Light detection device

Abstract

A first light detection device according to one embodiment of the present disclosure comprises: a first electrode; a third electrode disposed facing the first electrode; a photoelectric conversion layer provided between the first electrode and the third electrode; an oxide semiconductor layer provided between the first electrode and the photoelectric conversion layer; an oxide layer provided between the photoelectric conversion layer and the oxide semiconductor layer; and an intermediate layer provided between the photoelectric conversion layer and the oxide layer and including one or more materials. Ei HOMO ≤ ENB HOMO is satisfied where the HOMO energy of a material having the highest HOMO energy included in the photoelectric conversion layer is Ei HOMO, and the HOMO energy of a material having the highest HOMO energy among the one or more materials included in the intermediate layer is ENB HOMO.

Description

Photodetector

[0001] The present disclosure relates to a photodetector including a photoelectric conversion layer using, for example, an organic material.

[0002] For example, Patent Document 1 discloses an imaging element in which a photoelectric conversion section is formed by stacking a first electrode, a photoelectric conversion layer, and a second electrode, and an oxide film and an oxide semiconductor layer are formed between the first electrode and the photoelectric conversion layer from the photoelectric conversion layer side.

[0003] International Publication No. 2020 / 017330

[0004] Incidentally, photodetectors are required to have high charge transport properties.

[0005] It would be desirable to provide a photodetector device that allows for improved electron transport properties.

[0006] A first photodetector according to an embodiment of the present disclosure includes a first electrode, a third electrode disposed opposite to the first electrode, a photoelectric conversion layer provided between the first electrode and the third electrode, an oxide semiconductor layer provided between the first electrode and the photoelectric conversion layer, an oxide layer provided between the photoelectric conversion layer and the oxide semiconductor layer, and an intermediate layer provided between the photoelectric conversion layer and the oxide layer and containing one or more materials, and the HOMO energy of a material having the highest HOMO energy included in the photoelectric conversion layer is set to E ｉ ＨＯＭＯ , the HOMO energy of the material with the highest HOMO energy among one or more materials contained in the intermediate layer is E ＮＢ ＨＯＭＯ In this case, E ｉ ＨＯＭＯ ≦E ＮＢ ＨＯＭＯ Meet the following.

[0007] In the first photodetector according to the embodiment of the present disclosure, an intermediate layer is provided between the photoelectric conversion layer and the oxide layer. The intermediate layer adjusts the HOMO energy of the material having the highest HOMO energy contained in the photoelectric conversion layer to E ｉ ＨＯＭＯ , the HOMO energy of the material with the highest HOMO energy among one or more materials contained in the intermediate layer is E ＮＢＨＯＭＯ In this case, E ｉ ＨＯＭＯ ≦E ＮＢ ＨＯＭＯ This forms a potential gradient in the stacking direction of the photoelectric conversion layer.

[0008] A second photodetector according to an embodiment of the present disclosure includes a first electrode, a third electrode disposed opposite to the first electrode, a photoelectric conversion layer provided between the first electrode and the third electrode, an oxide semiconductor layer provided between the first electrode and the photoelectric conversion layer, and a -1E12 cm －２ <N<1E12cm －２ and an intermediate layer having a fixed charge amount that satisfies the above.

[0009] In the second photodetector according to the embodiment of the present disclosure, a thickness of −1E12 cm between the photoelectric conversion layer and the oxide semiconductor layer is －２ <N<1E12cm －２ A potential control layer having a fixed charge amount that satisfies the above formula is provided. This forms a potential gradient in the stacking direction of the photoelectric conversion layer.

[0010] A third photodetector according to an embodiment of the present disclosure includes a first electrode, a third electrode disposed opposite the first electrode, a photoelectric conversion layer provided between the first electrode and the third electrode, an oxide semiconductor layer provided between the first electrode and the photoelectric conversion layer, an oxide layer provided between the photoelectric conversion layer and the oxide semiconductor layer, and an intermediate layer provided between the photoelectric conversion layer and the oxide layer and containing an organic material having an electron-donating group.

[0011] A fourth photodetector according to an embodiment of the present disclosure includes a first electrode, a third electrode disposed opposite to the first electrode, a photoelectric conversion layer provided between the first electrode and the third electrode, and an intermediate layer provided between the photoelectric conversion layer and the first electrode to control the potential of the photoelectric conversion layer, and the HOMO energy of the intermediate layer is set to E ＮＢ ＨＯＭＯ , where WF is the work function of the first electrode, |E ＮＢ ＨＯＭＯ |≦WF is satisfied.

[0012] In a third embodiment of the photodetector according to the present disclosure, an intermediate layer containing an organic material having an electron-donating group is formed between the photoelectric conversion layer and the oxide layer. In a fourth embodiment of the photodetector according to the present disclosure, the intermediate layer is provided between the photoelectric conversion layer and the first electrode. The HOMO energy of the intermediate layer is set to E ＮＢ ＨＯＭＯ , where WF is the work function of the first electrode, |E ＮＢ ＨＯＭＯ |≦WF is satisfied. As a result, a potential gradient is formed in the stacking direction of the photoelectric conversion layer.

[0013] FIG. 1 is a cross-sectional view schematically illustrating an example of a configuration of a photodetector according to a first embodiment of the present disclosure. FIG. 2 is a plan view schematically illustrating an example of a pixel configuration of a photodetector device including 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. 4A is a diagram illustrating an example of energy levels of each layer on a storage electrode of the photoelectric conversion unit shown in FIG. 3. FIG. 4B is a diagram illustrating another example of energy levels of each layer on a storage electrode of 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 an operation of the photodetector shown in FIG. 1 . FIG. 14 is a cross-sectional view schematically illustrating an example of the configuration of a photoelectric conversion unit according to Modification 1 of the present disclosure. FIG. 15A is a diagram illustrating an example of the energy levels of each layer on the storage electrode of the photoelectric conversion unit shown in FIG. 14 . FIG. 15B is a diagram illustrating another example of the energy levels of each layer on the storage electrode of the photoelectric conversion unit shown in FIG. 14 . FIG. 16 is a cross-sectional view schematically illustrating an example of the configuration of a photodetector according to a second embodiment of the present disclosure. FIG. 17 is a cross-sectional view schematically illustrating an example of the configuration of the photoelectric conversion unit shown in FIG. 16 . FIG. 18 is a diagram illustrating the energy levels of each layer on the storage electrode of the photoelectric conversion unit shown in FIG. 17 . FIG. 19 is a cross-sectional view schematically illustrating an example of the configuration of a photoelectric conversion unit according to Modification 2 of the present disclosure. FIG. 20 is a cross-sectional view schematically illustrating an example of the configuration of a photodetector according to a third embodiment of the present disclosure. FIG. 21 is a cross-sectional view schematically illustrating an example of the configuration of the photoelectric conversion unit shown in FIG. 20 . Fig. 22 is a diagram showing the energy levels of each layer on the storage electrode of the photoelectric conversion unit shown in Fig. 21. Fig. 23 is a cross-sectional view showing an example of the configuration of a photodetector element according to a fourth embodiment of the present disclosure. Fig. 24 is a cross-sectional schematic view showing an example of the configuration of the photoelectric conversion unit shown in Fig. 23.FIG. 25 is a diagram showing the energy levels of each layer on the storage electrode of the photoelectric conversion unit shown in FIG. 24 . FIG. 26A is a cross-sectional view schematically showing an example of the configuration of a photodetector according to Modification 3 of the present disclosure. FIG. 26B is a plan view schematically showing an example of the pixel configuration of a photodetector device including the photodetector element shown in FIG. 26A . FIG. 27A is a cross-sectional view schematically showing an example of the configuration of a photodetector element according to Modification 4 of the present disclosure. FIG. 27B is a plan view schematically showing an example of the pixel configuration of a photodetector device including the photodetector element shown in FIG. 27A . FIG. 28 is a cross-sectional view schematically showing an example of the configuration of a photodetector element according to Modification 5 of the present disclosure. FIG. 29 is a cross-sectional view schematically showing an example of the configuration of a photodetector element according to Modification 6 of the present disclosure. FIG. 30A is a cross-sectional view schematically showing another example of the configuration of a photodetector element according to Modification 6 of the present disclosure. FIG. 30B is a plan view schematically showing an example of the pixel configuration of a photodetector device including the photodetector element shown in FIG. 30A . FIG. 31A is a cross-sectional view schematically showing another example of the configuration of a photodetector element according to Modification 6 of the present disclosure. FIG. 31B is a plan view schematic diagram illustrating an example of a pixel configuration of a photodetector having the photodetector shown in FIG. 31A. FIG. 32 is a cross-sectional schematic diagram illustrating another example of the configuration of a photodetector according to Modification Example 6 of the present disclosure. FIG. 33 is a block diagram illustrating a configuration of a photodetector using the photodetector shown in FIG. 1 etc. as a pixel. FIG. 34 is a functional block diagram illustrating an example of an electronic device (camera) using the photodetector shown in FIG. 33. FIG. 35A is a schematic diagram illustrating an example of the overall configuration of a photodetection system using the photodetector shown in FIG. 33. FIG. 35B is a diagram illustrating an example of the circuit configuration of the photodetection system shown in FIG. 35A. FIG. 36 is a diagram illustrating an example of a schematic configuration of an endoscopic surgery system. FIG. 37 is a block diagram illustrating an example of the functional configuration of a camera head and a CCU. FIG. 38 is a block diagram illustrating an example of a schematic configuration of a vehicle control system. FIG. 39 is an explanatory diagram illustrating an example of the installation positions of an outside vehicle information detection unit and an imaging unit.

[0014] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. The following description is a specific example of the present disclosure, and the present disclosure is not limited to the following aspects. Furthermore, the present disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc. of each component shown in each drawing. The order of description is as follows: 1. First embodiment (example of a photodetector having a potential control layer made of an organic material between a photoelectric conversion layer and a protective layer) 1-1. Configuration of the photodetector 1-2. Method for manufacturing the photodetector 1-3. Signal acquisition operation of the photodetector 1-4. Actions and effects 2. Modification 1 (another example of the configuration of the photoelectric conversion section) 3. Second embodiment (example of a photodetector having a potential control layer made of an inorganic material between a photoelectric conversion layer and an oxide semiconductor layer) 3-1. Configuration of the photodetector 3-2. Actions and effects 4. Modification 2 (another example of the configuration of the photoelectric conversion section) 5. Third embodiment (example of a photodetector having a potential control layer made of an inorganic material between a photoelectric conversion layer and a protective layer) 5-1. 5. Structure of photodetector element 5-2. Actions and effects 6. Fourth embodiment (example of photodetector element having an electric field generation layer made of an organic material between the photoelectric conversion layer and the protective layer) 6-1. Structure of photodetector element 6-2. Actions and effects 7. Modifications 7-1. Modification 3 (example of photodetector element that separates light using color filters) 7-2. Modification 4 (another example of photodetector element that separates light using color filters) 7-3. Modification 5 (example of photodetector element in which multiple photoelectric conversion units are stacked) 7-4. Modification 6 (other modified example of photodetector element) 8. Application examples 9. Application examples

[0015] 1. First Embodiment FIG. 1 illustrates a cross-sectional configuration of a photodetector element (photodetector element 1) according to a first embodiment of the present disclosure. The photodetector element 1 constitutes one pixel (unit pixel P) repeatedly arranged in an array in a pixel section 100A of a photodetector device (e.g., photodetector device 100, see FIG. 33 ), such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor used in electronic devices such as digital still cameras and video cameras. FIG. 2 illustrates a schematic diagram of an example of a pixel configuration of the photodetector device 100 having the photodetector element 1 illustrated in FIG. 1 , and FIG. 1 illustrates a cross section taken along line II illustrated in FIG. 2 . FIG. 3 illustrates an enlarged schematic diagram of an example of a cross-sectional configuration of a main portion (photoelectric conversion section 20) of the photodetector element 1 illustrated in FIG. 1 . In the pixel section 100A, as illustrated in FIG. 2 , pixel units 1a each consisting of four unit pixels P arranged in, for example, two rows and two columns are repeated, and are repeatedly arranged in an array consisting of row and column directions.

[0016] The photodetector element 1 of this embodiment has a photoelectric conversion section 20 provided on a semiconductor substrate 30, in which a lower electrode 21 consisting of a readout electrode 21A and a storage electrode 21B, an insulating layer 22, an oxide semiconductor layer 23, a protective layer 24, a potential control layer 25, a photoelectric conversion layer 26, and an upper electrode 27 are stacked in this order.

[0017] Here, the readout electrode 21A corresponds to a specific example of a "first electrode" in the first embodiment of the present disclosure, and the storage electrode 21B corresponds to a specific example of a "second electrode" in the first embodiment of the present disclosure. The protective layer 24 corresponds to a specific example of an "oxide layer" in the first embodiment of the present disclosure. The potential control layer 25 corresponds to a specific example of an "intermediate layer" in the first embodiment of the present disclosure. The photoelectric conversion layer 26 corresponds to a specific example of a "photoelectric conversion layer" in the first embodiment of the present disclosure. The upper electrode 27 corresponds to a specific example of a "third electrode" in the first embodiment of the present disclosure.

[0018] (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 30A) 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.

[0019] 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.

[0020] 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.

[0021] The surface (second surface 30B) 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 30B 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, wiring layers 41, 42, and 43 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., in a peripheral region 1B around the pixel portion 100A.

[0022] In the drawings, the first surface 30A side of the semiconductor substrate 30 is represented as a light incident side S1, and the second surface 30B side is represented as a wiring layer side S2.

[0023] In the photoelectric conversion unit 20, an oxide semiconductor layer 23, a protective layer 24 formed using an inorganic material, a potential control layer 25 formed using an organic material, and a photoelectric conversion layer 26 formed using an organic material are stacked in this order from the lower electrode 21 side between a lower electrode 21 and an upper electrode 27 that are arranged opposite to each other. As will be described in detail later, the potential control layer 25 controls the potential of the photoelectric conversion layer 26, and controls the energy (E ｉ ＨＯＭＯ ) or more HOMO energy (E ＮＢ ＨＯＭＯ The photoelectric conversion layer 26 is formed using a material having the above-mentioned properties. The photoelectric conversion layer 26 is configured to include 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.

[0024] 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 unit 100A, and has an opening 22H above the readout electrode 21A that constitutes the lower electrode 21. The readout electrode 21A is electrically connected to the oxide semiconductor layer 23 through this opening 22H.

[0025] Note that, although FIG. 1 shows an example in which the oxide semiconductor layer 23, the protective layer 24, the potential control layer 25, the photoelectric conversion layer 26, and the upper electrode 27 are formed separately for each photodetection element 1, the oxide semiconductor layer 23, the protective layer 24, the potential control layer 25, the photoelectric conversion layer 26, and the upper electrode 27 may be provided as, for example, a continuous layer common to a plurality of photodetection elements 1.

[0026] Between the first surface 30A 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.

[0027] 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.

[0028] A through electrode 34 is provided between the first surface 30A and the second surface 30B 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 30A side of the semiconductor substrate 30 to the second surface 30B side of the semiconductor substrate 30 via the through electrode 34, thereby improving its characteristics.

[0029] 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 readout electrode 21A via, for example, a pad portion 39A and an upper first contact 39C.

[0030] 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 130 around the pixel 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.

[0031] 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.

[0032] The structure and materials of each part will be described in detail below.

[0033] 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.

[0034] The lower electrode 21 is composed of, for example, a readout electrode 21A and a storage electrode 21B arranged in parallel on the interlayer insulating layer 29. The readout electrode 21A is for transferring carriers generated in the photoelectric conversion layer 26 to the floating diffusion FD1, and one readout electrode 21A is provided for each pixel unit 1a, which is made up of, for example, four unit pixels P arranged in two rows and two columns.

[0035] The readout electrode 21A is connected to the floating diffusion FD1 via, for example, the upper first contact 39C, the pad portion 39A, the through electrode 34, the connection portion 41A, and the lower second contact 46.

[0036] The storage electrode 21B is provided for each pixel 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 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 storage electrode 21B is preferably larger than the readout electrode 21A, thereby enabling a larger number of carriers to be stored. As shown in FIG. 6 , the voltage application unit 56 is connected to the storage electrode 21B via wiring such as an upper first contact 39C and an upper second contact 39D.

[0037] The lower electrode 21 is made of, for example, a light-transmitting conductive film. The lower electrode 21 preferably has a work function of 4.0 eV or more and 5.5 eV or less. The material for the lower electrode 21 is, for example, InP doped with tin (Sn) as a dopant. ２ O ３ The crystallinity of the ITO thin film may be high or low (approaching amorphous). In addition to the above, the constituent material of the lower electrode 21 may be tin oxide (SnO ２ )-based materials, for example, ATO with Sb added as a dopant, and FTO with fluorine added as a dopant, can be used. Zinc oxide (ZnO) or a zinc oxide-based material with a dopant added can also be used. Examples of ZnO-based materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, boron zinc oxide with boron (B) added, and indium zinc oxide (IZO) with indium (In) added. Furthermore, zinc oxide with indium and gallium added as dopants (IGZO, In-GaZnO4) can also be used. In addition, materials constituting the lower electrode 21 include CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３or TiO ２ Alternatively, spinel oxides or YbFe ２ O ４ Oxides having such a structure may also be used.

[0038] Furthermore, when optical transparency is not required for the lower electrode 21 (for example, when light is incident from the upper electrode 27 side), a single metal or alloy having a small work function (for example, φ=3.5 eV to 4.5 eV) can be used. Specific examples include alkali metals (for example, lithium (Li), sodium (Na), and potassium (K)) and their fluorides or oxides, and alkaline earth metals (for example, magnesium (Mg) and calcium (Ca)) and their fluorides or oxides. Other examples include aluminum (Al), Al—Si—Cu alloys, zinc (Zn), tin (Sn), thallium (Tl), Na—K alloys, Al—Li alloys, Mg—Ag alloys, and rare earth metals such as In and ytterbium (Yb), or alloys thereof.

[0039] Furthermore, examples of materials for the lower electrode 21 include metals such as platinum (Pt), gold (Au), palladium (Pd), chromium (Cr), nickel (Ni), aluminum (Al), silver (Ag), tantalum (Ta), tungsten (W), copper (Cu), titanium (Ti), indium (In), tin (Sn), iron (Fe), cobalt (Co), and molybdenum (Mo), alloys containing these metal elements, conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and graphene. Other examples of materials for the lower electrode 21 include organic materials (conductive polymers) such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate (PEDOT / PSS). Alternatively, the above materials may be mixed with a binder (polymer) to form a paste or ink, which may then be cured and used as an electrode.

[0040] The lower electrode 21 can be formed as a single layer or a laminated film made of the above materials. The film thickness of the lower electrode 21 in the lamination direction (hereinafter simply referred to as thickness) is, for example, 20 nm to 200 nm, and preferably 30 nm to 150 nm.

[0041] The insulating layer 22 serves to electrically separate the storage electrode 21B 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. The insulating layer 22 has an opening 22H provided above the readout electrode 21A of the lower electrode 21, and the readout 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.

[0042] The oxide semiconductor layer 23 is for accumulating carriers generated in the photoelectric conversion layer 26. The oxide semiconductor layer 23 can be formed using an oxide semiconductor material containing at least one element selected from the group consisting of indium (In), gallium (Ga), silicon (Si), zinc (Zn), aluminum (Al), and tin (Sn). In this embodiment, electrons among the carriers generated in the photoelectric conversion layer 26 are used as signal charges. For this reason, the oxide semiconductor layer 23 can be formed using an n-type oxide semiconductor material. Specifically, the oxide semiconductor layer 23 can be formed using IGZO, Ga ２ O ３ , GZO, IZO, ITO, InGaAlO, InGaSiO, etc. The thickness of the oxide semiconductor layer 23 is, for example, 10 nm to 300 nm.

[0043] The protective layer 24 is intended to prevent oxygen from being released from the oxide semiconductor layer 23. The protective layer 24 can be formed using a metal oxide containing at least one element selected from the group consisting of tantalum (Ta), titanium (Ti), vanadium (V), niobium (Nb), tungsten (W), zirconium (Zr), hafnium (Hf), scandium (Sc), yttrium (Y), lanthanum (La), gallium (Ga), and magnesium (Mg). Specifically, the constituent material of the protective layer 24 can be, for example, tantalum oxide (Ta). ２ O ５ ), titanium oxide (TiO ２ ), vanadium oxide (V ２ O ５ ), niobium oxide (Nb ２ O ５ ), tantalum oxide (W ２ O ３ ), zirconium oxide (ZrO ２ ), hafnium oxide (HfO ２ ), scandium oxide (Sc ２ O ３ ), yttrium oxide (Y ２ O ３ ), lanthanum oxide (La ２ O ３ ), gallium oxide (Ga ２ O ３ ) and magnesium oxide (MgO).

[0044] The potential control layer 25 is for controlling the potential of the photoelectric conversion layer 26 as described above. Specifically, the potential control layer 25 suppresses the effect of negative fixed charges in the protective layer 24 on the photoelectric conversion layer 26 and is capable of accumulating holes. FIG. 4A shows an example of the energy levels of the insulating layer 22, oxide semiconductor layer 23, protective layer 24, potential control layer 25, photoelectric conversion layer 26, and upper electrode 27 stacked above the storage electrode 21B, as indicated by line A-A in FIG. 3. The vacuum level is defined as the zero reference, and the closer to the vacuum level, the higher (shallower) the energy is. The values ​​of the HOMO and lowest unoccupied molecular orbital (LUMO) are negative numbers, while the work function and electron affinity are positive numbers. In FIG. 4A, the top of the vertical axis is the zero reference of the vacuum level, and the lower (deeper) the lower it is. The HOMO energy of the material with the highest HOMO energy contained in the photoelectric conversion layer 26, which will be described later, is defined as E ｉ ＨＯＭＯ The HOMO energy of the material with the highest HOMO energy among one or more materials included in the potential control layer is E ＮＢ ＨＯＭＯ In this case, the potential control layer 25 has E ｉ ＨＯＭＯ ≦E ＮＢ ＨＯＭＯ Here, in the above inequality, E ＮＢ ＨＯＭＯ Is E ｉ ＨＯＭＯ or E ＮＢ ＨＯＭＯ E is better ｉ ＨＯＭＯ This means that the material is closer to (higher or shallower than) the vacuum level than the material in the photoelectric conversion layer 26. The same applies to the subsequent inequalities. As a result, an electric field is applied to the photoelectric conversion layer 26 in the stacking direction (Z-axis direction), and a potential gradient is formed as shown in FIG. 4A. The material with the highest HOMO contained in the photoelectric conversion layer 26 is, for example, a hole transport material.

[0045] The potential control layer 25 is formed using an organic material. Examples of organic materials that satisfy the above relationship include naphthalocyanine derivatives and dioxaanthanthrene compounds. Among the above organic materials, it is preferable that the HOMO be at least 0.1 eV shallower than the HOMO of the photoelectric conversion layer 26, and that the LUMO be at most 0.4 eV shallower than the LUMO of the photoelectric conversion layer 26, and preferably be deeper than the LUMO of the photoelectric conversion layer 26. However, many of the above organic materials tend to have a LUMO shallower than the LUMO of the photoelectric conversion layer 26. Therefore, it is preferable that the potential control layer 25 have a thickness of, for example, 10 nm or less.

[0046] The potential control layer 25 has a thickness of, for example, −1E12 cm －２ <N<1E12cm －２ Here, the "fixed charge" in the potential control layer 25 made of an organic material refers to high-density holes or the like that exist spatially in a thermal equilibrium state, which are generated when the HOMO of the potential control layer 25 is higher than the HOMO or valence band of an adjacent layer.

[0047] The potential control layer 25 can be formed using one or more materials. When forming the potential control layer 25 using a single material, for example, the material is selected from organic materials that satisfy the above relationship. When forming the potential control layer 25 using multiple materials, at least one of the materials may be selected from organic materials that satisfy the above relationship. FIG. 4B shows another example of the energy levels of the insulating layer 22, oxide semiconductor layer 23, protective layer 24, potential control layer 25, photoelectric conversion layer 26, and upper electrode 27 stacked above the storage electrode 21B. As shown in FIG. 4B , including at least one of the above organic materials (the dotted pattern region in the figure) can suppress the effect of negative fixed charges in the protective layer 24 on the photoelectric conversion layer 26, thereby forming a potential gradient in the photoelectric conversion layer 26. Furthermore, forming the potential control layer 25 using multiple materials has the advantage of making it easier to form an electron channel.

[0048] The electric field applied to the photoelectric conversion layer 26 can be measured as follows. First, the photocurrent flowing between the readout electrode 21A and the upper electrode 27 is measured, and its voltage dependence is obtained. When the potential control layer 25 is present, a photocurrent flows even if the potential difference between the readout electrode 21A and the upper electrode 27 is small. On the other hand, when the potential control layer 25 is not present, a photocurrent does not flow if the potential difference between the readout electrode 21A and the upper electrode 27 is small. Specifically, when the photocurrent value when the potential difference is 0.2 V is I1 and the photocurrent value when the potential difference is 10 V is I2, the value of I1 / I2 is 0.5 or more.

[0049] The photoelectric conversion layer 26 absorbs, for example, 60% or more of a predetermined wavelength included at least in the visible light range to the near-infrared range, thereby separating charges. The photoelectric conversion layer 26 absorbs, for example, some or all of the wavelengths in the visible light range and the near-infrared range, from 400 nm to 1300 nm. The photoelectric conversion layer 26 is composed of, for example, two or more organic materials that function as p-type or n-type semiconductors, and has a junction between the p-type and n-type semiconductors (p / n junction). Alternatively, the photoelectric conversion layer 26 may have a stacked structure (p-type semiconductor layer / n-type semiconductor layer) of a layer made of a p-type semiconductor (p-type semiconductor layer) and a layer made of an n-type semiconductor (n-type semiconductor layer), a stacked structure (p-type semiconductor layer / bulk hetero layer) of a p-type semiconductor layer and a mixed layer (bulk hetero layer) of p-type and n-type semiconductors, or a stacked structure (n-type semiconductor layer / bulk hetero layer) of an n-type semiconductor layer and a bulk hetero layer. Alternatively, the layer may be formed solely from a mixed layer (bulk hetero layer) of p-type and n-type semiconductors.

[0050] A p-type semiconductor is a hole transport material that functions relatively as an electron donor, and an n-type semiconductor is an electron transport material that functions relatively as an electron acceptor. The photoelectric conversion layer 26 provides a field where excitons (electron-hole pairs) generated upon light absorption separate into electrons and holes. Specifically, the electron-hole pairs separate into electrons and holes at the interface (p / n junction) between the electron donor and electron acceptor.

[0051] Examples of p-type semiconductors include naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, perylene derivatives, tetracene derivatives, pentacene derivatives, quinacridone derivatives, thiophene derivatives, thienothiophene derivatives, benzothiophene derivatives, benzothienobenzothiophene (BTBT) derivatives, dinaphthothienothiophene (DNTT) derivatives, dianthracenothienothiophene (DATT) derivatives, benzobisbenzothiophene (BBBT) derivatives, thienothiophene derivatives, benzothienobenzothiophene (BTBT) derivatives, dibenzothienothiophene (DNTT) derivatives, dianthracenothienothiophene (DATT) derivatives, benzobisbenzothiophene (BBBT) derivatives, and thienothiophene derivatives. Examples of p-type semiconductors include thienoacene-based materials such as dibenzothienobisbenzothiophene (TBBT) derivatives, dibenzothienobisbenzothiophene (DBTBT) derivatives, dithienobenzodithiophene (DTBDT) derivatives, dibenzothienodithiophene (DBTDT) derivatives, benzodithiophene (BDT) derivatives, naphthodithiophene (NDT) derivatives, anthracenodithiophene (ADT) derivatives, tetracenodithiophene (TDT) derivatives, and pentacenodithiophene (PDT) derivatives. Examples of p-type semiconductors include triphenylamine derivatives, carbazole derivatives, picene derivatives, chrysene derivatives, fluoranthene derivatives, phthalocyanine derivatives, subphthalocyanine derivatives, subporphyrazine derivatives, metal complexes having heterocyclic compounds as ligands, polythiophene derivatives, polybenzothiadiazole derivatives, and polyfluorene derivatives.

[0052] As an n-type semiconductor, for example, fullerene C ６０ , fullerene C ７０ , fullerene C ７４Examples of the substituents contained in the fullerene derivatives include fullerenes and their derivatives, such as higher fullerenes and endohedral fullerenes. Examples of the substituents contained in the fullerene derivatives include halogen atoms, linear, branched, or cyclic alkyl groups or phenyl groups, groups having linear or condensed aromatic compounds, groups having halides, partial fluoroalkyl groups, perfluoroalkyl groups, silyl alkyl groups, silyl alkoxy groups, aryl silyl groups, aryl sulfanyl groups, alkyl sulfanyl groups, aryl sulfonyl groups, alkyl sulfonyl groups, aryl sulfide groups, alkyl sulfide groups, amino groups, alkyl amino groups, aryl amino groups, hydroxy groups, alkoxy groups, acyl amino groups, acyloxy groups, carbonyl groups, carboxy groups, carboxamido groups, carboalkoxy groups, acyl groups, sulfonyl groups, cyano groups, nitro groups, groups having chalcogenides, phosphine groups, phosphonic groups, and derivatives thereof. Specific examples of the fullerene derivatives include fullerene fluorides, PCBM fullerene compounds, and fullerene polymers. Other examples of n-type semiconductors include organic semiconductors and optically transparent inorganic metal oxides whose HOMO and LUMO levels are lower (deeper) than those of p-type semiconductors.

[0053] Examples of n-type organic semiconductors include heterocyclic compounds containing nitrogen atom, oxygen atom or sulfur atom.Specific examples include pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, isoquinoline derivatives, acridine derivatives, phenazine derivatives, phenanthroline derivatives, tetrazole derivatives, pyrazole derivatives, imidazole derivatives, thiazole derivatives, oxazole derivatives, imidazole derivatives, benzimidazole derivatives, benzotriazole derivatives, benzoxazole derivatives, benzoxazole derivatives, carbazole derivatives, benzofuran derivatives, dibenzofuran derivatives, subporphyrazine derivatives, polyphenylenevinylene derivatives, polybenzothiadiazole derivatives, polyfluorene derivatives, etc., which have such organic molecules as a part of molecular skeleton, organic metal complexes, subphthalocyanine derivatives, quinacridone derivatives, cyanine derivatives and merocyanine derivatives.

[0054] In addition to the p-type and n-type semiconductors, the photoelectric conversion layer 26 may further include an organic material, a so-called dye material, that absorbs 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, an n-type semiconductor, and a dye material, the p-type and n-type semiconductors are preferably materials that are optically transparent in the visible light range. This allows the photoelectric conversion layer 26 to selectively convert light in the wavelength range absorbed by the dye material.

[0055] The photoelectric conversion layer 26 has a thickness of, for example, 10 nm or more and 500 nm or less, and preferably has a thickness of 100 nm or more and 400 nm or less.

[0056] The upper electrode 27 is made of, for example, a light-transmitting conductive film, similar to the lower electrode 11. The upper electrode 27 is made of, for example, InP doped with tin (Sn) as a dopant. ２ O ３ The crystallinity of the ITO thin film may be high or low (approaching amorphous). In addition to the above, the constituent material of the lower electrode 11 may be tin oxide (SnO ２ )-based materials, for example, ATO with Sb added as a dopant, and FTO with fluorine added as a dopant can be used. Zinc oxide (ZnO) or a zinc oxide-based material with a dopant added can also be used. Examples of ZnO-based materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, boron zinc oxide with boron (B) added, and indium zinc oxide (IZO) with indium (In) added. Furthermore, zinc oxide with indium and gallium added as dopants (IGZO, In-GaZnO4) can also be used. In addition, materials constituting the lower electrode 11 include CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO３ or TiO ２ Alternatively, spinel oxides or YbFe ２ O ４ Oxides having such a structure may also be used.

[0057] Furthermore, if optical transparency is not required for the upper electrode 27, a single metal or alloy having a large work function (for example, φ=4.5 eV to 5.5 eV) can be used. Specific examples include Au, Ag, Cr, Ni, Pd, Pt, Fe, iridium (Ir), germanium (Ge), osmium (Os), rhenium (Re), tellurium (Te), and alloys thereof.

[0058] Furthermore, examples of materials for the upper electrode 27 include metals such as Pt, Au, Pd, Cr, Ni, Al, Ag, Ta, W, Cu, Ti, In, Sn, Fe, Co, and Mo, alloys containing these metal elements, conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and conductive substances such as graphene. Other examples of materials for the upper electrode 27 include organic materials (conductive polymers) such as PEDOT / PSS. Furthermore, the above materials may be mixed with a binder (polymer) to form a paste or ink, which may then be cured and used as an electrode.

[0059] The upper electrode 27 can be formed as a single layer or a multilayer film made of the above materials. The thickness of the upper electrode 27 is, for example, 20 nm to 200 nm, preferably 30 nm to 150 nm.

[0060] The photoelectric conversion unit 20 may have other layers provided between the lower electrode 21 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 a buffer layer that also serves as a hole blocking film, a work function adjustment layer, or the like, provided between the photoelectric conversion layer 26 and the upper electrode 27. The photoelectric conversion layer 26 may have a pin bulk heterostructure in which, for example, a p-type blocking layer, a layer containing a p-type semiconductor and an n-type semiconductor (i-layer), and an n-type blocking layer are stacked.

[0061] The insulating layer 28 covers the first surface 30A 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 30A of the semiconductor substrate 30 to the side surface of an opening 34H (see FIG. 1 ) 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.

[0062] 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.

[0063] 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).

[0064] 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.

[0065] A shield electrode 21C is provided on the interlayer insulating layer 29 together with the readout electrode 21A and the storage electrode 21B. The shield electrode 21C is intended to prevent capacitive coupling between adjacent pixel units 1a, and is provided around each pixel unit 1a, for example, each of which is made up of four unit pixels P arranged in a 2-row by 2-column array, to which a fixed potential is applied. The shield electrode 21C further extends between adjacent pixels in the row direction (Y-axis direction) and column direction (X-axis direction) within the pixel unit 1a.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] The through electrode 34 is provided between the first surface 30A and the second surface 30B 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 next 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.

[0071] The pad portions 39A, 39B, the upper first contact 39C, the upper second contact 39D, 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).

[0072] 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.

[0073] 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 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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 30B 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.

[0079] 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.

[0080] Further provided on the second surface 30B side of the semiconductor substrate 30 are a reset transistor TR2rst, an amplifier transistor TR2amp, and a selection transistor TR2sel that constitute a 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 a control section of the photoelectric conversion region 32R.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] (1-2. Method for Manufacturing Photodetector) The photodetector 1 of this embodiment can be manufactured, for example, as follows.

[0089] 7 to 12 show the process sequence of 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 30A of the semiconductor substrate 30.

[0090] 7, n+ regions that will become floating diffusions FD1 to FD3 are formed on the second surface 30B 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 30B 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.

[0091] 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 30A of the semiconductor substrate 30. After the ion implantation, an annealing process is performed.

[0092] Next, a support substrate (not shown) or another semiconductor substrate is bonded to the multilayer wiring layer 40 provided on the second surface 30B 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 30A 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).

[0093] 8, the semiconductor substrate 30 is processed from the first surface 30A 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 30A to the second surface 30B of the semiconductor substrate 30 and reaches, for example, the connection portion 41A.

[0094] Next, for example, a fixed charge layer 28A and a dielectric layer 28B are sequentially formed on the first surface 30A 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 and 39B 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 and 39B, and the surface of the interlayer insulating layer 29 is planarized using CMP (chemical mechanical polishing).

[0095] Subsequently, as shown in FIG. 9, openings 29H1 and 29H2 are formed on the pad portions 39A and 39B, respectively, and then a conductive material such as Al is filled into the openings 29H1 and 29H2 to form an upper first contact 39C and an upper second contact 39D.

[0096] 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 then the conductive film 21x is processed by dry etching or wet etching. The photoresist PR is then removed, thereby forming the read electrode 21A and the storage electrode 21B, as shown in FIG.

[0097] Next, as shown in FIG. 12 , an insulating layer 22, an oxide semiconductor layer 23, a protective layer 24, a potential control 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 can be formed using, for example, a sputtering method. The protective layer 24 can be formed using, for example, an ALD method. The potential control layer 25 and the photoelectric conversion layer 26 are formed using, for example, a vacuum deposition method. The upper electrode 27 is formed using, for example, a sputtering method, similar to the lower electrode 21. 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 .

[0098] As described above, when forming other layers containing organic materials, such as a buffer layer that also serves as a hole-blocking film or a work function adjustment layer, 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 consistent vacuum process). Furthermore, the method for forming the potential control layer 25 and 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.

[0099] (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, blue, and red light during this passage. The signal acquisition operation for each color will be described below.

[0100] (Acquisition of Green Signal by Photoelectric Conversion Unit 20) Of the light incident on the photodetector element 1, green light (G) is first selectively detected (absorbed) by the photoelectric conversion unit 20 and photoelectrically converted.

[0101] The photoelectric conversion unit 20 is connected to the gate Gamp of the amplifier transistor AMP 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 11 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 AMP.

[0102] In addition, a reset gate Grst of the reset transistor RST is disposed next to the floating diffusion FD1, so that the charge accumulated in the floating diffusion FD1 is reset by the reset transistor RST.

[0103] Since the photoelectric conversion unit 20 is connected not only to the amplifier transistor AMP but also to the floating diffusion FD1 via the through electrode 34, the charge accumulated in the floating diffusion FD1 can be easily reset by the reset transistor RST.

[0104] On the other hand, if the through electrode 34 and the floating diffusion FD1 are not connected, it becomes difficult to reset the charge accumulated in the floating diffusion FD1, and a large voltage must be applied to extract the charge to the upper electrode 27 side. 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.

[0105] 13 shows an example of operation of the photodetector element 1. (A) shows the potential at the 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 storage electrode 21B individually.

[0106] 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 storage electrode 21B. Here, the relationship between potentials V1 and V2 is V2 > V1. As a result, the charge (signal charge; electrons) generated by photoelectric conversion is attracted to the storage electrode 21B and accumulated in the region of the semiconductor layer 18 facing the storage electrode 21B (accumulation period). Incidentally, the potential of the region of the semiconductor layer 18 facing the 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.

[0107] 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).

[0108] After the reset operation is completed, the charge is read out. Specifically, at timing t2, the drive circuit applies a potential V3 to the readout electrode 21A and a potential V4 to the storage electrode 21B. Here, the potentials V3 and V4 are set to V3 > V4. As a result, the charge stored in the region corresponding to the storage electrode 21B is read out from the readout electrode 21A to the floating diffusion FD1. That is, the charge stored in the semiconductor layer 18 is read out to the control unit (transfer period).

[0109] After the read operation is completed, the drive circuit again applies potential V1 to the read electrode 21A and potential V2 to the storage electrode 21B, causing the charges generated by photoelectric conversion to be attracted to the storage electrode 21B and stored in the region of the photoelectric conversion layer 26 facing the storage electrode 21B (storage period).

[0110] (Acquisition of Blue and Red Signals by Photoelectric Conversion Regions 32B and 32R) Next, of the light transmitted through the photoelectric conversion unit 20, blue light (B) is absorbed and photoelectrically converted in the photoelectric conversion region 32B, and red light (R) is absorbed and photoelectrically converted in the photoelectric conversion region 32R, respectively. In the photoelectric conversion region 32B, electrons corresponding to the incident blue light (B) are accumulated in the n-region of the photoelectric conversion region 32B, and the accumulated electrons are transferred to the floating diffusion FD2 by the transfer transistor Tr2. Similarly, in the photoelectric conversion region 32R, electrons corresponding to the incident red light (R) are accumulated in the n-region of the photoelectric conversion region 32R, and the accumulated electrons are transferred to the floating diffusion FD3 by the transfer transistor Tr3.

[0111] (1-4. Actions and Effects) In the photodetector element 1 of this embodiment, a potential control layer 25 for controlling the potential of the photoelectric conversion layer 26 is provided between the protective layer 24 formed on the oxide semiconductor layer 23 and the photoelectric conversion layer 26. The potential control layer 25 controls the HOMO energy of the material with the highest HOMO energy contained in the photoelectric conversion layer 26 to E ｉ ＨＯＭＯ The HOMO energy of the material with the highest HOMO energy among one or more materials included in the potential control layer is E ＮＢ ＨＯＭＯ In this case, the potential control layer 25 has E ｉ ＨＯＭＯ ≦E ＮＢ ＨＯＭＯ This forms a potential gradient in the stacking direction of the photoelectric conversion layer 26. This will be described below.

[0112] In recent years, as pixel size has decreased in CCD image sensors and CMOS image sensors, the number of photons incident on each pixel has decreased, resulting in a decrease in sensitivity and a decrease in S / N. In addition, currently widely used image sensors have red, green, and blue pixels, each of which is fitted with a primary color filter, arranged in a Bayer pattern. However, in each color pixel, light other than the corresponding color light (e.g., green and blue light in the case of a red pixel) does not pass through the color filter and is not used for photoelectric conversion, resulting in a loss of sensitivity. Furthermore, the creation of color signals by interpolating between pixels creates the problem of false colors.

[0113] To solve these problems, an image sensor has been proposed in which three photoelectric conversion layers are stacked vertically to obtain three-color photoelectric conversion signals per pixel. As a structure in which three photoelectric conversion layers are stacked per pixel, for example, an image sensor has been proposed in which a photoelectric conversion unit that detects green light and generates a corresponding signal charge is provided above a silicon substrate, and blue and red light are detected by two PDs stacked within the silicon substrate. Other proposed structures include a back-illuminated structure in which a single organic photoelectric conversion film is provided above a silicon substrate and two inorganic photoelectric conversion units are provided within the silicon substrate, with the circuit formation surface formed on the opposite side from the light-receiving surface, and a structure in which an oxide semiconductor film and an insulating film for charge storage and transfer are provided directly below the photoelectric conversion film, and multiple electrodes (charge readout electrodes and charge storage electrodes) are used as lower electrodes.

[0114] In the former case, when an organic photoelectric conversion layer is formed in a back-illuminated configuration, no circuitry or wiring is formed between the inorganic photoelectric conversion unit and the organic photoelectric conversion unit, allowing the inorganic photoelectric conversion unit and the organic photoelectric conversion unit to be closer to each other within the same pixel. This reduces the F-number dependency of each color, thereby suppressing variations in sensitivity between colors. In the latter case, a charge storage electrode is disposed opposite the photoelectric conversion layer via an insulating layer, allowing charges generated by photoelectric conversion to be stored in the oxide semiconductor film. This allows the charge storage unit to be completely depleted and erased at the start of exposure. As a result, it is possible to suppress phenomena such as increased kTC noise, deterioration of random noise, and degradation of image quality.

[0115] In the image sensor having an insulating film and an oxide semiconductor film stacked between a plurality of electrodes and a photoelectric conversion layer as described above, defects caused by oxygen detachment from the oxide semiconductor layer have been a problem, and as described above, a structure has been proposed in which an oxide film is stacked on the oxide semiconductor film to prevent oxygen detachment from the oxide semiconductor layer. However, when an oxide film is formed between the oxide semiconductor film and the photoelectric conversion layer, negative fixed charges in the oxide film cause a problem of deterioration in the characteristics of the photoelectric conversion layer.

[0116] In contrast to this, in the present embodiment, the HOMO energy (E ｉ ＨＯＭＯ ) and the HMO energy (E ＮＢ ＨＯＭＯ ) is provided. The potential control layer 25 is capable of accumulating holes and suppresses the influence of negative fixed charges in the protective layer 24 on the photoelectric conversion layer 26. This allows an electric field to be applied to the photoelectric conversion layer 26 in the stacking direction, and as shown in FIGS. 4A and 4B , a potential gradient is formed in the stacking direction of the photoelectric conversion layer 26.

[0117] As described above, the photodetector element 1 of this embodiment can achieve both high reliability and high electron transport properties.

[0118] Next, second to fourth embodiments and modifications (modifications 1 to 6) of the present disclosure will be described. In the following, the same components as those in the first embodiment will be denoted by the same reference numerals, and their description will be omitted as appropriate.

[0119] 14 is a schematic diagram illustrating an example of a cross-sectional configuration of a main portion (photoelectric conversion unit 20A) of a photodetector element according to Modification 1 of the present disclosure. Similar to the photoelectric conversion unit 20 of the first embodiment, the photoelectric conversion unit 20A, together with two photoelectric conversion regions 32B and 32R, constitutes, as the photodetector element 1, one pixel (unit pixel P) that is repeatedly arranged in an array in a pixel unit 100A of a photodetector device (e.g., photodetector device 100) such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0120] In the first embodiment, an example in which the potential control layer 25 consisting of one layer is provided between the protective layer 24 and the photoelectric conversion layer 26 has been described, but the present invention is not limited to this. In the photoelectric conversion unit 20A of this modification, the potential control layer 25 consisting of multiple layers (here, two layers, a first layer 25A and a second layer 25B) is provided between the protective layer 24 and the photoelectric conversion layer 26.

[0121] In the photoelectric conversion unit 20A, an oxide semiconductor layer 23, a protective layer 24 formed using an inorganic material, a potential control layer 25 formed using an organic material, and a photoelectric conversion layer 26 also formed using an organic material are stacked in this order from the lower electrode 21 side between an opposing lower electrode 21 and an upper electrode 27. The potential control layer 25 is made of a stacked film, and has a first layer 25A and a second layer 25B stacked in this order from the photoelectric conversion layer 26 side.

[0122] 15A shows an example of the energy levels of the insulating layer 22, oxide semiconductor layer 23, protective layer 24, potential control layer 25, photoelectric conversion layer 26, and upper electrode 27, which are stacked above the storage electrode 21B, as shown by line A-A in FIG. 14. As described above, the potential control layer 25 has a first layer 25A and a second layer 25B stacked in this order from the photoelectric conversion layer 26 side. The vacuum level is defined as the zero level, and the closer to the vacuum level, the higher (shallower) the energy is. The HOMO energy of the material with the highest HOMO energy contained in the photoelectric conversion layer 26 is defined as E ｉ ＨＯＭＯ , the HOMO energy of the material with the highest HOMO energy contained in the first layer 25A is E ＮＢ１ ＨＯＭＯ, the HOMO energy of the material with the highest HOMO energy contained in the second layer 25B is E ＮＢ２ ＨＯＭＯ In this case, the first layer 25A and the second layer 25B have E ｉ ＨＯＭＯ >E ＮＢ１ ＨＯＭＯ , and E ＮＢ１ ＨＯＭＯ <E ＮＢ２ ＨＯＭＯ As a result, an electric field is applied to the photoelectric conversion layer 26 in the stacking direction (Z-axis direction), and a potential gradient is formed as shown in Fig. 15A. The material having the highest HOMO contained in the photoelectric conversion layer 26 is, for example, a hole transport material.

[0123] The first layer 25A can be formed using, for example, an organic material commonly used as a hole-blocking layer. The second layer 25B can be formed using, for example, a naphthalocyanine derivative or a dioxaanthanthrene-based compound, which are listed as examples of materials for the potential control layer 25 in the first embodiment. Among the above organic materials, it is preferable to use an organic material having a HOMO that is 0.1 eV or more shallower than the HOMO of the photoelectric conversion layer 26, and a LUMO that is at most 0.4 eV shallower than the LUMO of the photoelectric conversion layer 26, and preferably deeper than the LUMO of the photoelectric conversion layer 26. However, many of the above organic materials tend to have a LUMO shallower than the LUMO of the photoelectric conversion layer 26. Therefore, it is preferable that the second layer 25B have a thickness of, for example, 10 nm or less. The second layer 25B can further have a thickness of, for example, -1E12 cm. －２ <N<1E12cm －２ The fixed charge satisfies the following:

[0124] The first layer 25A and the second layer 25B can each be formed using one or more materials. When forming the second layer 25B, at least one of the organic materials may be selected. FIG. 15B shows another example of the energy levels of the insulating layer 22, oxide semiconductor layer 23, protective layer 24, potential control layer 25, photoelectric conversion layer 26, and upper electrode 27 stacked above the storage electrode 21B. As shown in FIG. 15B, including at least one of the organic materials (the dotted pattern area in the figure) can suppress the effect of negative fixed charges in the protective layer 24 on the photoelectric conversion layer 26, thereby forming a potential gradient in the photoelectric conversion layer 26. Furthermore, forming the second layer 25B using multiple materials has the advantage of making it easier to form an electron channel.

[0125] In this manner, in the photoelectric conversion unit 20A of this modified example, the potential control layer 25 including the first layer 25A and the second layer 25B stacked in this order from the photoelectric conversion layer 26 side is provided between the protective layer 24 and the photoelectric conversion layer 26. The first layer 25A and the second layer 25B adjust the HOMO energy of the material with the highest HOMO energy contained in the photoelectric conversion layer 26 to E ｉ ＨＯＭＯ , the HOMO energy of the material with the highest HOMO energy contained in the first layer 25A is E ＮＢ１ ＨＯＭＯ , the HOMO energy of the material with the highest HOMO energy contained in the second layer 25B is E ＮＢ２ ＨＯＭＯ In this case, E ｉ ＨＯＭＯ >E ＮＢ１ ＨＯＭＯ , and E ＮＢ１ ＨＯＭＯ <E ＮＢ２ ＨＯＭＯ In this configuration, an electric field can be applied to the photoelectric conversion layer 26 in the stacking direction, and a potential gradient is formed in the stacking direction of the photoelectric conversion layer 26, as shown in Figures 15A and 15B. Therefore, the same effects as those of the first embodiment can be obtained.

[0126] 3. Second Embodiment FIG. 16 illustrates a cross-sectional configuration of a photodetector element (photodetector element 2) according to a second embodiment of the present disclosure. The photodetector element 2 constitutes one pixel (unit pixel P) repeatedly arranged in an array in a pixel section 100A of a photodetector device (e.g., photodetector device 100), such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor used in electronic devices such as digital still cameras and video cameras. FIG. 17 illustrates an enlarged schematic cross-sectional configuration of a main portion (photoelectric conversion section 60) of the photodetector element 2 illustrated in FIG. 16. In the pixel section 100A, as in the first embodiment, a pixel unit consisting of, for example, 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.

[0127] The photodetector element 2 of this embodiment has a photoelectric conversion section 60 provided on a semiconductor substrate 30, in which a lower electrode 61 consisting of a readout electrode 61A and a storage electrode 61B, an insulating layer 62, an oxide semiconductor layer 63, a potential control layer 64, a photoelectric conversion layer 65, and an upper electrode 66 are stacked in this order.

[0128] Here, the readout electrode 61A corresponds to a specific example of a "first electrode" in the second embodiment of the present disclosure, and the storage electrode 61B corresponds to a specific example of a "second electrode" in the second embodiment of the present disclosure. The potential control layer 64 corresponds to a specific example of an "intermediate layer" in the second embodiment of the present disclosure. The photoelectric conversion layer 65 corresponds to a specific example of a "photoelectric conversion layer" in the second embodiment of the present disclosure. The upper electrode 66 corresponds to a specific example of a "third electrode" in the second embodiment of the present disclosure.

[0129] (3-1. Configuration of Photodetector) The photodetector 2 is, for example, a so-called vertical spectroscopic type in which one photoelectric conversion unit 60 and two photoelectric conversion regions 32B, 32R are stacked vertically. The photoelectric conversion unit 60 is provided on the back surface (first surface 30A) 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.

[0130] The photoelectric conversion unit 60 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 60 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 element 2 to acquire multiple types of color signals in one pixel without using color filters.

[0131] 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.

[0132] The surface (second surface 30B) 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 30B 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, wiring layers 41, 42, and 43 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., in a peripheral region 1B around the pixel portion 100A.

[0133] In the drawings, the first surface 30A side of the semiconductor substrate 30 is represented as a light incident side S1, and the second surface 30B side is represented as a wiring layer side S2.

[0134] The photoelectric conversion section 60 has an oxide semiconductor layer 63, a potential control layer 64 formed using an inorganic material, and a photoelectric conversion layer 65 formed using an organic material stacked in this order from the lower electrode 61 side between a lower electrode 61 and an upper electrode 66 that are arranged opposite to each other. As will be described in detail later, the potential control layer 64 has a thickness of −1E12 cm －２ <N<1E12cm －２ The photoelectric conversion layer 65 includes 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.

[0135] The photoelectric conversion unit 60 further includes an insulating layer 62 between the lower electrode 61 and the oxide semiconductor layer 63. The insulating layer 62 is provided, for example, over the entire surface of the pixel unit 100A, and has an opening 22H above the readout electrode 61A that constitutes the lower electrode 61. The readout electrode 61A is electrically connected to the oxide semiconductor layer 63 through this opening 22H.

[0136] Note that, although Figure 16 shows an example in which the oxide semiconductor layer 63, the potential control layer 64, the photoelectric conversion layer 65, and the upper electrode 66 are formed separately for each photodetection element 2, the oxide semiconductor layer 63, the potential control layer 64, the photoelectric conversion layer 65, and the upper electrode 66 may be provided as, for example, a continuous layer common to a plurality of photodetection elements 2.

[0137] Between the first surface 30A of the semiconductor substrate 30 and the lower electrode 61, 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.

[0138] 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.

[0139] A through electrode 34 is provided between the first surface 30A and the second surface 30B of the semiconductor substrate 30. The through electrode 34 is electrically connected to the readout electrode 61A, and the photoelectric conversion unit 60 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 2 to efficiently transfer carriers (electrons in this case) generated in the photoelectric conversion unit 60 provided on the first surface 30A side of the semiconductor substrate 30 to the second surface 30B side of the semiconductor substrate 30 via the through electrode 34, thereby improving its characteristics.

[0140] 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 readout electrode 61A via, for example, a pad portion 39A and an upper first contact 39C.

[0141] A protective layer 51 is provided above the photoelectric conversion unit 60. Within the protective layer 51, for example, wiring 52 and a light-shielding film 53 are provided, which electrically connect the upper electrode 66 and the peripheral circuit unit 130 around the pixel unit 100A. Optical members such as a planarization layer (not shown) and an on-chip lens 54 are further provided above the protective layer 51.

[0142] In the photodetector element 2 of this embodiment, light incident on the photoelectric conversion unit 60 from the light incident side S1 is absorbed by the photoelectric conversion layer 65. The excitons thus generated move to the interface between the electron donors and electron acceptors that make up the photoelectric conversion layer 65, 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 by an internal electric field caused by the difference in work function between the anode (e.g., the upper electrode 66) and the cathode (e.g., the lower electrode 61), 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 61 and the upper electrode 66.

[0143] The structure and materials of each part will be described in detail below.

[0144] The photoelectric conversion section 60 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.

[0145] The lower electrode 61 is composed of, for example, a readout electrode 61A and a storage electrode 61B arranged in parallel on the interlayer insulating layer 29. The readout electrode 61A is for transferring carriers generated in the photoelectric conversion layer 65 to the floating diffusion FD1, and one readout electrode 61A is provided for each pixel unit 1a, which is made up of, for example, four unit pixels P arranged in two rows and two columns.

[0146] The readout electrode 61A is connected to the floating diffusion FD1 via, for example, the upper first contact 39C, the pad portion 39A, the through electrode 34, the connection portion 41A, and the lower second contact 46.

[0147] The storage electrode 61B is provided for each pixel to store, as signal charges, electrons, among the carriers generated in the photoelectric conversion layer 65, in the oxide semiconductor layer 63. The storage electrode 61B is provided for each unit pixel P in a region that directly faces the light-receiving surfaces of the photoelectric conversion regions 32B and 32R formed in the semiconductor substrate 30 and covers these light-receiving surfaces. The storage electrode 61B is preferably larger than the readout electrode 61A, allowing it to store a larger number of carriers. As shown in FIG. 6 , the voltage application unit 56 is connected to the storage electrode 61B via wiring, such as the upper first contact 39C and the upper second contact 39D.

[0148] The lower electrode 61 is made of, for example, a light-transmitting conductive film. The lower electrode 61 preferably has a work function of 4.0 eV or more and 5.5 eV or less. The material for the lower electrode 61 is, for example, InP doped with tin (Sn) as a dopant. ２ O ３ The crystallinity of the ITO thin film may be high or low (approaching amorphous). In addition to the above, the lower electrode 61 may also be made of tin oxide (SnO ２ )-based materials, for example, ATO with Sb added as a dopant, and FTO with fluorine added as a dopant can be used. Zinc oxide (ZnO) or a zinc oxide-based material with a dopant added can also be used. Examples of ZnO-based materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, boron zinc oxide with boron (B) added, and indium zinc oxide (IZO) with indium (In) added. Furthermore, zinc oxide with indium and gallium added as dopants (IGZO, In-GaZnO4) can also be used. In addition, materials constituting the lower electrode 61 include CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３or TiO ２ Alternatively, spinel oxides or YbFe ２ O ４ Oxides having such a structure may also be used.

[0149] Furthermore, when optical transparency is not required for the lower electrode 61 (for example, when light is incident from the upper electrode 27 side), a single metal or alloy having a small work function (for example, φ=3.5 eV to 4.5 eV) can be used. Specific examples include alkali metals (for example, lithium (Li), sodium (Na), and potassium (K)) and their fluorides or oxides, and alkaline earth metals (for example, magnesium (Mg) and calcium (Ca)) and their fluorides or oxides. Other examples include aluminum (Al), Al—Si—Cu alloys, zinc (Zn), tin (Sn), thallium (Tl), Na—K alloys, Al—Li alloys, Mg—Ag alloys, and rare earth metals such as In and ytterbium (Yb), or alloys thereof.

[0150] Furthermore, examples of materials for the lower electrode 61 include metals such as platinum (Pt), gold (Au), palladium (Pd), chromium (Cr), nickel (Ni), aluminum (Al), silver (Ag), tantalum (Ta), tungsten (W), copper (Cu), titanium (Ti), indium (In), tin (Sn), iron (Fe), cobalt (Co), and molybdenum (Mo), alloys containing these metal elements, conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and graphene. Other examples of materials for the lower electrode 61 include organic materials (conductive polymers) such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate (PEDOT / PSS). Alternatively, the above materials may be mixed with a binder (polymer) to form a paste or ink, which may then be cured and used as an electrode.

[0151] The lower electrode 61 can be formed as a single layer or a laminated film made of the above materials. The film thickness of the lower electrode 61 in the lamination direction (hereinafter simply referred to as thickness) is, for example, 20 nm to 200 nm, and preferably 30 nm to 150 nm.

[0152] The insulating layer 62 serves to electrically separate the storage electrode 61B from the oxide semiconductor layer 63. The insulating layer 62 is provided, for example, on the interlayer insulating layer 29 so as to cover the lower electrode 61. An opening 22H is provided in the insulating layer 62 above the readout electrode 61A of the lower electrode 61, and the readout electrode 61A and the oxide semiconductor layer 63 are electrically connected via this opening 22H. The insulating layer 62 is made of, for example, silicon oxide (SiO ｘ ), silicon nitride (SiN ｘ The insulating layer 62 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 62 is, for example, 20 nm to 500 nm.

[0153] The oxide semiconductor layer 63 is for accumulating carriers generated in the photoelectric conversion layer 65. The oxide semiconductor layer 63 can be formed using an oxide semiconductor material containing at least one element selected from the group consisting of indium (In), gallium (Ga), silicon (Si), zinc (Zn), aluminum (Al), and tin (Sn). In this embodiment, electrons among the carriers generated in the photoelectric conversion layer 65 are used as signal charges. For this reason, the oxide semiconductor layer 63 can be formed using an n-type oxide semiconductor material. Specifically, the oxide semiconductor layer 63 can be formed using IGZO, Ga ２ O ３ , GZO, IZO, ITO, InGaAlO, InGaSiO, etc. The thickness of the oxide semiconductor layer 63 is, for example, 10 nm to 300 nm.

[0154] As described above, the potential control layer 64 is for controlling the potential of the photoelectric conversion layer 65. The potential control layer 64 has a resistivity of −1E12 cm －２ <N<1E12cm －２18 shows an example of the energy levels of the insulating layer 62, the oxide semiconductor layer 63, the potential control layer 64, the photoelectric conversion layer 65, and the upper electrode 66 stacked above the storage electrode 61B, as shown by the line A-A in FIG. 17. When the energy level between the oxide semiconductor layer 63 and the photoelectric conversion layer 65 is -1E12 cm －２ <N<1E12cm －２ By providing the potential control layer 64 having a fixed charge amount that satisfies the above, it is possible to control the potential (amount of charge) applied to the photoelectric conversion layer 65 and the potential control layer 64, and a potential gradient such as that shown in FIG. 18 is formed in the photoelectric conversion layer 65.

[0155] The potential control layer 64 is formed using an inorganic material. Specifically, the potential control layer 64 is formed using a metal oxide containing at least one element selected from the group consisting of titanium (Ti), tantalum (Ta), vanadium (V), niobium (Nb), tungsten (W), zirconium (Zr), hafnium (Hf), scandium (Sc), yttrium (Y), lanthanum (La), gallium (Ga), magnesium (Mg), silicon (Si), and aluminum (Al).

[0156] The thickness of the potential control layer 64 is preferably, for example, 1 atom or more and 10 nm or less.

[0157] The amount of fixed charge in the potential control layer 64 can be calculated using the capacitance-voltage method. Specifically, it is calculated from the following equation (1) where V is the voltage, C is the capacitance, q is the elementary charge, and N is the fixed charge. The measurement method uses an electrode on the insulating film side (for example, the lower electrode 61) and an electrode on the organic layer side (for example, the upper electrode 66) to determine the capacitance between them. The voltage V is swept, and the fixed charge N is calculated from the value of the capacitance C of the accumulation region using the above equation. The amount of fixed charge in the potential control layer 75 of the third embodiment, which will be described later, can also be determined in a similar manner. (Equation 1) N=CV / q (1)

[0158] The photoelectric conversion layer 65 absorbs, for example, 60% or more of a predetermined wavelength included at least in the visible light range to the near-infrared range, thereby separating charges. The photoelectric conversion layer 65 absorbs, for example, some or all of the wavelengths in the visible light range and the near-infrared range, from 400 nm to 1300 nm. The photoelectric conversion layer 65 is composed of, for example, two or more organic materials that function as p-type or n-type semiconductors, and has a junction between the p-type and n-type semiconductors (p / n junction). Alternatively, the photoelectric conversion layer 65 may have a stacked structure (p-type semiconductor layer / n-type semiconductor layer) of a layer made of a p-type semiconductor (p-type semiconductor layer) and a layer made of an n-type semiconductor (n-type semiconductor layer), a stacked structure (p-type semiconductor layer / bulk hetero layer) of a p-type semiconductor layer and a mixed layer (bulk hetero layer) of p-type and n-type semiconductors, or a stacked structure (n-type semiconductor layer / bulk hetero layer) of an n-type semiconductor layer and a bulk hetero layer. Alternatively, the layer may be formed solely from a mixed layer (bulk hetero layer) of p-type and n-type semiconductors.

[0159] The p-type semiconductor is a hole transport material that functions relatively as an electron donor, and the n-type semiconductor is an electron transport material that functions relatively as an electron acceptor. The photoelectric conversion layer 65 provides a field where excitons (electron-hole pairs) generated upon light absorption separate into electrons and holes. Specifically, the electron-hole pairs separate into electrons and holes at the interface (p / n junction) between the electron donor and electron acceptor.

[0160] Examples of p-type semiconductors include naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, perylene derivatives, tetracene derivatives, pentacene derivatives, quinacridone derivatives, thiophene derivatives, thienothiophene derivatives, benzothiophene derivatives, benzothienobenzothiophene (BTBT) derivatives, dinaphthothienothiophene (DNTT) derivatives, dianthracenothienothiophene (DATT) derivatives, benzobisbenzothiophene (BBBT) derivatives, thienothiophene derivatives, benzothienobenzothiophene (BTBT) derivatives, dibenzothienothiophene (DNTT) derivatives, dianthracenothienothiophene (DATT) derivatives, benzobisbenzothiophene (BBBT) derivatives, and thienothiophene derivatives. Examples of p-type semiconductors include thienoacene-based materials such as dibenzothienobisbenzothiophene (TBBT) derivatives, dibenzothienobisbenzothiophene (DBTBT) derivatives, dithienobenzodithiophene (DTBDT) derivatives, dibenzothienodithiophene (DBTDT) derivatives, benzodithiophene (BDT) derivatives, naphthodithiophene (NDT) derivatives, anthracenodithiophene (ADT) derivatives, tetracenodithiophene (TDT) derivatives, and pentacenodithiophene (PDT) derivatives. Examples of p-type semiconductors include triphenylamine derivatives, carbazole derivatives, picene derivatives, chrysene derivatives, fluoranthene derivatives, phthalocyanine derivatives, subphthalocyanine derivatives, subporphyrazine derivatives, metal complexes having heterocyclic compounds as ligands, polythiophene derivatives, polybenzothiadiazole derivatives, and polyfluorene derivatives.

[0161] As an n-type semiconductor, for example, fullerene C ６０ , fullerene C ７０ , fullerene C ７４Examples of the substituents contained in the fullerene derivatives include fullerenes and their derivatives, such as higher fullerenes and endohedral fullerenes. Examples of the substituents contained in the fullerene derivatives include halogen atoms, linear, branched, or cyclic alkyl groups or phenyl groups, groups having linear or condensed aromatic compounds, groups having halides, partial fluoroalkyl groups, perfluoroalkyl groups, silyl alkyl groups, silyl alkoxy groups, aryl silyl groups, aryl sulfanyl groups, alkyl sulfanyl groups, aryl sulfonyl groups, alkyl sulfonyl groups, aryl sulfide groups, alkyl sulfide groups, amino groups, alkyl amino groups, aryl amino groups, hydroxy groups, alkoxy groups, acyl amino groups, acyloxy groups, carbonyl groups, carboxy groups, carboxamido groups, carboalkoxy groups, acyl groups, sulfonyl groups, cyano groups, nitro groups, groups having chalcogenides, phosphine groups, phosphonic groups, and derivatives thereof. Specific examples of the fullerene derivatives include fullerene fluorides, PCBM fullerene compounds, and fullerene polymers. Other examples of n-type semiconductors include organic semiconductors and optically transparent inorganic metal oxides whose HOMO and LUMO levels are lower (deeper) than those of p-type semiconductors.

[0162] Examples of n-type organic semiconductors include heterocyclic compounds containing nitrogen atom, oxygen atom or sulfur atom.Specific examples include pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, isoquinoline derivatives, acridine derivatives, phenazine derivatives, phenanthroline derivatives, tetrazole derivatives, pyrazole derivatives, imidazole derivatives, thiazole derivatives, oxazole derivatives, imidazole derivatives, benzimidazole derivatives, benzotriazole derivatives, benzoxazole derivatives, benzoxazole derivatives, carbazole derivatives, benzofuran derivatives, dibenzofuran derivatives, subporphyrazine derivatives, polyphenylenevinylene derivatives, polybenzothiadiazole derivatives, polyfluorene derivatives, etc., which have such organic molecules as a part of molecular skeleton, organic metal complexes, subphthalocyanine derivatives, quinacridone derivatives, cyanine derivatives and merocyanine derivatives.

[0163] In addition to the p-type and n-type semiconductors, the photoelectric conversion layer 65 may further include an organic material, a so-called dye material, that absorbs light in a predetermined wavelength range while transmitting light in other wavelength ranges. When the photoelectric conversion layer 65 is formed using three types of organic materials, i.e., a p-type semiconductor, an n-type semiconductor, and a dye material, the p-type and n-type semiconductors are preferably materials that are optically transparent in the visible light range. This allows the photoelectric conversion layer 65 to selectively convert light in the wavelength range absorbed by the dye material into electricity.

[0164] The photoelectric conversion layer 65 has a thickness of, for example, 10 nm or more and 500 nm or less, and preferably has a thickness of 100 nm or more and 400 nm or less.

[0165] The upper electrode 66 is made of, for example, a light-transmitting conductive film, similar to the lower electrode 11. The upper electrode 66 is made of, for example, InP doped with tin (Sn) as a dopant. ２ O ３ The crystallinity of the ITO thin film may be high or low (approaching amorphous). In addition to the above, the constituent material of the lower electrode 11 may be tin oxide (SnO ２ )-based materials, for example, ATO with Sb added as a dopant, and FTO with fluorine added as a dopant can be used. Zinc oxide (ZnO) or a zinc oxide-based material with a dopant added can also be used. Examples of ZnO-based materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, boron zinc oxide with boron (B) added, and indium zinc oxide (IZO) with indium (In) added. Furthermore, zinc oxide with indium and gallium added as dopants (IGZO, In-GaZnO4) can also be used. In addition, materials constituting the lower electrode 11 include CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO３ or TiO ２ Alternatively, spinel oxides or YbFe ２ O ４ Oxides having such a structure may also be used.

[0166] Furthermore, if optical transparency is not required for the upper electrode 66, a single metal or alloy having a large work function (for example, φ=4.5 eV to 5.5 eV) can be used. Specific examples include Au, Ag, Cr, Ni, Pd, Pt, Fe, iridium (Ir), germanium (Ge), osmium (Os), rhenium (Re), tellurium (Te), and alloys thereof.

[0167] Furthermore, examples of materials that can be used to form the upper electrode 66 include metals such as Pt, Au, Pd, Cr, Ni, Al, Ag, Ta, W, Cu, Ti, In, Sn, Fe, Co, and Mo, alloys containing these metal elements, conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and graphene. Other examples of materials that can be used to form the upper electrode 66 include organic materials (conductive polymers) such as PEDOT / PSS. Alternatively, the above materials can be mixed with a binder (polymer) to form a paste or ink, which can then be cured and used as an electrode.

[0168] The upper electrode 66 can be formed as a single layer or a laminated film made of the above materials. The thickness of the upper electrode 66 is, for example, 20 nm to 200 nm, preferably 30 nm to 150 nm.

[0169] The photoelectric conversion unit 60 may have other layers provided between the lower electrode 61 and the photoelectric conversion layer 65 and between the photoelectric conversion layer 65 and the upper electrode 66. For example, the photoelectric conversion unit 60 may have a buffer layer that also serves as a hole blocking film, a work function adjustment layer, or the like, provided between the photoelectric conversion layer 65 and the upper electrode 66. The photoelectric conversion layer 65 may have a pin bulk heterostructure in which, for example, a p-type blocking layer, a layer containing a p-type semiconductor and an n-type semiconductor (i-layer), and an n-type blocking layer are stacked.

[0170] (3-2. Actions and Effects) The photodetector element 2 of this embodiment has a thickness of −1E12 cm between the oxide semiconductor layer 63 and the photoelectric conversion layer 65. －２ <N<1E12cm －２ The potential control layer 64 is provided with a fixed charge amount that satisfies the above condition. The potential (amount of charge) applied to the photoelectric conversion layer 65 and the potential control layer 64 can be controlled, and for example, the sign of the potential of the potential control layer 64 can be reversed (from negative to positive). As a result, a potential gradient is formed in the stacking direction for the photoelectric conversion layer 65, as shown in FIG.

[0171] As described above, the photodetector element 2 of this embodiment can achieve both high reliability and high electron transport properties.

[0172] 19 is a schematic diagram illustrating an example of a cross-sectional configuration of a main portion (photoelectric conversion unit 60A) of a photodetector element according to Modification 2 of the present disclosure. Similar to the photoelectric conversion unit 60 of the second embodiment, the photoelectric conversion unit 60A, for example, constitutes a photodetector element 2 together with two photoelectric conversion regions 32B, 32R, to form one pixel (unit pixel P) repeatedly arranged in an array in a pixel unit 100A of a photodetector device (for example, the photodetector device 100) such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0173] In the second embodiment, an example in which the potential control layer 64 consisting of one layer is provided between the oxide semiconductor layer 63 and the photoelectric conversion layer 65 has been described, but the present invention is not limited to this. In the photoelectric conversion unit 60A of this modification, the potential control layer 64 consisting of multiple layers (here, two layers, a first layer 64A and a second layer 64B) is provided between the oxide semiconductor layer 63 and the photoelectric conversion layer 65.

[0174] The photoelectric conversion unit 60A has an oxide semiconductor layer 63, a potential control layer 64 formed using an inorganic material, and a photoelectric conversion layer 65 formed using an organic material stacked in this order from the lower electrode 61 side between an opposing lower electrode 61 and an upper electrode 66. The potential control layer 64 is made of a laminated film, and has a first layer 64A and a second layer 64B with different atomic compositions stacked in this order from the photoelectric conversion layer 65 side.

[0175] The first layer 64A is −1E12 cm －２ <N<1E12cm －２ and controls the potential applied to the photoelectric conversion layer 65. The first layer 64A is formed using a metal oxide containing at least one element selected from titanium (Ti), tantalum (Ta), vanadium (V), niobium (Nb), tungsten (W), zirconium (Zr), hafnium (Hf), scandium (Sc), yttrium (Y), lanthanum (La), gallium (Ga), magnesium (Mg), silicon (Si), and aluminum (Al), which are listed as materials for the potential control layer 64 in the second embodiment. The thickness of the first layer 64A is preferably, for example, not less than 1 atom and not more than 10 nm.

[0176] The second layer 64B serves to terminate interface defects in the oxide semiconductor layer 23 and to prevent the detachment of terminated elements (e.g., oxygen). The second layer 64B is made of, for example, titanium oxide (TiO ２ ) and silicon oxide (SiO ２ ) can be used. ２ When the second layer 64B is formed using TiO, if the film thickness is about 1 nm or less, a photoelectric conversion current can flow from the photoelectric conversion layer 65 to the oxide semiconductor layer 63 by the tunnel effect. ２ When the second layer 64B is formed using the above material, there are no particular restrictions, but the thickness may be about 10 nm or less.

[0177] In this manner, in the photoelectric conversion section 60A of this modification, the potential control layer 64 including the first layer 64A and the second layer 64B stacked in this order from the photoelectric conversion layer 65 side is provided between the oxide semiconductor layer 63 and the photoelectric conversion layer 65. The first layer 64A has a conductivity of −1E12 cm－２ <N<1E12cm －２ and controls the potential (amount of charge) applied to the photoelectric conversion layer 65 and the potential control layer 64. The second layer 64B terminates interfacial defects in the oxide semiconductor layer 23 and prevents detachment of terminated elements (e.g., oxygen). In this way, by forming the potential control layer 64 as a stacked film of the first layer 64A and the second layer 64B having different atomic compositions, it becomes easier to control traps on the surface of the oxide semiconductor layer 63 in addition to controlling the potential of the photoelectric conversion layer 65. Therefore, in addition to the effects of the second embodiment, it is possible to further improve the electron transport characteristics.

[0178] 5. Third Embodiment Fig. 20 illustrates a cross-sectional configuration of a photodetector element (photodetector element 3) according to a third embodiment of the present disclosure. The photodetector element 3 constitutes one pixel (unit pixel P) repeatedly arranged in an array in a pixel section 100A of a photodetector device (e.g., photodetector device 100) such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor used in electronic devices such as digital still cameras and video cameras. Fig. 21 illustrates an enlarged schematic cross-sectional configuration of a main portion (photoelectric conversion section 70) of the photodetector element 3 illustrated in Fig. 20. In the pixel section 100A, as in the first embodiment, a pixel unit consisting of, for example, 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.

[0179] The photodetector element 3 of this embodiment has a photoelectric conversion section 70 provided on a semiconductor substrate 30, in which a lower electrode 71 consisting of a readout electrode 71A and a storage electrode 71B, an insulating layer 72, an oxide semiconductor layer 73, a protective layer 74, a potential control layer 75, a photoelectric conversion layer 76, and an upper electrode 77 are stacked in this order.

[0180] Here, the readout electrode 71A corresponds to a specific example of a "first electrode" in the third embodiment of the present disclosure, and the storage electrode 71B corresponds to a specific example of a "second electrode" in the third embodiment of the present disclosure. The protective layer 74 corresponds to a specific example of an "oxide layer" in the third embodiment of the present disclosure. The potential control layer 75 corresponds to a specific example of an "intermediate layer" in the third embodiment of the present disclosure. The photoelectric conversion layer 76 corresponds to a specific example of a "photoelectric conversion layer" in the third embodiment of the present disclosure. The upper electrode 77 corresponds to a specific example of a "third electrode" in the third embodiment of the present disclosure.

[0181] (5-1. Configuration of Photodetector) The photodetector 3 is, for example, a so-called vertical spectroscopic type in which one photoelectric conversion unit 70 and two photoelectric conversion regions 32B, 32R are stacked vertically. The photoelectric conversion unit 70 is provided on the back surface (first surface 30A) 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.

[0182] The photoelectric conversion unit 70 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 70 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 3 to acquire multiple types of color signals in one pixel without using color filters.

[0183] 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.

[0184] The surface (second surface 30B) 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 30B 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, wiring layers 41, 42, and 43 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., in a peripheral region 1B around the pixel portion 100A.

[0185] In the drawings, the first surface 30A side of the semiconductor substrate 30 is represented as a light incident side S1, and the second surface 30B side is represented as a wiring layer side S2.

[0186] The photoelectric conversion unit 70 has an oxide semiconductor layer 73, a protective layer 74 formed using an inorganic material, a potential control layer 75 formed using an inorganic material, and a photoelectric conversion layer 76 formed using an organic material stacked in this order from the lower electrode 71 side between a lower electrode 71 and an upper electrode 77 that are arranged opposite to each other. As will be described in detail later, the potential control layer 75 has a thickness of −1E12 cm －２ <N<1E12cm －２ The photoelectric conversion layer 76 includes 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.

[0187] The photoelectric conversion unit 70 further includes an insulating layer 72 between the lower electrode 71 and the oxide semiconductor layer 73. The insulating layer 72 is provided, for example, over the entire surface of the pixel unit 100A, and has an opening 22H above the readout electrode 71A that constitutes the lower electrode 71. The readout electrode 71A is electrically connected to the oxide semiconductor layer 73 through this opening 22H.

[0188] Note that, in FIG. 20 , an example is shown in which the oxide semiconductor layer 73, the protective layer 74, the potential control layer 75, the photoelectric conversion layer 76, and the upper electrode 77 are formed separately for each photodetection element 3, but the oxide semiconductor layer 73, the protective layer 74, the potential control layer 75, the photoelectric conversion layer 76, and the upper electrode 77 may be provided as, for example, a continuous layer common to a plurality of photodetection elements 3.

[0189] Between the first surface 30A of the semiconductor substrate 30 and the lower electrode 71, 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.

[0190] 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.

[0191] A through electrode 34 is provided between the first surface 30A and the second surface 30B of the semiconductor substrate 30. The through electrode 34 is electrically connected to the readout electrode 71A, and the photoelectric conversion unit 70 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 3 to efficiently transfer carriers (electrons in this case) generated in the photoelectric conversion unit 70 provided on the first surface 30A side of the semiconductor substrate 30 to the second surface 30B side of the semiconductor substrate 30 via the through electrode 34, thereby improving its characteristics.

[0192] 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 71A via, for example, a pad portion 39A and an upper first contact 39C.

[0193] A protective layer 51 is provided above the photoelectric conversion unit 70. Within the protective layer 51, for example, wiring 52 and a light-shielding film 53 that electrically connect the upper electrode 77 and the peripheral circuit unit 130 around the pixel 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.

[0194] In the photodetector element 3 of this embodiment, light incident on the photoelectric conversion unit 70 from the light incident side S1 is absorbed by the photoelectric conversion layer 76. The excitons thus generated move to the interface between the electron donor and electron acceptor constituting the photoelectric conversion layer 76, where they dissociate 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 by an internal electric field due to the difference in work function between the anode (e.g., upper electrode 77) and the cathode (e.g., lower electrode 71), 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 71 and the upper electrode 77.

[0195] The structure and materials of each part will be described in detail below.

[0196] The photoelectric conversion section 70 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.

[0197] The lower electrode 71 is composed of, for example, a readout electrode 71A and a storage electrode 71B arranged in parallel on the interlayer insulating layer 29. The readout electrode 71A is used to transfer carriers generated in the photoelectric conversion layer 76 to the floating diffusion FD1, and one readout electrode 71A is provided for each pixel unit 1a, which is made up of, for example, four unit pixels P arranged in two rows and two columns.

[0198] The read electrode 71A is connected to the floating diffusion FD1 via, for example, the upper first contact 39C, the pad portion 39A, the through electrode 34, the connection portion 41A, and the lower second contact 46.

[0199] The storage electrode 71B is provided for each pixel to store, as signal charges, electrons, among the carriers generated in the photoelectric conversion layer 76, in the oxide semiconductor layer 73. The storage electrode 71B is provided for each unit pixel P in an area that directly faces the light-receiving surfaces of the photoelectric conversion regions 32B and 32R formed in the semiconductor substrate 30 and covers these light-receiving surfaces. The storage electrode 71B is preferably larger than the readout electrode 71A, allowing it to store a larger number of carriers. As shown in FIG. 6 , the voltage application unit 56 is connected to the storage electrode 71B via wiring, such as the upper first contact 39C and the upper second contact 39D.

[0200] The lower electrode 71 is made of, for example, a light-transmitting conductive film. The lower electrode 71 preferably has a work function of 4.0 eV or more and 5.5 eV or less. The material for the lower electrode 71 is, for example, InP doped with tin (Sn). ２ O ３ The crystallinity of the ITO thin film may be high or low (approaching amorphous). In addition to the above, the constituent material of the lower electrode 71 may be tin oxide (SnO ２)-based materials, for example, ATO with Sb added as a dopant, and FTO with fluorine added as a dopant, can be used. Zinc oxide (ZnO) or a zinc oxide-based material with a dopant added can also be used. Examples of ZnO-based materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, boron zinc oxide with boron (B) added, and indium zinc oxide (IZO) with indium (In) added. Furthermore, zinc oxide with indium and gallium added as dopants (IGZO, In-GaZnO4) can also be used. In addition, materials constituting the lower electrode 71 include CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３ or TiO ２ Alternatively, spinel oxides or YbFe ２ O ４ Oxides having such a structure may also be used.

[0201] Furthermore, when optical transparency is not required for the lower electrode 71 (e.g., when light is incident from the upper electrode 27 side), a single metal or alloy having a small work function (e.g., φ=3.5 eV to 4.5 eV) can be used. Specific examples include alkali metals (e.g., lithium (Li), sodium (Na), and potassium (K)) and their fluorides or oxides, and alkaline earth metals (e.g., magnesium (Mg) and calcium (Ca)) and their fluorides or oxides. Other examples include aluminum (Al), Al—Si—Cu alloys, zinc (Zn), tin (Sn), thallium (Tl), Na—K alloys, Al—Li alloys, Mg—Ag alloys, and rare earth metals such as In and ytterbium (Yb), or alloys thereof.

[0202] Furthermore, examples of materials that can be used to form the lower electrode 71 include metals such as platinum (Pt), gold (Au), palladium (Pd), chromium (Cr), nickel (Ni), aluminum (Al), silver (Ag), tantalum (Ta), tungsten (W), copper (Cu), titanium (Ti), indium (In), tin (Sn), iron (Fe), cobalt (Co), and molybdenum (Mo), alloys containing these metal elements, conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and graphene. Other examples of materials that can be used to form the lower electrode 71 include organic materials (conductive polymers) such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate (PEDOT / PSS). Alternatively, the above materials can be mixed with a binder (polymer) to form a paste or ink, which can then be cured and used as an electrode.

[0203] The lower electrode 71 can be formed as a single layer or a laminated film made of the above materials. The film thickness of the lower electrode 71 in the lamination direction (hereinafter simply referred to as thickness) is, for example, 20 nm to 200 nm, and preferably 30 nm to 150 nm.

[0204] The insulating layer 72 serves to electrically separate the storage electrode 71B from the oxide semiconductor layer 73. The insulating layer 72 is provided, for example, on the interlayer insulating layer 29 so as to cover the lower electrode 71. An opening 22H is provided in the insulating layer 72 above the readout electrode 71A of the lower electrode 71, and the readout electrode 71A and the oxide semiconductor layer 73 are electrically connected via this opening 22H. The insulating layer 72 is made of, for example, silicon oxide (SiO ｘ ), silicon nitride (SiN ｘ The insulating layer 72 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 72 is, for example, 20 nm to 500 nm.

[0205] The oxide semiconductor layer 73 is for accumulating carriers generated in the photoelectric conversion layer 76. The oxide semiconductor layer 73 can be formed using an oxide semiconductor material containing at least one element selected from the group consisting of indium (In), gallium (Ga), silicon (Si), zinc (Zn), aluminum (Al), and tin (Sn). In this embodiment, electrons among the carriers generated in the photoelectric conversion layer 76 are used as signal charges. For this reason, the oxide semiconductor layer 73 can be formed using an n-type oxide semiconductor material. Specifically, the oxide semiconductor layer 73 can be formed using IGZO, Ga ２ O ３ , GZO, IZO, ITO, InGaAlO, InGaSiO, etc. The oxide semiconductor layer 73 has a thickness of, for example, 10 nm to 300 nm.

[0206] The protective layer 74 is intended to prevent oxygen from being released from the oxide semiconductor layer 63. The protective layer 74 can be formed using a metal oxide containing at least one element selected from the group consisting of silicon (Si), aluminum (Al), tantalum (Ta), titanium (Ti), vanadium (V), niobium (Nb), tungsten (W), zirconium (Zr), hafnium (Hf), scandium (Sc), yttrium (Y), lanthanum (La), gallium (Ga), and magnesium (Mg). Specifically, the protective layer 74 can be made of a material such as silicon oxide (SiO ２ ), aluminum oxide (Al ２ O ３ ), tantalum oxide (Ta ２ O ５ ), titanium oxide (TiO ２ ), vanadium oxide (V ２ O ５ ), niobium oxide (Nb ２ O ５ ), tantalum oxide (W ２ O ３ ), zirconium oxide (ZrO ２ ), hafnium oxide (HfO ２ ), scandium oxide (Sc ２ O ３ ), yttrium oxide (Y ２ O３ ), lanthanum oxide (La ２ O ３ ), gallium oxide (Ga ２ O ３ ) and magnesium oxide (MgO).

[0207] As described above, the potential control layer 75 is for controlling the potential of the photoelectric conversion layer 76. Specifically, the potential control layer 75 suppresses the influence of negative fixed charges in the protective layer 74 on the photoelectric conversion layer 76 and is capable of accumulating holes. The potential control layer 75 has a capacitance of −1E12 cm －２ <N<1E12cm －２ 22 shows an example of the energy levels of the insulating layer 72, oxide semiconductor layer 73, protective layer 74, potential control layer 75, photoelectric conversion layer 76, and upper electrode 77 stacked above the storage electrode 71B, as shown by line A-A in FIG. 21. The vacuum level is defined as the zero level, and the closer to the vacuum level the higher (shallower) the energy is. The conduction band energy of the inorganic material contained in the potential control layer 75 is defined as E ＰＣ Ｃ , the LUMO energy of the hole transport material contained in the photoelectric conversion layer 76 is E ｉ ＬＵＭＯ , the conduction band energy of the protective layer 74 is E Ｏｘ Ｃ In this case, E ＰＣ Ｃ >E ｉ ＬＵＭＯ , and E ＰＣ Ｃ >E Ｏｘ Ｃ It is preferable to satisfy the following condition. As a result, an electric field is applied to the photoelectric conversion layer 76 in the stacking direction (Z-axis direction), and a potential gradient is formed as shown in FIG.

[0208] The potential control layer 75 is made of, for example, silicon nitride (Si ３ N ４ ), silicon oxide (SiO ２ ), lanthanum oxide (La ２ O ３ ), lutetium oxide (Lu ２ O ３ ), yttrium oxide (Y２ O ３ ), germanium oxide (GeO ２ ), strontium oxide (SrO) and niobium oxide (Nb ２ O ５ Table 1 summarizes the band gap, electron affinity, and fixed charge amount of the above oxides.

[0209]

[0210] In addition, for example, titanium oxide (TiO ２ ) or silicon oxide (SiO ２ The potential control layer 75 can be formed by nitriding the surface of the protective layer 74 containing Cr.

[0211] The thickness of the potential control layer 75 is preferably, for example, 2 nm or less, so that the potential control layer 75 can function as a tunnel oxide film to extract carriers.

[0212] The photoelectric conversion layer 76 absorbs, for example, 60% or more of a predetermined wavelength included in at least the visible light range to the near-infrared range, thereby separating charges. The photoelectric conversion layer 76 absorbs, for example, some or all of the wavelengths in the visible light range (400 nm or more and less than 1300 nm) and the near-infrared range. The photoelectric conversion layer 76 is configured, for example, by including two or more organic materials that function as p-type or n-type semiconductors, and has a junction between the p-type and n-type semiconductors (p / n junction). Alternatively, the photoelectric conversion layer 76 may have a stacked structure (p-type semiconductor layer / n-type semiconductor layer) of a layer made of a p-type semiconductor (p-type semiconductor layer) and a layer made of an n-type semiconductor (n-type semiconductor layer), a stacked structure (p-type semiconductor layer / bulk hetero layer) of a p-type semiconductor layer and a mixed layer (bulk hetero layer) of p-type and n-type semiconductors, or a stacked structure (n-type semiconductor layer / bulk hetero layer) of an n-type semiconductor layer and a bulk hetero layer. Alternatively, the layer may be formed solely from a mixed layer (bulk hetero layer) of p-type and n-type semiconductors.

[0213] The p-type semiconductor is a hole transport material that functions relatively as an electron donor, and the n-type semiconductor is an electron transport material that functions relatively as an electron acceptor. The photoelectric conversion layer 76 provides a field where excitons (electron-hole pairs) generated upon light absorption separate into electrons and holes. Specifically, the electron-hole pairs separate into electrons and holes at the interface (p / n junction) between the electron donor and electron acceptor.

[0214] Examples of p-type semiconductors include naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, perylene derivatives, tetracene derivatives, pentacene derivatives, quinacridone derivatives, thiophene derivatives, thienothiophene derivatives, benzothiophene derivatives, benzothienobenzothiophene (BTBT) derivatives, dinaphthothienothiophene (DNTT) derivatives, dianthracenothienothiophene (DATT) derivatives, benzobisbenzothiophene (BBBT) derivatives, thienothiophene derivatives, benzothienobenzothiophene (BTBT) derivatives, dibenzothienothiophene (DNTT) derivatives, dianthracenothienothiophene (DATT) derivatives, benzobisbenzothiophene (BBBT) derivatives, and thienothiophene derivatives. Examples of p-type semiconductors include thienoacene-based materials such as dibenzothienobisbenzothiophene (TBBT) derivatives, dibenzothienobisbenzothiophene (DBTBT) derivatives, dithienobenzodithiophene (DTBDT) derivatives, dibenzothienodithiophene (DBTDT) derivatives, benzodithiophene (BDT) derivatives, naphthodithiophene (NDT) derivatives, anthracenodithiophene (ADT) derivatives, tetracenodithiophene (TDT) derivatives, and pentacenodithiophene (PDT) derivatives. Examples of p-type semiconductors include triphenylamine derivatives, carbazole derivatives, picene derivatives, chrysene derivatives, fluoranthene derivatives, phthalocyanine derivatives, subphthalocyanine derivatives, subporphyrazine derivatives, metal complexes having heterocyclic compounds as ligands, polythiophene derivatives, polybenzothiadiazole derivatives, and polyfluorene derivatives.

[0215] As an n-type semiconductor, for example, fullerene C ６０ , fullerene C ７０ , fullerene C ７４Examples of the substituents contained in the fullerene derivatives include fullerenes and their derivatives, such as higher fullerenes and endohedral fullerenes. Examples of the substituents contained in the fullerene derivatives include halogen atoms, linear, branched, or cyclic alkyl groups or phenyl groups, groups having linear or condensed aromatic compounds, groups having halides, partial fluoroalkyl groups, perfluoroalkyl groups, silyl alkyl groups, silyl alkoxy groups, aryl silyl groups, aryl sulfanyl groups, alkyl sulfanyl groups, aryl sulfonyl groups, alkyl sulfonyl groups, aryl sulfide groups, alkyl sulfide groups, amino groups, alkyl amino groups, aryl amino groups, hydroxy groups, alkoxy groups, acyl amino groups, acyloxy groups, carbonyl groups, carboxy groups, carboxamido groups, carboalkoxy groups, acyl groups, sulfonyl groups, cyano groups, nitro groups, groups having chalcogenides, phosphine groups, phosphonic groups, and derivatives thereof. Specific examples of the fullerene derivatives include fullerene fluorides, PCBM fullerene compounds, and fullerene polymers. Other examples of n-type semiconductors include organic semiconductors and optically transparent inorganic metal oxides whose HOMO and LUMO levels are lower (deeper) than those of p-type semiconductors.

[0216] Examples of n-type organic semiconductors include heterocyclic compounds containing nitrogen atom, oxygen atom or sulfur atom.Specific examples include pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, isoquinoline derivatives, acridine derivatives, phenazine derivatives, phenanthroline derivatives, tetrazole derivatives, pyrazole derivatives, imidazole derivatives, thiazole derivatives, oxazole derivatives, imidazole derivatives, benzimidazole derivatives, benzotriazole derivatives, benzoxazole derivatives, benzoxazole derivatives, carbazole derivatives, benzofuran derivatives, dibenzofuran derivatives, subporphyrazine derivatives, polyphenylenevinylene derivatives, polybenzothiadiazole derivatives, polyfluorene derivatives, etc., which have such organic molecules as a part of molecular skeleton, organic metal complexes, subphthalocyanine derivatives, quinacridone derivatives, cyanine derivatives and merocyanine derivatives.

[0217] In addition to the p-type and n-type semiconductors, the photoelectric conversion layer 76 may further include an organic material, a so-called dye material, that absorbs light in a predetermined wavelength range while transmitting light in other wavelength ranges. When the photoelectric conversion layer 76 is formed using three types of organic materials, i.e., a p-type semiconductor, an n-type semiconductor, and a dye material, the p-type and n-type semiconductors are preferably materials that are optically transparent in the visible light range. This allows the photoelectric conversion layer 76 to selectively convert light in the wavelength range absorbed by the dye material.

[0218] The photoelectric conversion layer 76 has a thickness of, for example, 10 nm or more and 500 nm or less, and preferably has a thickness of 100 nm or more and 400 nm or less.

[0219] The upper electrode 77 is made of, for example, a light-transmitting conductive film, similar to the lower electrode 11. The upper electrode 77 is made of, for example, InP doped with tin (Sn) as a dopant. ２ O ３ The crystallinity of the ITO thin film may be high or low (approaching amorphous). In addition to the above, the constituent material of the lower electrode 11 may be tin oxide (SnO ２ )-based materials, for example, ATO with Sb added as a dopant, and FTO with fluorine added as a dopant can be used. Zinc oxide (ZnO) or a zinc oxide-based material with a dopant added can also be used. Examples of ZnO-based materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, boron zinc oxide with boron (B) added, and indium zinc oxide (IZO) with indium (In) added. Furthermore, zinc oxide with indium and gallium added as dopants (IGZO, In-GaZnO4) can also be used. In addition, materials constituting the lower electrode 11 include CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO３ or TiO ２ Alternatively, spinel oxides or YbFe ２ O ４ Oxides having such a structure may also be used.

[0220] Furthermore, if optical transparency is not required for the upper electrode 77, a single metal or alloy having a large work function (for example, φ=4.5 eV to 5.5 eV) can be used. Specific examples include Au, Ag, Cr, Ni, Pd, Pt, Fe, iridium (Ir), germanium (Ge), osmium (Os), rhenium (Re), tellurium (Te), and alloys thereof.

[0221] Furthermore, examples of materials that can be used to form the upper electrode 77 include metals such as Pt, Au, Pd, Cr, Ni, Al, Ag, Ta, W, Cu, Ti, In, Sn, Fe, Co, and Mo, alloys containing these metal elements, conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and graphene. Other examples of materials that can be used to form the upper electrode 77 include organic materials (conductive polymers) such as PEDOT / PSS. Alternatively, the above materials can be mixed with a binder (polymer) to form a paste or ink, which can then be cured and used as an electrode.

[0222] The upper electrode 77 can be formed as a single layer or a multilayer film made of the above materials. The thickness of the upper electrode 77 is, for example, 20 nm to 200 nm, and preferably 30 nm to 150 nm.

[0223] The photoelectric conversion unit 70 may have other layers provided between the lower electrode 71 and the photoelectric conversion layer 76 and between the photoelectric conversion layer 76 and the upper electrode 77. For example, the photoelectric conversion unit 70 may have a buffer layer that also serves as a hole blocking film, a work function adjustment layer, or the like, provided between the photoelectric conversion layer 76 and the upper electrode 77. The photoelectric conversion layer 76 may have a pin bulk heterostructure in which, for example, a p-type blocking layer, a layer containing a p-type semiconductor and an n-type semiconductor (i-layer), and an n-type blocking layer are stacked.

[0224] (5-2. Actions and Effects) The photodetector element 3 of this embodiment has a thickness of −1E12 cm between the protective layer 74 and the photoelectric conversion layer 76. －２ <N<1E12cm －２ The potential control layer 75 is provided with a fixed charge amount that satisfies the above requirement. The potential control layer 75 is capable of accumulating holes and suppresses the influence of the negative fixed charge in the protective layer 74 on the photoelectric conversion layer 26. This makes it possible to apply an electric field to the photoelectric conversion layer 76 in the stacking direction, and as shown in FIG. 22 , a potential gradient is formed in the stacking direction of the photoelectric conversion layer 76.

[0225] As described above, the photodetector element 3 of this embodiment can achieve both high reliability and high electron transport properties.

[0226] 6. Fourth Embodiment FIG. 23 illustrates a cross-sectional configuration of a photodetector element (photodetector element 4) according to a fourth embodiment of the present disclosure. The photodetector element 4 constitutes one pixel (unit pixel P) repeatedly arranged in an array in a pixel section 100A of a photodetector device (e.g., photodetector device 100), such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor used in electronic devices such as digital still cameras and video cameras. FIG. 24 illustrates an enlarged schematic cross-sectional configuration of a main portion (photoelectric conversion section 80) of the photodetector element 4 illustrated in FIG. 23. In the pixel section 100A, as in the first embodiment, a pixel unit consisting of, for example, 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.

[0227] The photodetector element 4 of this embodiment has a photoelectric conversion section 80 provided on a semiconductor substrate 30, in which a lower electrode 81 consisting of a readout electrode 81A and a storage electrode 81B, an insulating layer 82, an oxide semiconductor layer 83, a protective layer 84, an electric field generating layer 85, a photoelectric conversion layer 86, and an upper electrode 87 are stacked in this order.

[0228] Here, the readout electrode 81A corresponds to a specific example of a "first electrode" in the fourth embodiment of the present disclosure, and the storage electrode 81B corresponds to a specific example of a "second electrode" in the fourth embodiment of the present disclosure. The electric field generation layer 85 corresponds to a specific example of an "intermediate layer" in the fourth embodiment of the present disclosure. The photoelectric conversion layer 86 corresponds to a specific example of a "photoelectric conversion layer" in the fourth embodiment of the present disclosure. The upper electrode 87 corresponds to a specific example of a "third electrode" in the fourth embodiment of the present disclosure.

[0229] (6-1. Configuration of Photodetector) The photodetector 4 is, for example, a so-called vertical spectroscopic type in which one photoelectric conversion unit 80 and two photoelectric conversion regions 32B, 32R are stacked vertically. The photoelectric conversion unit 80 is provided on the back surface (first surface 30A) 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.

[0230] The photoelectric conversion unit 80 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 80 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 element 4 to acquire multiple types of color signals in one pixel without using color filters.

[0231] 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.

[0232] The surface (second surface 30B) 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 30B 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, wiring layers 41, 42, and 43 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., in a peripheral region 1B around the pixel portion 100A.

[0233] In the drawings, the first surface 30A side of the semiconductor substrate 30 is represented as a light incident side S1, and the second surface 30B side is represented as a wiring layer side S2.

[0234] The photoelectric conversion unit 80 includes an oxide semiconductor layer 83, a protective layer 84 formed using an inorganic material, an electric field generating layer 85 formed using an organic material, and a photoelectric conversion layer 86 formed using an organic material, stacked in this order from the lower electrode 81 side between an opposing lower electrode 81 and an upper electrode 87. As will be described in detail later, the electric field generating layer 85 is formed using an organic material having an electron-donating group. The photoelectric conversion layer 86 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.

[0235] The photoelectric conversion unit 80 further includes an insulating layer 82 between the lower electrode 81 and the oxide semiconductor layer 83. The insulating layer 82 is provided, for example, over the entire surface of the pixel unit 100A, and has an opening 22H above the readout electrode 81A that constitutes the lower electrode 81. The readout electrode 81A is electrically connected to the oxide semiconductor layer 83 through this opening 22H.

[0236] Note that, although Figure 23 shows an example in which the oxide semiconductor layer 83, the protective layer 84, the electric field generation layer 85, the photoelectric conversion layer 86, and the upper electrode 87 are formed separately for each photodetection element 4, the oxide semiconductor layer 83, the protective layer 84, the electric field generation layer 85, the photoelectric conversion layer 86, and the upper electrode 87 may be provided as, for example, a continuous layer common to a plurality of photodetection elements 4.

[0237] Between the first surface 30A of the semiconductor substrate 30 and the lower electrode 81, 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.

[0238] 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.

[0239] A through electrode 34 is provided between the first surface 30A and the second surface 30B of the semiconductor substrate 30. The through electrode 34 is electrically connected to the readout electrode 81A, and the photoelectric conversion unit 80 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 4 to efficiently transfer carriers (electrons in this case) generated in the photoelectric conversion unit 80 provided on the first surface 30A side of the semiconductor substrate 30 to the second surface 30B side of the semiconductor substrate 30 via the through electrode 34, thereby improving its characteristics.

[0240] 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 readout electrode 81A via, for example, a pad portion 39A and an upper first contact 39C.

[0241] A protective layer 51 is provided above the photoelectric conversion unit 80. Within the protective layer 51, for example, wiring 52 and a light-shielding film 53 that electrically connect the upper electrode 87 and the peripheral circuit unit 130 around the pixel 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.

[0242] In the photodetector element 4 of this embodiment, light incident on the photoelectric conversion unit 80 from the light incident side S1 is absorbed by the photoelectric conversion layer 86. The resulting excitons migrate to the interface between the electron donors and electron acceptors that make up the photoelectric conversion layer 86, where they dissociate 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 by an internal electric field caused by the difference in work function between the anode (e.g., the upper electrode 87) and the cathode (e.g., the lower electrode 81), 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 81 and the upper electrode 87.

[0243] The structure and materials of each part will be described in detail below.

[0244] The photoelectric conversion section 80 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.

[0245] The lower electrode 81 is composed of, for example, a readout electrode 81A and a storage electrode 81B arranged in parallel on the interlayer insulating layer 29. The readout electrode 81A is for transferring carriers generated in the photoelectric conversion layer 86 to the floating diffusion FD1, and one readout electrode 81A is provided for each pixel unit 1a, which is made up of, for example, four unit pixels P arranged in two rows and two columns.

[0246] The read electrode 81A is connected to the floating diffusion FD1 via, for example, the upper first contact 39C, the pad portion 39A, the through electrode 34, the connection portion 41A, and the lower second contact 46.

[0247] The storage electrode 81B is provided for each pixel to store, as signal charges, electrons, among the carriers generated in the photoelectric conversion layer 86, in the oxide semiconductor layer 83. The storage electrode 81B is provided for each unit pixel P in a region that directly faces the light-receiving surfaces of the photoelectric conversion regions 32B and 32R formed in the semiconductor substrate 30 and covers these light-receiving surfaces. The storage electrode 81B is preferably larger than the readout electrode 81A, allowing it to store a larger number of carriers. As shown in FIG. 6 , the voltage application unit 56 is connected to the storage electrode 81B via wiring, such as the upper first contact 39C and the upper second contact 39D.

[0248] The lower electrode 81 is made of, for example, a light-transmitting conductive film. The lower electrode 81 preferably has a work function of 4.0 eV or more and 5.5 eV or less. The material for the lower electrode 81 is, for example, InP doped with tin (Sn) as a dopant. ２ O ３ The crystallinity of the ITO thin film may be high or low (approaching amorphous). In addition to the above, the constituent material of the lower electrode 81 may be tin oxide (SnO ２)-based materials, for example, ATO with Sb added as a dopant, and FTO with fluorine added as a dopant can be used. Zinc oxide (ZnO) or a zinc oxide-based material with a dopant added can also be used. Examples of ZnO-based materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, boron zinc oxide with boron (B) added, and indium zinc oxide (IZO) with indium (In) added. Furthermore, zinc oxide with indium and gallium added as dopants (IGZO, In-GaZnO4) can also be used. In addition, materials constituting the lower electrode 81 include CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３ or TiO ２ Alternatively, spinel oxides or YbFe ２ O ４ Oxides having such a structure may also be used.

[0249] Furthermore, when optical transparency is not required for the lower electrode 81 (for example, when light is incident from the upper electrode 27 side), a single metal or alloy having a small work function (for example, φ=3.5 eV to 4.5 eV) can be used. Specific examples include alkali metals (for example, lithium (Li), sodium (Na), and potassium (K)) and their fluorides or oxides, and alkaline earth metals (for example, magnesium (Mg) and calcium (Ca)) and their fluorides or oxides. Other examples include aluminum (Al), Al—Si—Cu alloys, zinc (Zn), tin (Sn), thallium (Tl), Na—K alloys, Al—Li alloys, Mg—Ag alloys, and rare earth metals such as In and ytterbium (Yb), or alloys thereof.

[0250] Furthermore, examples of materials constituting the lower electrode 81 include metals such as platinum (Pt), gold (Au), palladium (Pd), chromium (Cr), nickel (Ni), aluminum (Al), silver (Ag), tantalum (Ta), tungsten (W), copper (Cu), titanium (Ti), indium (In), tin (Sn), iron (Fe), cobalt (Co), and molybdenum (Mo), alloys containing these metal elements, conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and conductive materials such as graphene. Other examples of materials constituting the lower electrode 81 include organic materials (conductive polymers) such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate (PEDOT / PSS). Alternatively, the above materials may be mixed with a binder (polymer) to form a paste or ink, which may then be cured and used as an electrode.

[0251] The lower electrode 81 can be formed as a single layer film or a laminated film made of the above materials. The film thickness of the lower electrode 81 in the lamination direction (hereinafter simply referred to as thickness) is, for example, 20 nm to 200 nm, and preferably 30 nm to 150 nm.

[0252] The insulating layer 82 serves to electrically separate the storage electrode 81B from the oxide semiconductor layer 83. The insulating layer 82 is provided, for example, on the interlayer insulating layer 29 so as to cover the lower electrode 81. An opening 22H is provided in the insulating layer 82 above the readout electrode 81A of the lower electrode 81, and the readout electrode 81A and the oxide semiconductor layer 83 are electrically connected via this opening 22H. The insulating layer 82 is made of, for example, silicon oxide (SiO ｘ ), silicon nitride (SiN ｘ The insulating layer 82 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 82 is, for example, 20 nm to 500 nm.

[0253] The oxide semiconductor layer 83 is for accumulating carriers generated in the photoelectric conversion layer 86. The oxide semiconductor layer 83 can be formed using an oxide semiconductor material containing at least one element selected from the group consisting of indium (In), gallium (Ga), silicon (Si), zinc (Zn), aluminum (Al), and tin (Sn). In this embodiment, electrons among the carriers generated in the photoelectric conversion layer 86 are used as signal charges. For this reason, the oxide semiconductor layer 83 can be formed using an n-type oxide semiconductor material. Specifically, the oxide semiconductor layer 83 can be formed using IGZO, Ga ２ O ３ , GZO, IZO, ITO, InGaAlO, InGaSiO, etc. The oxide semiconductor layer 83 has a thickness of, for example, 10 nm to 300 nm.

[0254] The protective layer 84 is intended to prevent oxygen from being released from the oxide semiconductor layer 63. The protective layer 84 can be formed using a metal oxide containing at least one element selected from the group consisting of tantalum (Ta), titanium (Ti), vanadium (V), niobium (Nb), tungsten (W), zirconium (Zr), hafnium (Hf), scandium (Sc), yttrium (Y), lanthanum (La), gallium (Ga), and magnesium (Mg). Specifically, the constituent material of the protective layer 84 can be, for example, tantalum oxide (Ta). ２ O ５ ), titanium oxide (TiO ２ ), vanadium oxide (V ２ O ５ ), niobium oxide (Nb ２ O ５ ), tantalum oxide (W ２ O ３ ), zirconium oxide (ZrO ２ ), hafnium oxide (HfO ２ ), scandium oxide (Sc ２ O ３ ), yttrium oxide (Y ２ O ３ ), lanthanum oxide (La ２ O ３ ), gallium oxide (Ga ２ O ３) and magnesium oxide (MgO).

[0255] The field-generating layer 85 is for controlling the potential of the photoelectric conversion layer 86. Specifically, the field-generating layer 85 suppresses the influence of negative fixed charges in the protective layer 84 on the photoelectric conversion layer 86 and is capable of accumulating holes. FIG. 25 shows an example of the energy levels of the insulating layer 82, oxide semiconductor layer 83, protective layer 84, field-generating layer 85, photoelectric conversion layer 86, and upper electrode 87 stacked above the storage electrode 81B, as shown by line A-A in FIG. 24. The field-generating layer 85 adjusts the HOMO energy of the organic material contained in the field-generating layer 85 to E ＮＢ ＨＯＭＯ , where WF is the work function of the lower electrode 81, |E ＮＢ ＨＯＭＯ It is formed using an organic material that satisfies |≦WF. This eliminates the effect of negative fixed charges in the protective layer 84 on the photoelectric conversion layer 86, and an electric field is applied to the photoelectric conversion layer 86 in the stacking direction (Z-axis direction), forming a potential gradient as shown in Fig. 25. Furthermore, the internal electric field of the photoelectric conversion layer 86 can be increased by shifting the vacuum level.

[0256] Furthermore, it is preferable that the work function, conduction band, HOMO, and LUMO of each of lower electrode 81, oxide semiconductor layer 83, field-generating layer 85, and photoelectric conversion layer 86 satisfy the following relational expressions (2) to (4): (Equation 2) |LUMO of field-generating layer|<|LUMO of photoelectric conversion layer|<|HOMO of field-generating layer|<|HOMO of photoelectric conversion layer| ... (2) (Equation 3) 0<|HOMO of field-generating layer|-|LUMO of photoelectric conversion layer|<1 ... (3) (Equation 4) |HOMO of field-generating layer|<|conduction band of oxide semiconductor| ... (4)

[0257] The present technology can also be applied to photodetecting elements 8A to 8D in which a lower electrode 81 (described later) is provided for each unit pixel P, and the insulating layer 82, oxide semiconductor layer 83, and protective layer 84 are omitted. In this case, it is preferable that the electric field generating layer 85 satisfies the following relational expression (5): |HOMO of electric field generating layer|<|work function of lower electrode| (5)

[0258] An example of an organic material that satisfies the above relationship is an organic material having an electron-donating group. Specific examples of the electron-donating group include a hydroxyl group, a methoxy group, an amino group, an acetylamino group, a dimethylamino group, and a pyridyl group. Specific examples of the organic material include benzothiadiazole, tetrakisdimethylamine, benzimidazole, an organic ruthenium complex, and derivatives thereof, each of which has the above electron-donating group. The thickness of the electric field generating layer 85 is preferably, for example, 1 nm or more and 30 nm or less.

[0259] The photoelectric conversion layer 86 absorbs, for example, 60% or more of a predetermined wavelength included at least in the visible light range to the near-infrared range, thereby separating charges. The photoelectric conversion layer 86 absorbs, for example, some or all of the wavelengths in the visible light range and the near-infrared range, from 400 nm to 1300 nm. The photoelectric conversion layer 86 is configured, for example, by including two or more organic materials that function as p-type or n-type semiconductors, and has a junction between the p-type and n-type semiconductors (p / n junction). Alternatively, the photoelectric conversion layer 86 may have a stacked structure (p-type semiconductor layer / n-type semiconductor layer) of a layer made of a p-type semiconductor (p-type semiconductor layer) and a layer made of an n-type semiconductor (n-type semiconductor layer), a stacked structure (p-type semiconductor layer / bulk hetero layer) of a p-type semiconductor layer and a mixed layer (bulk hetero layer) of p-type and n-type semiconductors, or a stacked structure (n-type semiconductor layer / bulk hetero layer) of an n-type semiconductor layer and a bulk hetero layer. Alternatively, the layer may be formed solely from a mixed layer (bulk hetero layer) of p-type and n-type semiconductors.

[0260] A p-type semiconductor is a hole transport material that functions relatively as an electron donor, and an n-type semiconductor is an electron transport material that functions relatively as an electron acceptor. The photoelectric conversion layer 86 provides a field where excitons (electron-hole pairs) generated upon light absorption separate into electrons and holes. Specifically, the electron-hole pairs separate into electrons and holes at the interface (p / n junction) between the electron donor and electron acceptor.

[0261] Examples of p-type semiconductors include naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, perylene derivatives, tetracene derivatives, pentacene derivatives, quinacridone derivatives, thiophene derivatives, thienothiophene derivatives, benzothiophene derivatives, benzothienobenzothiophene (BTBT) derivatives, dinaphthothienothiophene (DNTT) derivatives, dianthracenothienothiophene (DATT) derivatives, benzobisbenzothiophene (BBBT) derivatives, thienothiophene derivatives, benzothienobenzothiophene (BTBT) derivatives, dibenzothienothiophene (DNTT) derivatives, dianthracenothienothiophene (DATT) derivatives, benzobisbenzothiophene (BBBT) derivatives, and thienothiophene derivatives. Examples of p-type semiconductors include thienoacene-based materials such as dibenzothienobisbenzothiophene (TBBT) derivatives, dibenzothienobisbenzothiophene (DBTBT) derivatives, dithienobenzodithiophene (DTBDT) derivatives, dibenzothienodithiophene (DBTDT) derivatives, benzodithiophene (BDT) derivatives, naphthodithiophene (NDT) derivatives, anthracenodithiophene (ADT) derivatives, tetracenodithiophene (TDT) derivatives, and pentacenodithiophene (PDT) derivatives. Examples of p-type semiconductors include triphenylamine derivatives, carbazole derivatives, picene derivatives, chrysene derivatives, fluoranthene derivatives, phthalocyanine derivatives, subphthalocyanine derivatives, subporphyrazine derivatives, metal complexes having heterocyclic compounds as ligands, polythiophene derivatives, polybenzothiadiazole derivatives, and polyfluorene derivatives.

[0262] As an n-type semiconductor, for example, fullerene C ６０ , fullerene C ７０ , fullerene C ７４Examples of the substituents contained in the fullerene derivatives include fullerenes and their derivatives, such as higher fullerenes and endohedral fullerenes. Examples of the substituents contained in the fullerene derivatives include halogen atoms, linear, branched, or cyclic alkyl groups or phenyl groups, groups having linear or condensed aromatic compounds, groups having halides, partial fluoroalkyl groups, perfluoroalkyl groups, silyl alkyl groups, silyl alkoxy groups, aryl silyl groups, aryl sulfanyl groups, alkyl sulfanyl groups, aryl sulfonyl groups, alkyl sulfonyl groups, aryl sulfide groups, alkyl sulfide groups, amino groups, alkyl amino groups, aryl amino groups, hydroxy groups, alkoxy groups, acyl amino groups, acyloxy groups, carbonyl groups, carboxy groups, carboxamido groups, carboalkoxy groups, acyl groups, sulfonyl groups, cyano groups, nitro groups, groups having chalcogenides, phosphine groups, phosphonic groups, and derivatives thereof. Specific examples of the fullerene derivatives include fullerene fluorides, PCBM fullerene compounds, and fullerene polymers. Other examples of n-type semiconductors include organic semiconductors and optically transparent inorganic metal oxides whose HOMO and LUMO levels are lower (deeper) than those of p-type semiconductors.

[0263] Examples of n-type organic semiconductors include heterocyclic compounds containing nitrogen atom, oxygen atom or sulfur atom.Specific examples include pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, isoquinoline derivatives, acridine derivatives, phenazine derivatives, phenanthroline derivatives, tetrazole derivatives, pyrazole derivatives, imidazole derivatives, thiazole derivatives, oxazole derivatives, imidazole derivatives, benzimidazole derivatives, benzotriazole derivatives, benzoxazole derivatives, benzoxazole derivatives, carbazole derivatives, benzofuran derivatives, dibenzofuran derivatives, subporphyrazine derivatives, polyphenylenevinylene derivatives, polybenzothiadiazole derivatives, polyfluorene derivatives, etc., which have such organic molecules as a part of molecular skeleton, organic metal complexes, subphthalocyanine derivatives, quinacridone derivatives, cyanine derivatives and merocyanine derivatives.

[0264] In addition to the p-type and n-type semiconductors, the photoelectric conversion layer 86 may further include an organic material, a so-called dye material, that absorbs light in a predetermined wavelength range while transmitting light in other wavelength ranges. When the photoelectric conversion layer 86 is formed using three types of organic materials, i.e., a p-type semiconductor, an n-type semiconductor, and a dye material, the p-type and n-type semiconductors are preferably materials that are optically transparent in the visible light range. This allows the photoelectric conversion layer 86 to selectively convert light in the wavelength range absorbed by the dye material into electricity.

[0265] The photoelectric conversion layer 86 has a thickness of, for example, 10 nm or more and 500 nm or less, and preferably has a thickness of 100 nm or more and 400 nm or less.

[0266] The upper electrode 87 is made of, for example, a light-transmitting conductive film, similar to the lower electrode 11. The upper electrode 87 is made of, for example, InP doped with tin (Sn) as a dopant. ２ O ３ The crystallinity of the ITO thin film may be high or low (approaching amorphous). In addition to the above, the constituent material of the lower electrode 11 may be tin oxide (SnO ２ )-based materials, for example, ATO with Sb added as a dopant, and FTO with fluorine added as a dopant can be used. Zinc oxide (ZnO) or a zinc oxide-based material with a dopant added can also be used. Examples of ZnO-based materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, boron zinc oxide with boron (B) added, and indium zinc oxide (IZO) with indium (In) added. Furthermore, zinc oxide with indium and gallium added as dopants (IGZO, In-GaZnO4) can also be used. In addition, materials constituting the lower electrode 11 include CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO３ or TiO ２ Alternatively, spinel oxides or YbFe ２ O ４ Oxides having such a structure may also be used.

[0267] Furthermore, if optical transparency is not required for the upper electrode 87, a single metal or alloy having a large work function (for example, φ=4.5 eV to 5.5 eV) can be used. Specific examples include Au, Ag, Cr, Ni, Pd, Pt, Fe, iridium (Ir), germanium (Ge), osmium (Os), rhenium (Re), tellurium (Te), and alloys thereof.

[0268] Furthermore, examples of materials that can be used to form the upper electrode 87 include metals such as Pt, Au, Pd, Cr, Ni, Al, Ag, Ta, W, Cu, Ti, In, Sn, Fe, Co, and Mo, alloys containing these metal elements, conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and graphene. Other examples of materials that can be used to form the upper electrode 87 include organic materials (conductive polymers) such as PEDOT / PSS. Alternatively, the above materials can be mixed with a binder (polymer) to form a paste or ink, which can then be cured and used as an electrode.

[0269] The upper electrode 87 can be formed as a single layer or a laminated film made of the above materials. The thickness of the upper electrode 87 is, for example, 20 nm to 200 nm, preferably 30 nm to 150 nm.

[0270] The photoelectric conversion unit 80 may have other layers provided between the lower electrode 81 and the photoelectric conversion layer 86 and between the photoelectric conversion layer 86 and the upper electrode 87. For example, the photoelectric conversion unit 80 may have a buffer layer that also serves as a hole blocking film, a work function adjustment layer, or the like, provided between the photoelectric conversion layer 86 and the upper electrode 87. The photoelectric conversion layer 86 may have a pin bulk heterostructure in which, for example, a p-type blocking layer, a layer containing a p-type semiconductor and an n-type semiconductor (i-layer), and an n-type blocking layer are stacked.

[0271] (6-2. Actions and Effects) As described above, in an image sensor in which an insulating film and an oxide semiconductor film are stacked between a plurality of electrodes and a photoelectric conversion layer, the occurrence of defects due to oxygen detachment from the oxide semiconductor layer has been an issue, and a structure has been proposed in which an oxide film is stacked on the oxide semiconductor film to prevent oxygen detachment from the oxide semiconductor layer. However, when an oxide film is formed between the oxide semiconductor film and the photoelectric conversion layer, negative fixed charges in the oxide film cause a problem in that the internal electric field of the photoelectric conversion layer deteriorates.

[0272] In contrast, in the photodetector element 4 of this embodiment, an electric field generating layer 85 is provided between the protective layer 84 and the photoelectric conversion layer 86. This electric field generating layer 85 is formed using an organic material having an electron-donating group. This allows a potential gradient to be formed in the stacking direction of the photoelectric conversion layer 86, as shown in FIG.

[0273] As described above, the photodetector element 4 of this embodiment can achieve both high reliability and high electron transport properties.

[0274] Incidentally, the HOMO energy (E ＮＢ ＨＯＭＯ ) and the work function (WF) of the lower electrode 81 is expressed as |E ＮＢ ＨＯＭＯ If |>WF, the energy barrier of the electric field generating layer 85 with respect to the photoelectric conversion layer 86 becomes large, and the transport characteristics of carriers (electrons) from the photoelectric conversion layer 86 to the lower electrode 81 deteriorate. Furthermore, if the electric field generating layer 85 is formed using an organic material containing an electron-donating group, the influence of the fixed charges of the protective layer 84 can be eliminated by positively charging the electric field generating layer 85, and a desired potential gradient can be formed in the photoelectric conversion layer 86.

[0275] In contrast, in this embodiment, the HOMO energy of the organic material contained in the electric field generating layer 85 is set to E ＮＢ ＨＯＭＯ , where WF is the work function of the lower electrode 81, |E ＮＢ ＨＯＭＯSince the photoelectric conversion layer 86 is formed so as to satisfy |≦WF, an electric field can be applied to the photoelectric conversion layer 86 efficiently in the stacking direction.

[0276] Furthermore, in the photodetector element 4 of this embodiment, the internal electric field of the photoelectric conversion layer 86 can be increased by shifting the vacuum level, thereby reducing the dark current, thereby improving the external quantum efficiency (EQE) and photoresponsivity.

[0277] 7. Modifications (7-1. Modification 3) FIG. 26A is a schematic diagram illustrating a cross-sectional configuration of a photodetector element 5 according to Modification 3 of the present disclosure. FIG. 26B is a schematic diagram illustrating an example of the planar configuration of the photodetector element 5 illustrated in FIG. 26A , where FIG. 26A illustrates a cross section taken along line II-II in FIG. 26B . The photodetector element 5 is, for example, a stacked photodetector element in which a photoelectric conversion region 32 and a photoelectric conversion unit (e.g., the photoelectric conversion unit 20 of the first embodiment) are stacked. In a pixel unit 100A of a photodetector device (e.g., the photodetector device 100) including this photodetector element 5, 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. 26B .

[0278] In the photodetector element 5 of this modified example, a color filter 55 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 20 (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 on a diagonal line, and one color filter that selectively transmits red light (R) and blue light (B) is arranged on each diagonal line that is perpendicular to the diagonal line. In the unit pixels (Pr, Pg, Pb) provided with each color filter, the corresponding color light is detected, for example, in the photoelectric conversion section 20. That is, in the pixel section 100A, the unit pixels (Pr, Pg, Pb) that detect red light (R), green light (G), and blue light (B), respectively, are arranged in a Bayer pattern.

[0279] The photoelectric conversion unit 20 absorbs light corresponding to some or all of the wavelengths in the visible light region of 400 nm or more and less than 750 nm, for example, to generate excitons (electron-hole pairs), and is composed of a lower electrode 21, an insulating layer (insulating layer 22), an oxide semiconductor layer 23, a protective layer 24, a potential control layer 25, a photoelectric conversion layer 26, and an upper electrode 27 stacked in this order.

[0280] The photoelectric conversion region 32 detects, for example, an infrared light region of 750 nm or more and 1300 nm or less.

[0281] In the photodetector element 5, light in the visible light region (red light (R), green light (G), and blue light (B)) that passes through the color filter 55 is absorbed by the photoelectric conversion unit 20 of the unit pixel (Pr, Pg, Pb) to which each color filter is provided, while other light, for example, light in the infrared light region (e.g., 750 nm or more and 1000 nm or less) (infrared light (IR)), passes through the photoelectric conversion unit 20. The infrared light (IR) that passes through the photoelectric conversion unit 20 is detected in the photoelectric conversion region 32 of each unit pixel Pr, Pg, Pb, and signal charges corresponding to the infrared light (IR) are generated in each unit pixel Pr, Pg, Pb. In other words, a photodetector device 100 including the photodetector element 5 is capable of simultaneously generating both visible light images and infrared light images.

[0282] Furthermore, the photodetector device 100 including the photodetector element 5 can acquire a visible light image and an infrared light image at the same position in the XZ in-plane direction, thereby realizing high integration in the XY in-plane direction.

[0283] (7-2. Modification 4) Fig. 27A is a schematic diagram illustrating a cross-sectional configuration of a photodetector element 6 according to Modification 4 of the present disclosure. Fig. 27B is a schematic diagram illustrating an example of the planar configuration of the photodetector element 6 illustrated in Fig. 27A, and Fig. 27A illustrates a cross section taken along line III-III illustrated in Fig. 27B. Modification 4 above illustrates an example in which the color filter 55 is provided above the photoelectric conversion unit 20 (on the light incident side S1). However, the color filter 55 may be provided, for example, between the photoelectric conversion region 32 and the photoelectric conversion unit 20, as illustrated in Fig. 27A.

[0284] In the photodetector element 6, for example, the color filter 55 has a configuration in which a color filter (color filter 55R) that selectively transmits at least red light (R) and a color filter (color filter 55B) that selectively transmits at least blue light (B) are arranged diagonally to each other within the pixel unit 1a. The photoelectric conversion unit 20 (photoelectric conversion layer 26) 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 20 and the color filters 55R and 55B, respectively. In the photodetector element 6 of this modified example, the area of ​​the photoelectric conversion section for each 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.

[0285] 28 is a schematic diagram illustrating a cross-sectional configuration of a photodetector 7 according to a fifth modification of the present disclosure. The photodetector 7 of this modification has two photoelectric conversion units 20, 90 and one photoelectric conversion region 32 stacked in the vertical direction.

[0286] The photoelectric conversion units 20 and 90 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 90 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 element 7 to acquire multiple types of color signals in one pixel without using color filters.

[0287] The photoelectric conversion unit 90 is stacked, for example, above the photoelectric conversion unit 20, and has the same configuration as the photoelectric conversion unit 20. Specifically, the photoelectric conversion unit 90 has a lower electrode 91, an insulating layer 92, an oxide semiconductor layer 93, a protective layer 94, a potential control layer 95, a photoelectric conversion layer 96, and an upper electrode 97 stacked in this order. Like the photoelectric conversion unit 20, the lower electrode 91 is made up of multiple electrodes (e.g., a readout electrode 91A and a storage electrode 91B) and is electrically isolated by the insulating layer 92. An interlayer insulating layer 99 is provided between the photoelectric conversion unit 90 and the photoelectric conversion unit 20.

[0288] A through electrode 98 is connected to the readout electrode 91A, which penetrates the interlayer insulating layer 99 and the photoelectric conversion unit 20 and is electrically connected to the readout electrode 21A of the photoelectric conversion unit 20. Furthermore, the readout electrode 91A is electrically connected to a floating diffusion FD provided in the semiconductor substrate 30 via the through electrodes 34 and 98, and can temporarily store carriers generated in the photoelectric conversion layer 96. Furthermore, the readout electrode 91A is electrically connected to an amplifier transistor AMP and the like provided in the semiconductor substrate 30 via the through electrodes 34 and 98.

[0289] (7-4. Modification 6) FIG. 29 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector element (photodetector element 8A) according to Modification 6 of the present disclosure. FIG. 30A is a schematic diagram illustrating another example of a cross-sectional configuration of a photodetector element (photodetector element 8B) according to Modification 6 of the present disclosure. FIG. 30B is a schematic diagram illustrating an example of a planar configuration of the photodetector element 8B shown in FIG. 30A. FIG. 31A is a schematic diagram illustrating another example of a cross-sectional configuration of a photodetector element (photodetector element 8C) according to Modification 6 of the present disclosure. FIG. 31B is a schematic diagram illustrating an example of a planar configuration of the photodetector element 8C shown in FIG. 31A. FIG. 32 is a schematic diagram illustrating another example of a cross-sectional configuration of a photodetector element (photodetector element 8D) according to Modification 6 of the present disclosure. Like the photodetector element 1 of the first embodiment described above, the photodetector elements 8A to 8D are used as imaging elements such as CMOS image sensors used in electronic devices such as digital still cameras and video cameras. The photodetecting elements 8A to 8D of this modification differ from the above-described embodiment in that the lower electrode 21 is composed of one electrode for each unit pixel P.

[0290] Similar to the photodetector element 1, the photodetector element 8A has one photoelectric conversion unit 20 and two photoelectric conversion regions 32B, 32R stacked in the vertical direction for each unit pixel P. The photoelectric conversion unit 20 is provided on the back surface (first surface 30A) 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.

[0291] As described above, the photodetection elements 8A to 8D of this modified example have the same configuration as the photodetection element 1, except that the lower electrodes 21, 91 of the photoelectric conversion units 20, 90 consist of a single electrode, and the insulating layers 22, 92, the oxide semiconductor layers 23, 93, and the protective layers 24, 94 are not provided between the lower electrodes 21, 91 and the potential control layers 25, 95.

[0292] In this way, the configuration of the photoelectric conversion unit 20 is not limited to the photodetector element 1 of the first embodiment described above, and the configuration of the photoelectric conversion units 20, 90 of the photodetector elements 8A to 8D of this modified example can also obtain the same effects as those of the first embodiment described above.

[0293] Although the photodetecting elements 5 to 7 and 8A to 8D of the above-described modified examples 3 to 6 have the photoelectric conversion unit 20 of the above-described first embodiment as the photoelectric conversion unit, the present invention is not limited to this. The photoelectric conversion units of the photodetecting elements 5 to 7 and 8A to 8D can be the photoelectric conversion units 20A, 60, 60A, 70, and 80 described in the above-described second and third embodiments and modified examples 1 and 2.

[0294] 8. Application Examples Application Example 1 FIG. 33 shows an example of the overall configuration of a photodetector (photodetector 100) including the photodetector element (for example, photodetector element 1) shown in FIG. 1 and the like.

[0295] 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 for each pixel, and outputs the signal as a pixel signal. The photodetector 100 has a pixel section 100A as an imaging area on a semiconductor substrate 30, and also has, in a peripheral region of the pixel section 100A, for example, a vertical drive circuit 111, a column signal processing circuit 112, a horizontal drive circuit 113, an output circuit 114, a control circuit 115, and input / output terminals 116.

[0296] The pixel 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.

[0297] 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 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.

[0298] 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.

[0299] 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.

[0300] 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.

[0301] 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.

[0302] The input / output terminal 116 is used to exchange signals with the outside.

[0303] (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.

[0304] FIG. 34 is a block diagram showing an example of the configuration of electronic device 1000. As shown in FIG.

[0305] As shown in Figure 34, 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.

[0306] 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 .

[0307] 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.

[0308] 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.

[0309] Application Example 3 Fig. 35A schematically illustrates an example of the overall configuration of a light detection system 2000 including the light detection device 100. Fig. 35B illustrates 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.

[0310] The photodetector 2002 can detect light L1 and light L2. Light L1 is external ambient light reflected by the object (measurement target) 2100 ( FIG. 35A ). 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 .

[0311] 9. 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.

[0312] FIG. 36 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.

[0313] 36 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.

[0314] 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.

[0315] 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.

[0316] 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.

[0317] 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.

[0318] 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.

[0319] 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.

[0320] 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.

[0321] 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.

[0322] 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.

[0323] 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.

[0324] 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.

[0325] FIG. 37 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG.

[0326] 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.

[0327] 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.

[0328] 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.

[0329] 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.

[0330] 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.

[0331] 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.

[0332] 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.

[0333] 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.

[0334] 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 .

[0335] 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.

[0336] 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.

[0337] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102 .

[0338] 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.

[0339] 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.

[0340] 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.

[0341] 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.

[0342] 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.

[0343] Although an endoscopic surgery system has been described as an example here, the technology according to the present disclosure may also be applied to other systems, such as a microsurgery system.

[0344] (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).

[0345] FIG. 38 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.

[0346] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 38, 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.

[0347] 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.

[0348] 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.

[0349] 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.

[0350] 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.

[0351] 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.

[0352] 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.

[0353] 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.

[0354] 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.

[0355] 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. 38, 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.

[0356] FIG. 39 is a diagram showing an example of the installation position of the imaging unit 12031.

[0357] In FIG. 39, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0358] 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.

[0359] 39 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.

[0360] 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.

[0361] 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.

[0362] 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.

[0363] 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.

[0364] 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 elements (e.g., photodetector element 1) according to the first to fourth embodiments and their modified examples 1 to 6 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 high-resolution captured images with little noise, thereby enabling high-precision control using the captured images in the mobile object control system.

[0365] Although the first to fourth embodiments, variations 1 to 6, and application examples have been described above, the present disclosure is not limited to the above embodiments and various modifications are possible. For example, in the first embodiment, the photodetector element is configured by stacking a photoelectric conversion unit 20 that detects green light and photoelectric conversion regions 32B and 32R that detect blue light and red light, respectively. However, the present disclosure is not limited to this structure. For example, the photoelectric conversion unit may be configured to detect red light or blue light, or the photoelectric conversion region may be configured to detect green light.

[0366] Furthermore, the number and ratio of these photoelectric conversion units and photoelectric conversion regions are not limited, and two or more photoelectric conversion units may be provided, or color signals of multiple colors may be obtained using only the photoelectric conversion units.

[0367] Furthermore, in the above embodiments, the lower electrode 21 is made up of two electrodes, the readout electrode 21A and the storage electrode 21B, but three or more electrodes, such as a transfer electrode and an exhaust electrode, may also be provided.

[0368] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0369] The present technology can also be configured as follows. According to the present technology configured as follows, it is possible to improve charge transport characteristics. (1) A light-emitting device comprising: a first electrode; a third electrode disposed opposite to the first electrode; a photoelectric conversion layer provided between the first electrode and the third electrode; an oxide semiconductor layer provided between the first electrode and the photoelectric conversion layer; an oxide layer provided between the photoelectric conversion layer and the oxide semiconductor layer; and an intermediate layer provided between the photoelectric conversion layer and the oxide layer and containing one or more materials, wherein the HOMO energy of the material having the highest HOMO energy contained in the photoelectric conversion layer is set to E ｉ ＨＯＭＯ The HOMO energy of the material having the highest HOMO energy among the one or more materials contained in the intermediate layer is E ＮＢ ＨＯＭＯ In this case, E ｉ ＨＯＭＯ ≦E ＮＢ ＨＯＭＯ(2) The photodetector according to (1), wherein the one or more materials are organic materials. (3) The photodetector according to (1) or (2), wherein the film thickness of the intermediate layer is 10 nm or less. (4) The photodetector according to any one of (1) to (3), wherein the intermediate layer is a laminated film in which a plurality of layers containing organic materials are laminated. (5) The intermediate layer has a first layer and a second layer laminated in this order from the photoelectric conversion layer side, and the HOMO energy of the material contained in the first layer with the highest HOMO energy is set to E ＮＢ１ ＨＯＭＯ , the HOMO energy of the material having the highest HOMO energy contained in the second layer is E ＮＢ２ ＨＯＭＯ In this case, E ｉ ＨＯＭＯ >E ＮＢ１ ＨＯＭＯ , and E ＮＢ１ ＨＯＭＯ <E ＮＢ２ ＨＯＭＯ (6) The photodetector according to any one of (1) to (4), wherein the second layer has a thickness of 10 nm or less. (7) The intermediate layer has a thickness of −1E12 cm －２ <N<1E12cm －２(8) The photodetector according to any one of (1) to (6), further comprising: a second electrode arranged in parallel with the first electrode; and an insulating layer provided between the first electrode and the second electrode and the oxide semiconductor layer, the insulating layer having an opening above the first electrode, the first electrode and the oxide semiconductor layer being electrically connected via the opening. (9) The photodetector according to (8), wherein voltages are applied to the first electrode and the second electrode individually. (10) The photodetector according to any one of (1) to (6), further comprising: a first electrode; a third electrode arranged opposite to the first electrode; a photoelectric conversion layer provided between the first electrode and the third electrode; an oxide semiconductor layer provided between the first electrode and the photoelectric conversion layer; and an insulating layer provided between the photoelectric conversion layer and the oxide semiconductor layer and having a fixed charge satisfying -1E12 cm －２ <N<1E12cm －２ and an intermediate layer having a fixed charge amount satisfying the formula: (11) The photodetector according to (10), wherein the intermediate layer is made of an inorganic material. (12) The photodetector according to (10) or (11), wherein the intermediate layer contains a metal oxide or a metal nitride containing at least one element selected from the group consisting of titanium, tantalum, vanadium, niobium, tungsten, zirconium, hafnium, scandium, yttrium, lanthanum, ruthenium, germanium, strontium, gallium, magnesium, silicon, and aluminum. (13) The photodetector according to any one of (10) to (12), wherein the intermediate layer is made of a stack of films having different atomic compositions. (14) The photodetector according to any one of (10) to (13), wherein the film thickness of the intermediate layer is from 1 atom to 10 nm. (15) The photodetector according to any one of (11) to (14), further comprising an oxide layer containing titanium oxide or silicon oxide between the photoelectric conversion layer and the oxide semiconductor layer, and the intermediate layer is made of a nitride layer formed by nitriding a surface of the oxide layer. (16) The photoelectric conversion layer includes a hole transport material, and the conduction band energy of the inorganic material is set to E ＰＣＣ , the LUMO energy of the hole transport material is E ｉ ＬＵＭＯ , the conduction band energy of the oxide layer is E Ｏｘ Ｃ In this case, E ＰＣ Ｃ >E ｉ ＬＵＭＯ , and E ＰＣ Ｃ >E Ｏｘ Ｃ (17) The photodetector according to (16), wherein the intermediate layer has a film thickness of 2 nm or less. (18) A photodetector comprising: a first electrode; a third electrode disposed opposite the first electrode; a photoelectric conversion layer provided between the first electrode and the third electrode; an oxide semiconductor layer provided between the first electrode and the photoelectric conversion layer; an oxide layer provided between the photoelectric conversion layer and the oxide semiconductor layer; and an intermediate layer provided between the photoelectric conversion layer and the oxide layer and containing an organic material having an electron-donating group. (19) A photodetector comprising: a first electrode; a third electrode disposed opposite the first electrode; a photoelectric conversion layer provided between the first electrode and the third electrode; an oxide semiconductor layer provided between the photoelectric conversion layer and the oxide semiconductor layer; and an intermediate layer provided between the photoelectric conversion layer and the oxide layer and containing an organic material having an electron-donating group. ＮＢ ＨＯＭＯ , where WF is the work function of the first electrode, |E ＮＢ ＨＯＭＯ(20) The photodetector according to (18), wherein |≦WF is satisfied. (21) The photodetector according to any one of (18) to (20), wherein a HOMO of the intermediate layer and a conduction band of the oxide semiconductor layer satisfy |HOMO of intermediate layer|<|Conduction band of oxide semiconductor|. (22) The photodetector according to any one of (18) to (21), further comprising: a second electrode arranged in parallel with the first electrode; and an insulating layer provided between the first electrode and the oxide semiconductor layer, and between the second electrode and the oxide semiconductor layer, the insulating layer having an opening above the first electrode, wherein the first electrode and the oxide semiconductor layer are electrically connected via the opening. (23) A semiconductor device comprising: a first electrode; a third electrode disposed opposite to the first electrode; a photoelectric conversion layer provided between the first electrode and the third electrode; and an intermediate layer provided between the photoelectric conversion layer and the first electrode, wherein the HOMO energy of the intermediate layer is set to E ＮＢ ＨＯＭＯ , where WF is the work function of the first electrode, |E ＮＢ ＨＯＭＯ A photodetector that satisfies |≦WF.

[0370] This application claims priority based on Japanese Patent Application No. 2023-116234, filed on July 14, 2023, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0371] 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 semiconductor device comprising: a first electrode; a third electrode disposed opposite to the first electrode; a photoelectric conversion layer provided between the first electrode and the third electrode; an oxide semiconductor layer provided between the first electrode and the photoelectric conversion layer; an oxide layer provided between the photoelectric conversion layer and the oxide semiconductor layer; and an intermediate layer provided between the photoelectric conversion layer and the oxide layer and containing one or more materials, wherein the HOMO energy of a material having the highest HOMO energy contained in the photoelectric conversion layer is defined as E ｉ ＨＯＭＯ The HOMO energy of the material having the highest HOMO energy among the one or more materials contained in the intermediate layer is E ＮＢ ＨＯＭＯ In this case, E ｉ ＨＯＭＯ ≦E ＮＢ ＨＯＭＯ Meet the optical detection device.

2. The optical detection device of claim 1, wherein said one or more materials are organic materials.

3. The photodetector according to claim 1, wherein the intermediate layer has a thickness of 10 nm or less.

4. The photodetector according to claim 1, wherein the intermediate layer is a laminated film in which a plurality of layers containing an organic material are laminated.

5. The intermediate layer has a first layer and a second layer stacked in this order from the photoelectric conversion layer side, and the HOMO energy of the material having the highest HOMO energy contained in the first layer is set to E ＮＢ１ ＨＯＭＯ The HOMO energy of the material having the highest HOMO energy contained in the second layer is E ＮＢ２ ＨＯＭＯ In this case, E ｉ ＨＯＭＯ >E ＮＢ１ ＨＯＭＯ , and E ＮＢ１ ＨＯＭＯ <E ＮＢ２ ＨＯＭＯ The photodetector according to claim 1 , 6. The photodetector according to claim 5, wherein the second layer has a thickness of 10 nm or less.

7. The intermediate layer is -1E12cm －２ <N<1E12cm －２ The photodetector according to claim 1 , wherein the photodetector has a fixed charge amount satisfying the following:

8. The photodetector device of claim 1, further comprising: a second electrode arranged in parallel with the first electrode; and an insulating layer provided between the first electrode and the oxide semiconductor layer, and having an opening above the first electrode, the first electrode and the oxide semiconductor layer being electrically connected via the opening.

9. The optical detection device according to claim 8, wherein a voltage is applied to the first electrode and the second electrode individually.

10. A first electrode; a third electrode disposed opposite to the first electrode; a photoelectric conversion layer provided between the first electrode and the third electrode; an oxide semiconductor layer provided between the first electrode and the photoelectric conversion layer; and a semiconductor layer having a capacitance of −1E12 cm －２ <N<1E12cm －２ and an intermediate layer having a fixed charge amount satisfying the above.

11. The optical detection device according to claim 10, wherein the intermediate layer is made of an inorganic material.

12. The optical detection device of claim 10, wherein the intermediate layer comprises a metal oxide or a metal nitride containing at least one of the elements titanium, tantalum, vanadium, niobium, tungsten, zirconium, hafnium, scandium, yttrium, lanthanum, ruthenium, germanium, strontium, gallium, magnesium, silicon, and aluminum.

13. The photodetector according to claim 10, wherein the intermediate layer is made of a laminated film having different atomic compositions.

14. The photodetector according to claim 10, wherein the thickness of the intermediate layer is from 1 atom to 10 nm.

15. The photodetector according to claim 11, further comprising an oxide layer containing titanium oxide or silicon oxide between the photoelectric conversion layer and the oxide semiconductor layer, and the intermediate layer is made of a nitride layer formed by nitriding the surface of the oxide layer.

16. The photoelectric conversion layer contains a hole transport material, and the conduction band energy of the inorganic material is E ＰＣ Ｃ , the LUMO energy of the hole transport material is E ｉ ＬＵＭＯ , the conduction band energy of the oxide layer is E Ｏｘ Ｃ In this case, E ＰＣ Ｃ >E ｉ ＬＵＭＯ , and E ＰＣ Ｃ >E Ｏｘ Ｃ The optical detection device according to claim 15 , 17. The photodetector according to claim 16, wherein the intermediate layer has a thickness of 2 nm or less.

18. A photodetector comprising: a first electrode; a third electrode disposed opposite the first electrode; a photoelectric conversion layer provided between the first electrode and the third electrode; an oxide semiconductor layer provided between the first electrode and the photoelectric conversion layer; an oxide layer provided between the photoelectric conversion layer and the oxide semiconductor layer; and an intermediate layer provided between the photoelectric conversion layer and the oxide layer, the intermediate layer including an organic material having an electron-donating group.

19. The HOMO energy of the organic material is E ＮＢ ＨＯＭＯ , where WF is the work function of the first electrode, |E ＮＢ ＨＯＭＯ The light detection device according to claim 18 , wherein |≦WF is satisfied.

20. The optical detection device according to claim 18, wherein the electron donating group is any one of a hydroxy group, a methoxy group, an amino group, an acetylamino group, a dimethylamino group, and a pyridyl group.

21. The photodetector according to claim 18, wherein the HOMO of the intermediate layer and the conduction band of the oxide semiconductor layer satisfy |HOMO of intermediate layer|<|conduction band of oxide semiconductor|.

22. The photodetector device of claim 18, further comprising: a second electrode arranged in parallel with the first electrode; and an insulating layer provided between the first electrode and the oxide semiconductor layer, and having an opening above the first electrode, the first electrode and the oxide semiconductor layer being electrically connected via the opening.

23. A semiconductor device comprising: a first electrode; a third electrode disposed opposite to the first electrode; a photoelectric conversion layer provided between the first electrode and the third electrode; and an intermediate layer provided between the photoelectric conversion layer and the first electrode, wherein the HOMO energy of the intermediate layer is set to E ＮＢ ＨＯＭＯ , where WF is the work function of the first electrode, |E ＮＢ ＨＯＭＯ A photodetector that satisfies |≦WF.

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