JP2017005196A - Solid-state imaging device and method for manufacturing solid-state imaging device, photoelectric conversion device, imaging device, electronic device, and photoelectric conversion device. - Google Patents

Abstract

Proper photoelectric conversion is performed with high spectral characteristics and high photoelectric conversion efficiency for light of a specific wavelength.
A photoelectric conversion layer that photoelectrically converts incident light, a hole transport layer that transports holes to the photoelectric conversion layer, and an electron transport layer that transports electrons to the photoelectric conversion layer are a pair of electrodes. The photoelectric conversion layer, which is laminated between them, is composed of a layered organic perovskite material that selectively absorbs light only in a specific wavelength region. The present technology can be applied to a solid-state imaging device.
[Selection] Figure 6

Description

  The present technology relates to a solid-state imaging device, a method for manufacturing the solid-state imaging device, a photoelectric conversion device, an imaging apparatus, an electronic device, and a photoelectric conversion device, and in particular, a solid-state imaging device that can realize photoelectric conversion using light of a specific wavelength. The present invention relates to a method for manufacturing a solid-state imaging element, a photoelectric conversion element, an imaging apparatus, an electronic device, and a photoelectric conversion element.

  There is a need for a vertical spectral imager called a vertical spectral solid-state imaging device that requires high color reproducibility. In order to realize this vertical spectral imager, not only high photoelectric conversion characteristics but also high selective spectral properties are required.

  As the vertical spectroscopic solid-state imaging device, one using a silicon (Si) material is known.

  However, in a vertical spectral solid-state imaging device using a silicon material, since the light absorption coefficient is small, it is necessary to increase the film thickness. There was a limit to the characteristics.

  Therefore, in recent years, a vertical spectroscopic solid-state imaging device having a multilayer structure in which photoelectric conversion films formed of organic materials are stacked has been proposed.

  For example, a solid-state imaging device in which organic photoelectric conversion films that respectively absorb blue light, green light, and red light are sequentially stacked is disclosed (see Patent Document 1). In the solid-state imaging device disclosed in Patent Document 1, light of each color is extracted by photoelectrically converting light corresponding to each color in each organic photoelectric conversion film.

  In addition, a solid-state imaging device in which an organic photoelectric conversion film that absorbs green light and a silicon photodiode are sequentially stacked is disclosed (see Patent Document 2). In the solid-state imaging device disclosed in Patent Document 2, a green light signal is extracted by an organic photoelectric conversion film, and a blue light signal and a red light signal are separated by using a difference in light penetration depth by a silicon photodiode. Has been removed.

  Furthermore, a photoelectric conversion element for a solar cell using a 3D organic perovskite material that is a hybrid material of an organic material and an inorganic material is known as a photoelectric conversion element exhibiting high photoelectric conversion efficiency (see Non-Patent Document 1).

JP 2003-234460 A JP 2005-303266 A

Scientific reports 2: 591 (2012) Published 21 August 2012

  However, in any of the organic photoelectric conversion films of Patent Documents 1 and 2 described above, photoelectric conversion cannot be performed after the light of each color is sufficiently selectively spectrally separated.

  In addition, the 3D type organic perovskite material used in the technology of Non-Patent Document 1 absorbs the entire visible light region, and its absorption on the long wavelength side is moderate and the wavelength steepness is low. Therefore, it was difficult to perform spectroscopic conversion after effective selective spectroscopy.

  For this reason, a method of attaching a color filter can be considered, but the cost becomes high. Moreover, since it is necessary to use it as a vertical spectroscopic element, if a color filter is used, the sensitivity of a required spectral characteristic cannot be obtained, so that the color filter cannot be used essentially.

  The present technology has been made in view of such a situation, and in particular, enables photoelectric conversion with high selectivity to light of a specific wavelength and high photoelectric conversion efficiency.

  A solid-state imaging device according to one aspect of the present technology includes a photoelectric conversion layer that photoelectrically converts incident light, a hole transport layer that transports holes to the photoelectric conversion layer, and an electron that transports electrons to the photoelectric conversion layer. An electron transport layer and a pair of electrodes, wherein the photoelectric conversion layer, the hole transport layer, and the electron transport layer are stacked between the pair of electrodes, and the photoelectric conversion layer has a specific wavelength It consists of a layered organic perovskite material that selectively absorbs light only in the region.

  The layered organic perovskite material may be (RNH3) n-Metal-X (2 + n), and R is at least one of aromatic or heterocyclic compounds having a primary amine. The metal may be a metal including at least one of Pb, Sn, and Mn, and the X includes at least one of F, Cl, Br, and I. Halogen may be used, and n may be a natural number.

  With the structure of R, it is possible to control the absorption wavelength maximum peak and the absorption wavelength distribution shape of light in a specific wavelength region that is selectively absorbed in the layered organic perovskite material.

  The electron transport layer may contain any one of TiO2, NiO, WO3, and TA2O5.

  The hole transport layer may contain any of Spiro-OMeTAD, TiO2, ZnO, and SnO2.

  A method of manufacturing a solid-state imaging device according to one aspect of the present technology includes: a first step of forming a first electrode; and an electron transport layer that transports electrons to the photoelectric conversion layer on an upper layer of the first electrode. A third step of forming the photoelectric conversion layer made of a layered organic perovskite material that selectively absorbs light only in a specific wavelength region, on the upper layer of the electron transport layer, and A fourth step of forming a hole transport layer for transporting holes to the photoelectric conversion layer for photoelectric conversion of incident light on the photoelectric conversion layer; and a second electrode on the hole transport layer. Forming a fifth step.

  The photoelectric conversion element according to one aspect of the present technology includes a photoelectric conversion layer that photoelectrically converts incident light, a hole transport layer that transports holes to the photoelectric conversion layer, and an electron that transports electrons to the photoelectric conversion layer. An electron transport layer and a pair of electrodes, wherein the photoelectric conversion layer, the hole transport layer, and the electron transport layer are stacked between the pair of electrodes, and the photoelectric conversion layer has a specific wavelength It consists of a layered organic perovskite material that selectively absorbs light only in the region.

  An imaging device according to an aspect of the present technology includes a photoelectric conversion layer that photoelectrically converts incident light, a hole transport layer that transports holes to the photoelectric conversion layer, and an electron that transports electrons to the photoelectric conversion layer. An electron transport layer and a pair of electrodes, wherein the photoelectric conversion layer, the hole transport layer, and the electron transport layer are stacked between the pair of electrodes, and the photoelectric conversion layer has a specific wavelength region It consists of a layered organic perovskite material that selectively absorbs only light.

  An electronic device according to one aspect of the present technology includes a photoelectric conversion layer that photoelectrically converts incident light, a hole transport layer that transports holes to the photoelectric conversion layer, and an electron that transports electrons to the photoelectric conversion layer. An electron transport layer and a pair of electrodes, wherein the photoelectric conversion layer, the hole transport layer, and the electron transport layer are stacked between the pair of electrodes, and the photoelectric conversion layer has a specific wavelength region It consists of a layered organic perovskite material that selectively absorbs only light.

  The photoelectric conversion element according to one aspect of the present technology includes a photoelectric conversion layer that photoelectrically converts incident light, a hole transport layer that transports holes to the photoelectric conversion layer, and an electron that transports electrons to the photoelectric conversion layer. An electron transport layer and a pair of electrodes, wherein the photoelectric conversion layer, the hole transport layer, and the electron transport layer are stacked between the pair of electrodes, and the photoelectric conversion layer has a specific wavelength It consists of a layered organic perovskite material that selectively absorbs light only in the region.

  In one aspect of the present technology, incident light is photoelectrically converted by the photoelectric conversion layer, holes are transported to the photoelectric conversion layer by the hole transport layer, and to the photoelectric conversion layer by the electron transport layer. Electrons are transported, and the photoelectric conversion layer, the hole transport layer, and the electron transport layer are stacked between a pair of electrodes, and the photoelectric conversion layer selectively selects light only in a specific wavelength region. It is formed of a layered organic perovskite material that absorbs in water.

  According to one aspect of the present technology, it is possible to appropriately photoelectrically convert light having a specific wavelength with high spectral characteristics and high photoelectric conversion efficiency.

It is a figure explaining the example of composition of one embodiment of the solid-state image sensing device to which this art is applied. It is a figure which shows the SEM observation result of the spin coat by a layered organic perovskite material. It is a figure explaining the spectral characteristic of the photoelectric conversion element which consists of a layered organic perovskite material. It is a figure explaining the photoelectric conversion characteristic of the photoelectric conversion element which consists of layered organic perovskite material. It is a figure explaining the voltage-current characteristic of the photoelectric conversion element which consists of a layered organic perovskite material. It is a figure explaining the structural example of the photoelectric conversion element which consists of layered organic perovskite material. It is a flowchart explaining the manufacturing method of the photoelectric conversion element which consists of a layered organic perovskite material. It is the schematic which shows the structure of the solid-state image sensor to which the photoelectric conversion element which concerns on this technique is applied. It is sectional drawing which showed the outline in the unit pixel of the solid-state image sensor to which the photoelectric conversion element which concerns on this technique was applied. It is a block diagram explaining the composition of the electronic equipment to which the photoelectric conversion element concerning this art is applied.

<Configuration example of embodiment of solid-state imaging device to which the present technology is applied>
FIG. 1 is a diagram illustrating a configuration example of an embodiment of a vertical spectral solid-state imaging device using a photoelectric conversion film to which the present technology is applied.

  The configuration example of the vertical spectroscopic solid-state imaging device using the photoelectric conversion film has three types of configurations including the first to third solid-state imaging devices 11 shown from the left in FIG. In any of the three types of configurations, a photoelectric conversion element including any one of a photoelectric conversion film and a photodiode is laminated from the light source at the top in FIG. 1 toward the bottom in the drawing.

  More specifically, as shown in the upper left part of FIG. 1, the first solid-state imaging element 11 is provided with a photoelectric conversion element 21 made of a photoelectric conversion film that photoelectrically converts G (green) light in the uppermost layer. Below, photoelectric conversion elements 31 and 32 made of silicon photodiodes of B (blue) and R (red) colors are stacked from above.

  With such a configuration, as shown in the lower left part of FIG. 1, photoelectric conversion is performed by light in the G (green) color (dashed line) wavelength band by the photoelectric conversion element 21, and then the wavelength band is sequentially shorter. The photoelectric conversion elements 31 and 32 sequentially perform photoelectric conversion with light of B (blue) color (broken line) and R (red) color (solid line), so that RGB (red, green, blue) is spectrally dispersed in the vertical direction. And photoelectrically converted.

  Further, as shown in the upper center portion of FIG. 1, the second solid-state imaging device 11 is a photoelectric conversion composed of a photoelectric conversion film that photoelectrically converts B (blue) and G (green) light in order from the top layer. Elements 22 and 21 are provided, and a photoelectric conversion element 32 made of a silicon photodiode of R (red) is laminated thereon.

  With such a configuration, as shown in the lower center of FIG. 1, photoelectric conversion is performed by light in the B (blue) and G (green) wavelength bands in order of decreasing wavelength band by the photoelectric conversion elements 22 and 21. Thereafter, the photoelectric conversion is performed by R (red) color light by the photoelectric conversion element 32, whereby RGB (red, green, blue) is dispersed in the vertical direction and photoelectrically converted.

  Further, as shown in the upper right part of FIG. 1, the third solid-state imaging device 11 photoelectrically converts B (blue), G (green), and R (red) light in order from the top layer. The photoelectric conversion elements 22, 21, 23 made of photoelectric conversion films are stacked.

  With such a configuration, as shown in the lower center of FIG. 1, B (blue) color, G (green) color, and R (red) color in order of decreasing wavelength band by photoelectric conversion elements 22, 21, and 23. By performing photoelectric conversion with light in the wavelength band of RGB, RGB (red, green, blue) is dispersed in the vertical direction to generate pixel signals.

  Here, the photoelectric conversion elements 21 to 23 formed of a photoelectric conversion film are formed of a thin film of a layered (2D: 2 Dimension) organic perovskite material.

  The layered organic perovskite material is one material group of organic-inorganic perovskite type compounds and is described, for example, as organic-inorganic layered perovskite type compound (RNH3) 2-Metal-X4. It has a self-organized structure in which organic layers (RNH3 +) and inorganic semiconductor layers (PbX64-) are alternately stacked. When R is a small functional group such as methyl, it takes a 3D type structure and has a broad absorption spectrum.

  However, when R has a functional group larger than, for example, a phenyl group, it has a layered 2D structure instead of a 3D structure. It is known that a 2D structure has a steep spectral characteristic at a specific wavelength.

  The layered organic perovskite material constituting the photoelectric conversion film used in the photoelectric conversion elements 21 to 23 is a material represented by the following general formula (1).

(RNH3) n-Metal-X (2n)
General formula (1)

  Here, in the general formula (1), R is at least one of aromatic or heterocyclic compounds having a primary amine. Metal is a metal containing at least one of Pb, Sn, and Mn. Furthermore, X is a halogen containing at least one kind from F, Cl, Br, and I. N is a natural number.

The layered organic perovskite material is synthesized as follows. That is, first, as shown in the following reaction formula (1), phenethylamine (MA) is reacted with hydrogen iodide (HI) to synthesize a phenethylamine hydrogen iodide salt (MAH ⁺ I ⁻ ). Next, as shown in the following reaction formula (2), in a dimethylformamide organic solvent, phenethylamine hydroiodide salt (MAH ⁺ I ⁻ ) and lead iodide (PbI2) are added to a halogenated amine. An ink having a layered organic perovskite ((MAH) 2PbI4) dissolved therein is prepared by dissolution at a ratio of 2: 1.

  Furthermore, the layered organic perovskite material is formed as a photoelectric conversion layer by spin-coating the ink, in which the layered organic perovskite is dissolved, onto the washed glass. Here, the coating conditions are, for example, a rotational speed of 2000 rpm and a rotational time of 60 s. Under these conditions, the film thickness of the layered organic perovskite material produced is about 200 nm.

  When the layered organic perovskite material thus produced is observed with, for example, an SEM (Scanning Electron Microscope), good flatness is shown as shown in FIG.

  Further, when the spectral characteristics of the layered organic perovskite material are measured using an ultraviolet-visible spectroscopic evaluation apparatus, for example, as shown in FIG. 3, the absorption peaked in the vicinity of 522 nm. As shown in FIG. 3, the light absorption coefficient α per thickness is about 80,000 for 522 nm where the absorption rate is a peak, and it has been confirmed that the absorption coefficient has a high absorption coefficient. It is shown that the material is suitable for the G (green) color photoelectric conversion element 21.

  Furthermore, when the external quantum efficiency with respect to the wavelength is obtained using an IPCE (Incident Photon to Current Conversion Efficiency) spectrum apparatus, as shown in FIG. 4, the photoelectric conversion efficiency (= external quantum efficiency EQE) is around 522 nm, as shown in FIG. It is shown to be about 30%, indicating that good photoelectric conversion efficiency can be obtained. As a result, the layered organic perovskite material is shown to be a suitable material for the G (green) photoelectric conversion element 21 from the viewpoint of photoelectric conversion efficiency.

  FIG. 4 shows the photoelectric conversion characteristic of the negative bias −0.2 V IPCE of the photoelectric conversion element 21 in the solid-state imaging device 11. The photoelectric conversion characteristics of IPCE in FIG. 4 reflect the spectral characteristics of the layered organic perovskite material in FIG. 3, and show that 500 to 520 nm visible light is selectively photoelectrically converted.

  A photoelectric conversion element using a layered organic perovskite material having such characteristics is provided as, for example, the uppermost photoelectric conversion element 21 of the vertical solid-state first solid-state imaging element 11 shown in the upper left part of FIG. Then, only light having a wavelength of 500 to 520 nm is selectively absorbed and light having a wavelength of 450 to 500 nm and 540 nm or more is transmitted, so that it functions as a preferable G (green) photoelectric conversion element.

  Similarly, as shown by the second solid-state image sensor 11 in the upper center of FIG. 1 or the third solid-state image sensor 11 in the upper right part, the photoelectric conversion element 21 forms a vertical spectral type solid-state image sensor. It is also possible to insert between other photoelectric conversion elements 22 and 32 or between 22 and 23.

  Further, when the dark current and the bright current were measured with respect to the voltage-current characteristics for the layered organic perovskite material, the results shown in FIG. 5 were obtained. That is, as shown in FIG. 5, the dark current in the light-shielded state shows good diode characteristics, and the bright current in the light-irradiated state shows an increase in current. It is shown that it functions as a conversion element.

  FIG. 5 shows the voltage-current characteristics of the negative bias-0.2 V IPCE dark current and the bright current of the photoelectric conversion element 21 in the solid-state imaging device 11, the dotted line is the dark current, and the solid line is the bright current. Represents.

<Configuration example of photoelectric conversion element using layered organic perovskite material>
Next, a configuration example of the photoelectric conversion elements 21 to 23 using the layered organic perovskite material will be described with reference to FIG. Here, the photoelectric conversion element 21 that selectively photoelectrically converts G (green) light among the photoelectric conversion elements 21 to 23 will be described, but the same applies to the photoelectric conversion elements 22 and 23. is there.

  A glass layer 51 is provided in the lowermost layer in the figure, and an electrode layer 52 made of ATO (antimony-doped tin oxide) / ITO (indium tin oxide), which is a transparent conductive material, is formed thereon.

  On the electrode layer 52, a Compact TiO2 layer 53 is formed as an electron transport layer. The Compact TiO2 layer 53 may be a layer made of other materials as long as an electron transport layer is formed, for example, a layer formed of NiO, WO3, or TA2O5.

  A porous TiO2 layer 54 is formed on the Compact TiO2 layer 53. On the porous TiO2 layer 54, a 2D Perovskite (layered organic perovskite material) layer 55 is formed as a photoelectric conversion element layer. On the 2D Perovskite layer 55, a Spiro-OMeTAD layer 56 serving as a hole transport layer is formed. Here, Spiro-OMeTAD is the compound 1 represented by the following chemical formula (1).

  The Spiro-OMeTAD layer 56 may be a layer made of another material as long as a hole transport layer can be formed, for example, a layer formed of TiO2, ZnO, or SnO2. A MoOx layer 57 is formed on the Spiro-OMeTAD layer 56, and an Au layer 58 is further formed thereon.

<Method for Producing Photoelectric Conversion Element Using Layered Organic Perovskite Material>
Next, a method for manufacturing a photoelectric conversion element using a layered organic perovskite material will be described with reference to the flowchart of FIG.

  In step S11, etching is performed with a width of 5 mm on one side of the material 25 mm on which the ITO / ATO layer 52 and the glass layer 51 are laminated, and the ITO / ATO layer 52 is partially removed. Further, the glass layer 51 is subjected to ultrasonic cleaning (neutral detergent cleaning, distilled water cleaning, isopropyl alcohol cleaning, acetone cleaning, and distilled water cleaning), and further UV ozone pretreatment is performed.

  In step S12, an ethanol solution (2.5%) in which Ti isopropoxide is dissolved is applied to the side on which the above-described ITO / ATO layer 52 is laminated by using a spray method. Heating at 500 ° C. for 20 minutes forms a Compact TiO 2 layer 53 that serves as an electron transport layer. The film thickness of the Compact TiO2 layer 53 is, for example, about 30 nm.

  More specifically, the electron transport layer is preferably a layer made of, for example, a porous electron transport material. As the porous electron transport material, for example, one or more of TiO2, WO3, ZnO, Nb2O5, Ta2O5, SrTiO3, and organic electron transport materials can be employed. In addition, when using an inorganic semiconductor, the donor may be doped. Furthermore, when an organic electron transport material is used, the thickness of the electron transport layer is preferably about 10 to 2000 nm, and more preferably about 20 to 1500 nm. By setting the thickness of the electron transport layer within the above range, it is possible to more reliably suppress the leakage current and collect electrons from the light absorption layer.

  In step S13, a TIO2 paste is spin-coated on the Compact TiO2 layer 53, and then heated at 500 ° C. for 20 minutes to form a porous TiO2 layer 54. The porous TiO2 layer 54 is about 160 nm, for example.

  In step S14, an ink in which a layered organic perovskite material is dissolved is spin-coated on the porous TiO2 layer 54, and then heated at 100 ° C. for 5 minutes to form a 2D Perovskite layer 55 made of a layered organic perovskite thin film. Is done. Thereafter, the etched portion of the 2D Perovskite layer 55 is wiped off in the process of step S11.

  In step S15, an ink mixed with 1.82 ml of chlorobenzene, 14.7 mg of Spiro-OMeTAD, 17 mg of Li-TFSI, and 49 mg of 4-tert-butylpyridine is spin-coated on the 2D Perovskite layer 55, so that A Spiro-OMeTAD layer 56 serving as a hole transport layer is formed.

  In step S <b> 16, the MoOx layer 57 and the Au layer 58 are formed by vapor deposition on the Spiro-OMeTAD layer 56 using a vacuum vapor deposition machine. Here, the film thickness of the MoOx layer 57 is, for example, about 30 nm, and the film thickness of the Au layer 58 is, for example, deposited by a thickness of about 100 nm.

  That is, in the photoelectric conversion film applied to the solid-state imaging device of the present technology, the hole transport layer is provided on one side of the light absorption layer. In addition to spiro-MeO-TAD, materials used for the hole transport layer include, for example, iodides such as selenium and copper iodide (CuI), cobalt complexes such as layered cobalt oxide, CuSCN, MoO3, NiO , WO3, organic hole transport material and the like.

  More specifically, examples of the iodide include copper iodide (CuI). Examples of the layered cobalt oxide include AxCoO2 (A = Li, Na, K, Ca, Sr, Ba; 0 ≦ x ≦ 1). Examples of the organic hole transport material include polythiophene derivatives such as poly-3-hexylthiophene (P3HT) and polyethylenedioxythiophene (PEDOT), 2,2 ′, 7,7′-tetrakis- (N, N— Fluorene derivatives such as di-p-methoxyphenylamine) -9,9'-spirobifluorene (spiro-MeO-TAD), carbazole derivatives such as polyvinylcarbazole, triphenylamine derivatives, diphenylamine derivatives, polysilane derivatives, polyaniline derivatives, etc. Is mentioned. The thickness of the hole transport layer is not particularly limited, but is preferably about 0.01 to 10 μm.

  The hole transport layer described above can be formed not only by a coating method but also by a non-vacuum process such as a plating method or a spray method, and can also be formed by a vapor deposition process. Furthermore, the hole transport layer desirably has an electron blocking capability. When the hole transport layer does not have an electron blocking property, a second hole transport layer having another electron blocking property may be provided.

  Furthermore, in the above, an example has been described in which any of the Compact TiO2 layer 53, the porous TiO2 layer 54, the 2D Perovskite layer 55, and the Spiro-OMeTAD layer 56 is formed by a coating process. . However, other methods may be used as long as these layers can be formed, for example, a vapor deposition process, a transfer process, an ALD (Atomic Layer Deposition) method, a sputtering method, and a PLD (Pulsed Laser Deposition) method. .

  Moreover, the film thickness of each layer mentioned above is an example, and should just be in a predetermined range, for example, the range of the preferable film thickness of the Compact TiO2 layer 53 is the range of 2 nm to 100 nm. The preferred thickness range of the porous TiO2 layer 54 is in the range of 50 nm to 300 nm. Furthermore, a preferable film thickness range of the 2D Perovskite layer 55 which is a photoelectric conversion layer is in a range of 300 nm to 1000 nm. In addition, the preferable film thickness range of the Spiro-OMeTAD layer 56 that is the hole transport layer is in the range of 50 nm to 300 nm.

  Through the above processing, it is possible to generate a photoelectric conversion element 21 using a photoelectric conversion film material having high selectivity and high photoelectric conversion characteristics with respect to light of a specific wavelength.

<Control of properties of layered organic perovskite ((RNH3) n-Metal-X (2n))>
The layered organic perovskite ((RNH3) n-Metal-X (2n)) material has a maximum absorption wavelength peak and an absorption wavelength due to a combination of at least one of aromatic or heterocyclic compounds having a primary amine as R. Can be controlled. Similarly, the layered organic perovskite ((RNH3) n-Metal-X (2n)) material has a maximum absorption wavelength due to the combination of X, F, Cl, Br, and a halogen containing at least one kind of I. The shape of the peak and absorption wavelength can be controlled.

Regarding R, for example, a layered organic perovskite ((RNH3) n-Metal-X (2n) is obtained by any one of compounds 2 to 25 represented by the following chemical formulas (2) to (25), or a combination thereof. ) It is possible to control the absorption wavelength maximum peak and the distribution shape of the absorption wavelength of the material.

  Therefore, the characteristics can be controlled by various combinations of R and halogen X, which are aromatic or heterocyclic compounds having this primary amine, and, for example, photoelectric conversion that selectively photoelectrically converts G (green) light. It becomes possible to generate not only the conversion element 21 but also photoelectric conversion elements 22 and 23 having high selectivity for B (blue) or R (red) light and high photoelectric conversion characteristics. .

  In addition, the first to third solid-state image pickup elements 11 in FIG. 1 show examples of solid-state image pickup elements having three colors of RGB (red, green, and blue) as light sources. Even in the case of using color, the layered organic perovskite ((RNH3) n-Metal-X (2n)) material that selectively photoelectrically converts the corresponding color light (corresponding wavelength light) By generating the photoelectric conversion film, a photoelectric conversion element that selectively photoelectrically converts the corresponding light can be generated. For example, by generating a layered organic perovskite ((RNH3) n-Metal-X (2n)) material that selectively photoelectrically converts light corresponding to a yellow wavelength as a light source, and generating a photoelectric conversion element, In addition to the three colors of RGB (red, green, and blue), it is also possible to capture an image using four colors of Y (yellow) as light sources.

<Configuration of solid-state image sensor>
Next, with reference to FIG. 8 and FIG. 9, a configuration of a solid-state imaging element to which the photoelectric conversion element according to the present technology is applied will be described. FIG. 8 is a schematic diagram illustrating a structure of a solid-state imaging element to which the photoelectric conversion element according to the present technology is applied.

  Here, in FIG. 8, pixel regions 201, 211, and 231 are regions in which photoelectric conversion elements including a photoelectric conversion film according to the present technology are arranged. The control circuits 202, 212, and 242 are arithmetic processing circuits that control each configuration of the solid-state imaging device, and the logic circuits 203, 223, and 243 process signals that are photoelectrically converted by the photoelectric conversion elements in the pixel region. This is a signal processing circuit.

  For example, as illustrated in configuration A in FIG. 9, a solid-state imaging device to which the photoelectric conversion element according to the present technology is applied includes a pixel region 201, a control circuit 202, and a logic circuit 203 in one semiconductor chip 200. And may be formed.

  9, the solid-state imaging device to which the photoelectric conversion element according to the present technology is applied includes a pixel region 211 and a control circuit 212 in the first semiconductor chip 210. A multilayer solid-state imaging device in which a logic circuit 223 is formed in the second semiconductor chip 220 may be used.

  Furthermore, as illustrated in the configuration C of FIG. 9, in the solid-state imaging device to which the photoelectric conversion element according to the present technology is applied, the pixel region 231 is formed in the first semiconductor chip 230, and the second semiconductor chip 240 Alternatively, a stacked solid-state imaging device in which a control circuit 242 and a logic circuit 243 are formed may be used.

  In the solid-state imaging device shown in the configuration B and the configuration C in FIG. 9, at least one of the control circuit and the logic circuit is formed in a semiconductor chip different from the semiconductor chip in which the pixel region is formed. Therefore, since the solid-state imaging device shown in the configuration B and the configuration C in FIG. 9 can expand the pixel region as compared with the solid-state imaging device shown in the configuration A, the number of pixels mounted in the pixel region is increased, and the plane The resolution can be improved. Therefore, the solid-state imaging device to which the photoelectric conversion element according to the present technology is applied is more preferably the stacked solid-state imaging device shown in the configuration B and the configuration C in FIG.

  Next, a specific structure of the solid-state imaging device to which the photoelectric conversion device according to the present technology is applied will be described with reference to FIG. FIG. 9 is a cross-sectional view schematically illustrating a unit pixel of a solid-state imaging element to which the photoelectric conversion element according to the present technology is applied. Note that the solid-state imaging device 300 illustrated in FIG. 9 is a back-illuminated solid-state imaging device in which light enters from a surface opposite to the surface on which the pixel transistors and the like are formed. In FIG. 9, the upper side of the drawing is the light receiving surface, and the lower side is the circuit forming surface on which the pixel transistors and peripheral circuits are formed.

  As shown in FIG. 9, the solid-state imaging device 300 includes a photoelectric conversion element including a first photodiode PD1 formed on the semiconductor substrate 330 and a second photodiode PD2 formed on the semiconductor substrate 330 in the photoelectric conversion region 320. And a photoelectric conversion element including the organic photoelectric conversion film 310 formed on the back surface side of the semiconductor substrate 330 is stacked in the light incident direction.

  The first photodiode PD1 and the second photodiode PD2 are formed in a well region 331 that is a first conductivity type (for example, p-type) semiconductor region of a semiconductor substrate 330 made of silicon.

  The first photodiode PD1 has an n-type semiconductor region 332 formed of a second conductivity type (for example, n-type) impurity formed on the light receiving surface side of the semiconductor substrate 330 and a part thereof reaching the surface side of the semiconductor substrate 330. And an extension portion 332a formed to extend in the direction. A high-concentration p-type semiconductor region 334 serving as a charge storage layer is formed on the surface of the extension 332a. The extension 332a is formed as an extraction layer for extracting signal charges accumulated in the n-type semiconductor region 332 of the first photodiode PD1 to the surface side of the semiconductor substrate 330.

  The second photodiode PD2 includes an n-type semiconductor region 336 formed on the light receiving surface side of the semiconductor substrate 330, a high-concentration p-type semiconductor region 338 formed on the surface side of the semiconductor substrate 330 and serving as a charge storage layer, Consists of.

  In the first photodiode PD1 and the second photodiode PD2, the dark current generated at the interface of the semiconductor substrate 330 can be suppressed by forming the p-type semiconductor region at the interface of the semiconductor substrate 330.

  Here, the second photodiode PD2 formed in the region farthest from the light receiving surface is, for example, a red photoelectric conversion element that absorbs red light and performs photoelectric conversion. The first photodiode PD1 formed on the light receiving surface side of the second photodiode PD2 is, for example, a blue photoelectric conversion element that absorbs blue light and performs photoelectric conversion.

  The organic photoelectric conversion film 310 is formed on the back surface of the semiconductor substrate 330 via the antireflection film 302 and the insulating film 306. The organic photoelectric conversion film 310 is sandwiched between the upper electrode 312 and the lower electrode 308 to form a photoelectric conversion element. Here, the organic photoelectric conversion film 310 is, for example, an organic film that absorbs green light and performs photoelectric conversion, and is formed of the photoelectric conversion film according to the present technology described above. The upper electrode 312 and the lower electrode 308 are formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

  The lower electrode 308 is connected to a vertical transfer path 348 formed from the back surface side to the front surface side of the semiconductor substrate 330 via a contact plug 304 penetrating the antireflection film 302. The vertical transfer path 348 is formed from a back surface side of the semiconductor substrate 330 with a stacked structure of a connection portion 340, a potential barrier layer 342, a charge storage layer 344, and a p-type semiconductor region 346.

  The connection portion 340 is formed of an n-type impurity region having a high impurity concentration formed on the back side of the semiconductor substrate 330, and is formed for ohmic contact with the contact plug 304. The potential barrier layer 342 is made of a low-concentration p-type impurity region, and forms a potential barrier between the connection portion 340 and the charge storage layer 344. The charge storage layer 344 stores the signal charge transferred from the organic photoelectric conversion film 310 and is formed of an n-type impurity region having a lower concentration than the connection portion 340. Note that a high-concentration p-type semiconductor region 346 is formed on the surface of the semiconductor substrate 330. Such p-type semiconductor region 346 suppresses dark current generated at the interface of the semiconductor substrate 330.

  Here, on the surface side of the semiconductor substrate 330, a multilayer wiring layer 350 including wirings 358 stacked in a plurality of layers via the interlayer insulating layer 351 is formed. In addition, readout circuits 352, 354, and 356 corresponding to the first photodiode PD1, the second photodiode PD2, and the organic photoelectric conversion film 310 are formed in the vicinity of the surface of the semiconductor substrate 330. The read circuits 352, 354, and 356 read output signals from the respective photoelectric conversion elements and transfer them to a logic circuit (not shown). Further, a support substrate 360 is formed on the surface of the multilayer wiring layer 350.

  On the other hand, a light shielding film 316 is formed on the light receiving surface side of the upper electrode 312 so as to shield the extension 332a of the first photodiode PD1 and the vertical transfer path 348. Here, a region divided by the light shielding films 316 is a photoelectric conversion region 320. An on-chip lens 318 is formed on the light shielding film 316 with a planarizing film 314 interposed therebetween.

  The solid-state imaging element 300 to which the photoelectric conversion element according to the present technology is applied has been described above. In the solid-state imaging device 300 to which the photoelectric conversion device according to the present technology is applied, color separation or the like is not formed in the unit pixel because color separation is performed in the vertical direction.

<Configuration of electronic equipment>
Next, with reference to FIG. 10, a configuration of an electronic apparatus to which the photoelectric conversion element according to the present technology is applied will be described. FIG. 10 is a block diagram illustrating a configuration of an electronic device to which the photoelectric conversion element according to the present technology is applied.

  As shown in FIG. 10, the electronic apparatus 400 includes an optical system 402, a solid-state imaging device 404, a DSP (Digital Signal Processor) circuit 406, a control unit 408, an output unit 412, an input unit 414, and a frame memory. 416, a recording unit 418, and a power supply unit 420.

  Here, the DSP circuit 406, the control unit 408, the output unit 412, the input unit 414, the frame memory 416, the recording unit 418, and the power supply unit 420 are connected to each other via the bus line 410.

  The optical system 402 takes in incident light from a subject and forms an image on the imaging surface of the solid-state imaging element 404. In addition, the solid-state imaging device 404 includes a photoelectric conversion device according to the present technology, converts the amount of incident light imaged on the imaging surface by the optical system 402 into an electrical signal in units of pixels, and outputs the electrical signal.

  The DSP circuit 406 processes the pixel signal transferred from the solid-state image sensor 404 and outputs it to the output unit 412, the frame memory 416, the recording unit 418, and the like. In addition, the control unit 408 includes, for example, an arithmetic processing circuit and the like, and controls the operation of each component of the electronic device 400.

  The output unit 412 is a panel type display device such as a liquid crystal display or an organic electroluminescence display, for example, and displays a moving image or a still image captured by the solid-state image sensor 404. Note that the output unit 412 may include an audio output device such as a speaker and headphones. The input unit 414 is a device for a user to input an operation, such as a touch panel or a button, and issues operation commands for various functions of the electronic device 400 according to the user's operation.

  The frame memory 416 temporarily stores a moving image or a still image captured by the solid-state image sensor 404. The recording unit 418 records a moving image or a still image captured by the solid-state imaging device 404 on a removable storage medium such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory.

  The power supply unit 420 appropriately supplies various power sources serving as operation power sources for the DSP circuit 406, the control unit 408, the output unit 412, the input unit 414, the frame memory 416, and the recording unit 418 to these supply targets.

  The electronic device 400 to which the photoelectric conversion element according to the present technology is applied has been described above. The electronic device 400 to which the photoelectric conversion element according to the present technology is applied may be, for example, an imaging device.

  In the above description, the solid-state imaging device and the electronic apparatus to which the photoelectric conversion element according to the present technology is applied have been described. However, the present invention can also be applied to other technologies, such as solar cells and light. It is also possible to apply as a sensor using

  Although one embodiment of the present technology has been described in detail with reference to the accompanying drawings, the technical scope of the present technology is not limited to such an example. It is obvious that a person having ordinary knowledge in the technical field of the present technology can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that it belongs to the technical scope of the present technology.

  Further, the effects described in the present specification are merely illustrative or exemplary and are not limited. That is, the present technology can exhibit other effects that are apparent to those skilled in the art from the description of the present specification in addition to or instead of the above effects.

In addition, this technique can also take the following structures.
<1> a photoelectric conversion layer that photoelectrically converts incident light;
A hole transport layer for transporting holes to the photoelectric conversion layer;
An electron transport layer for transporting electrons to the photoelectric conversion layer;
A pair of electrodes,
The photoelectric conversion layer, the hole transport layer, and the electron transport layer are stacked between the pair of electrodes,
The photoelectric conversion layer is made of a layered organic perovskite material that selectively absorbs light only in a specific wavelength region.
<2> The layered organic perovskite material is
(RNH3) n-Metal-X (2 + n)
And
R is at least one of aromatic or heterocyclic compounds having a primary amine,
The Metal is a metal containing at least one of Pb, Sn, and Mn,
X is a halogen containing at least one of F, Cl, Br, and I;
Said n is a natural number. The solid-state image sensor as described in <1>.
<3> The structure of R controls the absorption wavelength maximum peak and the absorption wavelength distribution shape of light in a specific wavelength region that is selectively absorbed in the layered organic perovskite material. Solid-state image sensor.
<4> The solid-state imaging device according to any one of <1> to <3>, wherein the electron transport layer includes any one of TiO2, NiO, WO3, and TA2O5.
<5> The solid-state imaging device according to any one of <1> to <4>, wherein the hole transport layer includes any one of Spiro-OMeTAD, TiO2, ZnO, and SnO2.
<6> a first step of forming a first electrode;
A second step of forming an electron transport layer for transporting electrons to the photoelectric conversion layer on the first electrode;
A third step of forming the photoelectric conversion layer made of a layered organic perovskite material that selectively absorbs light only in a specific wavelength region on the electron transport layer;
A fourth step of forming a hole transport layer that transports holes to the photoelectric conversion layer that photoelectrically converts incident light on the photoelectric conversion layer;
And a fifth step of forming a second electrode on an upper layer of the hole transport layer.
<7> a photoelectric conversion layer that photoelectrically converts incident light;
A hole transport layer for transporting holes to the photoelectric conversion layer;
An electron transport layer for transporting electrons to the photoelectric conversion layer;
A pair of electrodes,
The photoelectric conversion layer, the hole transport layer, and the electron transport layer are stacked between the pair of electrodes,
The photoelectric conversion layer is made of a layered organic perovskite material that selectively absorbs light only in a specific wavelength region.
<8> a photoelectric conversion layer that photoelectrically converts incident light;
A hole transport layer for transporting holes to the photoelectric conversion layer;
An electron transport layer for transporting electrons to the photoelectric conversion layer;
A pair of electrodes,
The photoelectric conversion layer, the hole transport layer, and the electron transport layer are stacked between the pair of electrodes,
The photoelectric conversion layer is an imaging device made of a layered organic perovskite material that selectively absorbs light only in a specific wavelength region.
<9> a photoelectric conversion layer that photoelectrically converts incident light;
A hole transport layer for transporting holes to the photoelectric conversion layer;
An electron transport layer for transporting electrons to the photoelectric conversion layer;
A pair of electrodes,
The photoelectric conversion layer, the hole transport layer, and the electron transport layer are stacked between the pair of electrodes,
The photoelectric conversion layer is an electronic device made of a layered organic perovskite material that selectively absorbs light only in a specific wavelength region.
<10> a photoelectric conversion layer that photoelectrically converts incident light;
A hole transport layer for transporting holes to the photoelectric conversion layer;
An electron transport layer for transporting electrons to the photoelectric conversion layer;
A pair of electrodes,
The photoelectric conversion layer, the hole transport layer, and the electron transport layer are stacked between the pair of electrodes,
The photoelectric conversion layer is made of a layered organic perovskite material that selectively absorbs light only in a specific wavelength region.

  DESCRIPTION OF SYMBOLS 11 Solid-state image sensor, 21-23 Photoelectric conversion element (photoelectric conversion film) 31, 32 Photoelectric conversion element (photodiode), 51 Glass layer, 52 Electrode layer, 53 Compact TiO2 layer, 54 Porous TiO2 layer, 55 2D Perovskite layer , 56 Spiro-OMeTAD layer, 57 MoOx layer, 58 Au layer

Claims (10)

A photoelectric conversion layer for photoelectrically converting incident light;
A hole transport layer for transporting holes to the photoelectric conversion layer;
An electron transport layer for transporting electrons to the photoelectric conversion layer;
A pair of electrodes,
The photoelectric conversion layer, the hole transport layer, and the electron transport layer are stacked between the pair of electrodes,
The photoelectric conversion layer is made of a layered organic perovskite material that selectively absorbs light only in a specific wavelength region. The layered organic perovskite material is
(RNH3) n-Metal-X (2 + n)
And
R is at least one of aromatic or heterocyclic compounds having a primary amine,
The Metal is a metal containing at least one of Pb, Sn, and Mn,
X is a halogen containing at least one of F, Cl, Br, and I;
The solid-state imaging device according to claim 1, wherein n is a natural number. The solid-state imaging according to claim 2, wherein the structure of R controls the absorption wavelength maximum peak and the distribution shape of the absorption wavelength of light in a specific wavelength region that is selectively absorbed in the layered organic perovskite material. element. The solid-state imaging device according to claim 1, wherein the electron transport layer includes any one of TiO 2, NiO, WO 3, and TA 2 O 5. The solid-state imaging device according to claim 1, wherein the hole transport layer includes any one of Spiro-OMeTAD, TiO 2, ZnO, and SnO 2. A first step of forming a first electrode;
A second step of forming an electron transport layer for transporting electrons to the photoelectric conversion layer on the first electrode;
A third step of forming the photoelectric conversion layer made of a layered organic perovskite material that selectively absorbs light only in a specific wavelength region on the electron transport layer;
A fourth step of forming a hole transport layer that transports holes to the photoelectric conversion layer that photoelectrically converts incident light on the photoelectric conversion layer;
And a fifth step of forming a second electrode on an upper layer of the hole transport layer. A photoelectric conversion layer for photoelectrically converting incident light;
A hole transport layer for transporting holes to the photoelectric conversion layer;
An electron transport layer for transporting electrons to the photoelectric conversion layer;
A pair of electrodes,
The photoelectric conversion layer, the hole transport layer, and the electron transport layer are stacked between the pair of electrodes,
The photoelectric conversion layer is made of a layered organic perovskite material that selectively absorbs light only in a specific wavelength region. A photoelectric conversion layer for photoelectrically converting incident light;
A hole transport layer for transporting holes to the photoelectric conversion layer;
An electron transport layer for transporting electrons to the photoelectric conversion layer;
A pair of electrodes,
The photoelectric conversion layer, the hole transport layer, and the electron transport layer are stacked between the pair of electrodes,
The photoelectric conversion layer is an imaging device made of a layered organic perovskite material that selectively absorbs light only in a specific wavelength region. A photoelectric conversion layer for photoelectrically converting incident light;
A hole transport layer for transporting holes to the photoelectric conversion layer;
An electron transport layer for transporting electrons to the photoelectric conversion layer;
A pair of electrodes,
The photoelectric conversion layer, the hole transport layer, and the electron transport layer are stacked between the pair of electrodes,
The photoelectric conversion layer is an electronic device made of a layered organic perovskite material that selectively absorbs light only in a specific wavelength region. A photoelectric conversion layer for photoelectrically converting incident light;
A hole transport layer for transporting holes to the photoelectric conversion layer;
An electron transport layer for transporting electrons to the photoelectric conversion layer;
A pair of electrodes,
The photoelectric conversion layer, the hole transport layer, and the electron transport layer are stacked between the pair of electrodes,
The photoelectric conversion layer is made of a layered organic perovskite material that selectively absorbs light only in a specific wavelength region.

Images