Photoelectric conversion element and image pickup element

Abstract

To provide a photoelectric conversion element and imaging device, capable of improving heat resistance and electrical properties.SOLUTION: A photoelectric conversion element 10 includes: a lower electrode 11; an upper electrode 15; a photoelectric conversion layer 13; and buffer layers 12, 14 provided between the lower electrode 11 and the photoelectric conversion layer 13 and between the upper electrode 15 and the photoelectric conversion layer 13 and containing at least two types of material contained in the photoelectric conversion layer 13.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to, for example, a photoelectric conversion element using an organic material and an imaging element including the same. [Background technology]

[0002] For example, Patent Document 1 discloses a photoelectric conversion element in which an electron blocking layer and a hole blocking layer are provided between a pair of opposing electrodes and a photoelectric conversion layer, respectively. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-236008 A Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, organic photoelectric conversion elements are required to have both heat resistance and current characteristics.

[0005] It is desirable to provide a photoelectric conversion element and an imaging element that can improve heat resistance and electrical characteristics. [Means for solving the problem]

[0006] The photoelectric conversion element according to an embodiment of the present disclosure includes a first electrode, a second electrode disposed opposite to the first electrode, and a photodiode disposed between the first electrode and the second electrode. The organic semiconductor material includes a first organic semiconductor material which is a dye material, a second organic semiconductor material which is an n-type semiconductor having electron transport properties, and a third organic semiconductor material which is a p-type semiconductor having hole transport properties. Photoelectric conversion layer, and between the first electrode and the photoelectric conversion layer and a second buffer layer provided between the second electrode and the photoelectric conversion layer, the second buffer layer including two materials contained in the photoelectric conversion layer, namely, a first organic semiconductor material and a second organic semiconductor material or a third organic semiconductor material, and the dye material is any one of BODIPY dye B represented by formula (1-2) to be described later, BODIPY dye C represented by formula (1-3) to be described later, BODIPY dye D represented by formula (1-4) to be described later, a subphthalocyanine derivative represented by formula (2-1) to be described later, a merocyanine derivative represented by formula (3) to be described later, a zinc complex represented by formula (1-5) to be described later, and a perylene derivative represented by formula (4-1) to be described later. .

[0007] The imaging element according to the embodiment of the present disclosure includes one or more photoelectric conversion elements according to the embodiment of the present disclosure for each of a plurality of pixels. Effect of the Invention

[0008] In the photoelectric conversion element according to the embodiment of the present disclosure and the imaging element according to the embodiment, a first electrode and a photoelectric conversion layer disposed opposite each other are provided. a first buffer layer on the Between the second electrode and the photoelectric conversion layer a second buffer layer is provided on each of the photoelectric conversion layers, and the second buffer layer is formed using two types of organic semiconductor material, that is, a first organic semiconductor material that is a dye material contained in the photoelectric conversion layer, and a second organic semiconductor material or a third organic semiconductor material. This results in a photoelectric conversion layer Second buffer layer Improve the bonding condition with the [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic cross-sectional view illustrating a configuration of a photoelectric conversion element according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram illustrating an example of the energy levels of materials contained in each layer of the photoelectric conversion element shown in FIG. [Diagram 3] 2 is a cross-sectional view illustrating an example of the configuration of an imaging element including the photoelectric conversion element shown in FIG. [Figure 4] 4 is a plan view illustrating a configuration of a unit pixel of the image sensor illustrated in FIG. [Diagram 5] 4 is a schematic cross-sectional view for explaining a method of manufacturing the image sensor shown in FIG. 3. [Figure 6] FIG. 6 is a schematic cross-sectional view showing a step following FIG. 5. [Figure 7] 1. FIG. 4 is a schematic cross-sectional view illustrating another example of the configuration of an imaging element including the photoelectric conversion element shown in FIG. [Figure 8] 8 is an equivalent circuit diagram of the image sensor shown in FIG. 7. [Figure 9] 2 is a schematic diagram showing an arrangement of transistors constituting a lower electrode and a control unit of the image sensor shown in FIG. 1. [Figure 10] 1 is a schematic cross-sectional view illustrating an example of a configuration of an imaging element according to Modification 1 of the present disclosure. [Figure 11] 11 is a schematic cross-sectional view illustrating an example of a configuration of an imaging element according to Modification 2 of the present disclosure. FIG. [Figure 12A] 11 is a schematic cross-sectional view illustrating an example of a configuration of an imaging element according to Modification 3 of the present disclosure. FIG. [Figure 12B] 12B is a schematic diagram illustrating a planar configuration of the imaging element illustrated in FIG. 12A. [Figure 13]4 is a block diagram showing an overall configuration of the imaging element shown in FIG. 3 etc. [Figure 14] 14 is a functional block diagram illustrating an example of an electronic device (camera) using the image sensor illustrated in FIG. 13. [Figure 15] 1 is a diagram illustrating an example of a schematic configuration of an endoscopic surgery system. [Figure 16] 2 is a block diagram showing an example of a functional configuration of a camera head and a CCU. FIG. [Figure 17] 1 is a block diagram showing an example of a schematic configuration of a vehicle control system; [Figure 18] 4 is an explanatory diagram showing an example of the installation positions of an outside-vehicle information detection unit and an imaging unit; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 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. Embodiment (Example in which a buffer layer containing at least two materials contained in the photoelectric conversion layer is provided between a pair of opposing electrodes and a photoelectric conversion layer) 1-1. Photoelectric conversion element configuration 1-2. Image sensor configuration example 1 1-3.Image sensor configuration example 2 1-4. Actions and Effects 2. Variations 2-1. Modification 1 (another example of the configuration of the image sensor) 2-2. Modification 2 (another example of the configuration of the image sensor) 3-2. Modification 3 (another example of the configuration of the image sensor) 3. Application Examples 4. Application Examples 5. Working Example

[0011] <1. Preferred embodiment> 1 is a schematic diagram showing an example of a cross-sectional configuration of a photoelectric conversion element (photoelectric conversion element 10) according to an embodiment of the present disclosure. The photoelectric conversion element 10 constitutes one pixel (unit pixel P) in an imaging element (imaging element 1, see FIG. 13, for example) such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor used in electronic devices such as digital still cameras and video cameras. The photoelectric conversion element 10 according to the present embodiment includes a lower electrode 11, a buffer layer 12, a photoelectric conversion layer 13, a buffer layer 14, and an upper electrode 15 stacked in this order, and one or both of the buffer layers 12 and 14 are formed by containing the two types of materials contained in the photoelectric conversion layer 13.

[0012] (1-1. Configuration of photoelectric conversion element) The photoelectric conversion element 10 absorbs light corresponding to a part or all of the wavelengths in a selective wavelength band (for example, the visible light region of 400 nm to 760 nm) to generate electron-hole pairs. In an imaging element described later (for example, imaging element 1A, see FIG. 3 for example), of the electron-hole pairs generated by photoelectric conversion, for example, holes are read out from the lower electrode 11 side as signal charges. The configuration and materials of each part will be described below using the case where holes are read out as signal charges as an example.

[0013] The lower electrode 11 is made of, for example, a conductive film having optical transparency. Examples of the constituent material of the lower electrode 11 include indium tin oxide (ITO), In2O3 with tin (Sn) added as a dopant, and indium tin oxide including crystalline ITO and amorphous ITO. In addition to the above, the constituent material of the lower electrode 11 may be a tin oxide (SnO2)-based material with a dopant added, or a zinc oxide-based material with a dopant added. Examples of the zinc oxide-based material 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. In addition, the constituent material of the lower electrode 11 may be CuI, InSbO4, ZnMgO, CuInO2, MgIN2O4, CdO, ZnSnO3, TiO2, or the like. Furthermore, a spinel oxide or an oxide having a YbFe2O4 structure may be used. The lower electrode 11 formed using the above-mentioned materials generally has a high work function and functions as an anode electrode.

[0014] The buffer layer 12 is a so-called electron blocking layer (p-buffer layer) that selectively transports holes, among the charges generated in the photoelectric conversion layer 13, to the lower electrode 11 and inhibits the movement of electrons toward the lower electrode 11. The thickness of the buffer layer 12 is, for example, 0.5 nm to 100 nm, preferably 1 nm to 50 nm, and more preferably 3 nm to 20 nm. The configuration of the buffer layer 12 will be described together with the buffer layer 14 described later.

[0015] The photoelectric conversion layer 13 converts light energy into electrical energy. The photoelectric conversion layer 13 absorbs light with a part or all of the wavelengths in the range of, for example, 400 nm to 760 nm. The photoelectric conversion layer 13 is configured to include, for example, two or more organic materials that function as p-type semiconductors or n-type semiconductors, and has a junction surface (p / n junction surface) between a p-type semiconductor and an n-type semiconductor in the layer. The p-type semiconductor functions relatively as an electron donor, and the n-type semiconductor functions relatively as an electron acceptor. The photoelectric conversion layer 13 provides a place where excitons (electron-hole pairs) generated when light is absorbed are separated into electrons and holes, and specifically, the electron-hole pairs are separated into electrons and holes at the interface (p / n junction surface) between the electron donor and the electron acceptor.

[0016] The photoelectric conversion layer 13 is configured to include, in addition to the p-type semiconductor and the n-type semiconductor, an organic material that absorbs light in a predetermined wavelength band while transmitting light in other wavelength bands, so-called a dye material. When the photoelectric conversion layer 13 is formed using three types of organic materials, the p-type semiconductor, the n-type semiconductor, and the dye material, it is preferable that the p-type semiconductor and the n-type semiconductor are materials that have optical transparency in the visible region (for example, 400 nm to 760 nm). This allows the photoelectric conversion layer 13 to selectively convert light in the wavelength band absorbed by the dye material. The thickness of the photoelectric conversion layer 13 is, for example, 25 nm to 400 nm, and preferably 50 nm to 350 nm. More preferably, it is 150 nm to 300 nm.

[0017] In the present embodiment, the photoelectric conversion layer 13 is formed by containing, as a dye material, a compound represented by the following general formula (1) having a dipyrromethene skeleton that forms a complex with a disubstituted boron atom. The compound represented by the general formula (1) is, for example, a BODIPY dye that has an electron-accepting property and absorbs light having a wavelength of 450 nm or more and 650 nm or less.

[0018] [ka] (R1 and R4 are each independently a hydrogen atom or a deuterium atom. R2 and R3 are each independently an alkyl group, a cycloalkyl group, an alkoxy group, or an aryl ether group. R5 and R6 are each independently a hydrogen atom, a halogen atom, or an alkyl group. R7 is an aryl group, a heteroaryl group, or an alkenyl group. M is boron or an m-valent metal atom, and is at least one selected from germanium, beryllium, magnesium, aluminum, chromium, iron, nickel, copper, zinc, and platinum. L is a halogen atom, a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group. n is an integer of 1 to 6, and when n-1 is 2 or more, each L is each independently a halogen atom, a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group.)

[0019] Other examples of the dye material include subphthalocyanine represented by the following general formula (2) or a derivative thereof.

[0020] [ka] (R8 to R19 are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a straight-chain, branched, or cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an alkylsulfonyl group, an amino group, an alkylamino group, an arylamino group, a hydroxy group, an alkoxy group, an acylamino group, an acyloxy group, a phenyl group, a carboxy group, a carboxamido group, a carboalkoxy group, an acyl group, a sulfonyl group, a cyano group, and a nitro group, and any adjacent R8 to R19 may be a part of a condensed aliphatic ring or a condensed aromatic ring. The condensed aliphatic ring or the condensed aromatic ring may contain one or more atoms other than carbon. X is any substituent selected from the group consisting of a halogen atom, a hydroxy group, a thiol group, an imido group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkylthio group, and a substituted or unsubstituted arylthio group.)

[0021] Further examples of the dye material include perylene represented by the following general formula (4) or a derivative thereof.

[0022] [ka] (R20 to R31 are each independently selected from a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an alkylsulfonyl group, an amino group, an alkylamino group, an arylamino group, a hydroxy group, an alkoxy group, an acylamino group, an acyloxy group, an aryl group, a heteroaryl group, a carboxy group, a carboxamido group, a carboalkoxy group, an acyl group, a sulfonyl group, a cyano group and a nitro group.)

[0023] The dye material further includes merocyanine or a derivative thereof.

[0024] In addition, the photoelectric conversion layer 13 may contain other organic materials such as fullerene C 60 or derivatives thereof. Other organic materials constituting the photoelectric conversion layer 13 include, for example, thiophene derivatives having a benzodithiophene (BDT) skeleton and chrysene derivatives having a chrysene skeleton. The above organic materials function as p-type semiconductors or n-type semiconductors depending on the combination.

[0025] The photoelectric conversion layer 13 may contain an organic material other than the above-mentioned materials. As the organic material other than the above-mentioned materials, for example, any one of quinacridone, pentacene, benzothienobenzothiophene, naphthalene, anthracene, phenanthrene, tetracene, pyrene, and fluoranthene, or derivatives thereof, is preferably used. Alternatively, a polymer such as phenylenevinylene, fluorene, carbazole, indole, pyrrole, picoline, thiophene, acetylene, or diacetylene, or a derivative thereof may be used. In addition, metal complex dyes, cyanine dyes, phenylxanthene dyes, triphenylmethane dyes, rhodacyanine dyes, xanthene dyes, macrocyclic azaannulene dyes, azulene dyes, naphthoquinone, anthraquinone dyes, condensed polycyclic aromatics such as anthracene and pyrene, and chain compounds in which aromatic rings or heterocyclic compounds are condensed, or two nitrogen-containing heterocycles such as quinoline, benzothiazole, and benzoxazole having a squarylium group and a croconite methine group as a binding chain, or cyanine-like dyes bonded by a squarylium group and a croconite methine group, etc. can be preferably used. Note that, as the above-mentioned metal complex dyes, dithiol metal complex dyes, metal phthalocyanine dyes, metal porphyrin dyes, or ruthenium complex dyes are preferred, but are not limited thereto.

[0026] The buffer layer 14 is a so-called hole blocking layer (n-buffer layer) that selectively transports electrons among the charges generated in the photoelectric conversion layer 13 to the upper electrode 15 and inhibits the movement of holes toward the upper electrode 15. The thickness of the buffer layer 14 is, for example, 0.5 nm to 100 nm, preferably 1 nm to 50 nm, and more preferably 3 nm to 20 nm.

[0027] In this embodiment, one or both of the buffer layers 12 and 14 are formed containing two or more types of materials contained in the photoelectric conversion layer 13. This improves the affinity between the photoelectric conversion layer 13 and the buffer layers 12 and 14, and improves the heat resistance. Specific examples of the two materials constituting the buffer layers 12 and 14 include the following combinations.

[0028] As one of the materials contained in the photoelectric conversion layer 13 constituting the buffer layers 12 and 14, for example, a dye material is preferably used. Specific dye materials include BODIPY dye, subphthalocyanine or a derivative thereof, a metal complex having a dipyrromethene ligand, merocyanine or a derivative thereof, and perylene or a derivative thereof. Among these, it is more preferable to use a material having a molecular weight of 500 or more.

[0029] Another material contained in the photoelectric conversion layer 13 that constitutes the buffer layers 12 and 14 can be a p-type semiconductor or an n-type semiconductor. Specifically, the buffer layer 12 that functions as an electron blocking layer can be formed using the dye material and, for example, a p-type semiconductor contained in the photoelectric conversion layer 13. The buffer layer 14 that functions as a hole blocking layer can be formed using the dye material and, for example, an n-type semiconductor contained in the photoelectric conversion layer 13.

[0030] Each of the buffer layers 12 and 14 may further contain materials other than the above two materials.

[0031] This technology can also be applied to the case where electrons are read out as signal charges from the lower electrode 11 side, as in the image sensor 1B described later (see, for example, FIG. 7). In that case, the buffer layer 12 on the lower electrode 11 side is configured as a hole blocking layer (n buffer layer), and the buffer layer 14 on the upper electrode 15 side is configured as an electron blocking layer (p buffer layer). In that case, the buffer layer 12 is configured as a material contained in the photoelectric conversion layer 13, which is fullerene C 60 It is preferable to use a derivative thereof, which improves the mobility of electrons in the buffer layer 12 and promotes the movement of electrons generated in the photoelectric conversion layer 13 toward the lower electrode 11 side.

[0032] As described above, the material constituting the buffer layer 12 is fullerene C 60When using a derivative thereof, it is preferable to use, as the other material contained in the photoelectric conversion layer 13 constituting the buffer layer 12, a material having an energy level as shown in Fig. 2. Specifically, it is preferable to use, as the other material, a material having an energy difference with respect to the work function of the lower electrode 11 of 1.4 eV or more and a Highest Occupied Molecular Orbital (HOMO) level deeper than 6.2 eV. This makes it possible to prevent the intrusion of holes from the lower electrode 11.

[0033] Furthermore, as described above, fullerene C is used as the material for forming the buffer layer 12. 60 Another material when using fullerene C or its derivatives is 60 or its derivative has an energy difference of 1.7 eV or more with respect to the Lowest Unoccupied Molecular Orbital (LUMO) level, and is fullerene C 60 It is preferable to use a material that has a HOMO level shallower than that of fullerene C or its derivatives, which reduces charge generation in the buffer layer 12. Alternatively, another material is fullerene C 60 It is preferable to use a material whose LUMO level difference with respect to the derivatives thereof is 0 to 0.5 eV. This makes it possible to reduce the trapping of charges (electrons) in the buffer layer 12.

[0034] The buffer layer 12 is made of fullerene C 60 When the other material is a material contained in the photoelectric conversion layer 13 or a derivative thereof, the other material may be a material contained in the photoelectric conversion layer 13 or may be a material not contained in the photoelectric conversion layer 13. When the other material is a material contained in the photoelectric conversion layer 13, for example, the above-mentioned dye material can be mentioned. When the other material is a material not contained in the photoelectric conversion layer 13, the buffer layer 12 is preferably made of fullerene C 60 Or, the layer 12 is formed by further containing at least one of the materials contained in the photoelectric conversion layer 13 in addition to the derivative thereof and other materials.

[0035] The upper electrode 15 is made of a conductive film having optical transparency, similar to the lower electrode 11. In an image sensor 1 using the photoelectric conversion element 10 as one pixel, the upper electrode 15 may be separated for each pixel, or may be formed as an electrode common to each pixel. The thickness of the upper electrode 15 is, for example, 10 nm to 200 nm.

[0036] Other layers may be further provided between the photoelectric conversion layer 13 and the lower electrode 11, and between the photoelectric conversion layer 13 and the upper electrode 15. For example, in addition to the buffer layer 12, an undercoat layer or a hole transport layer may be provided between the lower electrode 11 and the photoelectric conversion layer 13. In addition to the buffer layer 14, a work function adjustment layer or an electron transport layer may be provided between the photoelectric conversion layer 13 and the upper electrode 15.

[0037] (1-2. Image sensor configuration example 1) 3 is a schematic diagram showing an example of a cross-sectional configuration of an imaging element (imaging element 1A) using the above-mentioned photoelectric conversion element 10. This imaging element 1A is a so-called vertical spectroscopic type in which one organic photoelectric conversion unit that selectively detects light in different wavelength ranges and performs photoelectric conversion, and two inorganic photoelectric conversion units 32B and 32R are stacked in the vertical direction. The above-mentioned photoelectric conversion element 10 is used as the organic photoelectric conversion unit. In the following, the organic photoelectric conversion unit will be described with the same reference numeral 10 as the above-mentioned photoelectric conversion element 10, assuming that the organic photoelectric conversion unit has the same configuration as the above-mentioned photoelectric conversion element 10.

[0038] In the imaging element 1A, the organic photoelectric conversion unit 10 is provided on the back surface (first surface 30S1) side of the semiconductor substrate 30. The inorganic photoelectric conversion units 32B, 32R are embedded in the semiconductor substrate 30 and are stacked in the thickness direction of the semiconductor substrate 30.

[0039] The organic photoelectric conversion unit 10 and the inorganic photoelectric conversion units 32B and 32R selectively detect light in different wavelength bands and perform photoelectric conversion. For example, the organic photoelectric conversion unit 10 acquires a green (G) color signal. The inorganic photoelectric conversion units 32B and 32R acquire blue (B) and red (R) color signals, respectively, due to differences in absorption coefficients. This makes it possible for the image sensor 1A to acquire multiple types of color signals in one pixel without using a color filter.

[0040] In the image sensor 1A, the case where holes among the electron-hole pairs generated by photoelectric conversion are read out as signal charges (where the p-type semiconductor region is the photoelectric conversion layer) will be described. In addition, in the figure, the "+ (plus)" attached to "p" and "n" indicates that the p-type or n-type impurity concentration is high.

[0041] The semiconductor substrate 30 is, for example, made of an n-type silicon (Si) substrate, and has a p-well 31 in a predetermined region. On a second surface (surface of the semiconductor substrate 30) 30S2 of the p-well 31, for example, various floating diffusions (floating diffusion layers) FD (for example, FD1, FD2, FD3), various transistors Tr (for example, a vertical transistor (transfer transistor) Tr2, a transfer transistor Tr3, an amplifier transistor (modulation element) AMP, and a reset transistor RST), and a multi-layer wiring layer 40 are provided. The multi-layer wiring layer 40 has, for example, a configuration in which wiring layers 41, 42, 43 are stacked in an insulating layer 44. In addition, a peripheral circuit (not shown) consisting of a logic circuit or the like is provided on the periphery of the semiconductor substrate 30.

[0042] In FIG. 3, the first surface 30S1 side of the semiconductor substrate 30 is represented as a light incident surface S1, and the second surface 30S2 side is represented as a wiring layer side S2.

[0043] The inorganic photoelectric conversion units 32B and 32R are configured, for example, by PIN (Positive Intrinsic Negative) type photodiodes, and each has a pn junction in a predetermined region of the semiconductor substrate 30. The inorganic photoelectric conversion units 32B and 32R are capable of splitting light in the vertical direction by utilizing the fact that the wavelength band absorbed varies depending on the depth of incidence of light in a silicon substrate.

[0044] The inorganic photoelectric conversion unit 32B selectively detects blue light and accumulates a signal charge corresponding to blue, and is disposed at a depth capable of efficiently photoelectrically converting blue light. The inorganic photoelectric conversion unit 32R selectively detects red light and accumulates a signal charge corresponding to red, and is disposed at a depth capable of efficiently photoelectrically converting red light. Note that blue (B) is a color corresponding to, for example, a wavelength band of 450 nm to 495 nm, and red (R) is a color corresponding to, for example, a wavelength band of 620 nm to 760 nm. Each of the inorganic photoelectric conversion units 32B and 32R may be capable of detecting light in a part or all of the wavelength bands.

[0045] Specifically, as shown in FIG. 3, each of the inorganic photoelectric conversion units 32B and 32R has, 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 pnp stacked structure). The n region of the inorganic photoelectric conversion unit 32B is connected to the vertical transistor Tr2. The p+ region of the inorganic photoelectric conversion unit 32B is bent along the vertical transistor Tr2 and connected to the p+ region of the inorganic photoelectric conversion unit 32R.

[0046] The vertical transistor Tr2 is a transfer transistor that transfers signal charges (here, holes) corresponding to blue that are generated and accumulated in the inorganic photoelectric conversion unit 32B to the floating diffusion FD2. Since the inorganic photoelectric conversion unit 32B is formed at a deep position from the second surface 30S2 of the semiconductor substrate 30, it is preferable that the transfer transistor of the inorganic photoelectric conversion unit 32B is composed of the vertical transistor Tr2.

[0047] The transfer transistor Tr3 transfers signal charges (here, holes) corresponding to red that are generated and accumulated in the inorganic photoelectric conversion unit 32R to the floating diffusion FD3, and is configured by, for example, a MOS transistor.

[0048] The amplifier transistor AMP is a modulation element that modulates the amount of charge generated in the organic photoelectric conversion section 10 into a voltage, and is configured of, for example, a MOS transistor.

[0049] The reset transistor RST resets the charge transferred from the organic photoelectric conversion section 10 to the floating diffusion FD1, and is composed of, for example, a MOS transistor.

[0050] The lower first contact 45, the lower second contact 46 and the upper contact 13B are made of, 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), tantalum (Ta), etc.

[0051] An organic photoelectric conversion section 10 is provided on the first surface 30S1 side of the semiconductor substrate 30. In the imaging element 1A, the lower electrode 11 is formed, for example, separately for each unit pixel P. The buffer layer 12, the photoelectric conversion layer 13, the buffer layer 14, and the upper electrode 15 are provided as a continuous layer common to a plurality of unit pixels P (for example, the pixel section 1a of the imaging element 1 shown in FIG. 13).

[0052] Between the first surface 30S1 of the semiconductor substrate 30 and the lower electrode 11, for example, insulating films 26, 27 and an interlayer insulating layer 28 are laminated in this order from the semiconductor substrate 30 side. A protective layer 51 is provided on the upper electrode 15. An on-chip lens layer 52 that constitutes an on-chip lens 52L and also serves as a planarizing layer is provided above the protective layer 51.

[0053] A through electrode 34 is provided between the first surface 30S1 and the second surface 30S2 of the semiconductor substrate 30. The organic photoelectric conversion unit 10 is connected to the gate Gamp of the amplifier transistor AMP and the floating diffusion FD1 via this through electrode 34. This allows the organic photoelectric conversion unit 10 to effectively transfer charges (holes) generated in the organic photoelectric conversion unit 10 on the first surface 30S1 side of the semiconductor substrate 30 to the second surface 30S2 side of the semiconductor substrate 30 via the through electrode 34, thereby improving the characteristics.

[0054] The through electrode 34 is provided, for example, for each unit pixel P. The through electrode 34 functions as a connector between the organic photoelectric conversion unit 10 and the gate Gamp of the amplifier transistor AMP and the floating diffusion FD1, and also serves as a transmission path for charges generated in the organic photoelectric conversion unit 10.

[0055] The lower end of the through electrode 34 is connected to, for example, a 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 are connected to the lower electrode 11 via a lower second contact 46. Note that, although the through electrode 34 is shown in FIG. 1 as having a cylindrical shape, the shape is not limited thereto, and may be, for example, a tapered shape.

[0056] It is preferable that a reset gate Grst of the reset transistor RST is disposed next to the floating diffusion FD1, as shown in Fig. 3. This makes it possible to reset the charge accumulated in the floating diffusion FD1 by the reset transistor RST.

[0057] In the organic photoelectric conversion section 10 of this embodiment, light incident on the imaging element 1A from the upper electrode 15 side is absorbed by the photoelectric conversion layer 13. The excitons generated by this move to the interface between the electron donor and electron acceptor constituting the photoelectric conversion layer 13, and are dissociated into excitons, that is, into electrons and holes. The charges (electrons and holes) generated here are carried to different electrodes by diffusion due to the difference in carrier concentration and an internal electric field due to the difference in work function between the anode (here, the lower electrode 11) and the cathode (here, the upper electrode 15), and are detected as photocurrent. In addition, the transport direction of the electrons and holes can be controlled by applying a potential between the lower electrode 11 and the upper electrode 15.

[0058] The insulating film 26 may be a film having a positive fixed charge or a film having a negative fixed charge. Examples of materials for a film having a negative fixed charge include hafnium oxide (HfO2), aluminum oxide (Al2O3), zirconium oxide (ZrO2), tantalum oxide (Ta2O5), and titanium oxide (TiO2). Materials other than those mentioned above include lanthanum oxide, praseodymium oxide, cerium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, aluminum nitride film, hafnium oxynitride film, and aluminum oxynitride film.

[0059] The insulating film 26 may have a structure in which two or more types of films are laminated together, which can further enhance the function as a hole accumulation layer, for example, in the case of a film having a negative fixed charge.

[0060] The material of the insulating film 27 is not particularly limited, but it is formed of, for example, a silicon oxide film, a TEOS film, a silicon nitride film, a silicon oxynitride film, or the like.

[0061] The interlayer insulating layer 28 is, for example, a single layer film made of one of silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), etc., or a laminated film made of two or more of these materials.

[0062] The protective layer 51 is made of a light-transmitting material, and is, for example, a single layer film made of any one 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.

[0063] An on-chip lens layer 52 is formed on the protective layer 51 so as to cover the entire surface. A plurality of on-chip lenses 52L (microlenses) are provided on the surface of the on-chip lens layer 52. The on-chip lenses 52L focus light incident from above onto the light receiving surfaces of the organic photoelectric conversion unit 10 and the inorganic photoelectric conversion units 32B and 32R. In this embodiment, since the multilayer wiring layer 40 is formed on the second surface 30S2 side of the semiconductor substrate 30, the light receiving surfaces of the organic photoelectric conversion unit 10 and the inorganic photoelectric conversion units 32B and 32R can be arranged close to each other, and the variation in sensitivity between colors that occurs depending on the F value of the on-chip lenses 52L can be reduced.

[0064] Fig. 4 is a plan view showing a configuration example of an image sensor 1A in which a plurality of photoelectric conversion units (e.g., the inorganic photoelectric conversion units 32B, 32R and the organic photoelectric conversion unit 10) to which the technology according to the present disclosure can be applied are stacked. That is, Fig. 4 shows an example of the planar configuration of a unit pixel P constituting the pixel unit 1a shown in Fig. 13, for example.

[0065] The unit pixel P has a photoelectric conversion region 1100 in which a red photoelectric conversion unit (inorganic photoelectric conversion unit 32R in FIG. 3), a blue photoelectric conversion unit (inorganic photoelectric conversion unit 32B in FIG. 3), and a green photoelectric conversion unit (organic photoelectric conversion unit 10 in FIG. 3) (none of which are shown in FIG. 4) that photoelectrically convert light of the respective wavelengths of R (Red), G (Green), and B (Blue) are stacked in three layers, for example, in the order of the green photoelectric conversion unit, the blue photoelectric conversion unit, and the red photoelectric conversion unit, from the light receiving surface (light incident surface S1 in FIG. 3). Furthermore, the unit pixel P has a Tr group 1110, a Tr group 1120, and a Tr group 1130 as charge readout units that read out charges corresponding to light of the respective wavelengths of RGB from the red photoelectric conversion unit, the green photoelectric conversion unit, and the blue photoelectric conversion unit. In the imaging element 1, in one unit pixel P, the light is split in the vertical direction, that is, in each layer serving as a red photoelectric conversion unit, a green photoelectric conversion unit, and a blue photoelectric conversion unit stacked in the photoelectric conversion region 1100, the light of each of the colors RGB is split.

[0066] The Tr group 1110, the Tr group 1120, and the Tr group 1130 are formed around the photoelectric conversion region 1100. The Tr group 1110 outputs a signal charge corresponding to R light generated and accumulated in the red photoelectric conversion unit as a pixel signal. The Tr group 1110 is composed of a transfer Tr (MOS FET) 1111, a reset Tr 1112, an amplifier Tr 1113, and a selection Tr 1114. The Tr group 1120 outputs a signal charge corresponding to B light generated and accumulated in the blue photoelectric conversion unit as a pixel signal. The Tr group 1120 is composed of a transfer Tr 1121, a reset Tr 1122, an amplifier Tr 1123, and a selection Tr 1124. The Tr group 1130 outputs a signal charge corresponding to G light generated and accumulated in the green photoelectric conversion unit as a pixel signal. The Tr group 1130 is made up of a transfer Tr 1131 , a reset Tr 1132 , an amplifier Tr 1133 and a selection Tr 1134 .

[0067] Transfer Tr1111 is composed of a gate G, a source / drain region S / D, and an FD (floating diffusion) 1115 (a source / drain region serving as the same). Transfer Tr1121 is composed of a gate G, a source / drain region S / D, and an FD2125. Transfer Tr1131 is composed of a gate G, a green photoelectric conversion unit (a source / drain region S / D connected to the same) in the photoelectric conversion region 1100, and an FD2135. The source / drain region of transfer Tr1111 is connected to a red photoelectric conversion unit in the photoelectric conversion region 1100, and the source / drain region S / D of transfer Tr1121 is connected to a blue photoelectric conversion unit in the photoelectric conversion region 1100.

[0068] The reset Tr 1112, 1132, and 1122, the amplifying Tr 1113, 1133, and 1123, and the selecting Tr 1114, 1134, and 1124 are each composed of a gate G and a pair of source / drain regions S / D arranged so as to sandwich the gate G therebetween.

[0069] The FD2115, 1135, and 1125 are connected to the source / drain regions S / D which are the sources of the reset Tr1112, 1132, and 1122, respectively, and are also connected to the gates G of the amplifier Tr1113, 1133, and 1123, respectively. A power supply Vdd is connected to the source / drain regions S / D common to the reset Tr1112 and the amplifier Tr1113, the reset Tr1132 and the amplifier Tr1133, and the reset Tr1122 and the amplifier Tr1123. A VSL (vertical signal line) is connected to the source / drain regions S / D which are the sources of the selection Tr1114, 1134, and 1124.

[0070] The imaging element 1A shown in FIG. 3 can be manufactured, for example, as follows.

[0071] 5 and 6 show the manufacturing method of the image sensor 1A in the order of steps. First, as shown in Fig. 5, a first conductivity type well, for example, a p-well 31, is formed in a semiconductor substrate 30, and inorganic photoelectric conversion units 32B, 32R of a second conductivity type (for example, n-type) are formed in this p-well 31. A p+ region is formed in the vicinity of the first surface 30S1 of the semiconductor substrate 30.

[0072] 5, n+ regions that become floating diffusions FD1 to FD3 are formed on the second surface 30S2 of the semiconductor substrate 30, and then a gate insulating layer 62 and a gate wiring layer 64 including the gates of the vertical transistor Tr2, the transfer transistor Tr3, the amplifier transistor AMP, and the reset transistor RST are formed. This forms the vertical transistor Tr2, the transfer transistor Tr3, the amplifier transistor AMP, and the reset transistor RST. Furthermore, a multilayer wiring layer 40 including the lower first contact 45, the lower second contact 46, wiring layers 41, 43, 43 including the connection portion 41A, and an insulating layer 44 is formed on the second surface 30S2 of the semiconductor substrate 30.

[0073] 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 laminated. Although not shown in Fig. 5, the buried oxide film and the holding substrate are bonded to the first surface 30S1 of the semiconductor substrate 30. After the ion implantation, an annealing process is performed.

[0074] Next, a support substrate (not shown) or another semiconductor substrate is bonded to the second surface 30S2 side (the multilayer wiring layer 40 side) of the semiconductor substrate 30, and the substrate is turned upside down. Next, the semiconductor substrate 30 is separated from the buried oxide film of the SOI substrate and the holding substrate, and the first surface 30S1 of the semiconductor substrate 30 is exposed. The above steps can be performed by techniques used in normal CMOS processes, such as ion implantation and CVD (Chemical Vapor Deposition).

[0075] 6, the semiconductor substrate 30 is processed from the first surface 30S1 side by, for example, dry etching to form an annular opening 30H. As shown in FIG. 6, the depth of the opening 30H penetrates from the first surface 30S1 to the second surface 30S2 of the semiconductor substrate 30 and reaches, for example, the connection portion 41A.

[0076] 6, for example, an insulating film 26 is formed on the first surface 30S1 of the semiconductor substrate 30 and the side surface of the opening 30H. The insulating film 26 may be formed by stacking two or more types of films. This makes it possible to further improve the function as a hole accumulation layer. After forming the insulating film 26, an insulating film 27 is formed.

[0077] Next, a conductor is embedded in the opening 30H to form the through electrode 34. As the conductor, 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) can be used.

[0078] Next, an interlayer insulating layer 28 is formed on the insulating film 27 and the through electrode 34, in which an upper first contact 29A, a pad portion 39A, an upper second contact 29B and a pad portion 39B are provided on the through electrode 34 to electrically connect the lower electrode 11 and the through electrode 34.

[0079] Thereafter, the lower electrode 11, the buffer layer 12, the photoelectric conversion layer 13, the buffer layer 14, the upper electrode 15, and the protective layer 51 are formed in this order on the interlayer insulating layer 28. The buffer layer 12, the photoelectric conversion layer 13, and the buffer layer 14 can be formed by, for example, a vacuum deposition method. Finally, the on-chip lens layer 52 having a plurality of on-chip lenses 52L on its surface is disposed. Through the above steps, the imaging element 1A shown in FIG. 1 is completed.

[0080] The method for forming the buffer layer 12, the photoelectric conversion layer 13, and the buffer layer 14 is not necessarily limited to a method using vacuum deposition, but other methods, such as a spin coating technique or a printing technique, may also be used.

[0081] In the imaging element 1A, when light is incident on the organic photoelectric conversion unit 10 through the on-chip lens 52L, the light passes through the organic photoelectric conversion unit 10 and the inorganic photoelectric conversion units 32B and 32R in this order, and is photoelectrically converted into green (G), blue (B), and red (R) light during the passage. The operation of acquiring signals of each color will be described below.

[0082] (Acquisition of a green signal by the organic photoelectric conversion unit 10) Of the light incident on the imaging element 1A, green light is first selectively detected (absorbed) by the organic photoelectric conversion section 10 and photoelectrically converted.

[0083] The organic photoelectric conversion unit 10 is connected to the gate Gamp of the amplifier transistor AMP and the floating diffusion FD1 via the through electrode 34. Thus, holes of the electron-hole pairs generated in the organic photoelectric conversion unit 10 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 organic photoelectric conversion unit 10 is modulated into a voltage by the amplifier transistor AMP.

[0084] 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.

[0085] Here, the organic photoelectric conversion unit 10 is connected not only to the amplifier transistor AMP but also to the floating diffusion FD1 via the through electrode 34, so that the charge accumulated in the floating diffusion FD1 can be easily reset by the reset transistor RST.

[0086] 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 is applied to pull it out to the upper electrode 15 side. This may damage the photoelectric conversion layer 13. In addition, a structure that enables resetting in a short time leads to an increase in dark noise, which is a trade-off, making this structure difficult to implement.

[0087] (Obtaining blue and red signals by inorganic photoelectric conversion units 32B and 32R) Next, of the light transmitted through the organic photoelectric conversion unit 10, the blue light is absorbed in the inorganic photoelectric conversion unit 32B, and the red light is absorbed in the inorganic photoelectric conversion unit 32R, in that order, and photoelectrically converted. In the inorganic photoelectric conversion unit 32B, electrons corresponding to the incident blue light are accumulated in the n-region of the inorganic photoelectric conversion unit 32B, and the accumulated electrons are transferred to the floating diffusion FD2 by the vertical transistor Tr2. Similarly, in the inorganic photoelectric conversion unit 32R, electrons corresponding to the incident red light are accumulated in the n-region of the inorganic photoelectric conversion unit 32R, and the accumulated electrons are transferred to the floating diffusion FD3 by the transfer transistor Tr3.

[0088] (1-3. Image sensor configuration example 2) Fig. 7 is a schematic diagram of another example (imaging element 1B) of the cross-sectional configuration of an imaging element using the above-mentioned organic photoelectric conversion section 10. Fig. 8 is an equivalent circuit diagram of the imaging element 1B shown in Fig. 7. Fig. 9 is a schematic diagram of the arrangement of transistors constituting the lower electrode 11 and control section of the imaging element 1B shown in Fig. 7. The above-mentioned organic photoelectric conversion section 10 can be used as the organic photoelectric conversion section of the imaging element 1B shown in Fig. 7, in addition to the imaging element 1A shown in Fig. 3.

[0089] In the imaging element 1B, the organic photoelectric conversion unit 10 has a lower electrode 11 composed of a plurality of electrodes (for example, two electrodes: a readout electrode 11A and a storage electrode 11B), and between the lower electrode 11 and the buffer layer 12, for example, an insulating layer 16 and a semiconductor layer 17 are laminated in this order. Of the lower electrode 11, the readout electrode 11A is electrically connected to the semiconductor layer 17 via an opening 16H provided in the insulating layer 16. In the imaging element 1B, for example, of electron-hole pairs generated by photoelectric conversion, electrons are read out as signal charges.

[0090] As described above, the lower electrode 11 is composed of the read electrode 11A and the storage electrode 11B which are formed separately. The read electrode 11A is for transferring the charge generated in the photoelectric conversion layer 13 to the floating diffusion FD1, and is connected to the floating diffusion FD1 via, for example, the upper second contact 29B, the pad portion 39A, the upper first contact 29A, the through electrode 34, the connection portion 41A, and the lower second contact 46. The storage electrode 11B is for storing electrons as signal charges among the charges generated in the photoelectric conversion layer 13 in the semiconductor layer 17. The storage electrode 11B is provided in a region covering the light receiving surfaces of the inorganic photoelectric conversion units 32B and 32R formed in the semiconductor substrate 30, facing the light receiving surfaces of these units. The storage electrode 11B is preferably larger than the read electrode 11A, and thus can store a large amount of charge. As shown in FIG. 9, the voltage application circuit 60 is connected to the storage electrode 11B via wiring.

[0091] The insulating layer 16 serves to electrically separate the storage electrode 11B from the semiconductor layer 17. The insulating layer 16 is provided, for example, on the interlayer insulating layer 28 so as to cover the lower electrode 11. The insulating layer 16 has an opening 22H provided on the read electrode 11A of the lower electrode 11, and the read electrode 11A and the semiconductor layer 17 are electrically connected through the opening 22H. The insulating layer 16 is, for example, a single layer film made of one of silicon oxide, silicon nitride, and silicon oxynitride, or a laminated film made of two or more of these materials. The insulating layer 16 has a thickness of, for example, 20 nm to 500 nm.

[0092] The semiconductor layer 17 is provided below the photoelectric conversion layer 13, specifically between the insulating layer 16 and the buffer layer 12, and is for accumulating signal charges generated in the photoelectric conversion layer 13. The semiconductor layer 17 is preferably formed using a material having a higher charge mobility and a larger band gap than the photoelectric conversion layer 13. For example, the band gap of the material constituting the semiconductor layer 17 is preferably 3.0 eV or more. Examples of such materials include oxide semiconductor materials such as IGZO and organic semiconductor materials. Examples of organic semiconductor materials include transition metal dichalcogenides, silicon carbide, diamond, graphene, carbon nanotubes, condensed polycyclic hydrocarbon compounds, and condensed heterocyclic compounds. The thickness of the semiconductor layer 17 is, for example, 10 nm or more and 300 nm or less. By providing the semiconductor layer 17 made of the above material between the lower electrode 11 and the photoelectric conversion layer 13, it is possible to prevent recombination of charges during charge accumulation and improve transfer efficiency.

[0093] Similar to the image sensor 1A, the semiconductor substrate 30 has a second surface 30S2 of the p-well 31 provided with transfer transistors Tr2 (transfer transistor TR2trs), Tr3 (transfer transistor TR3trs), an amplifier transistor AMP, a reset transistor RST (reset transistor Tr1rst), and a selection transistor SEL (selection transistor TR1sel), etc.

[0094] The reset transistor RST (reset transistor Tr1rst) is composed of 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 a floating diffusion FD1. The other source / drain region 36C constituting the reset transistor Tr1rst is connected to a power supply line VDD.

[0095] The amplifier transistor AMP is composed of a gate Gamp, a channel forming region 35A, and source / drain regions 35B and 35C. The gate Gamp is connected to the read electrode 21A and one of the source / drain regions 36B (floating diffusion FD1) of the reset transistor Tr1rst via the lower first contact 45, the connection portion 41A, the lower second contact 46, the through electrode 34, etc. In addition, one of the source / drain regions 35B shares an area with the other of the source / drain regions 36C constituting the reset transistor Tr1rst, and is connected to the power supply line VDD.

[0096] The selection transistor SEL (selection 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 selection line SEL1. One source / drain region 34B shares an area with the other source / drain region 35C constituting the amplifier transistor AMP, and the other source / drain region 34C is connected to a signal line (data output line) VSL1.

[0097] The transfer transistor Tr2 (transfer transistor TR2trs) is for transferring the signal charge corresponding to blue generated and accumulated in the inorganic photoelectric conversion unit 32B to the floating diffusion FD2, and is connected to a transfer gate line TG2. The floating diffusion FD2 is provided in a region 37C in the vicinity of the gate Gtrs2 of the transfer transistor TR2trs. The charge accumulated in the inorganic photoelectric conversion unit 32B is read out to the floating diffusion FD2 via a transfer channel formed along the gate Gtrs2.

[0098] The transfer transistor Tr3 (transfer transistor TR3trs) is for transferring the signal charge corresponding to red generated and accumulated in the inorganic photoelectric conversion unit 32R to the floating diffusion FD3, and is connected to the transfer gate line TG3. The floating diffusion FD3 is provided in the region 38C near the gate Gtrs3 of the transfer transistor TR3trs. The charge accumulated in the inorganic photoelectric conversion unit 32R is read out to the floating diffusion FD3 via a transfer channel formed along the gate Gtrs3.

[0099] Further, a reset transistor TR2rst, an amplifier transistor TR2amp, and a selection transistor TR2sel constituting a control unit of the inorganic photoelectric conversion unit 32B are provided on the second surface 30S2 side of the semiconductor substrate 30. Further, a reset transistor TR3rst, an amplifier transistor TR3amp, and a selection transistor TR3sel constituting a control unit of the inorganic photoelectric conversion unit 32R are provided.

[0100] The reset transistor TR2rst is composed of a gate, a channel forming region, and a source / drain region. 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.

[0101] The amplifier transistor TR2amp is composed of a gate, a channel forming region, and a source / drain region. 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 an area with one of the source / drain regions constituting the reset transistor TR2rst, and is connected to the power supply line VDD.

[0102] The selection transistor TR2sel is composed of a gate, a channel formation region, and a source / drain region. The gate is connected to a selection line SEL2. One of the source / drain regions constituting the selection transistor TR2sel shares the region with the other of the source / drain regions constituting the amplifier transistor TR2amp. The other of the source / drain regions constituting the selection transistor TR2sel is connected to a signal line (data output line) VSL2.

[0103] The reset transistor TR3rst is composed of a gate, a channel forming region, and a source / drain region. 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.

[0104] The amplifier transistor TR3amp is composed of a gate, a channel forming region, and a source / drain region. 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 an area with one of the source / drain regions constituting the reset transistor TR3rst, and is connected to the power supply line VDD.

[0105] The selection transistor TR3sel is composed of a gate, a channel formation region, and a source / drain region. The gate is connected to a selection line SEL3. One of the source / drain regions constituting the selection transistor TR3sel shares the 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.

[0106] 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 the vertical drive circuits that constitute the drive circuits. The signal lines (data output lines) VSL1, VSL2, and VSL3 are connected to the column signal processing circuits that constitute the drive circuits.

[0107] The lower first contact 45, the lower second contact 46, the upper first contact 29A, the upper second contact 29B and the upper third contact 29C are made of, 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), tantalum (Ta), etc.

[0108] (1-4. Actions and Effects) In the photoelectric conversion element 10 of the present embodiment, buffer layers 12 and 14 containing at least two kinds of materials contained in the photoelectric conversion layer 13 are provided between the lower electrode 11 and the upper electrode 15, which are arranged opposite to each other, and the photoelectric conversion layer 13. This improves the bonding state between the photoelectric conversion layer 13 and the buffer layers 12 and 14. This will be described below.

[0109] As described above, a photoelectric conversion element has been disclosed in which an electron blocking layer and a hole blocking layer are provided between a pair of opposing electrodes and a photoelectric conversion layer, respectively, thereby improving sensitivity, the S / N ratio of the photoelectrode / dark current, and response speed.

[0110] However, the photoelectric conversion element does not have sufficient heat resistance, and for example, the electron blocking property or hole blocking property may be deteriorated by annealing during the manufacturing process, which may deteriorate the dark current characteristics. Specifically, the buffer material undergoes a phase transition due to heating. Alternatively, the bonding state between the photoelectric conversion layer and the buffer layer may deteriorate due to mixing or diffusion with other materials, making it impossible to obtain the desired characteristics.

[0111] In contrast, in the present embodiment, buffer layers 12 and 14 containing two or more materials contained in the photoelectric conversion layer 13, for example, a dye material constituting the photoelectric conversion layer 13 and an n-type semiconductor or a p-type semiconductor, are provided between the lower electrode 11 and the upper electrode 15, which are disposed opposite to each other, and the photoelectric conversion layer 13. This improves the affinity between the photoelectric conversion layer 13 and the buffer layers 12 and 14, and improves heat resistance. In addition, deterioration of the dark current after annealing is suppressed.

[0112] As described above, in the photoelectric conversion element 10 of the present embodiment, the buffer layers 12, 14 using two or more materials contained in the photoelectric conversion layer 13 are provided between the lower electrode 11 and the photoelectric conversion layer 13, and between the photoelectric conversion layer 13 and the upper electrode 15, respectively, so that the bonding state between the photoelectric conversion layer 13 and the buffer layers 12, 14 is improved. This improves heat resistance. In addition, deterioration of the dark current after annealing is suppressed. This makes it possible to provide a photoelectric conversion element 10 having high heat resistance and excellent electrical characteristics, and an imaging element 1 (1A, 1B) including the same.

[0113] In the present embodiment, one of the materials constituting the buffer layers 12 and 14 is, for example, a dye material contained in the photoelectric conversion layer 13, and further, a BODIPY dye having a molecular weight of 500 or more, subphthalocyanine or a derivative thereof, a metal complex having a dipyrromethene ligand, merocyanine or a derivative thereof, and perylene or a derivative thereof. This makes it possible to improve the afterimage characteristics as well as the dark current.

[0114] Furthermore, in this embodiment, for example, in the case where electrons are read out as signal charges as in the image sensor 1B shown in FIG. 7, as one material contained in the photoelectric conversion layer 13 constituting the buffer layer (buffer layer 12) functioning as an electron blocking layer, for example, fullerene C 60 or a derivative thereof, and further, as another material constituting the buffer layer 12, a material having an energy difference of 1.4 eV or more with the lower electrode 11 and a HOMO level deeper than 6.2 eV is used. This makes it possible to prevent the intrusion of holes from the lower electrode 11.

[0115] In the case of reading out electrons as signal charges as in the image sensor 1B shown in FIG. 7, the buffer layer 12 may be made of fullerene C 60 or its derivative has an energy difference of 1.7 eV or more with respect to the LUMO level, and fullerene C 60 By using a material having a HOMO level shallower than that of fullerene C or its derivative, charge generation in the buffer layer 12 is reduced. 60 Alternatively, by using a material whose LUMO level difference with respect to its derivative is greater than 0 and smaller than 0.5 eV, it is possible to reduce the trapping of charges (electrons) in the buffer layer 12.

[0116] Next, modified examples 1 to 3 and application examples of the present disclosure will be described. In the following, the same components as those in the above embodiment are given the same reference numerals, and the description thereof will be omitted as appropriate.

[0117] <2. Modifications> (2-1. Variation 1) 10 is a schematic diagram showing a cross-sectional configuration of an imaging element 1C according to the first modification of the present disclosure. The imaging element 1C is an imaging element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, similar to the imaging element 1A of the above-described embodiment. The imaging element 1C of this modification has two organic photoelectric conversion units 10, 80 and one inorganic photoelectric conversion unit 32 stacked in the vertical direction.

[0118] The organic photoelectric conversion units 10 and 80 and the inorganic photoelectric conversion unit 32 selectively detect light in different wavelength ranges and perform photoelectric conversion. For example, the organic photoelectric conversion unit 10 acquires a green (G) color signal. For example, the organic photoelectric conversion unit 80 acquires a blue (B) color signal. For example, the inorganic photoelectric conversion unit 32 acquires a red (R) color signal. This makes it possible for the image sensor 1C to acquire multiple types of color signals in one pixel without using a color filter.

[0119] In the organic photoelectric conversion unit 10, 80, the lower electrode 11, 81 is composed of a plurality of electrodes (for example, two electrodes, a readout electrode 11A, 81A and a storage electrode 11B, 81B), and between the lower electrode 11, 81 and the buffer layer 12, 82, for example, an insulating layer 16, 86 and a semiconductor layer 17, 87 are laminated in this order. Of the lower electrode 11, 81, the readout electrode 11A, 81A is electrically connected to the semiconductor layer 17, 87 through an opening 16H, 86H provided in the insulating layer 16, 86. In the image sensor 1C, for example, of the electron-hole pairs generated by photoelectric conversion, the electrons are read out as signal charges.

[0120] A through electrode 88 is connected to the readout electrode 81A, which penetrates the interlayer insulating layer 88 and the organic photoelectric conversion unit 10 and is electrically connected to the readout electrode 21A of the organic photoelectric conversion unit 10. Furthermore, the readout electrode 81A is electrically connected to a floating diffusion FD provided in the semiconductor substrate 30 via the through electrodes 34, 88, and can temporarily store charges generated in the photoelectric conversion layer 84. Furthermore, the readout electrode 81A is electrically connected to an amplifier transistor AMP and the like provided in the semiconductor substrate 20 via the through electrodes 34, 88.

[0121] (2-2. Variation 2) 11 illustrates a cross-sectional configuration of an image sensor 1D according to Modification 2 of the present disclosure. As with image sensor 1A of the above-described embodiment, image sensor 1D is an image sensor such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras. Image sensor 1D of this modification has a configuration in which red photoelectric conversion unit 70R, green photoelectric conversion unit 70G, and blue photoelectric conversion unit 70B are stacked in this order above semiconductor substrate 30.

[0122] The red photoelectric conversion unit 70R, the green photoelectric conversion unit 70G, and the blue photoelectric conversion unit 70B each have a photoelectric conversion layer 73R, 73G, and 73B between a pair of electrodes, specifically, between the lower electrode 71R and the upper electrode 75R, between the lower electrode 71G and the upper electrode 75G, and between the lower electrode 71B and the upper electrode 75B. As in the above embodiment, buffer layers 72R, 72G, and 72B are respectively provided between the lower electrode 71R and the photoelectric conversion layer 73R, between the lower electrode 71G and the photoelectric conversion layer 73G, and between the lower electrode 71B and the photoelectric conversion layer 73B. As in the above embodiment, buffer layers 74R, 74G, and 74B are respectively provided between the upper electrode 75R and the photoelectric conversion layer 73R, between the upper electrode 75G and the photoelectric conversion layer 73G, and between the upper electrode 75B and the photoelectric conversion layer 73B. By forming the buffer layers 72R, 72G, 72B and the buffer layers 74R, 74G, 74B to contain the two types of materials contained in the photoelectric conversion layers 73R, 73G, 73B, respectively, as in the above embodiment, it is possible to obtain the same effects as in the above embodiment.

[0123] As described above, the imaging element 1D has a configuration in which the red photoelectric conversion unit 70R, the green photoelectric conversion unit 70G, and the blue photoelectric conversion unit 70B are stacked in this order above the semiconductor substrate 30. Specifically, the red photoelectric conversion unit 70R is stacked on the semiconductor substrate 30 via an insulating layer 77. The green photoelectric conversion unit 70G is stacked on the red photoelectric conversion unit 70R via an insulating layer 78. The blue photoelectric conversion unit 70B is stacked on the green photoelectric conversion unit 70G via an insulating layer 79. On the blue photoelectric conversion unit 70B, an on-chip lens 52L is provided via a protective layer 51 and an on-chip lens layer 52. In the semiconductor substrate 30, a red storage layer 310R, a green storage layer 310G, and a blue storage layer 310B are provided. Light incident on the on-chip lens 52L is photoelectrically converted in the red photoelectric conversion unit 70R, the green photoelectric conversion unit 70G, and the blue photoelectric conversion unit 70B, and signal charges are sent from the red photoelectric conversion unit 70R to the red storage layer 310R, from the green photoelectric conversion unit 70G to the green storage layer 310G, and from the blue photoelectric conversion unit 70B to the blue storage layer 310B.

[0124] The semiconductor substrate 30 is made of, for example, a p-type silicon substrate. The red storage layer 310R, the green storage layer 310G, and the blue storage layer 310B provided on the semiconductor substrate 30 each include an n-type semiconductor region, and the signal charges (electrons) supplied from the red photoelectric conversion unit 70R, the green photoelectric conversion unit 70G, and the blue photoelectric conversion unit 70B are stored in the n-type semiconductor region. The n-type semiconductor regions of the red storage layer 310R, the green storage layer 310G, and the blue storage layer 310B are formed by doping the semiconductor substrate 30 with an n-type impurity such as phosphorus (P) or arsenic (As). The semiconductor substrate 30 may be provided on a support substrate (not shown) made of glass or the like.

[0125] The semiconductor substrate 30 is provided with pixel transistors for reading out electrons from the red storage layer 310R, the green storage layer 310G, and the blue storage layer 310B, and transferring them to, for example, a vertical signal line (vertical signal line Lsig in FIG. 18 described below). The floating diffusions of the pixel transistors are provided in the semiconductor substrate 30, and are connected to the red storage layer 310R, the green storage layer 310G, and the blue storage layer 310B. The floating diffusions are formed of n-type semiconductor regions.

[0126] The insulating layers 76, 77, 78 are made of, for example, silicon oxide, silicon nitride, silicon oxynitride, hafnium oxide, etc. The insulating layer 76 may be made by stacking a plurality of types of insulating films. The insulating layer 76 may be made of an organic insulating material. The insulating layer 76 is provided with plugs and electrodes for connecting the red storage layer 310R and the red photoelectric conversion unit 70R, the green storage layer 310G and the green photoelectric conversion unit 70G, and the blue storage layer 310B and the blue photoelectric conversion unit 70B, respectively. The insulating layers 77, 78 may be made of metal oxides, metal sulfides, or organic substances in addition to the above materials. Examples of metal oxides include aluminum oxide, zirconium oxide, titanium oxide, zinc oxide, tungsten oxide, magnesium oxide, niobium oxide, tin oxide, and gallium oxide. Examples of metal sulfides include zinc sulfide and magnesium sulfide. The band gap of the constituent material of the insulating layers 77, 78 is preferably 3.0 eV or more.

[0127] As described above, the present technology is not limited to the element structure in which one organic photoelectric conversion unit 10 and two inorganic photoelectric conversion units 32B, 32R are stacked vertically, as in the imaging devices 1A, 1B of the above-mentioned embodiments. The present technology can also be applied to an imaging device 1C in which two organic photoelectric conversion units 10, 80 and one inorganic photoelectric conversion unit 32 are stacked vertically, as described above, and an imaging device 1D in which three organic photoelectric conversion units (red photoelectric conversion unit 70R, green photoelectric conversion unit 70G, and blue photoelectric conversion unit 70B) are stacked vertically, and the same effects as those of the above-mentioned embodiments can be obtained.

[0128] (2-3. Variation 3) Fig. 12A is a schematic diagram of a cross-sectional configuration of an imaging element 1E according to Modification 3 of the present disclosure. Fig. 12B is a schematic diagram of an example of the planar configuration of the imaging element 1E shown in Fig. 12A, and Fig. 12A is a cross-section taken along line II shown in Fig. 12B. The imaging element 1E is, for example, a stacked imaging element in which an inorganic photoelectric conversion section 32 and an organic photoelectric conversion section 60 are stacked, and in the pixel section 1a, for example, as shown in Fig. 12B, four pixels arranged in two rows and two columns are used as pixel units, which are repeated as a pixel unit, and are repeatedly arranged in an array in the row and column directions.

[0129] In the imaging element 1E, for example, a color filter 53 is provided between the inorganic photoelectric conversion section 32 and the organic photoelectric conversion section 60. The color filter 53 has a configuration in which a color filter 53R that selectively transmits at least red light (R) and a color filter 53B that selectively transmits at least blue light (B) are arranged diagonally in the pixel unit 1a. The organic photoelectric conversion section 60 (photoelectric conversion layer 64) has a configuration similar to that of the above embodiment, for example, and is configured to selectively absorb a wavelength corresponding to green light (G). The inorganic photoelectric conversion section 32R (unit pixel Pr) in which the color filter 53R is arranged and the inorganic photoelectric conversion section 32B (unit pixel Pb) in which the color filter 53B is arranged detect red light (R) and blue light (B), respectively. In the imaging element 1E of this modification, the area of ​​each photoelectric conversion section of RGB can be enlarged compared to an imaging element having a general Bayer array, so that the S / N ratio can be improved.

[0130] <3. Application Examples> (Application example 1) 13 shows the overall configuration of an image sensor 1 (image sensors 1A and 1B) in which the photoelectric conversion element 10 described in the above embodiment is used for each pixel. The image sensor 1 is a CMOS image sensor, and has a pixel section 1a as an imaging area on a semiconductor substrate 30, and also has a peripheral circuit section 130 in the peripheral region of the pixel section 1a, which includes, for example, a row scanning section 131, a horizontal selection section 133, a column scanning section 134, and a system control section 132.

[0131] The pixel section 1a has, for example, a plurality of unit pixels P (corresponding to photoelectric conversion elements 10) arranged two-dimensionally in a matrix. In the unit pixels P, for example, a pixel drive line Lread (specifically, a row selection line and a reset control line) is wired for each pixel row, and a vertical signal line Lsig is wired for each pixel column. The pixel drive line Lread transmits a drive signal for reading out a signal from the pixel. One end of the pixel drive line Lread is connected to an output terminal of the row scanning section 131 corresponding to each row.

[0132] The row scanning unit 131 is a pixel driving unit that is configured with a shift register, an address decoder, etc., and drives each unit pixel P of the pixel unit 1a, for example, row by row. A signal output from each unit pixel P of a pixel row selected and scanned by the row scanning unit 131 is supplied to the horizontal selection unit 133 through each vertical signal line Lsig. The horizontal selection unit 133 is configured with an amplifier, a horizontal selection switch, etc., provided for each vertical signal line Lsig.

[0133] The column scanning unit 134 is composed of a shift register, an address decoder, etc., and sequentially drives while scanning each horizontal selection switch of the horizontal selection unit 133. By the selective scanning by this column scanning unit 134, the signals of each pixel transmitted through each vertical signal line Lsig are output in sequence to the horizontal signal line 135, and transmitted to the outside of the semiconductor substrate 30 through the horizontal signal line 135.

[0134] A circuit portion consisting of row scanning section 131, horizontal selection section 133, column scanning section 134, and horizontal signal line 135 may be formed directly on semiconductor substrate 30, or may be disposed in an external control IC. Moreover, these circuit portions may be formed on another substrate connected by a cable or the like.

[0135] The system control unit 132 receives a clock and data instructing an operation mode provided from outside the semiconductor substrate 30, and also outputs data such as internal information of the image sensor 1. The system control unit 132 further has a timing generator that generates various timing signals, and performs drive control of peripheral circuits such as the row scanning unit 131, horizontal selection unit 133, and column scanning unit 134 based on the various timing signals generated by the timing generator.

[0136] (Application example 2) The imaging element 1 can be applied to any type of electronic device with an imaging function, such as a camera system such as a digital still camera or video camera, or a mobile phone with an imaging function. Fig. 14 shows a schematic configuration of an electronic device 2 (camera) as an example. The electronic device 2 is, for example, a video camera capable of taking still or moving images, and includes the imaging element 1, an optical system (optical lens) 210, a shutter device 211, a drive unit 213 that drives the imaging element 1 and the shutter device 211, and a signal processing unit 212.

[0137] The optical system 210 guides image light (incident light) from a subject to the pixel section 1a of the image sensor 1. This optical system 210 may be composed of a plurality of optical lenses. The shutter device 211 controls the light irradiation period and the light blocking period of the image sensor 1. The drive section 213 controls the transfer operation of the image sensor 1 and the shutter operation of the shutter device 211. The signal processing section 212 performs various signal processing on the signal output from the image sensor 1. The video signal Dout after the signal processing is stored in a storage medium such as a memory, or is output to a monitor, etc.

[0138] <4. Application Examples> (Application example to endoscopic surgery system) The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

[0139] FIG. 15 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.

[0140] 15 shows a state in which an operator (doctor) 11131 is 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.

[0141] 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 illustrated example, the endoscope 11100 is configured as a so-called rigid scope having a rigid lens barrel 11101, but the endoscope 11100 may be configured as a so-called flexible scope having a flexible lens barrel.

[0142] 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 observation target in 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.

[0143] An optical system and an image sensor are provided inside the camera head 11102, and reflected light (observation light) from an observation target is collected on 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 an observation image. The image signal is transmitted to a camera control unit (CCU) 11201 as RAW data.

[0144] The CCU 11201 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and performs overall control of 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 types of image processing on the image signal, such as development processing (demosaic processing), for displaying an image based on the image signal.

[0145] 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.

[0146] The light source device 11203 is composed of a light source such as an LED (light emitting diode), and supplies the endoscope 11100 with irradiation light when photographing an operation site or the like.

[0147] 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 irradiated light, magnification, focal length, etc.) of the endoscope 11100.

[0148] 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 sends gas into the body cavity of the patient 11132 via the insufflation tube 11111 to inflate the body cavity for the purpose of securing the field of view of the endoscope 11100 and securing the working space of the surgeon. The recorder 11207 is a device capable of recording various information related to the surgery. The printer 11208 is a device capable of printing various information related to the surgery in various formats such as text, image, or graph.

[0149] The light source device 11203 that supplies irradiation light to the endoscope 11100 when photographing the surgical site can be composed of a white light source composed of, for example, an LED, a laser light source, or a combination of these. When the white light source is composed of a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, so that the white balance of the captured image can be adjusted in the light source device 11203. In this case, it is also possible to capture images corresponding to each of the RGB colors in a time-division manner by irradiating the observation object with laser light from each of the RGB laser light sources in a time-division manner and controlling the driving of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, a color image can be obtained without providing a color filter to the image sensor.

[0150] The light source device 11203 may be controlled to change the intensity of the light it outputs at predetermined time intervals. The driving of the image sensor of the camera head 11102 may be controlled in synchronization with the timing of the change in the light intensity to obtain images in a time-division manner, and the images may be synthesized to generate an image with a high dynamic range that is free of so-called blackout and whiteout.

[0151] The light source device 11203 may be configured to supply light of a predetermined wavelength band corresponding to the special light observation. In the special light observation, for example, by utilizing the wavelength dependency of light absorption in body tissue, a narrow band light is irradiated compared to the irradiated light (i.e., white light) during normal observation, and a predetermined tissue such as blood vessels on the mucous membrane surface is photographed with high contrast, so-called narrow band imaging is performed. Alternatively, in the special light observation, a fluorescent observation may be performed in which an image is obtained by fluorescence generated by irradiating an excitation light. In the fluorescent observation, it is possible to irradiate an excitation light to a body tissue and observe the fluorescence from the body tissue (autofluorescence observation), or to locally inject a reagent such as indocyanine green (ICG) into the body tissue and irradiate the body 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 corresponding to such special light observation.

[0152] FIG. 16 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG.

[0153] 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 by a transmission cable 11400 so as to be able to communicate with each other.

[0154] 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 configured by combining a plurality of lenses including a zoom lens and a focus lens.

[0155] The imaging unit 11402 may include one imaging element (so-called single-plate type) or multiple imaging elements (so-called multiple-plate type). When the imaging unit 11402 is configured as a multiple-plate type, for example, each imaging element may generate an image signal corresponding to each of RGB, and a color image may be obtained by combining the image 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. By performing a 3D display, the surgeon 11131 can more accurately grasp the depth of the biological tissue in the surgical site. Note that when the imaging unit 11402 is configured as a multiple-plate type, the lens unit 11401 may also be provided in multiple systems corresponding to each imaging element.

[0156] 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 behind the objective lens.

[0157] 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 appropriately adjusted.

[0158] The communication unit 11404 is configured by a communication device for transmitting and receiving various information to and from the CCU 11201. The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 to the CCU 11201 via the transmission cable 11400 as RAW data.

[0159] 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 capturing the image, and / or information specifying the magnification and focus of the captured image.

[0160] The image capturing conditions such as the frame rate, exposure value, magnification, and focus may be appropriately specified by a user, or may be automatically set by the control unit 11413 of the CCU 11201 based on an 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.

[0161] 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.

[0162] The communication unit 11411 is configured with a communication device for transmitting and receiving various information to and from the camera head 11102. The communication unit 11411 receives an image signal transmitted from the camera head 11102 via the transmission cable 11400.

[0163] 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.

[0164] The image processing unit 11412 performs various types of image processing on the image signal, which is RAW data sent from the camera head 11102 .

[0165] The control unit 11413 performs various controls related to imaging of the surgical site etc. by the endoscope 11100 and 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.

[0166] Further, the control unit 11413 causes the display device 11202 to display the captured image showing the surgical site, etc., based on the image signal that has been image-processed by the image processing unit 11412. At this time, the control unit 11413 may recognize various objects in the captured image using various image recognition techniques. For example, the control unit 11413 can recognize surgical tools such as forceps, specific living body parts, bleeding, mist when the energy treatment tool 11112 is used, etc., by detecting the shape and color of the edge of an object included in the captured image. When the control unit 11413 causes the display device 11202 to display the captured image, it may use the recognition result to superimpose various types of surgery support information on the image of the surgical site. By superimposing and presenting the surgery support information to the surgeon 11131, the burden on the surgeon 11131 can be reduced and the surgeon 11131 can proceed with the surgery reliably.

[0167] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable for communication of electrical signals, an optical fiber for optical communication, or a composite cable of these.

[0168] Here, 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.

[0169] An example of an endoscopic surgery system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to the imaging unit 11402 among the configurations described above. By applying the technology according to the present disclosure to the imaging unit 11402, detection accuracy is improved.

[0170] Although an endoscopic surgery system has been described as an example here, the technology disclosed herein may also be applied to other systems, such as a microsurgery system.

[0171] (Example of application to moving objects) The technology according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of moving body such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility device, an airplane, a drone, a ship, a robot, a construction machine, an agricultural machine (tractor), etc.

[0172] FIG. 17 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a moving object control system to which the technology according to the present disclosure can be applied.

[0173] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 17, 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, as functional configurations of the integrated control unit 12050, a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (interface) 12053 are illustrated.

[0174] 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.

[0175] The body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as head lamps, back lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves or signals of various switches transmitted from a portable device that replaces a key may be input to the body system control unit 12020. The body system control unit 12020 receives the input of these radio waves or signals and controls the door lock device, power window device, lamps, and the like of the vehicle.

[0176] 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 an image outside the vehicle and receives the captured image. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for a person, a car, an obstacle, a sign, or characters on a road surface, based on the received image.

[0177] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal according to the amount of light received. The imaging unit 12031 can output the electrical signal as an image, or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0178] 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.

[0179] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, the steering mechanism, or the braking device based on the information inside and outside the vehicle acquired by the outside-of-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output a control command to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane departure warning, etc.

[0180] 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 the driver's operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle acquired by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0181] 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-vehicle 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-vehicle information detection unit 12030, and perform cooperative control for the purpose of preventing glare, such as switching from high beams to low beams.

[0182] The audio / video output unit 12052 transmits at least one output signal of audio and video to an output device capable of visually or audibly notifying information to passengers in the vehicle or the outside of the vehicle. In the example of Fig. 17, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are exemplified as the output device. The display unit 12062 may include at least one of an on-board display and a head-up display, for example.

[0183] FIG. 18 is a diagram showing an example of the installation position of the imaging unit 12031.

[0184] In FIG. 18, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0185] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided at positions such as the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided at the front nose and the imaging unit 12105 provided at the upper part of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided at the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided at the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 provided at the upper part of the windshield inside the vehicle cabin is mainly used to detect a preceding vehicle, a pedestrian, an obstacle, a traffic light, a traffic sign, a lane, or the like.

[0186] 18 shows an example of the imaging ranges of the imaging units 12101 to 12104. An 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 an imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, an overhead image of the vehicle 12100 viewed from above is obtained by superimposing the image data captured by the imaging units 12101 to 12104.

[0187] At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera made up of a plurality of imaging elements, or may be an imaging element having pixels for detecting a phase difference.

[0188] For example, the microcomputer 12051 can extract, as a preceding vehicle, a three-dimensional object that is the closest three-dimensional object on the travel path of the vehicle 12100 and travels at a predetermined speed (for example, 0 km / h or more) in approximately the same direction as the vehicle 12100, by calculating the distance to each three-dimensional object in the imaging ranges 12111 to 12114 and the change over time of this distance (relative speed with respect to the vehicle 12100) based on the distance information obtained from the imaging units 12101 to 12104. Furthermore, the microcomputer 12051 can set a vehicle distance to be secured in advance in front of the preceding vehicle, and perform automatic brake control (including follow-up stop control) and automatic acceleration control (including follow-up start control). In this way, cooperative control can be performed for the purpose of automatic driving that travels autonomously without relying on the driver's operation.

[0189] For example, the microcomputer 12051 classifies and extracts three-dimensional object data on 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. Then, the microcomputer 12051 determines a collision risk indicating 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.

[0190] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether or not a pedestrian is present in the captured images of the imaging units 12101 to 12104. The recognition of such a pedestrian is performed, for example, by a procedure of extracting feature points in the captured images of the imaging units 12101 to 12104 as infrared cameras, and a procedure of performing pattern matching processing on a series of feature points that indicate the contour of an object to determine whether or not the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the captured images of the imaging units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating a pedestrian at a desired position.

[0191] <5. Examples> Next, an embodiment of the present disclosure will be described.

[0192] (Experiment 1) In experiment 1, an evaluation device (photoelectric conversion element) having an n-buffer layer containing one (Experimental Example 1-1) or two (Experimental Example 1-2) materials contained in the photoelectric conversion layer was fabricated, and the dark current characteristics were evaluated before and after heating.

[0193] First, a glass substrate on which an ITO electrode (lower electrode) with a thickness of 50 nm was provided was cleaned by UV / ozone treatment. Then, the glass substrate was transferred to a vacuum deposition machine and a 1×10 -5While rotating the substrate holder under a reduced pressure of 0.1 Pa or less, a p-buffer layer having a thickness of 10 nm, a photoelectric conversion layer having a thickness of 200 nm, and an n-buffer layer having a thickness of 10 nm were successively formed on the glass substrate by using a resistance heating method. In this case, in Experimental Example 1-1, the n-buffer layer was formed using one of the constituent materials of the photoelectric conversion layer. In Experimental Example 1-2, the n-buffer layer was formed using two of the constituent materials of the photoelectric conversion layer. Next, an ITO electrode (upper electrode) having a thickness of 50 nm was formed on the n-buffer layer. As a result of the above, a photoelectric conversion element having a photoelectric conversion area of ​​1 mm x 1 mm was produced.

[0194] The dark current characteristics were evaluated using a semiconductor parameter analyzer. Specifically, the amount of light irradiated from a light source through a filter onto the photoelectric conversion element was set to 1.62 μW / cm. 2 When the bias voltage applied between the electrodes is 10 V, the current value (light current value) and the light intensity are 0 μW / cm 2 The current values ​​(dark current values) in the above cases were measured, and the dark current characteristics were calculated from these values. The wavelength of light irradiated to the element was selected to be equivalent to the maximum absorption wavelength in the visible range of each photoelectric conversion layer.

[0195] Table 1 summarizes the changes in dark current characteristics before and after heating in Experimental Example 1-1 and Experimental Example 1-2. The values ​​in Table 1 are relative values ​​when the dark current characteristics before heating in Experimental Example 1-1 are set to 1.0. In Experimental Example 1-1, in which an n-buffer layer was fabricated using one of the constituent materials of the photoelectric conversion layer, a deterioration in dark current characteristics of two or more orders of magnitude was confirmed before and after heating. On the other hand, in Experimental Example 1-2, in which an n-buffer layer was fabricated using two of the constituent materials of the photoelectric conversion layer, the change in dark current characteristics before and after heating was one order of magnitude or less. That is, it was found that the heat resistance of the buffer layer can be improved by using two or more constituent materials of the photoelectric conversion layer as the constituent material of the buffer layer.

[0196] [Table 1]

[0197] (Experiment 2) In experiment 2, an evaluation device (photoelectric conversion element) was fabricated using a dye material contained in the photoelectric conversion layer as one of the materials constituting the n-buffer layer, and the dark current characteristics were evaluated before and after heating.

[0198] (Experimental Example 2-1) First, in Experimental Example 2-1, a glass substrate on which an ITO electrode (lower electrode) having a thickness of 50 nm was provided was cleaned by UV / ozone treatment. Then, the glass substrate was transferred to a vacuum deposition machine and 1×10 -5 While rotating the substrate holder under reduced pressure of 0.1 Pa or less, a 10 nm thick p-buffer layer, a 200 nm thick photoelectric conversion layer, and a 10 nm thick n-buffer layer were successively formed on the glass substrate by resistance heating. 60 A film was formed using BODIPY dye A having a molecular weight of 483.02 and represented by the following formula (1-1). Next, an ITO electrode (upper electrode) having a thickness of 50 nm was formed on the n-buffer layer. In this way, a photoelectric conversion element having a photoelectric conversion area of ​​1 mm x 1 mm was produced.

[0199] (Experimental Example 2-2) A photoelectric conversion element was prepared in the same manner as in Experimental Example 2-1, except that BODIPY dye B having a molecular weight of 594.38 and represented by the following formula (1-2) was used instead of BODIPY dye A used in Experimental Example 2-1.

[0200] (Experimental Example 2-3) A photoelectric conversion element was prepared in the same manner as in Experimental Example 2-1, except that BODIPY dye C having a molecular weight of 699.35 and represented by the following formula (1-3) was used instead of BODIPY dye A used in Experimental Example 2-1.

[0201] (Experimental Example 2-4) A photoelectric conversion element was prepared in the same manner as in Experimental Example 2-1, except that BODIPY dye D represented by the following formula (1-4) and having a molecular weight of 706.46 was used instead of BODIPY dye A used in Experimental Example 2-1.

[0202] (Experimental Example 2-5) A photoelectric conversion element was prepared in the same manner as in Experimental Example 2-1, except that a subphthalocyanine derivative having a molecular weight of 632.24 and represented by the following formula (2-1) was used instead of the BODIPY dye A used in Experimental Example 2-1.

[0203] (Experimental Example 2-6) A photoelectric conversion element was prepared in the same manner as in Experimental Example 2-1, except that a merocyanine derivative having a molecular weight of 430.34 and represented by the following formula (3) was used instead of the BODIPY dye A used in Experimental Example 2-1.

[0204] (Experimental Example 2-7) A photoelectric conversion element was prepared in the same manner as in Experimental Example 2-1, except that a zinc complex having a molecular weight of 988.21 and represented by the following formula (1-5) was used instead of the BODIPY dye A used in Experimental Example 2-1.

[0205] (Experimental Example 2-8) In Experimental Example 2-8, a photoelectric conversion element was prepared using the same method as in Experimental Example 2-1, except that a p-buffer layer was formed using a benzodithiophene derivative and the following formula (4-1), and an n-buffer layer was formed using a naphthalene diimide (NDI) derivative.

[0206] [ka]

[0207] [ka]

[0208] Table 2 summarizes the dye material and its molecular weight used as one material of the n buffer layer in Experimental Example 2-1 to Experimental Example 2-7 and one material of the p buffer layer in Experimental Example 2-8, as well as the change in dark current characteristics before and after heating. The dark current characteristics before and after heating in each of Experimental Examples 2-1 to 2-8 were calculated from the current value when the bias voltage applied between the electrodes was 2.6 V, and the values ​​in Table 2 are relative values ​​when the dark current characteristic before heating in Experimental Example 2-6 is set to 1.0.

[0209] [Table 2]

[0210] From Table 2, it was found that, compared with Experimental Example 2-6 in which a merocyanine derivative having a molecular weight of 430.34 was used as a material constituting the n-buffer layer, Experimental Example 2-2 to Experimental Example 2-5 and Experimental Example 2-7 in which a BODIPY dye, a subphthalocyanine derivative, or a zinc complex was used had improved dark current characteristics before and after heating. On the other hand, in Experimental Example 2-1, a large deterioration in dark current characteristics was confirmed before and after heating. Also, in Experimental Example 2-8 in which a perylene derivative was used as a material constituting the p-buffer layer, it was found that the dark current characteristics were improved before and after heating, similar to Experimental Examples 2-2 to 2-5 and 2-7. From the above, it was found that the dark current characteristics can be improved by using a BODIPY dye, a subphthalocyanine derivative, or a zinc complex as a material constituting the n-buffer layer, or by using a perylene derivative as a material constituting the p-buffer layer, and further, it was found that the heat resistance can be further improved by using a BODIPY dye, a subphthalocyanine derivative, a zinc complex, or a perylene derivative having a molecular weight of 500 or more.

[0211] Although not shown here, the same results as those of Experimental Example 2-2 to Experimental Example 2-5 and Experimental Example 2-7 were obtained for merocyanine derivatives having a molecular weight of 500 or more. The same results as those of the dark current characteristics were obtained for the afterimage characteristics. That is, it was found that the afterimage characteristics can be improved while improving the heat resistance by using a BODIPY dye, a subphthalocyanine derivative, a zinc complex or a merocyanine derivative as one of the materials constituting the n-buffer layer, or a perylene derivative as one of the materials constituting the p-buffer layer, and further by using a BODIPY dye, a subphthalocyanine derivative, a zinc complex, a merocyanine derivative or a perylene derivative having a molecular weight of 500 or more among them.

[0212] Although the above describes the embodiments, modifications, examples, and application examples, the present disclosure is not limited to the above embodiments, and various modifications are possible. For example, the number and ratio of the organic photoelectric conversion unit and the inorganic photoelectric conversion unit are not limited, and two or more organic photoelectric conversion units may be provided, or color signals of multiple colors may be obtained by the organic photoelectric conversion unit alone. Furthermore, the organic photoelectric conversion unit and the inorganic photoelectric conversion unit are not limited to a structure in which they are stacked vertically, and may be arranged in parallel along the substrate surface.

[0213] In addition, although the above-mentioned embodiment and the like have exemplified the configuration of a back-illuminated solid-state imaging device, the present disclosure is also applicable to a front-illuminated solid-state imaging device. Furthermore, the photoelectric conversion element of the present disclosure does not need to include all of the components described in the above-mentioned embodiment, and conversely, may include other layers.

[0214] Furthermore, in the above embodiment, the imaging element 1 is configured by stacking an organic photoelectric conversion unit (photoelectric conversion element 10) that detects green light, and inorganic photoelectric conversion units 32B and 32R that detect blue light and red light, respectively, but the present disclosure is not limited to such a structure. For example, the photoelectric conversion element 10 may detect wavelengths in the visible light region (e.g., 400 nm or more and 760 nm or less), and the inorganic photoelectric conversion unit embedded in the semiconductor substrate 30 may detect wavelengths in the infrared light region (e.g., 700 nm or more and 1000 nm or less).

[0215] Furthermore, in the above-described embodiment and the like, an example has been given in which the photoelectric conversion element 10 is used as the imaging element constituting the imaging device 1, but the photoelectric conversion element 10 of the present disclosure may be applied to a solar cell.

[0216] It should be noted that the effects described in this specification are merely examples and are not limiting, and other effects may also be obtained.

[0217] The present disclosure may also have the following configuration. According to the present technology having the following configuration, a first electrode and a photoelectric conversion layer disposed opposite each other are provided. a first buffer layer on the Between the second electrode and the photoelectric conversion layer and a second buffer layer is provided on each of the first and second organic semiconductor materials, the second organic semiconductor material being a dye material contained in the photoelectric conversion layer, and the third organic semiconductor material being a dye material. Therefore, the photoelectric conversion layer Second buffer layer Therefore, the bonding state with the electrode is improved, and it is possible to improve the heat resistance and the electrical characteristics. [1] A first electrode; a second electrode disposed opposite the first electrode; provided between the first electrode and the second electrode The organic semiconductor material includes a first organic semiconductor material which is a dye material, a second organic semiconductor material which is an n-type semiconductor having electron transport properties, and a third organic semiconductor material which is a p-type semiconductor having hole transport properties. A photoelectric conversion layer; Between the first electrode and the photoelectric conversion layer a first buffer layer provided on the a second buffer layer provided between the second electrode and the photoelectric conversion layer; the second buffer layer includes two types of materials contained in the photoelectric conversion layer, namely, the first organic semiconductor material and the second organic semiconductor material or the third organic semiconductor material; The dye material is any one of BODIPY dye B represented by the following formula (1-2), BODIPY dye C represented by the following formula (1-3), BODIPY dye D represented by the following formula (1-4), a subphthalocyanine derivative represented by the following formula (2-1), a merocyanine derivative represented by the following formula (3), a zinc complex represented by the following formula (1-5), and a perylene derivative represented by the following formula (4-1). Photoelectric conversion element. [ka] [2] The second organic semiconductor material is fullerene C60 and its derivatives. [1] The photoelectric conversion element according to claim 1. [3] the first buffer layer contains two kinds of organic semiconductor materials, the second organic semiconductor material and the first organic semiconductor material or the third organic semiconductor material; The work function of the first electrode; The first buffer layer a difference between the highest occupied molecular orbital (HOMO) level of the first organic semiconductor material or the third organic semiconductor material contained in the first organic semiconductor material and the highest occupied molecular orbital (HOMO) level of the third organic semiconductor material is 1.4 eV or more; [1] or [2] above The photoelectric conversion element according to claim 1. [4] the first buffer layer contains two kinds of organic semiconductor materials, the second organic semiconductor material and the first organic semiconductor material or the third organic semiconductor material; the LUMO level of the second organic semiconductor material; The first buffer layer The difference between the HOMO level of the first organic semiconductor material or the HOMO level of the third organic semiconductor material is 1.7 eV or more. Any one of the above [1] to [3] The photoelectric conversion element according to claim 1. [5] the first buffer layer contains two kinds of organic semiconductor materials, the second organic semiconductor material and the first organic semiconductor material or the third organic semiconductor material; a difference in a Lowest Unoccupied Molecular Orbital (LUMO) level between the second organic semiconductor material and the first organic semiconductor material or the third organic semiconductor material is 0 or more and 0.5 eV or less; Any one of the above [1] to [4] The photoelectric conversion element according to claim 1. [6] a plurality of pixels each having a photoelectric conversion element as one or more organic photoelectric conversion units; The photoelectric conversion element is A first electrode; a second electrode disposed opposite the first electrode; provided between the first electrode and the second electrode The organic semiconductor material includes a first organic semiconductor material which is a dye material, a second organic semiconductor material which is an n-type semiconductor having electron transport properties, and a third organic semiconductor material which is a p-type semiconductor having hole transport properties. A photoelectric conversion layer; Between the first electrode and the photoelectric conversion layer a first buffer layer provided on the a second buffer layer provided between the second electrode and the photoelectric conversion layer; the second buffer layer includes two types of materials contained in the photoelectric conversion layer, namely, the first organic semiconductor material and the second organic semiconductor material or the third organic semiconductor material; The dye material is any one of BODIPY dye B represented by the following formula (1-2), BODIPY dye C represented by the following formula (1-3), BODIPY dye D represented by the following formula (1-4), a subphthalocyanine derivative represented by the following formula (2-1), a merocyanine derivative represented by the following formula (3), a zinc complex represented by the following formula (1-5), and a perylene derivative represented by the following formula (4-1). Image sensor. [ka] [7] Each pixel has one or more of the organic photoelectric conversion units and one or more inorganic photoelectric conversion units that perform photoelectric conversion in a wavelength range different from that of the organic photoelectric conversion units stacked therein. [6] The imaging element according to claim 1. [8] The inorganic photoelectric conversion unit is formed by embedding the inorganic photoelectric conversion unit in a semiconductor substrate, The organic photoelectric conversion unit is formed on a first surface side of the semiconductor substrate. [7] The imaging element according to claim 1. [9] the semiconductor substrate has a second surface opposite to the first surface, and a multilayer wiring layer is formed on the second surface side; [8] The imaging element according to claim 1.

[10] the organic photoelectric conversion unit performs photoelectric conversion in the visible light region, The inorganic photoelectric conversion unit performs photoelectric conversion in the infrared region. Any one of the above [7] to [9] The imaging element according to claim 1.

[11] A first electrode; a second electrode disposed opposite the first electrode; a photoelectric conversion layer provided between the first electrode and the second electrode; a buffer layer provided between the first electrode and the photoelectric conversion layer and included in the photoelectric conversion layer, the buffer layer including a first organic semiconductor material made of a dye material and a second organic semiconductor material; A photoelectric conversion element comprising:

[12] The second organic semiconductor material is fullerene C 60 or a derivative thereof.

[11] The photoelectric conversion element according to claim 1.

[13] A first electrode; a second electrode disposed opposite the first electrode; a photoelectric conversion layer provided between the first electrode and the second electrode; A fullerene C provided between the first electrode and the photoelectric conversion layer and contained in the photoelectric conversion layer. 60 and a buffer layer including a second organic semiconductor material having a LUMO level that is greater than or equal to 0 and less than or equal to 0.5 eV and has a difference in LUMO level from that of the first organic semiconductor material. A photoelectric conversion element comprising:

[14] the buffer layer is provided between the first electrode and the photoelectric conversion layer, a difference between a work function of the first electrode and a highest occupied molecular orbital (HOMO) level of the first organic semiconductor material is 1.4 eV or more, and a HOMO level of the second organic semiconductor material is deeper than 6.2 eV;

[13] The photoelectric conversion element according to claim 1.

[15] a difference between a LUMO level of the first organic semiconductor material and a HOMO level of the second organic semiconductor material is 1.7 eV or more, and the HOMO level of the first organic semiconductor material is shallower than the HOMO level of the second organic semiconductor material;

[13] or

[14] above The photoelectric conversion element according to claim 1. [Explanation of symbols]

[0218] 1, 1A, 1B, 1C, 1D, 1E...imaging element, 2...electronic device (camera), 10...photoelectric conversion element, 11...lower electrode, 11A...readout electrode, 11B...storage electrode, 12, 14...buffer layer, 13...photoelectric conversion layer, 15...upper electrode, 30...semiconductor substrate, 31...p-well, 32R, 32B...inorganic photoelectric conversion section, 26, 27...insulating film, 28...interlayer insulating layer, 30...semiconductor substrate, 31...p-well, 32B, 32R...inorganic photoelectric conversion section, 33...gate insulating layer, 34...through electrode, 40...multilayer wiring layer, 41, 42, 43...wiring layer, 41A...connection section, 45...lower first contact, 46...lower second contact, 47...gate wiring layer, 51...protective layer, 52...on-chip lens layer, 52L...on-chip lens, 53...light-shielding film.

Claims

1. A first electrode; a second electrode disposed opposite the first electrode; a photoelectric conversion layer provided between the first electrode and the second electrode, the photoelectric conversion layer including a first organic semiconductor material which is a dye material, a second organic semiconductor material which is an n-type semiconductor having an electron transport property, and a third organic semiconductor material which is a p-type semiconductor having a hole transport property; a first buffer layer provided between the first electrode and the photoelectric conversion layer; a second buffer layer provided between the second electrode and the photoelectric conversion layer; the second buffer layer includes two kinds of materials contained in the photoelectric conversion layer, that is, the first organic semiconductor material and the second organic semiconductor material or the third organic semiconductor material; The dye material is any one of BODIPY dye B represented by the following formula (1-2), BODIPY dye C represented by the following formula (1-3), BODIPY dye D represented by the following formula (1-4), a subphthalocyanine derivative represented by the following formula (2-1), a merocyanine derivative represented by the following formula (3), a zinc complex represented by the following formula (1-5), and a perylene derivative represented by the following formula (4-1). Photoelectric conversion element. 【Chemistry 1】

2. The photoelectric conversion element according to claim 1 , wherein the second organic semiconductor material is fullerene C60 or a derivative thereof.

3. The first buffer layer includes two types of organic semiconductor material, the second organic semiconductor material and the first organic semiconductor material or the third organic semiconductor material; 2. The photoelectric conversion element according to claim 1, wherein a difference between a work function of the first electrode and a highest occupied molecular orbital (HOMO) level of the first organic semiconductor material or the third organic semiconductor material contained in the first buffer layer is 1.4 eV or more.

4. The first buffer layer includes two types of organic semiconductor material, the second organic semiconductor material and the first organic semiconductor material or the third organic semiconductor material; 2. The photoelectric conversion element according to claim 1, wherein a difference between a LUMO level of the second organic semiconductor material and a HOMO level of the first organic semiconductor material or the third organic semiconductor material contained in the first buffer layer is 1.7 eV or more.

5. The first buffer layer includes two types of organic semiconductor material, the second organic semiconductor material and the first organic semiconductor material or the third organic semiconductor material; 2 . The photoelectric conversion element according to claim 1 , wherein a difference in a Lowest Unoccupied Molecular Orbital (LUMO) level between the second organic semiconductor material and the first organic semiconductor material or the third organic semiconductor material is 0 to 0.5 eV.

6. a plurality of pixels each having a photoelectric conversion element as one or a plurality of organic photoelectric conversion units; The photoelectric conversion element is A first electrode; a second electrode disposed opposite the first electrode; a photoelectric conversion layer provided between the first electrode and the second electrode, the photoelectric conversion layer including a first organic semiconductor material which is a dye material, a second organic semiconductor material which is an n-type semiconductor having an electron transport property, and a third organic semiconductor material which is a p-type semiconductor having a hole transport property; a first buffer layer provided between the first electrode and the photoelectric conversion layer; a second buffer layer provided between the second electrode and the photoelectric conversion layer; the second buffer layer includes two kinds of materials contained in the photoelectric conversion layer, that is, the first organic semiconductor material and the second organic semiconductor material or the third organic semiconductor material; The dye material is any one of BODIPY dye B represented by the following formula (1-2), BODIPY dye C represented by the following formula (1-3), BODIPY dye D represented by the following formula (1-4), a subphthalocyanine derivative represented by the following formula (2-1), a merocyanine derivative represented by the following formula (3), a zinc complex represented by the following formula (1-5), and a perylene derivative represented by the following formula (4-1). Image sensor. 【Chemistry 2】

7. The imaging element according to claim 6 , wherein each pixel includes one or more of the organic photoelectric conversion units and one or more inorganic photoelectric conversion units that perform photoelectric conversion in a wavelength range different from that of the organic photoelectric conversion units.

8. The inorganic photoelectric conversion unit is formed by embedding the inorganic photoelectric conversion unit in a semiconductor substrate, The imaging element according to claim 7 , wherein the organic photoelectric conversion section is formed on a first surface side of the semiconductor substrate.

9. 9. The image sensor according to claim 8, wherein the semiconductor substrate has a second surface opposite to the first surface, and a multilayer wiring layer is formed on the second surface side.

10. the organic photoelectric conversion unit performs photoelectric conversion in the visible light region, The image sensor according to claim 7 , wherein the inorganic photoelectric conversion section performs photoelectric conversion in an infrared light region.

Images