of the photoelectric conversion regions 32B and 32R may be capable of detecting light in some or all of the respective wavelength ranges.

[0057] The photoelectric conversion region 32B includes, for example, a p+ region that serves as a hole accumulation layer and an n region that serves as an electron accumulation layer. The photoelectric conversion region 32R includes, for example, a p+ region that serves as a hole accumulation layer and an n region that serves as an electron accumulation layer (having a p-n-p stacked structure). The n region of the photoelectric conversion region 32B is connected to the vertical transfer transistor Tr2. The p+ region of the photoelectric conversion region 32B bends along the transfer transistor Tr2 and connects to the p+ region of the photoelectric conversion region 32R.

[0058] The gate insulating layer 33 is configured, for example, as a single layer film made of one of silicon oxide, silicon nitride, silicon oxynitride, etc., or as a laminated film made of two or more of these materials.

[0059] The through electrode 34 is provided between the first surface 30S1 and the second surface 30S2 of the semiconductor substrate 30, and functions as a connector between the photoelectric conversion unit 20 and the gate Gamp of the amplifier transistor AMP and the floating diffusion FD1, and also serves as a transmission path for carriers generated in the photoelectric conversion unit 20. A reset gate Grst of the reset transistor RST is disposed adjacent to the floating diffusion FD1 (one of the source / drain regions 36B of the reset transistor RST). This makes it possible for the reset transistor RST to reset carriers accumulated in the floating diffusion FD1.

[0060] The pad portions 39A, 39B, 39C, the upper first contact 39D, the upper second contact 39E, the upper third contact 39F, the lower first contact 45, the lower second contact 46, and the wiring 52 can be formed using, for example, a doped silicon material such as PDAS (Phosphorus Doped Amorphous Silicon), or a metal material such as aluminum (Al), tungsten (W), titanium (Ti), cobalt (Co), hafnium (Hf), and tantalum (Ta).

[0061] The protective layer 51 and the on-chip lens 54 are made of a light-transmitting material, and are formed of, for example, a single layer film made of any of silicon oxide, silicon nitride, silicon oxynitride, etc., or a laminated film made of two or more of these materials. The thickness of this protective layer 51 is, for example, 100 nm to 30,000 nm.

[0062] The light-shielding film 53 is provided, for example, together with the wiring 52, in the protective layer 51 so as to cover at least the region of the readout electrode 21A that is in direct contact with the oxide semiconductor layer 23, but not the charge storage electrode 21B. The light-shielding film 53 can be formed using, for example, tungsten (W), aluminum (Al), an alloy of Al and copper (Cu), or the like.

[0063] Fig. 5 is an equivalent circuit diagram of the photodetector element 1 shown in Fig. 1. Fig. 6 is a schematic diagram showing the arrangement of the lower electrode 21 and transistors constituting the control section of the photodetector element 1 shown in Fig. 1.

[0064] The reset transistor RST (reset transistor TR1rst) resets carriers transferred from the photoelectric conversion unit 20 to the floating diffusion FD1, and is configured, for example, by a MOS transistor. Specifically, the reset transistor TR1rst is configured by a reset gate Grst, a channel formation region 36A, and source / drain regions 36B and 36C. The reset gate Grst is connected to a reset line RST1, and one source / drain region 36B of the reset transistor TR1rst also serves as the floating diffusion FD1. The other source / drain region 36C constituting the reset transistor TR1rst is connected to a power supply line VDD.

[0065] The amplifier transistor AMP (amplifier transistor TR1amp) is a modulation element that modulates the amount of charge generated in the photoelectric conversion unit 20 into a voltage, and is configured, for example, by a MOS transistor. Specifically, the amplifier transistor AMP is configured with a gate Gamp, a channel formation region 35A, and source / drain regions 35B and 35C. The gate Gamp is connected to the readout electrode 21A and one source / drain region 36B (floating diffusion FD1) of the reset transistor TR1rst via a lower first contact 45, a connection portion 41A, a lower second contact 46, a through-electrode 34, etc. Furthermore, one source / drain region 35B shares an area with the other source / drain region 36C that constitutes the reset transistor TR1rst, and is connected to the power supply line VDD.

[0066] The select transistor SEL (select transistor TR1sel) is composed of a gate Gsel, a channel formation region 34A, and source / drain regions 34B and 34C. The gate Gsel is connected to a select line SEL1. One source / drain region 34B shares an area with the other source / drain region 35C that constitutes the amplifier transistor AMP, and the other source / drain region 34C is connected to a signal line (data output line) VSL1.

[0067] The transfer transistor TR2 (transfer transistor TR2trs) transfers signal charges corresponding to blue generated and accumulated in the photoelectric conversion region 32B to the floating diffusion FD2. Because the photoelectric conversion region 32B is formed deep below the second surface 30S2 of the semiconductor substrate 30, the transfer transistor TR2trs in the photoelectric conversion region 32B is preferably configured as a vertical transistor. The transfer transistor TR2trs is connected to a transfer gate line TG2. A floating diffusion FD2 is provided in the region 37C near the gate Gtrs2 of the transfer transistor TR2trs. Carriers accumulated in the photoelectric conversion region 32B are read out to the floating diffusion FD2 via a transfer channel formed along the gate Gtrs2.

[0068] The transfer transistor TR3 (transfer transistor TR3trs) transfers the signal charges corresponding to red that are generated and accumulated in the photoelectric conversion region 32R to the floating diffusion FD3, and is configured, for example, by a MOS transistor. The transfer transistor TR3trs is connected to a transfer gate line TG3. A floating diffusion FD3 is provided in the region 38C near the gate Gtrs3 of the transfer transistor TR3trs. Carriers accumulated in the photoelectric conversion region 32R are read out to the floating diffusion FD3 via a transfer channel formed along the gate Gtrs3.

[0069] Further provided on the second surface 30S2 side of the semiconductor substrate 30 are a reset transistor TR2rst, an amplifier transistor TR2amp, and a selection transistor TR2sel that constitute the control section of the photoelectric conversion region 32B. Further provided are a reset transistor TR3rst, an amplifier transistor TR3amp, and a selection transistor TR3sel that constitute the control section of the photoelectric conversion region 32R.

[0070] The reset transistor TR2rst is composed of a gate, a channel forming region, and source / drain regions. The gate of the reset transistor TR2rst is connected to a reset line RST2, and one of the source / drain regions of the reset transistor TR2rst is connected to a power supply line VDD. The other source / drain region of the reset transistor TR2rst also serves as a floating diffusion FD2.

[0071] The amplifier transistor TR2amp is composed of a gate, a channel forming region, and source / drain regions. The gate is connected to the other source / drain region (floating diffusion FD2) of the reset transistor TR2rst. One of the source / drain regions constituting the amplifier transistor TR2amp shares the same region with one of the source / drain regions constituting the reset transistor TR2rst and is connected to the power supply line VDD.

[0072] The selection transistor TR2sel is composed of a gate, a channel formation region, and source / drain regions. The gate is connected to a selection line SEL2. One of the source / drain regions constituting the selection transistor TR2sel is shared with the other source / drain region constituting the amplifier transistor TR2amp. The other source / drain region constituting the selection transistor TR2sel is connected to a signal line (data output line) VSL2.

[0073] The reset transistor TR3rst is composed of a gate, a channel forming region, and source / drain regions. The gate of the reset transistor TR3rst is connected to a reset line RST3, and one of the source / drain regions constituting the reset transistor TR3rst is connected to a power supply line VDD. The other source / drain region constituting the reset transistor TR3rst also serves as a floating diffusion FD3.

[0074] The amplifier transistor TR3amp is composed of a gate, a channel forming region, and source / drain regions. The gate is connected to the other source / drain region (floating diffusion FD3) constituting the reset transistor TR3rst. One of the source / drain regions constituting the amplifier transistor TR3amp shares the same region with one of the source / drain regions constituting the reset transistor TR3rst and is connected to the power supply line VDD.

[0075] The selection transistor TR3sel is composed of a gate, a channel formation region, and source / drain regions. The gate is connected to a selection line SEL3. One of the source / drain regions constituting the selection transistor TR3sel shares the same region with the other of the source / drain regions constituting the amplifier transistor TR3amp. The other of the source / drain regions constituting the selection transistor TR3sel is connected to a signal line (data output line) VSL3.

[0076] The reset lines RST1, RST2, and RST3, the selection lines SEL1, SEL2, and SEL3, and the transfer gate lines TG2 and TG3 are connected to vertical drive circuits that constitute the drive circuit, and the signal lines (data output lines) VSL1, VSL2, and VSL3 are connected to a column signal processing circuit 112 that constitutes the drive circuit.

[0077] (1-2. Method for Manufacturing Photodetector) The photodetector 1 of this embodiment can be manufactured, for example, as follows.

[0078] 7 to 12 show the order of steps in the manufacturing method of the photodetector element 1. First, as shown in Fig. 7, for example, a p-well 31 is formed in a semiconductor substrate 30, and for example, n-type photoelectric conversion regions 32B and 32R are formed in this p-well 31. A p+ region is formed near the first surface 30S1 of the semiconductor substrate 30.

[0079] 7, n+ regions that will become floating diffusions FD1 to FD3 are formed on the second surface 30S2 of the semiconductor substrate 30, followed by the formation of a gate insulating layer 33 and a gate wiring layer 47 including the gates of the transfer transistor Tr2, the transfer transistor Tr3, the select transistor SEL, the amplifier transistor AMP, and the reset transistor RST. This results in the formation of the transfer transistor Tr2, the transfer transistor Tr3, the select transistor SEL, the amplifier transistor AMP, and the reset transistor RST. Furthermore, a multilayer wiring layer 40 is formed on the second surface 30S2 of the semiconductor substrate 30, which includes wiring layers 41 to 43, each including a lower first contact 45, a lower second contact 46, and a connection portion 41A, and an insulating layer 44.

[0080] The base of the semiconductor substrate 30 is, for example, an SOI (Silicon on Insulator) substrate in which the semiconductor substrate 30, a buried oxide film (not shown), and a holding substrate (not shown) are stacked. Although not shown in FIG. 7, the buried oxide film and the holding substrate are bonded to the first surface 30S1 of the semiconductor substrate 30. After the ion implantation, an annealing process is performed.

[0081] Next, a support substrate (not shown) or another semiconductor substrate is bonded to the multilayer wiring layer 40 provided on the second surface 30S2 side of the semiconductor substrate 30, and the semiconductor substrate 30 is then turned upside down. Subsequently, the semiconductor substrate 30 is separated from the buried oxide film of the SOI substrate and the support substrate, exposing the first surface 30S1 of the semiconductor substrate 30. The above steps can be performed using techniques used in ordinary CMOS processes, such as ion implantation and CVD (Chemical Vapor Deposition).

[0082] 8, the semiconductor substrate 30 is processed from the first surface 30S1 side by, for example, dry etching to form, for example, an annular opening 34H. As shown in FIG. 8, the depth of the opening 34H penetrates from the first surface 30S1 to the second surface 30S2 of the semiconductor substrate 30 and reaches, for example, the connection portion 41A.

[0083] Next, for example, a fixed charge layer 28A and a dielectric layer 28B are sequentially formed on the first surface 30S1 of the semiconductor substrate 30 and the side surfaces of the opening 34H. The fixed charge layer 28A can be formed, for example, by depositing a hafnium oxide film or an aluminum oxide film using atomic layer deposition (ALD). The dielectric layer 28B can be formed, for example, by depositing a silicon oxide film using plasma CVD. Next, pad portions 39A, 39B, and 39C are formed at predetermined positions on the dielectric layer 28B, each of which includes a barrier metal layer made of, for example, a titanium / titanium nitride (Ti / TiN) film and a tungsten film stacked together. This allows the pad portions 39A and 39B to be used as light-shielding films. After that, an interlayer insulating layer 29 is formed on the dielectric layer 28B and the pad portions 39A, 39B, and 39C, and the surface of the interlayer insulating layer 29 is planarized using CMP (chemical mechanical polishing).

[0084] Next, as shown in FIG. 9, openings 29H1, 29H2, and 29H3 are formed on the pad portions 39A, 39B, and 39C, respectively, and then a conductive material such as Al is filled into the openings 29H1, 29H2, and 29H3 to form an upper first contact 39D, an upper second contact 39E, and an upper third contact 39F.

[0085] 10, a conductive film 21x is formed on the interlayer insulating layer 29 by, for example, sputtering, and then patterned by photolithography. Specifically, a photoresist PR is formed at a predetermined position on the conductive film 21x, and the conductive film 21x is then processed by dry etching or wet etching. The photoresist PR is then removed, thereby forming the read electrode 21A, the charge storage electrode 21B, and the seal electrode 21C, as shown in FIG.

[0086] Next, as shown in FIG. 12 , an insulating layer 22, an oxide semiconductor layer 23, a protective layer 24, a charge confinement layer 25, a photoelectric conversion layer 26, and an upper electrode 27 are formed. The insulating layer 22 is formed by depositing a silicon oxide film using, for example, an ALD method, and then planarizing the surface of the insulating layer 22 using a CMP method. An opening 22H is then formed on the readout electrode 21A using, for example, wet etching. The oxide semiconductor layer 23 and the protective layer 24 can be formed using, for example, a sputtering method. The charge confinement layer 25 and the photoelectric conversion layer 26 are formed using, for example, a vacuum deposition method. The upper electrode 27 is formed, similarly to the lower electrode 21, using, for example, a sputtering method. Finally, a protective layer 51 including wiring 52 and a light-shielding film 53, and an on-chip lens 54 are disposed on the upper electrode 27. This completes the photodetector 1 shown in FIG. 1 .

[0087] As described above, when other layers containing organic materials, such as a buffer layer also serving as an electron blocking film, a buffer layer also serving as a hole blocking film, or a work function adjustment layer, are formed between the oxide semiconductor layer 23 and the photoelectric conversion layer 26 and between the photoelectric conversion layer 26 and the upper electrode 27, it is desirable to form each layer consecutively in a vacuum process (through a vacuum integrated process). Furthermore, the method for forming the photoelectric conversion layer 26 is not necessarily limited to a method using vacuum deposition, and for example, spin coating or printing may also be used. Furthermore, methods for forming the transparent electrodes (lower electrode 21 and upper electrode 27) include, in addition to sputtering, physical vapor deposition (PVD) methods such as vacuum deposition, reactive deposition, electron beam deposition, and ion plating, pyrosol deposition, various CVD methods including thermal decomposition of organometallic compounds, spray deposition, dipping, and MOCVD, electroless plating, and electrolytic plating, depending on the material constituting the transparent electrodes.

[0088] (1-3. Signal Acquisition Operation of Photodetection Element) In the photodetection element 1, when light is incident on the photoelectric conversion unit 20 via the on-chip lens 54, the light passes through the photoelectric conversion unit 20 and the photoelectric conversion regions 32B and 32R in that order, and is photoelectrically converted into green (G), blue (B), and red (R) color light during this passage. The signal acquisition operation for each color will be described below.

[0089] (Acquisition of Green Signal by Photoelectric Conversion Unit 20) Of the light incident on the photodetector element 1, first, green light is selectively detected (absorbed) by the photoelectric conversion unit 20 and photoelectrically converted.

[0090] The photoelectric conversion unit 20 is connected to the gate Gamp of the amplifier transistor TR1amp and the floating diffusion FD1 via the through electrode 34. Therefore, electrons of excitons generated in the photoelectric conversion unit 20 are extracted from the lower electrode 21 side, transferred to the second surface 30S2 side of the semiconductor substrate 30 via the through electrode 34, and accumulated in the floating diffusion FD1. At the same time, the amount of charge generated in the photoelectric conversion unit 20 is modulated into a voltage by the amplifier transistor TR1amp.

[0091] In addition, a reset gate Grst of the reset transistor TR1rst is disposed next to the floating diffusion FD1, so that carriers accumulated in the floating diffusion FD1 are reset by the reset transistor TR1rst.

[0092] The photoelectric conversion unit 20 is connected not only to the amplifier transistor TR1amp but also to the floating diffusion FD1 via the through electrode 34, so that carriers accumulated in the floating diffusion FD1 can be easily reset by the reset transistor TR1rst.

[0093] On the other hand, if the through electrode 34 and the floating diffusion FD1 are not connected, it becomes difficult to reset the carriers accumulated in the floating diffusion FD1, and a large voltage must be applied to extract them to the upper electrode 27. This may damage the photoelectric conversion layer 26. Furthermore, a structure that enables resetting in a short time increases dark noise, which is a trade-off, making this structure difficult to implement.

[0094] 13 shows an example of operation of the photodetector element 1. (A) shows the potential at the charge storage electrode 21B, (B) shows the potential at the floating diffusion FD1 (readout electrode 21A), and (C) shows the potential at the gate (Gsel) of the reset transistor TR1rst. In the photodetector element 1, voltages are applied to the readout electrode 21A and the charge storage electrode 21B individually.

[0095] In the photodetector element 1, during the accumulation period, a potential V1 is applied to the readout electrode 21A from the drive circuit, and a potential V2 is applied to the charge storage electrode 21B. Here, the relationship between potentials V1 and V2 is V2 > V1. As a result, carriers (signal charges; electrons) generated by photoelectric conversion are attracted to the charge storage electrode 21B and accumulated in the region of the oxide semiconductor layer 23 facing the charge storage electrode 21B (accumulation period). Incidentally, the potential of the region of the oxide semiconductor layer 23 facing the charge storage electrode 21B becomes more negative as the photoelectric conversion time elapses. Note that holes are sent from the upper electrode 27 to the drive circuit.

[0096] In the photodetector element 1, a reset operation is performed in the latter half of the accumulation period. Specifically, at timing t1, the scanning unit changes the voltage of the reset signal RST from low to high. As a result, in the unit pixel P, the reset transistor TR1rst is turned on, and as a result, the voltage of the floating diffusion FD1 is set to the power supply voltage and the voltage of the floating diffusion FD1 is reset (reset period).

[0097] After the reset operation is completed, carriers are read out. Specifically, at timing t2, the drive circuit applies a potential V3 to the readout electrode 21A and a potential V4 to the charge storage electrode 21B. Here, the potentials V3 and V4 are set to V3 > V4. As a result, the carriers stored in the region corresponding to the charge storage electrode 21B are read out from the readout electrode 21A to the floating diffusion FD1. That is, the carriers stored in the oxide semiconductor layer 23 are read out to the control unit (transfer period).

[0098] After the read operation is completed, the drive circuit again applies potential V1 to the read electrode 21A and potential V2 to the charge storage electrode 21B, causing carriers generated by photoelectric conversion to be attracted to the charge storage electrode 21B and stored in the region of the photoelectric conversion layer 26 facing the charge storage electrode 21B (storage period).

[0099] (Acquisition of Blue and Red Signals by Photoelectric Conversion Regions 32B and 32R) Next, of the light transmitted through the photoelectric conversion unit 20, the blue light is absorbed and photoelectrically converted in photoelectric conversion region 32B, and the red light is absorbed and photoelectrically converted in photoelectric conversion region 32R, respectively. In photoelectric conversion region 32B, electrons corresponding to the incident blue light are accumulated in the n-region of photoelectric conversion region 32B, and the accumulated electrons are transferred to floating diffusion FD2 by transfer transistor Tr2. Similarly, in photoelectric conversion region 32R, electrons corresponding to the incident red light are accumulated in the n-region of photoelectric conversion region 32R, and the accumulated electrons are transferred to floating diffusion FD3 by transfer transistor Tr3.

[0100] (1-4. Actions and Effects) In the photodetector element 1 of this embodiment, the charge confinement layer 25 is provided in the photoelectric conversion unit 20 between the lower electrode 21 including the readout electrode 21A, the charge storage electrode 21B, and the shield electrode 21C and the photoelectric conversion layer 26, at least outside the charge storage electrode 21B in plan view. This promotes the transport of carriers (e.g., electrons) generated outside the charge storage electrode 21B, specifically in the layer of the photoelectric conversion layer 26 above the shield electrode 21C, toward the readout electrode 21A. This will be described below.

[0101] 14 shows a cross-sectional configuration (A) of a typical photoelectric conversion unit 120 as a comparative example, and the potential of each unit (B). Generally, a weaker electric field is applied above the shield electrode 121C than the electric field applied above the charge storage electrode 121B. Therefore, carriers (e.g., electrons) generated in the layer of the photoelectric conversion layer 126 above the shield electrode 121C tend to be left behind above the shield electrode 121C without being transported to the oxide semiconductor layer 123. The carriers left behind above the shield electrode 121C recombine, causing a decrease in EQE.

[0102] In contrast to this, in the present embodiment, for example, a charge confinement layer 25 having excellent charge mobility in the in-plane direction (XY plane direction) of the charge confinement layer 25 among three-dimensional directions is provided at least outside the charge storage electrode 21B in a plan view between the oxide semiconductor layer 23 and the photoelectric conversion layer 26. This makes it easier for carriers (e.g., electrons) generated in the photoelectric conversion layer 26 above the shield electrode 21C to be transported to the readout electrode 21A side.

[0103] As a result, in the photodetector element 1 of this embodiment, compared to a general photodetector element, it is possible to read carriers (e.g., electrons) generated in the photoelectric conversion layer 26 between adjacent unit pixels P, where the shield electrode 21C is provided, for example. This makes it possible to improve the photodetection characteristics, particularly the EQE.

[0104] Next, modified examples of the present disclosure (modification examples 1 to 6) will be described. In the following, the same components as those in the above embodiment will be given the same reference numerals, and the description thereof will be omitted as appropriate.

[0105] 15 is a schematic diagram illustrating a cross-sectional configuration of a main portion (photoelectric conversion unit 20A) of a photodetector according to Modification 1 of the present disclosure. Photoelectric conversion unit 20A of this modification differs from the above embodiment in that a buffer layer 55 is provided between charge confinement layer 25 and photoelectric conversion layer 26. Here, buffer layer 55 corresponds to a specific example of a "second intermediate layer" in an embodiment of the present disclosure.

[0106] The buffer layer 55 is intended to prevent carriers (e.g., electrons) generated in the photoelectric conversion layer 26 above the shield electrode 21C from returning to the photoelectric conversion layer 26 when, for example, they diffuse through the charge confinement layer 25 toward the readout electrode 21A. The buffer layer 55 is also intended to improve photoelectric conversion efficiency by blocking excitons generated in the photoelectric conversion layer 26.

[0107] 16 shows an example of the relationship between the energy levels of the oxide semiconductor layer 23, protective layer 24, charge confinement layer 25, buffer layer 55, and photoelectric conversion layer 26 that constitute the photoelectric conversion unit 20A. When the LUMO of the photoelectric conversion layer 26 is E0, the conduction band energy of the protective layer 24 is E1, the conduction band energy of the oxide semiconductor layer 23 is E2, the LUMO of the charge confinement layer 25 is E4, and the LUMO of the buffer layer 55 is E5, it is preferable that at least E4≧E0≧E5 be satisfied. It is also preferable that E4−E1≧−0.4 be satisfied, and it is even more preferable that E1−E2≧−0.4 be satisfied.

[0108] The buffer layer 55 can be formed using, for example, the following materials. Examples of materials for the buffer layer 55 include 4,6-Bis(3,5-di(pyridin-4-yl)phenyl)-2-methylpyrimidine, 4,6-Bis(3,5-di-4-pyridinylphenyl)-2-methylpyrimidine (B4Py), subphthalocyanine, and subphthalocyanine derivatives. The thickness of the buffer layer 55 may be, for example, 1 nm or more, and the upper limit is, for example, 50 nm or less. If the thickness of the buffer layer 55 is too thin, coverage decreases, resulting in insufficient exciton blocking, while if the thickness is too thick, charge migration is inhibited, which is undesirable.

[0109] In this way, in this modification, the buffer layer 55 is provided between the charge confinement layer 25 and the photoelectric conversion layer 26. This makes it possible to more effectively confine carriers (e.g., electrons) in the charge confinement layer 25 in the low electric field region compared to the above embodiment, thereby further improving the EQE.

[0110] (2-2. Modification 2) FIG. 17 is a schematic diagram illustrating a cross-sectional configuration of a photodetector element 1A according to Modification 2 of the present disclosure. FIG. 18 is a schematic diagram illustrating an example of the planar configuration of the photodetector element 1A illustrated in FIG. 17. FIG. 19 is a schematic diagram illustrating an enlarged cross-sectional configuration of a main portion (photoelectric conversion unit 20B) of the photodetector element 1 illustrated in FIG. 17. Like the photodetector element 1 of the above embodiment, the photodetector element 1A is provided for each pixel (unit pixel P) in a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras. The photodetector element 1A of this modification differs from the above embodiment in that the lower electrode 21 is formed of one electrode for each unit pixel P.

[0111] Similar to the photodetector element 1, the photodetector element 1A has one photoelectric conversion unit 20B and two photoelectric conversion regions 32B and 32R stacked in the vertical direction for each unit pixel P. The photoelectric conversion unit 20B is provided on the back surface (first surface 30S1) side of the semiconductor substrate 30. The photoelectric conversion regions 32B and 32R are embedded in the semiconductor substrate 30 and stacked in the thickness direction of the semiconductor substrate 30.

[0112] As described above, the photodetection element 1A of this modified example has the same configuration as the photodetection element 1, except that the lower electrode 21 provided for each unit pixel P of the photoelectric conversion section 20B consists of a single electrode (e.g., readout electrode 21A), and the insulating layer 22, oxide semiconductor layer 23, and protective layer 24 are not provided between the lower electrode 21 and the photoelectric conversion layer 26.

[0113] 20 shows an example of the relationship between the energy levels of the layers (interlayer insulating layer 29, charge confinement layer 25, and photoelectric conversion layer 26) above shield electrode 21C that constitutes photoelectric conversion unit 20B. When the LUMO of photoelectric conversion layer 26 is E0 and the LUMO of charge confinement layer 25 is E4, it is preferable that at least E4≧E0 be satisfied.

[0114] In this way, in this modification, the buffer layer 55 is provided between the charge confinement layer 25 and the photoelectric conversion layer 26. This makes it possible to more effectively confine carriers (e.g., electrons) in the charge confinement layer 25 in the low electric field region compared to the above embodiment, thereby further improving the EQE.

[0115] In this way, the configuration of the photoelectric conversion unit is not limited to the photodetector element 1 of the above embodiment, and the same effects as those of the above embodiment can be obtained with the configuration of the photoelectric conversion unit 20B of the photodetector element 1A of this modified example.

[0116] In the photoelectric conversion unit 20B in which the insulating layer 22, the oxide semiconductor layer 23, and the protective layer 24 are not provided between the lower electrode 21 and the photoelectric conversion layer 26 as in this modification, holes may be read out as signal charges. In this case, when the HOMO of the photoelectric conversion unit 20B is E0, the HOMO of the buffer layer is E1, and the HOMO of the charge trapping layer is E2, it is preferable to satisfy at least |E0|≧|E2|. It is also preferable to satisfy |E1|≧|E0|≧|E2|. This allows for the same effects as those of the above embodiment to be obtained.

[0117] 21 is a schematic diagram illustrating a cross-sectional configuration of a main part (photoelectric conversion unit 20C) of a photodetector according to Modification 3 of the present disclosure. Photoelectric conversion unit 20C according to this modification differs from Modification 2 in that a buffer layer 55 is provided between charge confinement layer 25 and photoelectric conversion layer 26.

[0118] As in the first modification, the buffer layer 55 is intended to prevent carriers (e.g., electrons) generated in the photoelectric conversion layer 26 above the shield electrode 21C from returning to the photoelectric conversion layer 26 when, for example, they diffuse through the charge confinement layer 25 toward the readout electrode 21A. The buffer layer 55 is also intended to improve the photoelectric conversion efficiency by blocking excitons generated in the photoelectric conversion layer 26.

[0119] 22 shows an example of the relationship between the energy levels of the layers (interlayer insulating layer 29, charge confinement layer 25, buffer layer 55, and photoelectric conversion layer 26) above shield electrode 21C that constitutes photoelectric conversion unit 20A. When the LUMO of photoelectric conversion layer 26 is E0, the LUMO of charge confinement layer 25 is E4, and the LUMO of buffer layer 55 is E5, it is preferable that at least E4≧E0≧E5 be satisfied.

[0120] As described above, in this modification, in photoelectric conversion unit 20C in which oxide semiconductor layer 23 and protective layer 24 are not present between shield electrode 21C and charge confinement layer 25, buffer layer 55 is provided between charge confinement layer 25 and photoelectric conversion layer 26. Even in this configuration, carriers (e.g., electrons) can be effectively confined in charge confinement layer 25 in the low electric field region, as in modification 1. This makes it possible to further improve the EQE.

[0121] 23 is a schematic diagram illustrating a cross-sectional configuration of a photodetector 1B according to a fourth modification of the present disclosure. Similar to the photodetector 1 of the above embodiment, the photodetector 1B is provided for each pixel (unit pixel P) in a photodetector such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras. The photodetector 1B of this modification has two photoelectric conversion units 20, 80 and one photoelectric conversion region 32 stacked in the vertical direction.

[0122] The photoelectric conversion units 20 and 80 and the photoelectric conversion region 32 selectively detect light in different wavelength ranges and perform photoelectric conversion. For example, the photoelectric conversion unit 20 acquires a green (G) color signal. For example, the photoelectric conversion unit 80 acquires a blue (B) color signal. For example, the photoelectric conversion region 32 acquires a red (R) color signal. This makes it possible for the photodetector 1B to acquire multiple types of color signals in one pixel without using color filters.

[0123] The photoelectric conversion units 20 and 80 have a configuration similar to that of the photodetector element 1 of the above embodiment, for example. Specifically, like the photodetector element 1, the photoelectric conversion unit 20 includes a lower electrode 21, an insulating layer 22, an oxide semiconductor layer 23, a protective layer 24, a charge confinement layer 25, a photoelectric conversion layer 26, and an upper electrode 27 stacked in this order. The lower electrode 21 includes a plurality of electrodes (e.g., a readout electrode 21A, a charge storage electrode 21B, and a shield electrode 21C). Of the lower electrode 21, the readout electrode 21AA is electrically connected to the oxide semiconductor layer 23 through an opening 22H provided in the insulating layer 22. Like the photoelectric conversion unit 20, the photoelectric conversion unit 80 includes a lower electrode 81, an insulating layer 82, an oxide semiconductor layer 83, a protective layer 84, a charge confinement layer 85, a photoelectric conversion layer 86, and an upper electrode 87 stacked in this order. The lower electrode 81 is composed of a plurality of electrodes (for example, a read electrode 81A, a charge storage electrode 81B, and a shield electrode 81C). Of the lower electrode 81, the read electrode 81A is electrically connected to the oxide semiconductor layer 83 through an opening 82H provided in the insulating layer 82. Note that one or both of the oxide semiconductor layer 23 and the oxide semiconductor layer 83 may be omitted.

[0124] A through electrode 89 is connected to the read electrode 81A. The through electrode 89 penetrates the interlayer insulating layer 88 and the photoelectric conversion unit 20 and is electrically connected to the read electrode 21AA of the photoelectric conversion unit 20. The read electrode 81A is further electrically connected to a floating diffusion FD provided in the semiconductor substrate 30 via the through electrodes 34 and 89, and can temporarily store charges generated in the photoelectric conversion layer 86. The read electrode 81A is further electrically connected to an amplifier transistor AMP and the like provided in the semiconductor substrate 30 via the through electrodes 34 and 89.

[0125] (2-5. Modification 5) FIG. 24A is a schematic diagram illustrating a cross-sectional configuration of a photodetector element 1C according to Modification 5 of the present disclosure. FIG. 24B is a schematic diagram illustrating an example of the planar configuration of the photodetector element 1C illustrated in FIG. 24A, and FIG. 24A illustrates a cross section taken along line II-II illustrated in FIG. 24B. The photodetector element 1C is a stacked photodetector element in which, for example, a photoelectric conversion region 32 and a photoelectric conversion section 60 are stacked. In a pixel array section 100A of a photodetector device 100 including this photodetector element 1C, pixel units 1a each consisting of four unit pixels P arranged in two rows and two columns are repeated in an array formed in the row and column directions, as illustrated in FIG. 24B, for example.

[0126] In the photodetector element 1C of this modification, a color filter 56 that selectively transmits red light (R), green light (G), and blue light (B) is provided for each unit pixel P above the photoelectric conversion section 60 (on the light incident side S1). Specifically, in a pixel unit 1a consisting of four unit pixels P arranged in two rows and two columns, two color filters that selectively transmit green light (G) are arranged diagonally, and one color filter that selectively transmits red light (R) and blue light (B) is arranged on each diagonal that is perpendicular to the pixel unit 1a. In the unit pixels Pr, Pg, and Pb provided with each color filter, the corresponding color light is detected, for example, in the photoelectric conversion section 60. That is, in the pixel array section 100A, the unit pixels Pr, Pg, and Pb that detect red light (R), green light (G), and blue light (B), respectively, are arranged in a Bayer pattern.

[0127] The photoelectric conversion unit 60 absorbs light corresponding to some or all of the wavelengths in the visible light region of, for example, 400 nm or more and less than 750 nm to generate excitons (electron-hole pairs), and includes a lower electrode 61, an insulating layer (interlayer insulating layer 62), an oxide semiconductor layer 63, a protective layer 64, a charge confinement layer 65, a photoelectric conversion layer 66, and an upper electrode 67 stacked in this order. The lower electrode 61, the interlayer insulating layer 62, the oxide semiconductor layer 63, the protective layer 64, the charge confinement layer 65, the photoelectric conversion layer 66, and the upper electrode 67 have the same configurations as the lower electrode 21, the insulating layer 22, the oxide semiconductor layer 23, the protective layer 24, the charge confinement layer 25, the photoelectric conversion layer 26, and the upper electrode 27 of the photodetector element 1 in the above-described embodiment, etc. The lower electrode 61 includes, for example, a readout electrode 61A, a storage electrode 61B, and a shield electrode 61C that are independent of each other, and the readout electrode 61A is shared by, for example, four unit pixels P. The oxide semiconductor layer 63 may be omitted.

[0128] The photoelectric conversion region 32 detects, for example, an infrared light region of 750 nm or more and 1300 nm or less.

[0129] In the photodetector element 1C, light in the visible light region (red light (R), green light (G), and blue light (B)) that passes through the color filters 56 is absorbed by the photoelectric conversion units 60 of the unit pixels Pr, Pg, and Pb provided with each color filter, while other light, for example, light in the infrared light region (for example, 750 nm or more and 1000 nm or less) (infrared light (IR)), passes through the photoelectric conversion units 60. The infrared light (IR) that passes through the photoelectric conversion units 60 is detected in the photoelectric conversion regions 32 of each of the unit pixels Pr, Pg, and Pb, and signal charges corresponding to the infrared light (IR) are generated in each of the unit pixels Pr, Pg, and Pb. In other words, a photodetector device 100 including the photodetector element 1C is capable of simultaneously generating both visible light images and infrared light images.

[0130] Furthermore, the photodetector device 100 including the photodetector element 1C can acquire a visible light image and an infrared light image at the same position in the XZ in-plane direction, thereby enabling high integration in the XZ in-plane direction.

[0131] (2-6. Modification 6) Fig. 25A is a schematic diagram illustrating a cross-sectional configuration of a photodetector element 1D according to Modification 6 of the present disclosure. Fig. 25B is a schematic diagram illustrating an example of the planar configuration of the photodetector element 1D illustrated in Fig. 25A, and Fig. 25A illustrates a cross section taken along line III-III illustrated in Fig. 25B. In Modification 3 described above, the color filter 56 is provided above the photoelectric conversion unit 60 (on the light incident side S1). However, the color filter 56 may be provided, for example, between the photoelectric conversion region 32 and the photoelectric conversion unit 60, as illustrated in Fig. 25A.

[0132] In the photodetector element 1D, for example, the color filter 56 has a configuration in which a color filter (color filter 56R) that selectively transmits at least red light (R) and a color filter (color filter 56B) that selectively transmits at least blue light (B) are arranged diagonally opposite each other within the pixel unit 1a. The photoelectric conversion unit 60 (photoelectric conversion layer 66) is configured to selectively absorb light having a wavelength corresponding to green light (G), for example. The photoelectric conversion region 32R selectively absorbs light having a wavelength corresponding to red light (R), and the photoelectric conversion region 32B selectively absorbs light having a wavelength corresponding to blue light (B). This makes it possible to obtain signals corresponding to red light (R), green light (G), or blue light (B) in the photoelectric conversion regions 32 (photoelectric conversion regions 32R and 32B) that are arranged below the photoelectric conversion unit 60 and the color filters 56R and 56B, respectively. In the photodetector element 1D of this modified example, the area of ​​each photoelectric conversion section of RGB can be enlarged compared to a photoelectric conversion element having a general Bayer array, making it possible to improve the S / N ratio.

[0133] (2-5. Other Modifications) FIG. 26 illustrates another example (photodetection element 1E) of the cross-sectional configuration of the photodetection element 1B of Modification 2 according to another modification of the present disclosure. FIG. 27A schematically illustrates another example (photodetection element 1F) of the cross-sectional configuration of the photodetection element 1C of Modification 3 according to another modification of the present disclosure. FIG. 27B schematically illustrates an example of the planar configuration of the photodetection element 1F shown in FIG. 27A. FIG. 28A schematically illustrates another example (photodetection element 1G) of the cross-sectional configuration of the photodetection element 1D of Modification 4 according to another modification of the present disclosure. FIG. 28B schematically illustrates an example of the planar configuration of the photodetection element 1G shown in FIG. 28A.

[0134] In the above-described Modifications 4 to 6, examples have been shown in which the lower electrodes 21, 61, 81 constituting the photoelectric conversion units 60, 80 are each made up of a plurality of electrodes (for example, readout electrodes 21A, 61A and charge storage electrodes 21B, 61B) in the unit pixel P, but this is not limiting. As in the above-described Modification 1, the photodetector elements 1B, 1C, 1D according to Modifications 2 to 4 can also be applied to a case in which one electrode (for example, readout electrode 21A) is provided as the lower electrode for each unit pixel P and a shield electrode 21C is provided between adjacent unit pixels P, and the same effects as those of the above-described Modifications 4 to 6 can be obtained.

[0135] 3. Application Examples Application Example 1 FIG. 29 shows an example of the overall configuration of a photodetector 100 including the photodetector elements 1A to 1G shown in FIG. 1 and the like.

[0136] The photodetector 100 is, for example, a CMOS image sensor that captures incident light (image light) from a subject via an optical lens system (not shown), converts the amount of incident light imaged on an imaging surface into an electrical signal on a pixel-by-pixel basis, and outputs the signal as a pixel signal. The photodetector 100 has a pixel array 100A as an imaging area on a semiconductor substrate 30, and also has, in a peripheral region of the pixel array 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.

[0137] The pixel array section 100A has, for example, a plurality of unit pixels P arranged two-dimensionally in a matrix. For example, pixel drive lines Lread (specifically, row selection lines and reset control lines) are wired to each unit pixel P for each pixel row, and vertical signal lines Lsig are wired to each pixel column. The pixel drive lines Lread transmit drive signals for reading signals from the pixels. One end of each pixel drive line Lread is connected to an output terminal of the vertical drive circuit 111 corresponding to each row.

[0138] The vertical drive circuit 111 is a pixel drive unit that includes a shift register, an address decoder, etc., and drives each unit pixel P of the pixel array unit 100A, for example, row by row. Signals output from each unit pixel P of a pixel row selected and scanned by the vertical drive circuit 111 are supplied to a column signal processing circuit 112 through each vertical signal line Lsig. The column signal processing circuit 112 is configured with an amplifier, a horizontal selection switch, etc., provided for each vertical signal line Lsig.

[0139] The horizontal drive circuit 113 is configured with a shift register, an address decoder, etc., and scans and sequentially drives each horizontal selection switch of the column signal processing circuit 112. By selective scanning by this horizontal drive circuit 113, signals of each pixel transmitted through each vertical signal line Lsig are output in sequence to horizontal signal lines 121 and transmitted to the outside of the semiconductor substrate 30 through the horizontal signal lines 121.

[0140] The output circuit 114 processes and outputs signals sequentially supplied from each of the column signal processing circuits 112 via the horizontal signal line 121. The output circuit 114 may perform only buffering, or may perform black level adjustment, column variation correction, various digital signal processing, and the like, for example.

[0141] The circuit portion consisting of the vertical drive circuit 111, the column signal processing circuit 112, the horizontal drive circuit 113, the horizontal signal line 121, and the output circuit 114 may be formed directly on the semiconductor substrate 30, or may be disposed on an external control IC. Furthermore, these circuit portions may be formed on another substrate connected by a cable or the like.

[0142] The control circuit 115 receives a clock and data instructing an operation mode from outside the semiconductor substrate 30, and outputs data such as internal information of the photodetector 100. The control circuit 115 further has a timing generator that generates various timing signals, and controls the driving of peripheral circuits such as the vertical drive circuit 111, the column signal processing circuit 112, and the horizontal drive circuit 113 based on the various timing signals generated by the timing generator.

[0143] The input / output terminal 116 is used to exchange signals with the outside.

[0144] (Application Example 2) Furthermore, the photodetector 100 as described above can be applied to various electronic devices, such as imaging systems such as digital still cameras and digital video cameras, mobile phones with imaging functions, or other devices with imaging functions.

[0145] FIG. 30 is a block diagram showing an example of the configuration of electronic device 1000.

[0146] As shown in Figure 30, electronic device 1000 includes an optical system 1001, a photodetector 100, and a DSP (Digital Signal Processor) 1002, and is configured by connecting DSP 1002, memory 1003, display device 1004, recording device 1005, operation system 1006, and power supply system 1007 via a bus 1008, and is capable of capturing still images and moving images.

[0147] The optical system 1001 is configured to have one or more lenses, and receives incident light (image light) from an object and forms an image on the imaging surface of the photodetector 100 .

[0148] The photodetector 100 converts the amount of incident light that is imaged on the imaging surface by the optical system 1001 into an electrical signal for each pixel, and supplies the signal to the DSP 1002 as a pixel signal.

[0149] The DSP 1002 performs various signal processing on the signal from the photodetector 100 to acquire an image, and temporarily stores the image data in a memory 1003. The image data stored in the memory 1003 is recorded in a recording device 1005 or supplied to a display device 1004 to display the image. An operation system 1006 accepts various operations by a user and supplies operation signals to each block of the electronic device 1000, and a power supply system 1007 supplies power necessary to drive each block of the electronic device 1000.

[0150] 31A is a schematic diagram illustrating an example of the overall configuration of a light detection system 2000 including the light detection device 100. FIG. 31B is a diagram illustrating an example of the circuit configuration of the light detection system 2000. The light detection system 2000 includes a light emitting device 2001 serving as a light source unit that emits infrared light L2, and a light detection device 2002 serving as a light receiving unit having a photoelectric conversion element. The light detection device 100 described above can be used as the light detection device 2002. The light detection system 2000 may further include a system control unit 2003, a light source driving unit 2004, a sensor control unit 2005, a light source side optical system 2006, and a camera side optical system 2007.

[0151] The photodetector 2002 can detect light L1 and light L2. Light L1 is external ambient light reflected by the object (measurement target) 2100 ( FIG. 31A ). Light L2 is light emitted by the light-emitting device 2001 and then reflected by the object 2100. Light L1 is, for example, visible light, and light L2 is, for example, infrared light. Light L1 can be detected by a photoelectric conversion unit in the photodetector 2002, and light L2 can be detected by a photoelectric conversion region in the photodetector 2002. Image information of the object 2100 can be obtained from light L1, and distance information between the object 2100 and the photodetector system 2000 can be obtained from light L2. The photodetector system 2000 can be installed in, for example, an electronic device such as a smartphone or a mobile object such as a car. The light-emitting device 2001 can be configured, for example, by a semiconductor laser, a surface-emitting semiconductor laser, or a vertical-cavity surface-emitting laser (VCSEL). The method of detecting the light L2 emitted from the light-emitting device 2001 by the photodetector 2002 can be, for example, an iTOF method, but is not limited to this. In the iTOF method, the photoelectric conversion unit can measure the distance to the subject 2100, for example, by using the time-of-flight (TOF) of light. The method of detecting the light L2 emitted from the light-emitting device 2001 by the photodetector 2002 can also be, for example, a structured light method or a stereo vision method. For example, in the structured light method, a predetermined pattern of light is projected onto the subject 2100, and the distance between the photodetector system 2000 and the subject 2100 can be measured by analyzing the distortion of the pattern. In addition, in the stereo vision method, for example, two or more cameras are used to acquire two or more images of the subject 2100 viewed from two or more different viewpoints, thereby measuring the distance between the photodetector system 2000 and the subject. The light emitting device 2001 and the light detecting device 2002 can be controlled synchronously by a system control unit 2003 .

[0152] 4. Application Example Application Example to Endoscopic Surgery System The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

[0153] FIG. 32 is a diagram showing an example of a schematic configuration of an endoscopic surgery system to which the technology according to the present disclosure (the present technology) can be applied.

[0154] 32 shows an operator (doctor) 11131 performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgery system 11000. As shown in the figure, the endoscopic surgery system 11000 is composed of an endoscope 11100, other surgical tools 11110 such as an insufflation tube 11111 and an energy treatment tool 11112, a support arm device 11120 that supports the endoscope 11100, and a cart 11200 on which various devices for endoscopic surgery are mounted.

[0155] The endoscope 11100 is composed of a lens barrel 11101, a region of a predetermined length from the tip of which is inserted into a body cavity of a patient 11132, and a camera head 11102 connected to the base end of the lens barrel 11101. In the example shown, the endoscope 11100 is configured as a so-called rigid scope having a rigid lens barrel 11101, but the endoscope 11100 may also be configured as a so-called flexible scope having a flexible lens barrel.

[0156] An opening into which an objective lens is fitted is provided at the tip of the lens barrel 11101. A light source device 11203 is connected to the endoscope 11100, and light generated by the light source device 11203 is guided to the tip of the lens barrel by a light guide extending inside the lens barrel 11101, and is irradiated via the objective lens toward an object to be observed inside the body cavity of the patient 11132. The endoscope 11100 may be a direct-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0157] An optical system and an image sensor are provided inside the camera head 11102, and light reflected from the object of observation (observation light) is collected onto the image sensor by the optical system. The observation light is photoelectrically converted by the image sensor to generate an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. The image signal is sent to a camera control unit (CCU) 11201 as RAW data.

[0158] The CCU 11201 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and comprehensively controls the operations of the endoscope 11100 and the display device 11202. Furthermore, the CCU 11201 receives an image signal from the camera head 11102 and performs various image processing on the image signal, such as development processing (demosaic processing), to display an image based on the image signal.

[0159] Under the control of the CCU 11201, the display device 11202 displays an image based on an image signal that has been subjected to image processing by the CCU 11201.

[0160] The light source device 11203 is composed of a light source such as an LED (light emitting diode), and supplies irradiation light to the endoscope 11100 when photographing the surgical site, etc.

[0161] The input device 11204 is an input interface for the endoscopic surgery system 11000. A user can input various information and instructions to the endoscopic surgery system 11000 via the input device 11204. For example, the user inputs an instruction to change the imaging conditions (type of irradiation light, magnification, focal length, etc.) of the endoscope 11100.

[0162] The treatment tool control device 11205 controls the driving of the energy treatment tool 11112 for cauterizing tissue, incising, sealing blood vessels, etc. The insufflation device 11206 inflates the body cavity of the patient 11132 through the insufflation tube 11111 in order to ensure a clear field of view for the endoscope 11100 and a working space for the surgeon. The recorder 11207 is a device capable of recording various types of information related to the surgery. The printer 11208 is a device capable of printing various types of information related to the surgery in various formats such as text, images, or graphs.

[0163] The light source device 11203, which supplies illumination light to the endoscope 11100 when photographing the surgical site, can be configured from a white light source, such as an LED, a laser light source, or a combination of these. When the white light source is configured from a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, allowing the light source device 11203 to adjust the white balance of the captured image. In this case, it is also possible to time-share images corresponding to each RGB by irradiating the object of observation with laser light from each RGB laser light source and controlling the drive of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, color images can be obtained without providing a color filter to the image sensor.

[0164] Furthermore, the light source device 11203 may be controlled to change the intensity of light it outputs at predetermined time intervals. By controlling the driving of the image sensor of the camera head 11102 in synchronization with the timing of the change in light intensity to acquire images in a time-division manner and combining the images, it is possible to generate an image with a high dynamic range that is free from so-called blocked-up shadows and blown-out highlights.

[0165] The light source device 11203 may also be configured to supply light in a predetermined wavelength range compatible with special light observation. Special light observation, for example, utilizes the wavelength dependence of light absorption in body tissues to irradiate light with a narrower band than the light irradiated during normal observation (i.e., white light), thereby capturing high-contrast images of specific tissues, such as blood vessels on the surface of mucous membranes, known as narrow-band imaging. Alternatively, special light observation may involve fluorescence observation, in which images are obtained using fluorescence generated by irradiating excitation light. Fluorescence observation can involve irradiating excitation light onto body tissues and observing the fluorescence from the tissues (autofluorescence observation), or by locally injecting a reagent such as indocyanine green (ICG) into the body tissue and irradiating the tissue with excitation light corresponding to the fluorescent wavelength of the reagent to obtain a fluorescent image. The light source device 11203 may be configured to supply narrow-band light and / or excitation light compatible with such special light observation.

[0166] FIG. 33 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG.

[0167] The camera head 11102 has a lens unit 11401, an imaging unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. The CCU 11201 has a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are connected to each other via a transmission cable 11400 so that they can communicate with each other.

[0168] The lens unit 11401 is an optical system provided at the connection portion with the lens barrel 11101. Observation light taken in from the tip of the lens barrel 11101 is guided to the camera head 11102 and enters the lens unit 11401. The lens unit 11401 is composed of a combination of multiple lenses including a zoom lens and a focus lens.

[0169] The imaging unit 11402 may include one imaging element (a so-called single-chip type) or multiple imaging elements (a so-called multi-chip type). When the imaging unit 11402 is configured as a multi-chip type, for example, each imaging element may generate an image signal corresponding to each of RGB, and a color image may be obtained by combining these signals. Alternatively, the imaging unit 11402 may be configured to have a pair of imaging elements for acquiring image signals for the right eye and the left eye corresponding to a 3D (dimensional) display. The 3D display allows the surgeon 11131 to more accurately grasp the depth of the biological tissue at the surgical site. Note that when the imaging unit 11402 is configured as a multi-chip type, multiple lens units 11401 may be provided corresponding to each imaging element.

[0170] Furthermore, the imaging unit 11402 does not necessarily have to be provided in the camera head 11102. For example, the imaging unit 11402 may be provided inside the lens barrel 11101, immediately after the objective lens.

[0171] The driving unit 11403 is configured by an actuator, and moves the zoom lens and focus lens of the lens unit 11401 by a predetermined distance along the optical axis under the control of the camera head control unit 11405. This allows the magnification and focus of the image captured by the imaging unit 11402 to be adjusted appropriately.

[0172] The communication unit 11404 is configured by a communication device for transmitting and receiving various types of information to and from the CCU 11201. The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 to the CCU 11201 via the transmission cable 11400 as RAW data.

[0173] Furthermore, the communication unit 11404 receives a control signal for controlling the driving of the camera head 11102 from the CCU 11201 and supplies the control signal to the camera head control unit 11405. The control signal includes information on the imaging conditions, such as information specifying the frame rate of the captured image, information specifying the exposure value at the time of imaging, and / or information specifying the magnification and focus of the captured image.

[0174] The image capturing conditions such as the frame rate, exposure value, magnification, and focus may be appropriately specified by the user, or may be automatically set by the control unit 11413 of the CCU 11201 based on the acquired image signal. In the latter case, the endoscope 11100 is equipped with a so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function.

[0175] The camera head control unit 11405 controls the driving of the camera head 11102 based on a control signal received from the CCU 11201 via the communication unit 11404 .

[0176] The communication unit 11411 is configured by a communication device for transmitting and receiving various information to and from the camera head 11102. The communication unit 11411 receives an image signal transmitted from the camera head 11102 via the transmission cable 11400.

[0177] Furthermore, the communication unit 11411 transmits to the camera head 11102 a control signal for controlling the driving of the camera head 11102. The image signal and the control signal can be transmitted by electrical communication, optical communication, or the like.

[0178] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102 .

[0179] The control unit 11413 performs various controls related to the imaging of the surgical site, etc. by the endoscope 11100 and the display of the captured image obtained by imaging the surgical site, etc. For example, the control unit 11413 generates a control signal for controlling the driving of the camera head 11102.

[0180] Furthermore, the control unit 11413 displays the captured image showing the surgical site, etc., on the display device 11202 based on the image signal subjected to image processing by the image processing unit 11412. At this time, the control unit 11413 may recognize various objects in the captured image using various image recognition technologies. For example, the control unit 11413 can recognize surgical tools such as forceps, specific biological parts, bleeding, mist generated when using the energy treatment tool 11112, etc., by detecting the shape and color of the edges of objects included in the captured image. When displaying the captured image on the display device 11202, the control unit 11413 may use the recognition results to superimpose various surgical support information on the image of the surgical site. By superimposing the surgical support information and presenting it to the surgeon 11131, the burden on the surgeon 11131 can be reduced and the surgeon 11131 can proceed with the surgery reliably.

[0181] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable for electrical signal communication, an optical fiber for optical communication, or a composite cable of these.

[0182] In the illustrated example, communication is performed wired using a transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may also be performed wirelessly.

[0183] The above describes an example of an endoscopic surgery system to which the technology according to the present disclosure can be applied. The technology according to the present disclosure can be applied to the imaging unit 11402 among the components described above. By applying the technology according to the present disclosure to the imaging unit 11402, detection accuracy is improved.

[0184] Although an endoscopic surgery system has been described as an example here, the technology disclosed herein may also be applied to other systems, such as a microsurgery system.

[0185] (Application Example to Mobile Object) The technology according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of mobile object, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, a robot, construction machinery, or agricultural machinery (tractor).

[0186] FIG. 34 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology according to the present disclosure can be applied.

[0187] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 34, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional components of the integrated control unit 12050 are a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (interface) 12053.

[0188] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

[0189] The body system control unit 12020 controls the operation of various devices equipped in the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0190] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture images outside the vehicle and receives the captured images. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, characters on the road surface, etc. based on the received images.

[0191] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0192] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

[0193] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the outside-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the distance between vehicles, maintaining vehicle speed, vehicle collision warning, vehicle lane departure warning, etc.

[0194] In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle obtained by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0195] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the outside information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside information detection unit 12030, and perform cooperative control aimed at preventing glare, such as switching from high beams to low beams.

[0196] The audio / video output unit 12052 transmits at least one of audio and video output signals to an output device capable of visually or audibly notifying information to vehicle occupants or the outside of the vehicle. In the example of Fig. 34, the output devices are exemplified by an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.

[0197] FIG. 35 is a diagram showing an example of the installation position of the imaging unit 12031.

[0198] In FIG. 35, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0199] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided on the front nose and the imaging unit 12105 provided on the top of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 provided on the top of the windshield inside the vehicle cabin is mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0200] 35 shows an example of the imaging ranges of the imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 12101 to 12104, an overhead image of the vehicle 12100 viewed from above can be obtained.

[0201] At least one of the image capturing units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the image capturing units 12101 to 12104 may be a stereo camera made up of multiple image capturing elements, or may be an image capturing element having pixels for phase difference detection.

[0202] For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 can calculate the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the change in this distance over time (relative speed with respect to the vehicle 12100), thereby extracting as a preceding vehicle, in particular, the three-dimensional object that is the closest three-dimensional object on the path of the vehicle 12100 and traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or higher). Furthermore, the microcomputer 12051 can set a vehicle-to-vehicle distance to be maintained in advance in front of the preceding vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. In this way, cooperative control can be performed for the purpose of autonomous driving, which runs autonomously without relying on driver operation.

[0203] For example, the microcomputer 12051 classifies and extracts three-dimensional object data regarding three-dimensional objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from the imaging units 12101 to 12104, and can use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines a collision risk that indicates the risk of collision with each obstacle, and when the collision risk is equal to or greater than a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drive system control unit 12010.

[0204] At least one of the image capturing units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether a pedestrian is present in the images captured by the image capturing units 12101 to 12104. Such pedestrian recognition is performed, for example, by extracting feature points from the images captured by the image capturing units 12101 to 12104 as infrared cameras and performing pattern matching on a series of feature points that indicate the outline of an object to determine whether the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the image capturing units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular outline on the recognized pedestrian for emphasis. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating the pedestrian at a desired position.

[0205] The foregoing has described an example of a mobile object control system to which the technology according to the present disclosure can be applied. The technology according to the present disclosure can be applied to the image capture unit 12031 of the above-described configuration. Specifically, the photodetector element (e.g., photodetector element 1) according to the above-described embodiment and its modified examples can be applied to the image capture unit 12031. By applying the technology according to the present disclosure to the image capture unit 12031, it is possible to obtain a high-resolution captured image with little noise, thereby enabling high-precision control using the captured image in the mobile object control system.

[0206] The present technology has been described above by giving embodiments, variants 1 to 6, and other variants, as well as application examples and applied examples. However, the present disclosure is not limited to the above-described embodiments, etc., and various modifications are possible.

[0207] For example, in the above embodiment, the charge confinement layer 25 is selectively provided over the entire surface between the protective layer 24 and the photoelectric conversion layer 26 or above the shield electrode 21C. However, the charge confinement layer 25 may be omitted. Even when the charge confinement layer 25 is omitted, an electric field weaker than the electric field applied above the charge storage electrode 21B is applied above the shield electrode 21C. This prevents carriers (e.g., electrons) generated in the photoelectric conversion layer 26 above the shield electrode 21C from leaking to adjacent unit pixels P and facilitates transport of these electrons toward the readout electrode 21A. In addition, because the shield electrode 21C is electrically insulated from the photoelectric conversion layer 26 by the insulating layer 22 as described above, electrons generated by photoelectric conversion are prevented from being absorbed by the shield electrode 21C. This prevents crosstalk between adjacent unit pixels P and improves EQE.

[0208] Furthermore, in the above-described embodiment, electrons are read out from the lower electrode 21 as signal charges, but this is not limiting, and holes may be read out from the lower electrode 21 as signal charges.

[0209] Furthermore, in the above embodiment, the photodetector element is configured by stacking photoelectric conversion unit 20 using an organic material that detects green light (G) and photoelectric conversion region 32B and photoelectric conversion region 32R that detect blue light (B) and red light (R), respectively, but the present disclosure is not limited to this structure. That is, red light (R) or blue light (B) may be detected in a photoelectric conversion unit using an organic material, or green light (G) may be detected in a photoelectric conversion region made of an inorganic material.

[0210] Furthermore, the number and ratio of the photoelectric conversion units using these organic materials and the photoelectric conversion regions made of inorganic materials are not limited. Furthermore, the photoelectric conversion units using organic materials and the photoelectric conversion regions made of inorganic materials are not limited to a structure in which they are stacked vertically, and they may be arranged in parallel along the substrate surface.

[0211] Furthermore, in the above-described embodiments, the configuration of a back-illuminated imaging device has been exemplified, but the present disclosure can also be applied to a front-illuminated imaging device.

[0212] Furthermore, the photodetector element 1 and photodetector device 100 of the present disclosure do not need to include all of the components described in the above embodiments, and conversely, may include other components. For example, the photodetector device 100 may be provided with a shutter for controlling the incidence of light, or may be provided with an optical cut filter depending on the purpose of the photodetector element 1 and photodetector device 100. Furthermore, the arrangement of the pixels (Pr, Pg, Pb) that detect red light (R), green light (G), and blue light (B) may be an interline arrangement, a G-stripe RB checkerboard arrangement, a G-stripe RB complete checkerboard arrangement, a checkerboard complementary color arrangement, a stripe arrangement, a diagonal stripe arrangement, a primary color color difference arrangement, a field color difference sequential arrangement, a frame color difference sequential arrangement, a MOS type arrangement, an improved MOS type arrangement, a frame interleaved arrangement, or a field interleaved arrangement, in addition to the Bayer arrangement.

[0213] Furthermore, the photoelectric conversion unit (e.g., photoelectric conversion unit 20) of the present disclosure may be applied to, for example, a solar cell. When applied to a solar cell, the photoelectric conversion layer is preferably designed to broadly absorb wavelengths of, for example, 400 nm to 800 nm.

[0214] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0215] The present technology can also be configured as follows. According to the present technology configured as follows, the transport of charges present outside a first electrode toward the first electrode is promoted, thereby improving photodetection characteristics. (1) A photodetector comprising: a photoelectric conversion layer; a first electrode electrically connected to the photoelectric conversion layer; a second electrode arranged opposite the first electrode with the photoelectric conversion layer interposed therebetween; and a first intermediate layer provided between the first electrode and the photoelectric conversion layer at least outside the first electrode in a planar view, the first intermediate layer having a higher charge mobility in the in-plane direction than the photoelectric conversion layer in a stacking direction perpendicular to the in-plane direction. (2) The photodetector according to (1), further comprising a third electrode arranged in parallel with the first electrode and electrically insulated from the photoelectric conversion layer. (3) The photodetector according to (1) or (2), further comprising an oxide film provided between the first electrode, the third electrode, and the first intermediate layer, and an oxide semiconductor layer provided between the first electrode, the third electrode, and the oxide film, wherein |E4|≧|E0| is satisfied, where E0 is the LUMO of the photoelectric conversion layer, E1 is the conduction band energy of the oxide film, E2 is the conduction band energy of the oxide semiconductor layer, and E4 is the LUMO of the first intermediate layer. (4) The photodetector according to (3), further comprising a second intermediate layer between the photoelectric conversion layer and the first intermediate layer, wherein |E4|≧|E0|≧|E5| is satisfied, where E5 is the LUMO of the second intermediate layer. (5) The photodetector according to (3) or (4), wherein |E1|−|E4|≧−0.4 is satisfied. (6) The photodetector according to any one of (3) to (5), which satisfies |E2|-|E1|≧-0.4. (7) The photodetector according to any one of (1) to (6), in which molecules constituting the first intermediate layer are edge-on oriented with respect to the in-plane direction of the first electrode. (8) The photodetector according to any one of (1) to (7), in which the first intermediate layer includes an n-type semiconductor material. (9) The first intermediate layer is made of C ６０ Fullerene, C ６０(1) The photodetector according to any one of (1) to (8), which includes a fullerene derivative or a perylene derivative. (10) The photodetector according to any one of (1) to (9), wherein the film thickness of the first intermediate layer in the stacking direction is 60 nm or less. (11) The photodetector according to any one of (1) to (10), wherein the first electrode and the photoelectric conversion layer are electrically connected. (12) The photodetector according to any one of (2) to (11), further including an insulating layer between the first electrode and the third electrode and the oxide semiconductor layer, and wherein the first electrode is electrically connected to the photoelectric conversion layer through an opening provided in the insulating layer. (13) The photodetector according to any one of (10) to (12), further including a fourth electrode between the first electrode and the third electrode, the fourth electrode being electrically insulated from the photoelectric conversion layer by the insulating layer. (14) The photodetector according to any one of (2) to (13), comprising a plurality of pixels arranged in a two-dimensional array, wherein the first electrode is provided for each pixel and the third electrode is provided between adjacent pixels. (15) The photodetector according to any one of (2) to (13), comprising: a first electrode and a third electrode arranged in parallel; a second electrode arranged opposite the first electrode and the third electrode; and a photoelectric conversion layer provided between the first electrode, the third electrode, and the second electrode, wherein the third electrode is electrically insulated from the photoelectric conversion layer, and an electric field applied to the photoelectric conversion layer above the third electrode is weaker than an electric field applied to the photoelectric conversion layer above the first electrode. (16) The photodetector according to (15), wherein the first electrode is electrically connected to the photoelectric conversion layer. (17) An electronic device including a photodetector having: a photoelectric conversion layer; a first electrode electrically connected to the photoelectric conversion layer; a second electrode arranged opposite the first electrode with the photoelectric conversion layer in between; and a first intermediate layer provided between the first electrode and the photoelectric conversion layer at least outside the first electrode in a planar view, and having a higher charge mobility in the in-plane direction than the photoelectric conversion layer in the in-plane direction and a stacking direction perpendicular to the in-plane direction.

[0216] This application claims priority based on Japanese Patent Application No. 2023-142944, filed on September 4, 2023, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0217] Those skilled in the art will recognize that various modifications, combinations, subcombinations, and variations may occur depending on design requirements and other factors, and are intended to be within the scope of the appended claims and their equivalents.

Claims

1. A photodetector comprising: a photoelectric conversion layer; a first electrode electrically connected to the photoelectric conversion layer; a second electrode arranged opposite the first electrode with the photoelectric conversion layer between them; and a first intermediate layer provided between the first electrode and the photoelectric conversion layer, at least outside the first electrode in a planar view, and having a higher charge mobility in the in-plane direction than the photoelectric conversion layer, among the in-plane direction and a stacking direction perpendicular to the in-plane direction.

2. The photodetector according to claim 1, further comprising a third electrode arranged in parallel with said first electrode and electrically insulated from said photoelectric conversion layer.

3. The photodetector device of claim 1, further comprising an oxide film provided between the first electrode and the third electrode and the first intermediate layer, and an oxide semiconductor layer provided between the first electrode and the third electrode and the oxide film, wherein |E4|≧|E0| is satisfied when the LUMO of the photoelectric conversion layer is E0, the conduction band energy of the oxide film is E1, the conduction band energy of the oxide semiconductor layer is E2, and the LUMO of the first intermediate layer is E4.

4. The photodetector device according to claim 3, further comprising a second intermediate layer between the photoelectric conversion layer and the first intermediate layer, wherein |E4|≧|E0|≧|E5| is satisfied when the LUMO of the second intermediate layer is E5.

5. The optical detection device according to claim 3, wherein |E1|-|E4|≧-0.4 is satisfied.

6. The optical detection device according to claim 3, wherein |E2|-|E1|≧-0.4 is satisfied.

7. The photodetector according to claim 1, wherein the molecules constituting said first intermediate layer are oriented in an edge-on manner with respect to the in-plane direction of said first electrode.

8. The photodetector device of claim 1, wherein said first intermediate layer comprises an n-type semiconductor material.

9. The first intermediate layer is C ６０ Fullerene, C ６０ The optical detection device of claim 1 , comprising a fullerene derivative or a perylene derivative.

10. The photodetector according to claim 1, wherein the thickness of said first intermediate layer in said stacking direction is 60 nm or less.

11. The photodetector according to claim 1, wherein the first electrode and the photoelectric conversion layer are electrically connected.

12. The photodetector device of claim 2, further comprising an insulating layer between the first electrode and the third electrode and the oxide semiconductor layer, and the first electrode is electrically connected to the photoelectric conversion layer through an opening provided in the insulating layer.

13. The photodetector device according to claim 10, further comprising a fourth electrode between the first electrode and the third electrode, the fourth electrode being electrically insulated from the photoelectric conversion layer by the insulating layer.

14. The photodetection device according to claim 2, comprising a plurality of pixels arranged in a two-dimensional array, the first electrode being provided for each of the pixels, and the third electrode being provided between adjacent ones of the pixels.

15. A photodetector comprising: a first electrode and a third electrode arranged in parallel; a second electrode arranged opposite the first electrode and the third electrode; and a photoelectric conversion layer provided between the first electrode, the third electrode, and the second electrode, wherein the third electrode is electrically insulated from the photoelectric conversion layer; and an electric field applied to the photoelectric conversion layer above the third electrode is weaker than an electric field applied to the photoelectric conversion layer above the first electrode.

16. The photodetector device according to claim 15, wherein the first electrode is electrically connected to the photoelectric conversion layer.

17. An electronic device equipped with a photodetector having: a photoelectric conversion layer; a first electrode electrically connected to the photoelectric conversion layer; a second electrode arranged opposite the first electrode with the photoelectric conversion layer between them; and a first intermediate layer provided between the first electrode and the photoelectric conversion layer, at least outside the first electrode in a planar view, and having a higher charge mobility in the in-plane direction than the photoelectric conversion layer, among the in-plane direction and the stacking direction perpendicular to the in-plane direction.

Images