Image sensor

Abstract

An imaging element according to an aspect of the present disclosure is provided with a semiconductor substrate, a first pixel, and a plurality of second pixels adjacent to the first pixel. Each of the first pixel and the plurality of second pixels includes: a first photoelectric conversion layer; a first pixel electrode; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; a second photoelectric conversion layer; a second pixel electrode; and a second plug electrically connecting the semiconductor substrate and the second pixel electrode. When the imaging element is viewed from a direction normal to the semiconductor substrate, the distance between the first plug of the first pixel and the first plug of each of the plurality of second pixels is shorter than the distance between the first plug of the first pixel and the second plug of each of the plurality of second pixels.

Description

[Technical field]

[0001] The present disclosure relates to an imaging device. [Background technology]

[0002] Image sensors that use photoelectric conversion are widely used. Image sensors are typically sensitive to wavelength ranges corresponding to the colors red (R), green (G), and blue (B). R component signals, G component signals, and B component signals are each extracted from the image sensor. Security cameras and vehicle-mounted cameras may use image sensors that are sensitive to the near-infrared wavelength range.

[0003] In recent years, there has been a trend for pixel size to decrease as the pixel density of image sensors increases, and the area of ​​a photoelectric conversion unit such as a photodiode is also decreasing.

[0004] Patent Document 2 discloses an imaging element having a plurality of photoelectric conversion films. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2011-238781 A [Patent Document 2] JP 2005-268471 A Summary of the Invention [Problem to be solved by the invention]

[0006] One challenge for imaging devices is to improve image quality. [Means for solving the problem]

[0007] An imaging element according to one aspect of the present disclosure includes: A semiconductor substrate; A first pixel; a plurality of second pixels adjacent to the first pixel; Equipped with. Each of the first pixel and the plurality of second pixels is a first photoelectric conversion layer that converts light having a wavelength included in a first wavelength range into a first charge; a first pixel electrode that collects the first charges; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; a second photoelectric conversion layer disposed above the first photoelectric conversion layer or between the first photoelectric conversion layer and the semiconductor substrate in a normal direction of the semiconductor substrate, the second photoelectric conversion layer converting light having a wavelength included in a second wavelength range into a second charge; a second pixel electrode for collecting the second charges; a second plug electrically connecting the semiconductor substrate and the second pixel electrode; Includes. When viewed from the normal direction of the semiconductor substrate, the distance between the first plug of the first pixel and the first plug of each of the plurality of second pixels is shorter than the distance between the first plug of the first pixel and the second plug of each of the plurality of pixels. Effect of the Invention

[0008] According to the techniques of the present disclosure, image quality can be improved. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a configuration diagram of an imaging device according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view of the imaging element shown in FIG. [Figure 3A] FIG. 3A is a diagram showing the arrangement of pixel electrodes and plugs when the imaging element according to the first embodiment is viewed from the normal direction of a semiconductor substrate. [Figure 3B] FIG. 3B is a diagram showing another arrangement of pixel electrodes and plugs. [Figure 3C] FIG. 3C is a diagram showing yet another arrangement of pixel electrodes and plugs. [Figure 4A] FIG. 4A is a diagram showing another shape of the pixel electrode. [Figure 4B] FIG. 4B is a diagram showing the arrangement of plugs when the pixel has the pixel electrode shown in FIG. 4A. [Diagram 5] FIG. 5 is a cross-sectional view of an imaging element according to the second embodiment of the present disclosure. [Figure 6] FIG. 6 is a diagram showing the arrangement of pixel electrodes and plugs when the imaging element according to the second embodiment is viewed from the normal direction of the semiconductor substrate. [Figure 7] FIG. 7 is a plan view of the first pixel electrode. [Figure 8] FIG. 8 is a cross-sectional view of an imaging element according to a third embodiment of the present disclosure. [Figure 9] FIG. 9 is a diagram showing the arrangement of pixel electrodes and plugs when the imaging element according to the third embodiment is viewed from the normal direction of the semiconductor substrate. [Figure 10] FIG. 10 is a plan view of the second pixel electrode. [Figure 11] FIG. 11 is a plan view showing another positional relationship between the second pixel electrode, the first pixel electrode, and the first plug. [Figure 12A] FIG. 12A is a diagram showing another structure of a pixel of an imaging element having a two-layer structure. [Figure 12B] FIG. 12B is a diagram showing the arrangement of plugs when the pixel has the structure shown in FIG. 12A. [Figure 13A] FIG. 13A is a diagram showing yet another structure of a pixel of an imaging element having a two-layer structure. [Figure 13B] FIG. 13B is a diagram showing the arrangement of plugs when the pixel has the structure shown in FIG. 13A. [Figure 14A] FIG. 14A is a cross-sectional view of an imaging element according to a fourth embodiment of the present disclosure. [Figure 14B] FIG. 14B is a diagram showing the arrangement of pixel electrodes, plugs, and photodiodes when the imaging element according to the fourth embodiment is viewed from the normal direction of the semiconductor substrate. [Figure 15A] FIG. 15A is a configuration diagram of an imaging element according to a fifth embodiment of the present disclosure. [Figure 15B]FIG. 15B is a diagram showing the arrangement of plugs when the pixel has the structure shown in FIG. 15A. [Figure 16] FIG. 16 is a cross-sectional view of an imaging element according to the sixth embodiment of the present disclosure. [Figure 17] FIG. 17 is a diagram showing the arrangement of pixel electrodes and plugs when the image sensor according to the sixth embodiment is viewed from the normal direction of the semiconductor substrate. [Figure 18] FIG. 18 is a diagram showing the arrangement of pixel electrodes and plugs when the Bayer arrangement is applied to the image sensor according to the sixth embodiment. [Figure 19] FIG. 19 is a cross-sectional view of an imaging element according to the seventh embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (Findings on which this disclosure is based) The imaging element has a semiconductor substrate and a photoelectric conversion film disposed thereover, as disclosed in, for example, Patent Document 1. In recent years, in order to further increase the density of pixels, an imaging element having a stacked structure of multiple photoelectric conversion films has been proposed (Patent Document 2).

[0011] The present inventors have investigated the causes of impeding improvements in the image quality of image sensors, and have found the following problems.

[0012] The imaging element has plugs that connect pixel electrodes and a semiconductor substrate. As pixels become denser, crosstalk between the plugs becomes evident. Crosstalk between the plugs causes color mixing in the image to be obtained. For example, when crosstalk occurs between plugs corresponding to different colors, such as R and G, G and B, or B and R, the color difference between the subject and the obtained image becomes noticeable. Suppressing crosstalk between the plugs is beneficial for improving image quality.

[0013] It is predicted that crosstalk between plugs will become evident in an imaging element having the structure disclosed in Patent Document 2.

[0014] The present disclosure provides techniques for suppressing crosstalk between plugs.

[0015] (Summary of one aspect of the present disclosure) The imaging element according to the first aspect of the present disclosure includes: A semiconductor substrate; A first pixel; a plurality of second pixels adjacent to the first pixel; Equipped with. Each of the first pixel and the plurality of second pixels is a first photoelectric conversion layer that converts light having a wavelength included in a first wavelength range into a first charge; a first pixel electrode that collects the first charges; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; a second photoelectric conversion layer disposed above the first photoelectric conversion layer or between the first photoelectric conversion layer and the semiconductor substrate in a normal direction of the semiconductor substrate, the second photoelectric conversion layer converting light having a wavelength included in a second wavelength range into a second charge; a second pixel electrode for collecting the second charges; a second plug electrically connecting the semiconductor substrate and the second pixel electrode; Includes. When viewed from the normal direction of the semiconductor substrate, the distance between the first plug of the first pixel and the first plug of each of the plurality of second pixels is shorter than the distance between the first plug of the first pixel and the second plug of each of the plurality of pixels.

[0016] According to this configuration, crosstalk between plugs corresponding to different colors can be suppressed, and color mixing between pixels can be suppressed.

[0017] The plurality of second pixels include a pixel adjacent to the first pixel in a first direction; a pixel adjacent to the first pixel in a direction opposite to the first direction; a pixel adjacent to the first pixel in a second direction perpendicular to the first direction; a pixel adjacent to the first pixel in a direction opposite to the second direction; a pixel adjacent to the first pixel in a third direction between the first direction and the second direction; a pixel adjacent to the first pixel in a direction opposite to the third direction; a pixel adjacent to the first pixel in a fourth direction perpendicular to the third direction; and A pixel adjacent to the first pixel in a direction opposite to the fourth direction may be included.

[0018] In the second aspect of the present disclosure, for example, in the imaging element according to the first aspect, the second photoelectric conversion layer may be disposed above the first photoelectric conversion layer in the normal direction of the semiconductor substrate. With this configuration, the first plug can be made shorter than the second plug, so that crosstalk between the first plugs can be suppressed while crosstalk between the first plugs and the second plugs is suppressed.

[0019] In the third aspect of the present disclosure, for example, in the image sensor according to the second aspect, the first wavelength range may be a near-infrared wavelength range, and the second wavelength range may be a visible wavelength range. With this configuration, it is possible to prevent information of visible light and information of near-infrared light from being mixed together.

[0020] In a fourth aspect of the present disclosure, for example, in the imaging element according to the first aspect, the second photoelectric conversion layer may be disposed between the first photoelectric conversion layer and the semiconductor substrate in the normal direction of the semiconductor substrate. With this configuration, the second plug can be made shorter than the first plug, and therefore crosstalk between the second plugs can be suppressed while crosstalk between the first plug and the second plug is suppressed.

[0021] In the fifth aspect of the present disclosure, for example, in the image sensor according to the fourth aspect, the first wavelength range may be a visible light wavelength range, and the second wavelength range may be a near-infrared light wavelength range. With this configuration, it is possible to prevent information of visible light and information of near-infrared light from being mixed together.

[0022] In a sixth aspect of the present disclosure, for example, in the imaging element according to the fourth or fifth aspect, the first plug may not overlap the second pixel electrode when viewed from the normal direction of the semiconductor substrate. With this configuration, the variation in thickness of the second photoelectric conversion layer and the surface roughness of the second photoelectric conversion layer can be reduced.

[0023] In a seventh aspect of the present disclosure, for example, in the imaging element according to any one of the fourth to sixth aspects, the area of ​​the second pixel electrode may be smaller than four times the area of ​​the first pixel electrode when viewed from the normal direction of the semiconductor substrate. With this configuration, the second pixel electrode can be formed avoiding the first plug.

[0024] In an eighth aspect of the present disclosure, for example, in the image sensor according to the first aspect, the first wavelength range may include a red light wavelength range and a blue light wavelength range, the second wavelength range may include a green light wavelength range, the first photoelectric conversion layer may have sensitivity to the red light wavelength range and the blue light wavelength range, and the second photoelectric conversion layer may have sensitivity to the green light wavelength range. With this configuration, it is possible to increase the area of ​​the green sub-pixel having high luminosity while ensuring the benefits of a multi-layer structure.

[0025] In the ninth aspect of the present disclosure, for example, the imaging element according to the eighth aspect may further include a color filter that cuts off light in the red wavelength range and a color filter that cuts off light in the blue wavelength range. With this configuration, it is possible to provide the imaging element with sensitivity to the wavelength ranges of blue light, red light, and green light while ensuring the benefits of the multi-layer structure. This makes it possible to obtain a full-color image.

[0026] In a tenth aspect of the present disclosure, for example, in the imaging element according to the first aspect, each of the first pixel and the second pixels may further include a third photoelectric conversion layer that converts light having a wavelength included in a third wavelength range into a third charge, a third pixel electrode that collects the third charge, and a third plug that electrically connects the semiconductor substrate and each of the third pixel electrodes, and when viewed from the normal direction of the semiconductor substrate, the distance between the first plug of the first pixel and the first plug of each of the second pixels may be shorter than the distance between the first plug of the first pixel and the third plug of each of the second pixels. With this configuration, color separation can be improved.

[0027] An imaging element according to an eleventh aspect of the present disclosure, A semiconductor substrate; Two first pixels adjacent to each other; a second pixel adjacent to each of the two first pixels; Equipped with Each of the two first pixels is a first photoelectric conversion layer that converts light having a wavelength included in a first wavelength range into a first charge; a first pixel electrode that collects the first charges; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; The second pixel is a second photoelectric conversion layer that converts light having a wavelength included in the second wavelength range into a second charge; a second pixel electrode for collecting the second charges; a second plug electrically connecting the semiconductor substrate and the second pixel electrode; When viewed from a normal direction of the semiconductor substrate, the distance between the first plugs in the two first pixels is shorter than the distance between the first plug of one of the two first pixels and the second plug of the second pixel.

[0028] With this configuration, crosstalk between plugs corresponding to different colors can be suppressed, and color mixing between pixels can be suppressed.

[0029] In a twelfth aspect of the present disclosure, for example, the imaging element according to the eleventh aspect may further include a third pixel adjacent to each of the two first pixels, and the third pixel may include a third photoelectric conversion layer that converts light having a wavelength included in a third wavelength range into a third charge, a third pixel electrode that collects the third charge, and a third plug that electrically connects the semiconductor substrate and the third pixel electrode, and when viewed from the normal direction of the semiconductor substrate, the distance between the first plugs in the two first pixels may be shorter than the distance between the first plug of one of the two first pixels and the third plug of the third pixel. With this configuration, crosstalk between the first plug of the first pixel and the third plug of the third pixel is suppressed.

[0030] In a thirteenth aspect of the present disclosure, for example, in the image sensor according to the twelfth aspect, the two first pixels, the second pixel, and the third pixel may be arranged in a Bayer array. The image sensor of the thirteenth aspect can acquire a full-color image.

[0031] In a fourteenth aspect of the present disclosure, for example, in the image sensor according to any one of the eleventh to thirteenth aspects, the first wavelength range may be a wavelength range of green light.

[0032] An imaging element according to a fifteenth aspect of the present disclosure, A semiconductor substrate; At least one photoelectric conversion layer; a first pixel electrode electrically connected to the at least one photoelectric conversion layer and configured to collect charges corresponding to light in a first wavelength range; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; a second pixel electrode electrically connected to the at least one photoelectric conversion layer and configured to collect charges corresponding to light in a second wavelength range; a second plug electrically connecting the semiconductor substrate and the second pixel electrode; a third pixel electrode electrically connected to the at least one photoelectric conversion layer and configured to collect charges corresponding to light in a first wavelength range; a third plug electrically connecting the semiconductor substrate and the third pixel electrode; Equipped with When viewed from the normal direction of the semiconductor substrate, the distance between the first plug and the third plug is shorter than the distance between the first plug and the second plug.

[0033] With this configuration, crosstalk between plugs corresponding to different colors can be suppressed, and color mixing between pixels can be suppressed.

[0034] In a sixteenth aspect of the present disclosure, for example, in an imaging element relating to any one of the first to fifteenth aspects, the first pixel electrode may include a first storage electrode that accumulates the first charge in the first photoelectric conversion layer and a first readout electrode electrically connected to the semiconductor substrate via the first plug, and the second pixel electrode may include a second storage electrode that accumulates the second charge in the second photoelectric conversion layer and a second readout electrode electrically connected to the semiconductor substrate via the second plug.

[0035] An imaging element according to a seventeenth aspect of the present disclosure, A semiconductor substrate; A plurality of pixels; An imaging element comprising: Each of the plurality of pixels is A first photoelectric conversion layer; a first pixel electrode that collects charges generated in the first photoelectric conversion layer and corresponding to light in a first wavelength range; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; A second photoelectric conversion layer disposed above the first photoelectric conversion layer or between the first photoelectric conversion layer and the semiconductor substrate in a normal direction of the semiconductor substrate; a second pixel electrode that collects charges generated in the second photoelectric conversion layer and corresponding to light in a second wavelength range; a second plug electrically connecting the semiconductor substrate and the second pixel electrode; having When the imaging element is viewed from the normal direction of the semiconductor substrate, the distance between the first plugs is shorter than the distance between the first plug and the second plug in adjacent pixels.

[0036] According to this configuration, crosstalk between plugs corresponding to different colors can be suppressed, and color mixing between pixels can be suppressed.

[0037] An imaging element according to an eighteenth aspect of the present disclosure, A semiconductor substrate; A plurality of pixels; An imaging element comprising: The plurality of pixels includes a plurality of first pixels and a plurality of second pixels, Each of the plurality of first pixels includes a first photoelectric conversion layer, a first pixel electrode that collects charges generated in the first photoelectric conversion layer and corresponding to light in a first wavelength range, and a first plug that electrically connects the semiconductor substrate and the first pixel electrode; Each of the plurality of second pixels includes a second photoelectric conversion layer, a second pixel electrode that collects charges generated in the second photoelectric conversion layer and corresponding to light in a second wavelength range, and a second plug that electrically connects the semiconductor substrate and the second pixel electrode; When viewed from the normal direction of the semiconductor substrate, in adjacent pixels, the distance between the first plugs is shorter than the distance between the first plug and the second plug.

[0038] With this configuration, crosstalk between plugs corresponding to different colors can be suppressed, and color mixing between pixels can be suppressed.

[0039] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments.

[0040] (First embodiment) 1 shows a configuration of an imaging device 100A according to a first embodiment of the present disclosure. The imaging device 100A includes an imaging element 100. The imaging element 100 includes a semiconductor substrate 1 and a plurality of pixels 10. The plurality of pixels 10 are provided on the semiconductor substrate 1. Each pixel 10 is supported by the semiconductor substrate 1. A portion of the pixel 10 may be formed by the semiconductor substrate 1.

[0041] The semiconductor substrate 1 can be a circuit board including various electronic circuits, and is made of, for example, a Si substrate.

[0042] Each pixel 10 includes a photoelectric conversion unit 12. The photoelectric conversion unit 12 generates positive and negative charges, typically hole-electron pairs, upon receiving incident light. The photoelectric conversion unit 12 includes at least one photoelectric conversion layer disposed above the semiconductor substrate 1. In FIG. 1, the photoelectric conversion units 12 of each pixel 10 are shown spatially separated from one another. However, this is merely for convenience of explanation. The photoelectric conversion units 12 of the multiple pixels 10 may be continuously disposed on the semiconductor substrate 1 without any gaps between them. In other words, the photoelectric conversion units 12 of adjacent pixels may be electrically connected to one another.

[0043] 1, the pixels 10 are arranged in a plurality of rows and a plurality of columns, i.e., m rows and n columns. m and n are, independently, integers of 1 or more. The pixels 10 are arranged, for example, two-dimensionally on the semiconductor substrate 1 to form an imaging region. When the imaging device 100A is viewed in a plan view, the imaging element 100 can be defined as a region in which a photoelectric conversion layer exists.

[0044] In pixels arranged in m rows and n columns, if the pixel in x row and y column is represented as (x,y), the pixels adjacent to (x,y) are represented as (x-1,y-1), (x,y-1), (x+1,y-1), (x-1,y), (x+1,y), (x-1,y+1), (x,y+1), (x+1,y+1), (x+1,y+1), where x is a natural number less than m and y is a natural number less than n.

[0045] The number and arrangement of the pixels 10 are not particularly limited. In Fig. 1, the center of each pixel 10 is located on a lattice point of a square lattice. A plurality of pixels 10 may be arranged so that the center of each pixel 10 is located on a lattice point of a triangular lattice, a hexagonal lattice, or the like. By arranging the pixels 10 one-dimensionally, the image sensor 100 can be used as a line sensor.

[0046] The imaging device 100A has peripheral circuits formed on a semiconductor substrate 1.

[0047] The peripheral circuits include a vertical scanning circuit 52 and a horizontal signal readout circuit 54. The peripheral circuits may additionally include a control circuit 56 and a voltage supply circuit 58. The peripheral circuits may further include a signal processing circuit, an output circuit, and the like. Each circuit is provided on the semiconductor substrate 1. A part of the peripheral circuits may be disposed on a substrate other than the semiconductor substrate 1 on which the pixels 10 are formed.

[0048] The vertical scanning circuit 52 is also called a row scanning circuit. An address signal line 44 is provided corresponding to each row of the pixels 10, and the address signal line 44 is connected to the vertical scanning circuit 52. The signal line provided corresponding to each row of the pixels 10 is not limited to the address signal line 44, and a plurality of types of signal lines can be connected to the vertical scanning circuit 52 for each row of the pixels 10. The horizontal signal readout circuit 54 is also called a column scanning circuit. A vertical signal line 45 is provided corresponding to each column of the pixels 10, and the vertical signal line 45 is connected to the horizontal signal readout circuit 54.

[0049] The control circuit 56 receives command data, a clock, and the like provided from outside the imaging device 100A to control the entire imaging device 100A. Typically, the control circuit 56 has a timing generator and supplies drive signals to the vertical scanning circuit 52, the horizontal signal read circuit 54, the voltage supply circuit 58, and the like. The control circuit 56 can be realized, for example, by a microcontroller including one or more processors. The functions of the control circuit 56 may be realized by a combination of a general-purpose processing circuit and software, or may be realized by hardware specialized for such processing.

[0050] The voltage supply circuit 58 supplies a predetermined voltage to each pixel 10 via the voltage line 48. The voltage supply circuit 58 is not limited to a specific power supply circuit, and may be a circuit that converts a voltage supplied from a power source such as a battery into a predetermined voltage, or may be a circuit that generates a predetermined voltage. The voltage supply circuit 58 may be a part of the above-mentioned vertical scanning circuit 52. These circuits that constitute the peripheral circuits may be arranged in a peripheral region R2 outside the image sensor 100.

[0051] FIG. 2 shows a cross section of the image sensor 100.

[0052] Each pixel 10 has a plurality of photoelectric conversion layers. The plurality of photoelectric conversion layers include a first photoelectric conversion layer 121, a second photoelectric conversion layer 122, and a third photoelectric conversion layer 123. The first photoelectric conversion layer 121 may be a single layer shared by the plurality of pixels 10. The second photoelectric conversion layer 122 may be a single layer shared by the plurality of pixels 10. The third photoelectric conversion layer 123 may be a single layer shared by the plurality of pixels 10. However, each of the first photoelectric conversion layer 121, the second photoelectric conversion layer 122, and the third photoelectric conversion layer 123 may be divided for each pixel. "Shared by a plurality of pixels" means that it is shared between a specific pixel and at least one pixel adjacent to the specific pixel.

[0053] The first photoelectric conversion layer 121, the second photoelectric conversion layer 122, and the third photoelectric conversion layer 123 are made of a photoelectric conversion material. The photoelectric conversion material is typically an organic material.

[0054] The first photoelectric conversion layer 121 collects charges (first charges) corresponding to light in a first wavelength range. The second photoelectric conversion layer 122 collects charges (second charges) corresponding to light in a second wavelength range. The third photoelectric conversion layer 123 collects charges (third charges) corresponding to light in a third wavelength range. The first wavelength range is, for example, the wavelength range of blue light. The first photoelectric conversion layer 121 is made of a material sensitive to blue light. The second wavelength range is, for example, the wavelength range of green light. The second photoelectric conversion layer 122 is made of a material sensitive to green light. The third wavelength range is, for example, the wavelength range of red light. The third photoelectric conversion layer 123 is made of a material sensitive to red light.

[0055] In this embodiment, the first photoelectric conversion layer 121, the second photoelectric conversion layer 122, the third photoelectric conversion layer 123, and the semiconductor substrate 1 are arranged in this order. In the normal direction of the semiconductor substrate 1, the second photoelectric conversion layer 122 is arranged between the first photoelectric conversion layer 121 and the semiconductor substrate 1. In the normal direction of the semiconductor substrate 1, the third photoelectric conversion layer 123 is arranged between the second photoelectric conversion layer 122 and the semiconductor substrate 1. The arrangement order of the first photoelectric conversion layer 121, the second photoelectric conversion layer 122, and the third photoelectric conversion layer 123 is not limited to this order.

[0056] Each pixel 10 further has a plurality of pixel electrodes. The plurality of pixel electrodes include a first pixel electrode 13, a second pixel electrode 14, and a third pixel electrode 15. The first pixel electrode 13 is electrically connected to a first photoelectric conversion layer 121. The second pixel electrode 14 is electrically connected to a second photoelectric conversion layer 122. The third pixel electrode 15 is electrically connected to a third photoelectric conversion layer 123.

[0057] The first pixel electrode 13 and the second pixel electrode 14 are transparent electrodes that are translucent to visible light and / or near infrared light. The transparent electrodes are made of a transparent conductive oxide such as ITO (Indium Tin Oxide). The third pixel electrode 15 is a non-transparent electrode that is not translucent to visible light and / or near infrared light. Examples of materials for the non-transparent electrodes include metals, metal oxides, metal nitrides, conductive polysilicon, etc.

[0058] In this specification, "having light transmissivity" means that the transmittance of light in a specific wavelength range is 40% or more. The wavelength range of visible light is, for example, 400 nm to 780 nm. The wavelength range of near-infrared light is, for example, 780 nm to 2000 nm. The transmittance can be calculated by the method specified in Japanese Industrial Standard JIS R3106 (1998).

[0059] An insulating layer 8 is provided between the first pixel electrode 13 and the second pixel electrode 14. An insulating layer 9 is provided between the third pixel electrode 15 and the semiconductor substrate 1. The insulating layers 8 and 9 are made of an insulating material such as SiO2.

[0060] Each pixel 10 further has a plurality of counter electrodes. The plurality of counter electrodes include a first counter electrode 17 and a second counter electrode 18. The first counter electrode 17 and the second counter electrode 18 are each shared by a plurality of pixels 10. The first counter electrode 17 and the second counter electrode 18 are each a transparent electrode that is translucent to visible light and / or near-infrared light.

[0061] The first counter electrode 17 is provided corresponding to the first pixel electrode 13. The first photoelectric conversion layer 121 is sandwiched between the first counter electrode 17 and the first pixel electrode 13. The second counter electrode 18 is provided corresponding to the second pixel electrode 14 and the third pixel electrode 15. The second photoelectric conversion layer 122 is sandwiched between the second counter electrode 18 and the second pixel electrode 14. The third photoelectric conversion layer 123 is sandwiched between the second counter electrode 18 and the third pixel electrode 15. The first counter electrode 17 is electrically connected to the first photoelectric conversion layer 121. The second counter electrode 18 is electrically connected to the second photoelectric conversion layer 122. The second counter electrode 18 is electrically connected to the third photoelectric conversion layer 123.

[0062] In this embodiment, the second counter electrode 18 applies a voltage to both the second photoelectric conversion layer 122 and the third photoelectric conversion layer 123. However, the second counter electrode 18 may be configured to apply a voltage only to the second photoelectric conversion layer 122. A third counter electrode that applies a voltage to the third photoelectric conversion layer 123 may be provided.

[0063] Each pixel 10 may include a microlens. The microlenses may be arranged to form a surface of the image sensor 100. One or more microlenses may be arranged for each pixel 10. The microlenses may be arranged to focus light on an overlapping region between the first pixel electrode 13 and the second pixel electrode 14 when the image sensor 100 is viewed in plan.

[0064] Each pixel 10 further has a plurality of plugs. Each plug extends in a normal direction of the semiconductor substrate 1. The plurality of plugs include a first plug 31, a second plug 32, and a third plug 33. The first plug 31 electrically connects the semiconductor substrate 1 to the first pixel electrode 13. The second plug 32 electrically connects the semiconductor substrate 1 to the second pixel electrode 14. The third plug 33 electrically connects the semiconductor substrate 1 to the third pixel electrode 15.

[0065] The first plug 31, the second plug 32, and the third plug 33 are made of a conductive material, such as a metal, a metal oxide, a metal nitride, or conductive polysilicon.

[0066] The semiconductor substrate 1 has a plurality of charge storage regions. The charge storage regions may be parts of the pixels 10. Each charge storage region is an n-type or p-type impurity region. The plurality of charge storage regions include a first charge storage region 3, a second charge storage region 4, and a third charge storage region 5. The first plug 31 electrically connects the first charge storage region 3 to the first pixel electrode 13. The second plug 32 electrically connects the second charge storage region 4 to the second pixel electrode 14. The third plug 33 electrically connects the third charge storage region 5 to the third pixel electrode 15.

[0067] The semiconductor substrate 1 may have a number of transistors for reading out the charges stored in the first charge storage region 3, the second charge storage region 4 and the third charge storage region 5, and for resetting the stored charges.

[0068] The pixel electrode may be electrically connected to the charge storage region via a plug penetrating the semiconductor substrate and a wiring layer below the semiconductor substrate.

[0069] In this specification, "upper" and "lower" are defined based on the traveling direction of light. The side closer to the light incident surface is "upper", and the side farther from the light incident surface is "lower".

[0070] When the imaging element 10 is irradiated with light, electron-hole pairs are generated in each photoelectric conversion layer.

[0071] For example, when a voltage is applied between the first counter electrode 17 and the first pixel electrode 13 so that the potential of the first counter electrode 17 exceeds the potential of the first pixel electrode 13, holes which are positive charges are collected in the first pixel electrode 13, and electrons which are negative charges are collected in the first counter electrode 17. The holes collected in the first pixel electrode 13 are accumulated in the first plug 31 and the first charge accumulation region 3.

[0072] When a voltage is applied between the second opposing electrode 18 and the second pixel electrode 14 so that the potential of the second opposing electrode 18 exceeds the potential of the second pixel electrode 14, holes which are positive charges are collected in the second pixel electrode 14, and electrons which are negative charges are collected in the second opposing electrode 18. The holes collected in the second pixel electrode 14 are accumulated in the second plug 32 and the second charge accumulation region 4.

[0073] When a voltage is applied between the second opposing electrode 18 and the third pixel electrode 15 so that the potential of the second opposing electrode 18 exceeds the potential of the third pixel electrode 15, holes which are positive charges are collected in the third pixel electrode 15, and electrons which are negative charges are collected in the second opposing electrode 18. The holes collected in the third pixel electrode 15 are accumulated in the third plug 33 and the third charge accumulation region 5.

[0074] A blocking layer that prevents electric charges from flowing into the pixel electrode in the dark may be provided between the pixel electrode and the photoelectric conversion layer.

[0075] The imaging element 100 of this embodiment has a multi-layer structure. "Multi-layer" means that multiple photoelectric conversion layers exist in the normal direction of the semiconductor substrate 1. The multi-layer structure is advantageous in increasing the sensitivity of the pixel because it is possible to secure a sufficient area for the pixel electrode. In this embodiment, since there are three photoelectric conversion layers, it can be said that the imaging element 100 has a three-layer structure. The first photoelectric conversion layer 121, the second photoelectric conversion layer 122, and the third photoelectric conversion layer 123 typically have different photoelectric conversion characteristics from each other.

[0076] The arrangement of plugs for suppressing crosstalk between plugs will be described below.

[0077] 3A shows the arrangement of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the first plug 31, the second plug 32, and the third plug 33 when the imaging element 100 is viewed from the normal direction of the semiconductor substrate 1. In other words, FIG. 3A is a projection of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, and the first plug 31, the second plug 32, and the third plug 33 onto a plane perpendicular to the normal direction of the semiconductor substrate 1. The plugs in the upper layer penetrate the pixel electrodes in the lower layer as necessary. Alternatively, the pixel electrodes in the lower layer are cut out as necessary to avoid the plugs in the upper layer.

[0078] In this specification, viewing the imaging element 100 from the normal direction of the semiconductor substrate 1 is synonymous with viewing the imaging element 100 from a planar view.

[0079] When the imaging element 100 is viewed from the normal direction of the semiconductor substrate 1, in a plurality of adjacent pixels 10, the distance L1 between the first plugs 31 is shorter than the distance L2 between the first plugs 31 and the second plugs 32. In other words, the distance L2 between the first plugs 31 and the second plugs 32 is longer than the distance L1 between the first plugs 31. The distances L1 and L2 mean the shortest distances L1 and L2, respectively. With this configuration, crosstalk between plugs corresponding to different colors can be suppressed. This makes it possible to suppress color mixing. It is possible to sufficiently ensure the identity of colors between the obtained image and the subject. Specifically, it is possible to suppress color mixing between blue and green. In other words, it is possible to improve color separation.

[0080] Since the first pixel electrode 13 is the farthest from the semiconductor substrate 1, the first plug 31 is the longest plug. Therefore, crosstalk between the first plug 31 and other plugs is likely to become a problem. According to the present embodiment, since the first plug 31 is sufficiently far from the other plugs, the effect of suppressing crosstalk can be sufficiently obtained.

[0081] In addition, in the multiple pixels 10 adjacent to each other, the distance L1 between the first plugs 31 is shorter than the distance L3 between the first plugs 31 and the third plugs 33. In other words, the distance L3 between the first plugs 31 and the third plugs 33 is longer than the distance L1 between the first plugs 31. The distance L3 also means the shortest distance L3. With this configuration, it is possible to suppress the mixture of blue and red in addition to the mixture of blue and green. In other words, it is possible to improve the color separation.

[0082] The distance L1 between the first plugs 31 in the adjacent pixels 10 is shorter than the distance L2' between the first plug 31 and the second plug 32 in a specific pixel 10. In other words, the distance L2' between the first plug 31 and the second plug 32 in a specific pixel 10 is longer than the distance L1 between the first plugs 31 in the adjacent pixels 10. The distance L1 between the first plugs 31 in the adjacent pixels 10 is shorter than the distance L3' between the first plug 31 and the third plug 33 in the specific pixel 10. The distances L2' and L3' also refer to the shortest distances L2' and L3'.

[0083] According to this embodiment, the distance between long plugs is short and the distance between a long plug and a short plug is long in adjacent pixels 10. This configuration is highly effective in suppressing crosstalk.

[0084] In this specification, the "distance between plugs" means the distance between the centers of the plugs. The shape of the plugs in a plan view is not necessarily circular. Therefore, the "center of the plug" means the center of gravity of the plug.

[0085] A wiring layer may be provided between the semiconductor substrate 1 and the third photoelectric conversion layer 123. When a wiring layer is provided, the first plug 31, the second plug 32, and the third plug 33 may be electrically connected to the first charge accumulation region 3, the second charge accumulation region 4, and the third charge accumulation region 5, respectively, via the wiring layer. When the first plug 31, the second plug 32, and the third plug 33 are connected to the first charge accumulation region 3, the second charge accumulation region 4, and the third charge accumulation region 5, respectively, via the wiring layer, the "distance between the plugs" means the distance between the portions connecting the pixel electrode and the wiring layer.

[0086] In the image sensor 100 of this embodiment, there are eight pixels 10 adjacent to a particular pixel 10, except when the particular pixel 10 is a pixel 10 located at the outermost periphery of the image sensor 100. This also applies to the other embodiments.

[0087] In the example shown in Fig. 3A, the first pixel electrode 13, the second pixel electrode 14, and the third pixel electrode 15 have a rectangular shape. The first pixel electrode 13, the second pixel electrode 14, and the third pixel electrode 15 are typically square in shape. The shape of the pixel electrodes is not limited to a rectangle. The shape of the pixel electrodes may be a polygon other than a rectangle, a circle, or a shape with a part cut out.

[0088] 3B shows another arrangement of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, and the first plug 31, the second plug 32, and the third plug 33. In the example shown in FIG. 3B, in a plurality of adjacent pixels 10, the distance L1 between the first plugs 31 is shorter than the distance L2 between the first plug 31 and the second plug 32. In addition, in a plurality of adjacent pixels 10, the distance L1 between the first plugs 31 is shorter than the distance L3 between the first plug 31 and the third plug 33. Therefore, in the arrangement shown in FIG. 3B, the same effect as that described with reference to FIG. 3A can be obtained.

[0089] 3C shows yet another arrangement of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the first plug 31, the second plug 32, and the third plug 33. In the example shown in FIG. 3C, the distance L1 between the first plugs 31 in the adjacent pixels 10 is shorter than the distance L2 between the first plug 31 and the second plug 32. In addition, the distance L1 between the first plugs 31 in the adjacent pixels 10 is shorter than the distance L3 between the first plug 31 and the third plug 33. Therefore, the arrangement shown in FIG. 3C also provides the same effect as that described with reference to FIG. 3A.

[0090] 3B and 3C, the upper layer plug also penetrates the lower layer pixel electrode as necessary, or the lower layer pixel electrode is cut out as necessary to avoid the upper layer plug.

[0091] In the examples shown in FIGS. 3B and 3C, the first plug 31 and the second plug 32 are arranged diagonally. The first plug 31 and the second plug 32 may be arranged near the diagonal of the first pixel electrode 13. The first plug 31 and the second plug may be arranged on the diagonal of the first pixel electrode 13. With such an arrangement, crosstalk in a single pixel 10 can also be suppressed. "The plugs are arranged on the diagonal of the first pixel electrode 13" means that each plug overlaps with the diagonal of the smallest rectangle surrounding the first pixel electrode 13 when the imaging element is viewed in a plan view.

[0092] The third photoelectric conversion layer 123 is the photoelectric conversion layer located at the bottom. The third plug 33 is shorter than the first plug 31 and shorter than the second plug 32. The influence of crosstalk between the third plug 33 and other plugs is small. Therefore, the third plug 33 can be arranged at any position. In this embodiment, the third plug 33 is arranged in the central region of the third pixel electrode 15. With such a configuration, the distance between the first charge storage region 3, the second charge storage region 4, and the third charge storage region 5 can be sufficiently secured. This makes it possible to suppress crosstalk between the charge storage regions, and also to suppress crosstalk between the charge storage regions and the plugs. The design freedom of the third charge storage region 5 and the transistor connected to the third plug 33 is improved. The "central region of the pixel electrode" means a region having a certain width including the center of gravity of the pixel electrode when the pixel electrode is viewed in a plane. Specifically, when the pixel electrode has a roughly rectangular shape in a plane view, the pixel electrode is divided into nine rectangular regions so that the areas of the divided regions are equal to each other. Among the nine rectangular regions, the region including the center of gravity of the pixel electrode is the central region. When the pixel electrode has a notch or the like, the smallest rectangle surrounding the pixel electrode may be divided into nine. The center of gravity of the pixel electrode may be the center of gravity of the smallest rectangle surrounding the pixel electrode.

[0093] The third plug 33 may be disposed on the midpoint of a line segment connecting the first plug 31 and the second plug 32. The line segment connecting the first plug 31 and the second plug 32 means a line segment connecting the center of gravity of the first plug 31 and the center of gravity of the second plug 32 when the imaging element is viewed in a plan view. "The third plug 33 is disposed on the midpoint of the line segment" means that the third plug 33 overlaps with the midpoint.

[0094] The third plug 33 may be disposed at the center of the third pixel electrode 15. In other words, when the image sensor 100 is viewed in a plan view, the center of the third pixel electrode 15 may overlap with the third plug 33. The "center of the pixel electrode" may be the center of gravity of the pixel electrode when the pixel electrode is viewed in a plan view.

[0095] FIG. 4A shows another shape of the first pixel electrode 13, the second pixel electrode 14, and the third pixel electrode 15. FIG. 4B shows the arrangement of the first plug 31, the second plug 32, and the third plug 33 when the pixel 10 has the first pixel electrode 13, the second pixel electrode 14, and the third pixel electrode 15 shown in FIG. 4A. In the example shown in FIG. 4A and FIG. 4B, the first pixel electrode 13, the second pixel electrode 14, and the third pixel electrode 15 have a regular hexagonal shape in a planar view. Each pixel 10 of the image sensor 100 occupies a regular hexagonal area in a planar view. The multiple pixels 10 have a honeycomb structure or a structure in which a honeycomb structure is partially missing. The pixels with a honeycomb structure make it easy to collect plugs of the same color. "Planar view" is synonymous with viewing the image sensor 100 from the normal direction of the semiconductor substrate 1. The structure in which a honeycomb structure is partially missing means a structure formed by arranging multiple regular hexagons with parts cut out.

[0096] When the pixels 10 have a honeycomb structure, there are six pixels 10 adjacent to a particular pixel 10.

[0097] In this embodiment, the first plugs 31, the second plugs 32, and the third plugs 33 are arranged periodically, and the pixels 10 have translational symmetry. Therefore, crosstalk between the plugs can be uniformly reduced, and the variation in crosstalk between the pixels 10 can also be reduced.

[0098] Other embodiments will be described below. Elements common to the first embodiment and other embodiments are given the same reference numerals, and their description may be omitted. The descriptions of each embodiment may be mutually applied unless there is a technical contradiction. Each embodiment may be combined with each other unless there is a technical contradiction.

[0099] Second embodiment FIG. 5 shows a cross section of an imaging element 200 according to a second embodiment of the present disclosure. The imaging element 200 has a two-layer structure. In the normal direction of the semiconductor substrate 1, the second photoelectric conversion layer 122 is disposed above the first photoelectric conversion layer 121. In other words, the first photoelectric conversion layer 121 is disposed between the second photoelectric conversion layer 122 and the semiconductor substrate 1. The first plug 31 electrically connects the semiconductor substrate 1 to the first pixel electrode 13. The second plug 32 electrically connects the semiconductor substrate 1 to the second pixel electrode 14. According to this configuration, the first plug 31 can be made shorter than the second plug 32, and therefore crosstalk between the first plugs 31 can be suppressed while crosstalk between the first plugs 31 and the second plugs 32 is suppressed.

[0100] The first photoelectric conversion layer 121 collects charges corresponding to light in a first wavelength range. The second photoelectric conversion layer 122 collects charges corresponding to light in a second wavelength range. The first wavelength range and the second wavelength range are not limited to specific wavelength ranges. The first wavelength range and the second wavelength range may overlap as long as the central wavelength of the first wavelength range and the central wavelength of the second wavelength range are different. The same applies to the third wavelength range.

[0101] The first wavelength range is, for example, a wavelength range of light other than visible light. The first wavelength range is, for example, a wavelength range of near-infrared light. The first photoelectric conversion layer 121 can be made of a material sensitive to near-infrared light. The second wavelength range is, for example, a wavelength range of visible light. The second photoelectric conversion layer 122 can be made of a material sensitive to visible light. With this configuration, it is possible to suppress mixing of visible light information and near-infrared light information.

[0102] The imaging element 200 further includes a color filter 19. The color filter 19 is disposed above the first photoelectric conversion layer 121 and the second photoelectric conversion layer 122. The second photoelectric conversion layer 122 is irradiated with light that has passed through the color filter 19. The color filter 19 is, for example, a Bayer filter.

[0103] In this embodiment, the pixel 10 is composed of a plurality of sub-pixels 10a. The plurality of sub-pixels 10a includes a red sub-pixel 10r, a green sub-pixel 10g, a blue sub-pixel 10b arranged in two rows and two columns. The red sub-pixels 10r, the green sub-pixels 10g, the green sub-pixels 10g, and the blue sub-pixels 10b are arranged according to a Bayer array.

[0104] According to this embodiment, it is possible to obtain a full-color image by the second photoelectric conversion layer 122, while obtaining an image based on near-infrared light by the first photoelectric conversion layer 121.

[0105] Fig. 6 is a diagram showing the arrangement of the first pixel electrode 13, the second pixel electrode 14, the first plug 31, and the second plug 32 when the imaging element 200 is viewed from the normal direction of the semiconductor substrate 1. In other words, Fig. 6 is a projection diagram of the first pixel electrode 13, the second pixel electrode 14, the first plug 31, and the second plug 32 onto a plane perpendicular to the normal direction of the semiconductor substrate 1.

[0106] When the imaging element 200 is viewed from the normal direction of the semiconductor substrate 1, in a plurality of pixels 10 adjacent to each other, the distance L1 between the first plugs 31 is shorter than the distance L2 between the first plugs 31 and the second plugs 32. In other words, the distance L2 between the first plugs 31 and the second plugs 32 is longer than the distance L1 between the first plugs 31. With this configuration, crosstalk between plugs corresponding to different colors can be suppressed. Specifically, crosstalk between the first plugs 31 corresponding to near-infrared light and the second plugs 32 corresponding to visible light can be suppressed. As a result, mixing of near-infrared light information and visible light information can be suppressed. When a color filter is used, "visible light information" means information of red light, green light, and blue light, which are information of the three primary colors.

[0107] Near-infrared light information is likely to be used for purposes different from those for which visible light information is used. Therefore, it can be said that it is of great value if crosstalk between the first plug 31 and the second plug 32 can be suppressed to prevent the near-infrared light information and the visible light information from being mixed together.

[0108] In this embodiment, the first plugs 31 of a plurality of pixels 10 adjacent to each other are gathered together. This is advantageous in terms of ensuring a sufficient distance between the second plugs 32. A signal corresponding to visible light is transmitted to the second plug 32. A signal corresponding to near-infrared light is transmitted to the first plug 31. Compared to an image based on near-infrared light, an image based on visible light requires a higher resolution. Ensuring a sufficient distance between the second plugs 32 meets this requirement.

[0109] Specifically, in multiple adjacent pixels 10, the distance L3 between the second plugs 32 is longer than the distance L1 and longer than the distance L2. With this configuration, color mixing among red, green, and blue colors can be suppressed.

[0110] 7 is a plan view of the first pixel electrode 13. As shown in FIG. 7, the second plug 32 extends vertically to avoid the first pixel electrode 13, or passes through a through hole provided in the first pixel electrode 13. When the second plug 32 is present in the outer periphery of the pixel 10, a space for the second plug 32 can be secured by cutting out a part of the first pixel electrode 13 or removing a corner of the first pixel electrode 13. When the second plug 32 is present near the center of the pixel 10, a through hole for passing the second plug 32 is provided in the first pixel electrode 13.

[0111] Third embodiment 8 shows a cross section of an imaging element 300 according to a third embodiment of the present disclosure. The imaging element 300 of this embodiment differs from the imaging element 200 of the second embodiment in the arrangement of the plugs.

[0112] In the normal direction of the semiconductor substrate 1, the second photoelectric conversion layer 122 is disposed between the first photoelectric conversion layer 121 and the semiconductor substrate 1. In this embodiment, the first photoelectric conversion layer 121 is a layer for forming an image based on visible light, and the second photoelectric conversion layer 122 is a layer for forming an image based on near-infrared light. That is, except for the different names, the configuration of this embodiment is common to the configuration of the second embodiment. The layer for forming an image based on visible light is the upper layer, and the layer for forming an image based on near-infrared light is the lower layer. Even with such a configuration, the second plug 32 can be made shorter than the first plug 31, so that crosstalk between the first plug 31 and the second plug 32 can be suppressed while crosstalk between the second plugs 32 can be suppressed.

[0113] The first photoelectric conversion layer 121 collects charges corresponding to light in a first wavelength range. The second photoelectric conversion layer 122 collects charges corresponding to light in a second wavelength range. In this embodiment, the first wavelength range is the wavelength range of visible light. The second wavelength range is the wavelength range of near-infrared light. This configuration makes it possible to suppress mixing of visible light information and near-infrared light information.

[0114] Fig. 9 is a diagram showing the arrangement of the first pixel electrode 13, the second pixel electrode 14, the first plug 31, and the second plug 32 when the image sensor 300 is viewed from the normal direction of the semiconductor substrate 1. In other words, Fig. 9 is a projection diagram of the first pixel electrode 13, the second pixel electrode 14, the first plug 31, and the second plug 32 onto a plane perpendicular to the normal direction of the semiconductor substrate 1.

[0115] In this embodiment, the sub-pixels 10a include a red sub-pixel 10r, a green sub-pixel 10g, and a blue sub-pixel 10b arranged in two rows and two columns. The red sub-pixels 10r, the green sub-pixels 10g, and the blue sub-pixels 10b are arranged according to the Bayer array.

[0116] When the imaging element 300 is viewed from the normal direction of the semiconductor substrate 1, in a plurality of adjacent pixels 10, the distance L1 between the first plugs 31 is shorter than the distance L2 between the first plug 31 and the second plug 32. In detail, the distance L1 is the distance between the first plugs 31 of the green subpixels 10g adjacent to each other. In a plurality of adjacent pixels 10, the distance from the first plug 31 of the green subpixel 10g to the first plug 31 of the red subpixel 10r is longer than the above-mentioned distance L1. Similarly, in a plurality of adjacent pixels 10, the distance from the first plug 31 of the green subpixel 10g to the first plug 31 of the blue subpixel 10b is longer than the above-mentioned distance L1.

[0117] In this embodiment, crosstalk between plugs corresponding to different colors can also be suppressed. Specifically, crosstalk between the first plug 31 corresponding to visible light and the second plug 32 corresponding to near-infrared light can be suppressed. As a result, mixing of near-infrared light information and visible light information can be suppressed.

[0118] FIG. 10 is a plan view of the second pixel electrode 14. As shown in FIG. 10, the first plug 31 extends vertically avoiding the second pixel electrode 14. The second plug 32 is located, for example, in the central region of the pixel 10. According to this embodiment, the first plug 31 extending from the first pixel electrode 13 in the upper layer to the semiconductor substrate 1 does not penetrate the second pixel electrode 14 in the lower layer. The first plug 31 is disposed around the second pixel electrode 14 in a plan view. In other words, when the imaging element 300 is viewed from the normal direction of the semiconductor substrate 1, the first plug 31 is located outside the range of the second pixel electrode 14. According to such a configuration, the variation in thickness of the second photoelectric conversion layer 122, the surface roughness of the second photoelectric conversion layer 122, and the like can be reduced. As a result, the image quality obtained from the second photoelectric conversion layer 122 is improved.

[0119] FIG. 11 is a plan view showing another positional relationship between the second pixel electrode 14, the first pixel electrode 13, and the first plug 31. In the example shown in FIG. 11, the area of ​​the lower second pixel electrode 14 is smaller than the total area of ​​the four upper first pixel electrodes 13. In detail, the area of ​​the smallest rectangle surrounding the four first pixel electrodes 13 is larger than the area of ​​the second pixel electrode 14. According to such a configuration, the second pixel electrode 14 can be formed while avoiding the first plug 31, so that the variation in thickness of the second photoelectric conversion layer 122, which is the lower photoelectric conversion layer, and the surface roughness of the second photoelectric conversion layer 122 can be further reduced. The area and shape of the first pixel electrode 13 may be the same for each of the red subpixel 10r, the green subpixel 10g, the green subpixel 10g, and the blue subpixel 10b, or may be different from each other for each of the red subpixel 10r, the green subpixel 10g, the green subpixel 10g, and the blue subpixel 10b.

[0120] (Variation 1) FIG. 12A shows another structure of the pixel 10 of the imaging element 300 having a two-layer structure. In this modification, the upper first photoelectric conversion layer 121 (FIG. 8) has sensitivity to the wavelength range of red light and the wavelength range of blue light. The lower second photoelectric conversion layer 122 (FIG. 8) has sensitivity to the wavelength range of green light. That is, the first wavelength range includes the wavelength range of red light and the wavelength range of blue light. The second wavelength range includes the wavelength range of green light. The first photoelectric conversion layer 121 can be made using a mixed material of a photoelectric conversion material having sensitivity to the wavelength range of red light and a photoelectric conversion material having sensitivity to the wavelength range of blue light. The mixed material includes, for example, a fullerene derivative and phthalocyanine. The second photoelectric conversion layer 122 can be made using a photoelectric conversion material having sensitivity to the wavelength range of green light. The red sub-pixel 10r can occupy an area equal to half the area of ​​one pixel 10. The red sub-pixel 10r may occupy an area equal to half the area of ​​one pixel 10. The green sub-pixel 10g may occupy an area equal to half the area of ​​one pixel 10. Two green sub-pixels 10g exist in one pixel 10. This configuration ensures the benefits of the multi-layer structure while increasing the area of ​​the green sub-pixel 10g, which has high luminosity. Therefore, this modification makes it possible to obtain an image with sensitivity comparable to that of an image sensor having a Bayer array. In addition, the color of each pixel can be determined by image processing similar to that in an image sensor that employs a Bayer array.

[0121] In detail, in the square region of the pixel 10, the first pixel electrode 13 constituting the red sub-pixel 10r has a rectangular shape. The first pixel electrode 13 constituting the blue sub-pixel 10b also has a rectangular shape. The second pixel electrode 14 constituting the green sub-pixel 10g also has a rectangular shape. The longitudinal direction of the first pixel electrode 13 is perpendicular to the longitudinal direction of the second pixel electrode 14. However, the shapes of the first pixel electrode 13 and the second pixel electrode 14 are not particularly limited.

[0122] The color filter 19 includes a color filter 191 that cuts blue light and a color filter 192 that cuts red light. The first pixel electrode 13 constituting the red subpixel 10r is covered with the color filter 191 that cuts blue light. The first photoelectric conversion layer 121 constituting the red subpixel 10r is sensitive to red light. The first pixel electrode 13 constituting the blue subpixel 10b is covered with a color filter 192 that cuts red light. The first photoelectric conversion layer 121 constituting the blue subpixel 10b is sensitive to blue light. Green light passes through the color filter 19 and the first photoelectric conversion layer 121, and is absorbed by the second photoelectric conversion layer 122. The second photoelectric conversion layer 122 constituting the green subpixel 10g is sensitive to green light. The color filters 191 and 192 reliably separate the red light, the green light, and the blue light. An R signal, a G signal, and a B signal are extracted from the red sub-pixel 10r, the green sub-pixel 10g, and the blue sub-pixel 10b. According to this modification, it is possible to obtain an image with a sensitivity comparable to that of an image sensor having a Bayer array while ensuring the benefits of a multi-layer structure. According to this modification, it is possible to impart sensitivity to the wavelength ranges of blue light, red light, and green light to the image sensor. This makes it possible to obtain a full-color image. It is possible to determine the color of each pixel by image processing similar to that in an image sensor employing a Bayer array.

[0123] FIG. 12B shows the arrangement of the plugs 31 and 32 when the pixel 10 has the structure shown in FIG. 12A. In the plurality of adjacent pixels 10, the distance L1 between the first plugs 31 is shorter than the distance L2 between the first plug 31 and the second plug 32. In particular, in the plurality of adjacent pixels 10, the distance L1 between the first plug 31 of the blue subpixel 10b and the first plug 31 of the other blue subpixel 10b is equal to the distance L1 between the first plug 31 of the red subpixel 10r and the first plug 31 of the other red subpixel 10r. In the plurality of adjacent pixels 10, the distance L3 between the second plug 32 of the green subpixel 10g and the second plug 32 of the other green subpixel 10g is, for example, equal to the distance L1. In the plurality of adjacent pixels 10, the distance L4 between the first plug 31 of the blue subpixel 10b and the first plug 31 of the red subpixel 10r is approximately equal to the length of the long side of the first pixel electrode 13. The distance L4 also means the shortest distance L4. The distance L4 is longer than the distance L1. That is, in the multiple pixels 10 adjacent to each other, the first plugs 31 of two red subpixels 10r form a pair. The second plugs 32 of two green subpixels 10g form a pair. The first plugs 31 of two blue subpixels 10b form a pair. The distances between the plugs of subpixels of different colors are the distances L2 and L4, which are sufficiently longer than the distances L1 and L3.

[0124] Therefore, in this modified example, crosstalk between plugs corresponding to different colors can also be suppressed, thereby suppressing color mixing, and ensuring sufficient color identity between the obtained image and the subject.

[0125] According to this embodiment, the upper first photoelectric conversion layer 121 has sensitivity to the red light wavelength region and the blue light wavelength region, and the lower second photoelectric conversion layer 122 has sensitivity to the green light wavelength region. The second plug 32 of the green subpixel 10g is shorter than the first plug 31 of the red subpixel 10r and the first plug 31 of the blue subpixel 10b. Therefore, the second plug 32 of the green subpixel 10g is less susceptible to crosstalk. This makes it possible to suppress color mixing between the green color, which has a high luminosity factor, and other colors. This is very beneficial for improving image quality.

[0126] The upper first photoelectric conversion layer 121 may constitute the green subpixel 10g. The lower second photoelectric conversion layer 122 may constitute the red subpixel 10r and the blue subpixel 10b. In this case, the color filter 19 may be disposed between the first photoelectric conversion layer 121 and the second photoelectric conversion layer 122 in the normal direction of the semiconductor substrate 1.

[0127] (Variation 2) 13A shows yet another structure of the pixel 10 of the imaging element 300 having a two-layer structure. In this modification, the pixel 10 has a sub-pixel 10m including a first pixel electrode 13 and a sub-pixel 10i including a second pixel electrode 14. The sub-pixel 10m is a pixel for forming an image based on black and white light (i.e., only brightness). The sub-pixel 10i is a pixel for forming an image based on near-infrared light.

[0128] The sub-pixel 10m includes a first photoelectric conversion layer 121 and a first pixel electrode 13 (FIG. 8) in the upper layer. The sub-pixel 10i includes a second photoelectric conversion layer 122 and a second pixel electrode 14 (FIG. 8) in the lower layer. The first photoelectric conversion layer 121 in the upper layer has sensitivity to the wavelength range of visible light. The second photoelectric conversion layer 122 in the lower layer has sensitivity to the wavelength range of near-infrared light. That is, the first wavelength range includes the wavelength range of visible light. The second wavelength range includes the wavelength range of near-infrared light. The first photoelectric conversion layer 121 can be made using a photoelectric conversion material that has sensitivity to the wavelength range of visible light. The second photoelectric conversion layer 122 can be made using a photoelectric conversion material that has sensitivity to the wavelength range of near-infrared light.

[0129] FIG. 13B shows the arrangement of the first plugs 31 and the second plugs 32 when the pixel 10 has the structure shown in FIG. 13A. In a plurality of pixels 10 adjacent to each other, the distance L1 between the first plugs 31 is shorter than the distance L2 between the first plugs 31 and the second plugs 32. Therefore, in this modified example, crosstalk between plugs corresponding to different colors, black and white and near infrared, can be suppressed. This makes it possible to suppress color mixing. The color identity between the obtained image and the subject can be sufficiently ensured.

[0130] The adjacent pixels 10 to which the pair of first plugs 31 exhibiting the distance L1 belong may be different from the adjacent pixels 10 to which the first plug 31 and the second plug 32 exhibiting the distance L2 belong.

[0131] In a plurality of pixels 10 adjacent to each other, the distance L3 between the second plugs 32 may be equal to, shorter than, or longer than the distance L1 between the first plugs 31. The position of the first photoelectric conversion layer 121 may be interchanged with the position of the second photoelectric conversion layer 122. That is, the upper layer may be a layer sensitive to near-infrared light, and the lower layer may be a layer sensitive to visible light. The upper layer may be a layer sensitive to ultraviolet light, near-infrared light, red light, green light, blue light, or visible light, and the lower layer may be a layer sensitive to light in a wavelength range different from that of the upper layer.

[0132] (Fourth embodiment) 14A shows a cross section of an image sensor 400 according to the fourth embodiment. The image sensor 400 also has a two-layer structure. Each pixel of the image sensor 400 further includes a photodiode PD instead of the third photoelectric conversion layer 123, the third pixel electrode 15, the third plug 33, and the third charge accumulation region 5 of the image sensor 100 described with reference to FIG. 2.

[0133] The photodiode PD is provided on the semiconductor substrate 1. Each of the first pixel electrode 13 and the second pixel electrode 14 has light-transmitting properties. Between the photodiode PD and the second photoelectric conversion layer 122, a color filter 19r or a color filter 19b is provided. Each of the photodiodes PD is covered with the color filter 19r or the color filter 19b. Between the photodiode PD and the color filters 19r and 19b, an insulating layer 25 is provided. The insulating layer 25 is made of an insulating material such as SiO2. Between the first pixel electrode 13 and the color filters 19r and 19b, an insulating layer 7 is present. The insulating layer 7 also functions as a planarization layer and can be made of a transparent resin such as an acrylic resin or an epoxy resin. The imaging element 400 includes a condenser lens 21. The condenser lens 21 functions to effectively guide light to the photodiode PD. The condenser lens is synonymous with the microlens described above.

[0134] The first photoelectric conversion layer 121 has sensitivity to, for example, a wavelength range of near-infrared light. The first photoelectric conversion layer 121 can be made of a photoelectric conversion material having sensitivity to the wavelength range of near-infrared light. The second photoelectric conversion layer 122 has sensitivity to, for example, a wavelength range of green light. The second photoelectric conversion layer 122 can be made of a photoelectric conversion material having sensitivity to the wavelength range of green light. The photodiode PD is typically a silicon photodiode. The color filter 19r is a filter that cuts off red light. The color filter 19b is a filter that cuts off blue light.

[0135] Since the first photoelectric conversion layer 121 has sensitivity to the wavelength region of near-infrared light, and the second photoelectric conversion layer 122 has sensitivity to the wavelength region of green light, the red light and the blue light reach the color filters 19r and 19b. The red light is blocked by the color filter 19r, and only the blue light is incident on the photodiode PD. The blue light is blocked by the color filter 19b, and only the red light is incident on the photodiode PD. Therefore, the imaging element 400 can form an image based on near-infrared light and a full-color image.

[0136] FIG. 14B shows the arrangement of the first pixel electrode 13, the second pixel electrode 14, the first plug 31, the second plug 32, and the photodiode PD when the imaging element 400 is viewed from the normal direction of the semiconductor substrate 1. As the arrangement of the first plug 31 and the second plug 32 in the imaging element 400 of this embodiment, for example, an arrangement similar to the arrangement of the first plug 31 and the second plug 32 described with reference to FIG. 13B is adopted. That is, in a plurality of pixels 10 adjacent to each other, the distance L1 between the first plugs 31 is shorter than the distance L2 between the first plug 31 and the second plug 32. Therefore, even in this modified example, crosstalk between plugs corresponding to near-infrared light and green light, which are different colors of light, can be suppressed. This makes it possible to suppress color mixing. The color identity between the obtained image and the subject can be sufficiently ensured.

[0137] The adjacent pixels 10 to which the pair of first plugs 31 exhibiting the distance L1 belong may be different from the adjacent pixels 10 to which the first plug 31 and the second plug 32 exhibiting the distance L2 belong.

[0138] In multiple pixels 10 adjacent to each other, the distance L3 between the second plugs 32 may be equal to, shorter than, or longer than the distance L1 between the first plugs 31. The position of the first photoelectric conversion layer 121 may be interchanged with the position of the second photoelectric conversion layer 122. In other words, the upper layer may be a layer sensitive to green light, and the lower layer may be a layer sensitive to near-infrared light.

[0139] Fifth embodiment 15A shows the configuration of an imaging element 500 according to a fifth embodiment of the present disclosure. The imaging element 500 has a four-layer structure. In addition to the configuration of the imaging element 100 of the first embodiment, the imaging element 500 has a fourth photoelectric conversion layer 124, a fourth pixel electrode 16, and a fourth plug 34. That is, the pixel 10 of the imaging element 500 includes a sub-pixel 10i. The sub-pixel 10i is configured by the fourth pixel electrode 16.

[0140] In the normal direction of the semiconductor substrate 1, the fourth photoelectric conversion layer 124 is disposed, for example, between the third photoelectric conversion layer 123 and the semiconductor substrate 1. The fourth pixel electrode 16 is electrically connected to the fourth photoelectric conversion layer 124 and collects charges corresponding to light in a fourth wavelength range. The fourth wavelength range is, for example, a wavelength range of near-infrared light. The fourth photoelectric conversion layer 124 is made of a material sensitive to near-infrared light. The fourth plug 34 electrically connects the semiconductor substrate 1 and the fourth pixel electrode 16.

[0141] Visible light is absorbed by the upper first photoelectric conversion layer 121, the second photoelectric conversion layer 122, and the third photoelectric conversion layer 123. Since visible light does not reach the fourth photoelectric conversion layer 124 that is sensitive to near-infrared light, it is possible to form a sub-pixel 10i that is sensitive only to near-infrared light. An image based on near-infrared light can be obtained by the sub-pixel 10i.

[0142] Figure 15B shows an arrangement of the first plug 31, the second plug 32, the third plug 33 and the fourth plug 34 when the pixel 10 has the structure shown in Figure 15A. In Figure 15B, each plug is represented by four different symbols.

[0143] In the plurality of pixels 10 adjacent to each other, the distance L5 between the fourth plug 34 and the other fourth plug 34 is shorter than the distance L6 between the fourth plug 34 and the first plug 31. Therefore, in the present embodiment, crosstalk between plugs corresponding to different colors can be suppressed. Similarly, in the plurality of pixels 10 adjacent to each other, the distance L5 between the fourth plug 34 and the other fourth plug 34 is shorter than the distance between the fourth plug 34 and the second plug 32, and shorter than the distance between the fourth plug 34 and the third plug 33. This makes it possible to suppress color mixing.

[0144] In this embodiment, the photoelectric conversion layer sensitive to near-infrared light is the fourth photoelectric conversion layer 124, and the photoelectric conversion layer sensitive to blue light is the first photoelectric conversion layer 121. However, since the stacking order of each layer is arbitrary, it is also possible to define the photoelectric conversion layer sensitive to near-infrared light as the "first photoelectric conversion layer 121" and the photoelectric conversion layer sensitive to blue, green, or red light as the "second photoelectric conversion layer 122." In this case, in multiple pixels 10 adjacent to each other, the distance between the first plugs is significantly shorter than the distance between the first plug and the second plug.

[0145] The technical concepts explained in the above first to fifth embodiments can also be applied to an imaging element having only one photoelectric conversion layer.

[0146] Sixth embodiment FIG. 16 shows a cross section of an imaging element 600 according to a sixth embodiment of the present disclosure. The imaging element 600 has only one photoelectric conversion layer 120. In this embodiment, the pixels 10 include, for example, a plurality of sub-pixels that are first pixels 10i and a plurality of sub-pixels that are second pixels 10m. The sub-pixels 10i that are first pixels are pixels that have sensitivity in the wavelength range of near-infrared light. The sub-pixels that are first pixels 10i are, in particular, pixels for forming an image based on near-infrared light. The sub-pixels that are second pixels 10m are pixels that have sensitivity in the wavelength range of visible light. The sub-pixels that are second pixels 10m are, in particular, pixels for forming an image based on black and white light (i.e., only brightness). The photoelectric conversion layer 120 can be made using a mixed material of a photoelectric conversion material that is sensitive in the wavelength range of visible light and a photoelectric conversion material that is sensitive in the wavelength range of near-infrared light. A layer made of a photoelectric conversion material sensitive to the wavelength range of visible light and a layer made of a photoelectric conversion material sensitive to the wavelength range of near-infrared light may be stacked to form a single photoelectric conversion layer 120. The filter 19 blocks visible light from entering the photoelectric conversion layer 120 of the sub-pixel 10i, which is the first pixel, and blocks near-infrared light from entering the photoelectric conversion layer 120 of the sub-pixel 10m, which is the second pixel.

[0147] The photoelectric conversion layer 120 includes a first photoelectric conversion layer 120a and a second photoelectric conversion layer 120b. The first photoelectric conversion layer 120a and the second photoelectric conversion layer 120b each constitute a part of a continuous single photoelectric conversion layer 120. The first photoelectric conversion layer 120a is a part of the photoelectric conversion layer 120 that constitutes the sub-pixel 10i, which is a first pixel. The second photoelectric conversion layer 120b is a part of the photoelectric conversion layer 120 that constitutes the sub-pixel 10m, which is a second pixel. Between the pixels 10 adjacent to each other, the photoelectric conversion layer 120 may be spatially separated into a plurality of parts. That is, the first photoelectric conversion layer 120a and the second photoelectric conversion layer 120b may be separated.

[0148] Each of the sub-pixels 10i, which is the first pixel, has a first photoelectric conversion layer 120a, a first pixel electrode 63, and a first plug 66. The first pixel electrode 63 is electrically connected to the first photoelectric conversion layer 120a and collects charges corresponding to light in a first wavelength range. The first wavelength range is a wavelength range of near-infrared light. The first plug 66 electrically connects the semiconductor substrate 1 and the first pixel electrode 63. The tip of the first plug 66 is connected to a charge accumulation region 69.

[0149] Each of the sub-pixels 10m, which is the second pixel, has a second photoelectric conversion layer 120b, a second pixel electrode 64, and a second plug 67. The second pixel electrode 64 is electrically connected to the second photoelectric conversion layer 120b and collects charges corresponding to light in a second wavelength range. The second wavelength range is the wavelength range of visible light. The second plug 67 electrically connects the semiconductor substrate 1 and the second pixel electrode 64. The tip of the second plug 67 is connected to the charge accumulation region 70.

[0150] FIG. 17 shows the arrangement of the first pixel electrode 63, the second pixel electrode 64, the first plug 66, and the second plug 67 when the imaging element 600 is viewed from the normal direction of the semiconductor substrate 1. In this embodiment, the sub-pixel 10i which is the first pixel and the sub-pixel 10m which is the second pixel are arranged in a two-color checkered pattern. The distance La between the first plugs 66 in the sub-pixels 10i adjacent to each other is shorter than the distance Lc between the first plug 66 and the second plug 67 in the sub-pixels 10i which is the first pixel and the sub-pixels 10m which are the second pixel adjacent to each other. The distance La between the first plugs 66 in the sub-pixels 10i which are the first pixel and the sub-pixels 10m which are the second pixel adjacent to each other is equal to, for example, the distance Lb between the second plugs 67 in the sub-pixels 10m which are the second pixel and the sub-pixels 10i which are the second pixel adjacent to each other. In this embodiment as well, crosstalk between plugs corresponding to different colors can be suppressed.

[0151] (Variation 3) It is also possible to apply a Bayer array to the image sensor 600 shown in FIG. 16. Specifically, the color filter 19 may be a Bayer filter, and the photoelectric conversion layer 120 may be made of a photoelectric conversion material sensitive to visible light. In this case, the pixels 10 of the image sensor 600 include a plurality of G pixels 10gg as first pixels, a plurality of B pixels 10bb as second pixels, and a plurality of R pixels 10rr as third pixels. The first pixel electrode 63 collects charges corresponding to light in a first wavelength range. The first wavelength range is the wavelength range of green light. The second pixel electrode 64 collects charges corresponding to light in a second wavelength range. The second wavelength range is the wavelength range of blue light.

[0152] 18 shows an arrangement of a first pixel electrode 63, a second pixel electrode 64, a third pixel electrode 65, a first plug 66, a second plug 67, and a third plug 68 when the Bayer array is applied to the image sensor 600. A plurality of G pixels 10gg as first pixels, a plurality of B pixels 10bb as second pixels, and a plurality of R pixels 10rr as third pixels are arranged in the Bayer array. The image sensor 600 can acquire a full-color image.

[0153] The R pixel 10rr as the third pixel has a photoelectric conversion layer 12, a third pixel electrode 65, and a third plug 68. The third pixel electrode 65 is electrically connected to the photoelectric conversion layer 12 and collects charges corresponding to light in a third wavelength range. The third wavelength range is the wavelength range of red light. The third plug 68 electrically connects the semiconductor substrate 1 and the third pixel electrode 65.

[0154] The distance LA between the first plugs 66 in adjacent G pixels 10gg is shorter than the distance LB between the first plug 66 and the second plug 67 in the adjacent G pixel 10gg and B pixel 10bb. With this configuration, crosstalk between the first plug 66 of the G pixel 10gg, which is the first pixel, and the second plug 67 of the B pixel 10bb, which is the second pixel, is suppressed. As a result, it is possible to suppress color mixing between blue and green. In other words, it is possible to improve color separation.

[0155] Furthermore, the distance LA between the first plugs 66 is shorter than the distance LC between the first plug 66 and the third plug 68 in the adjacent G pixel 10gg and R pixel 10rr. With this configuration, crosstalk between the first plug 66 of the G pixel 10gg, which is the first pixel, and the third plug 68 of the R pixel 10rr, which is the third pixel, is suppressed. As a result, it is possible to suppress color mixing between red and green. In other words, it is possible to improve color separation.

[0156] Furthermore, the distance LA between the first plugs 66 is shorter than the distance LD between the second plug 67 and the third plug 68 in the adjacent B pixel 10bb and R pixel 10rr. With this configuration, crosstalk between the first plug 66 of the G pixel 10gg and the plugs of other pixels is particularly suppressed.

[0157] The above configuration can suppress color mixing between different colors, red, green, and blue. In this embodiment, the crosstalk suppression effect is the highest in the G pixel 10rr. Since the G pixel 10gg occupies an area equal to the total area of ​​the B pixel 10bb and the R pixel 10rr, the crosstalk in the first plug 66 of the G pixel 10gg is suppressed, thereby most effectively suppressing color mixing.

[0158] Moreover, by suppressing crosstalk between the first plugs of the G pixels, which have high luminosity, and the plugs of pixels of other colors, it is possible to effectively suppress color mixture between different colors.

[0159] Seventh embodiment FIG. 19 shows a cross section of an imaging element 700 according to a seventh embodiment of the present disclosure. The imaging element 700 differs from the imaging elements of the previous embodiments in the structure of the electrodes. In the imaging element 700, the first pixel electrode 13 has a first storage electrode 13a, a first readout electrode 13b, and a first transfer electrode 13c. The second pixel electrode 14 has a second storage electrode 14a, a second readout electrode 14b, and a second transfer electrode 14c. The third pixel electrode 15 has a third storage electrode 15a, a third readout electrode 15b, and a third transfer electrode 15c. The first transfer electrode 13c, the second transfer electrode 14c, and the third transfer electrode 15c may be omitted.

[0160] A first semiconductor layer 27 is provided between the first pixel electrode 13 and the first photoelectric conversion layer 121. A part of the insulating layer 8 is present between the first semiconductor layer 27 and the first pixel electrode 13. A second semiconductor layer 28 is provided between the second pixel electrode 14 and the second photoelectric conversion layer 122. A part of the insulating layer 8 is present between the second semiconductor layer 28 and the second pixel electrode 14. A third semiconductor layer 29 is provided between the third pixel electrode 15 and the third photoelectric conversion layer 123. A part of the insulating layer 9 is present between the third semiconductor layer 29 and the third pixel electrode 15. The first semiconductor layer 27, the second semiconductor layer 28, and the third semiconductor layer 29 are provided to more efficiently accumulate charges, and are made of a semiconductor material having light transmission properties.

[0161] The first storage electrode 13a and the first transfer electrode 13c face the first photoelectric conversion layer 121 through a part of the insulating layer 8, or through a part of the insulating layer 8 and the first semiconductor layer 27. At least a part of the first readout electrode 13b is in contact with the first photoelectric conversion layer 121 directly or through the first semiconductor layer 27. The first readout electrode 13b is connected to a first plug 31. The first storage electrode 13a, the first readout electrode 13b, and the first transfer electrode 13c are each electrically connected to a wiring not shown. A desired voltage can be applied to each of the first storage electrode 13a, the first readout electrode 13b, and the first transfer electrode 13c. The first storage electrode 13a can function as a charge storage electrode for attracting charges generated in the first photoelectric conversion film 121 according to the applied voltage and storing the charges in the first photoelectric conversion layer 121. When the imaging element 700 is viewed in plan, the first transfer electrode 13c is disposed between the first storage electrode 13a and the first readout electrode 13b. The first transfer electrode 13c plays a role of blocking the accumulated electric charge and controlling the transfer of the electric charge. By controlling the voltages applied to the first storage electrode 13a, the first readout electrode 13b, and the first transfer electrode 13c, the electric charge generated in the first photoelectric conversion layer 121 can be accumulated inside the first photoelectric conversion layer 121 or at the interface of the first photoelectric conversion layer 121, or the generated electric charge can be taken out to the first charge accumulation region 3. These explanations regarding the first pixel electrode 13 can also be applied to the second pixel electrode 14 and the third pixel electrode 15 by replacing "first" with "second" or "third."

[0162] According to the electrode structure of this embodiment, the charges generated in the photoelectric conversion layer can be efficiently collected and transferred, leading to improved sensitivity. The electrode structure of this embodiment can be applied to all of the embodiments described above. [Industrial Applicability]

[0163] The technology disclosed in this specification is useful for an image sensor. The image sensor can be applied to an image pickup device, an optical sensor, and the like. [Explanation of symbols]

[0164] 1. Semiconductor substrate 3 First charge storage region 4 Second charge storage region 5 Third charge storage region 10 pixels 10a, 10m, 10i subpixels 10r Red sub-pixel 10g Green subpixel 10b Blue sub-pixel 10rr R pixel 10gg G pixels 10bb B pixel 12 Photoelectric conversion section 13,63 First pixel electrode 14,64 Second pixel electrode 15,65 3rd pixel electrode 16 4th pixel electrode 17 First opposing electrode 18 Second counter electrode 19,191,192 Color Filters 31,66 First plug 32,67 2nd plug 33,68 3rd plug 34 4th plug 100,200,300,400,500,600,700 Image sensor 100A Imaging Device 120 Photoelectric conversion layer 121, 120a First photoelectric conversion layer 122, 120b Second photoelectric conversion layer 123 Third photoelectric conversion layer 124 4th photoelectric conversion layer PD Photodiode

Claims

1. A semiconductor substrate; A first pixel; a plurality of second pixels adjacent to the first pixel; Equipped with Each of the first pixel and the plurality of second pixels is a first photoelectric conversion layer that converts light having a wavelength included in a first wavelength range into a first charge; a first pixel electrode for collecting the first charges; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; a second photoelectric conversion layer disposed above the first photoelectric conversion layer or between the first photoelectric conversion layer and the semiconductor substrate in a normal direction of the semiconductor substrate, the second photoelectric conversion layer converting light having a wavelength included in a second wavelength range into a second charge; a second pixel electrode for collecting the second charges; a second plug electrically connecting the semiconductor substrate and the second pixel electrode; Including, when viewed from the normal direction of the semiconductor substrate, the shortest distance between the first plug of the first pixel and each of the first plugs of the plurality of second pixels is shorter than any of distances between the first plug of the first pixel and each of the second plugs of the first pixel and the plurality of second pixels; Image sensor.

2. The second photoelectric conversion layer is disposed above the first photoelectric conversion layer in the normal direction of the semiconductor substrate. The imaging device according to claim 1 .

3. the first wavelength range is a near-infrared wavelength range, The second wavelength range is a visible light wavelength range. The imaging device according to claim 2 .

4. The second photoelectric conversion layer is disposed between the first photoelectric conversion layer and the semiconductor substrate in the normal direction of the semiconductor substrate. The imaging device according to claim 1 .

5. the first wavelength range is a visible light wavelength range, The second wavelength range is a near-infrared wavelength range. The imaging device according to claim 4 .

6. When viewed from the normal direction of the semiconductor substrate, the first plug does not overlap the second pixel electrode. The imaging device according to claim 4 .

7. When viewed from the normal direction of the semiconductor substrate, the area of ​​the second pixel electrode is smaller than four times the area of ​​the first pixel electrode. The imaging device according to claim 4 .

8. A semiconductor substrate; A first pixel; a plurality of second pixels adjacent to the first pixel; Equipped with Each of the first pixel and the plurality of second pixels is a first photoelectric conversion layer that converts light having a wavelength included in a first wavelength range into a first charge; a first pixel electrode for collecting the first charges; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; a second photoelectric conversion layer disposed above the first photoelectric conversion layer or between the first photoelectric conversion layer and the semiconductor substrate in a normal direction of the semiconductor substrate, the second photoelectric conversion layer converting light having a wavelength included in a second wavelength range into a second charge; a second pixel electrode for collecting the second charges; a second plug electrically connecting the semiconductor substrate and the second pixel electrode; Including, when viewed from the normal direction of the semiconductor substrate, a distance between the first plug of the first pixel and each of the first plugs of the plurality of second pixels is shorter than a distance between the first plug of the first pixel and each of the second plugs of the first pixel and the plurality of second pixels; the first wavelength range includes a red light wavelength range and a blue light wavelength range, the second wavelength range includes a green light wavelength range, the first photoelectric conversion layer has sensitivity to the red light wavelength region and the blue light wavelength region, the second photoelectric conversion layer has sensitivity in the wavelength range of the green light; Image sensor.

9. A color filter that cuts off light in the red wavelength range; A color filter that blocks light in the blue wavelength range; Further comprising: The imaging device according to claim 8 .

10. Each of the first pixel and the plurality of second pixels is a third photoelectric conversion layer that converts light having a wavelength included in a third wavelength range into a third charge; a third pixel electrode for collecting the third charges; a third plug electrically connecting the semiconductor substrate to each of the third pixel electrodes; Further comprising: when viewed from the normal direction of the semiconductor substrate, a distance between the first plug of the first pixel and the first plug of each of the second pixels is shorter than a distance between the first plug of the first pixel and the third plug of each of the second pixels; The imaging device according to claim 1 .

11. A semiconductor substrate; Two first pixels adjacent to each other; a second pixel adjacent to each of the two first pixels; Equipped with Each of the two first pixels is a first photoelectric conversion layer that converts light having a wavelength included in a first wavelength range into a first charge; a first pixel electrode for collecting the first charges; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; The second pixel is a second photoelectric conversion layer that converts light having a wavelength included in the second wavelength range into a second charge; a second pixel electrode for collecting the second charges; a second plug electrically connecting the semiconductor substrate and the second pixel electrode; When viewed from a normal direction of the semiconductor substrate, a distance between the first plugs in the two first pixels is shorter than a distance between the first plug of one of the two first pixels and the second plug of the second pixel; Image sensor.

12. Further comprising a third pixel adjacent to each of the two first pixels, The third pixel is a third photoelectric conversion layer that converts light having a wavelength included in a third wavelength range into a third charge; a third pixel electrode for collecting the third charges; a third plug electrically connecting the semiconductor substrate and the third pixel electrode; When viewed from the normal direction of the semiconductor substrate, a distance between the first plugs in the two first pixels is shorter than a distance between the first plug of one of the two first pixels and the third plug of the third pixel. The imaging device according to claim 11.

13. the two first pixels, the second pixel, and the third pixel are arranged in a Bayer array; The imaging device according to claim 12.

14. The first wavelength range is a green light wavelength range. The imaging device according to claim 11 .

15. the first pixel electrode includes a first storage electrode configured to store the first charge in the first photoelectric conversion layer, and a first readout electrode electrically connected to the semiconductor substrate via the first plug; the second pixel electrode includes a second storage electrode configured to store the second charge in the second photoelectric conversion layer, and a second readout electrode electrically connected to the semiconductor substrate via the second plug; The imaging device according to claim 1 .

16. In a normal direction of the semiconductor substrate, the first pixel electrode is provided below the first photoelectric conversion layer, and the second pixel electrode is provided above the second photoelectric conversion layer. The imaging device according to claim 1 .

17. The first photoelectric conversion layer is provided in the same layer as the second photoelectric conversion layer. The imaging device according to claim 11.

18. The first photoelectric conversion layer is provided in the same layer as the second photoelectric conversion layer and the third photoelectric conversion layer. The imaging device according to claim 13.

Images