Imaging device and camera system

Abstract

This imaging device comprises: at least one first pixel; at least one second pixel adjacent to the at least one first pixel in plan view; and a photoelectric conversion layer that is continuous over the at least one first pixel and the at least one second pixel and is shared by the at least one first pixel and the at least one second pixel, the photoelectric conversion layer absorbing visible light. The at least one first pixel includes a first pixel electrode for collecting a first signal charge generated by the photoelectric conversion layer, the first pixel electrode having light-blocking properties with respect to visible light and near-infrared light. The at least one second pixel includes a photodiode that generates a second signal charge by absorbing near-infrared light transmitted through the photoelectric conversion layer.

Description

Imaging device and camera system

[0001] The present disclosure relates to an imaging device and a camera system.

[0002] Conventionally, imaging devices have been proposed that include a photodiode provided on a substrate and a photoelectric conversion layer laminated on the substrate, in which one of the photodiode and the photoelectric conversion layer converts visible light into electric charges, and the other converts near-infrared light into electric charges, thereby enabling imaging of both visible light and near-infrared light (see, for example, Patent Documents 1, 2, and 3).

[0003] JP 2017-208496 A JP 2008-218787 A JP 2017-11273 A

[0004] The present disclosure provides an imaging device and a camera system that can capture images of both visible light and near-infrared light, and that can improve sensitivity and reduce noise.

[0005] An imaging device according to one aspect of the present disclosure includes at least one first pixel, at least one second pixel adjacent to the at least one first pixel in a planar view, and a photoelectric conversion layer extending continuously across the at least one first pixel and the at least one second pixel and shared by the at least one first pixel and the at least one second pixel, the photoelectric conversion layer absorbing visible light. The at least one first pixel includes a first pixel electrode that collects first signal charges generated in the photoelectric conversion layer, the first pixel electrode having light-blocking properties against visible light and near-infrared light. The at least one second pixel includes a photodiode that generates second signal charges by absorbing the near-infrared light that has passed through the photoelectric conversion layer.

[0006] A camera system according to an aspect of the present disclosure includes the image capture device and a double band-pass filter having transmission bands in the wavelength bands of visible light and near-infrared light, respectively, wherein the visible light and near-infrared light that have passed through the double band-pass filter are incident on the photoelectric conversion layer.

[0007] A camera system according to an aspect of the present disclosure includes the image capture device described above and a light source that emits near-infrared light, wherein the image capture device detects reflected light generated when the near-infrared light emitted by the light source is reflected by an object.

[0008] According to the present disclosure, it is possible to provide an imaging device and a camera system that can capture images of both visible light and near-infrared light, and that can improve sensitivity and reduce noise.

[0009] FIG. 1 is a block diagram showing an example of a configuration of an imaging device according to a first embodiment. FIG. 2 is a schematic diagram showing an example of a circuit configuration of a visible pixel and a circuit connected to the visible pixel according to the first embodiment. FIG. 3 is a schematic diagram showing an example of a circuit configuration of a near-infrared pixel and a circuit connected to the near-infrared pixel according to the first embodiment. FIG. 4 is a plan view showing an example of a planar layout of a visible pixel and a near-infrared pixel according to the first embodiment. FIG. 5 is a cross-sectional view showing an example of a cross-sectional structure of a visible pixel and a near-infrared pixel according to the first embodiment. FIG. 6 is a diagram showing an example of an absorption spectrum of a photoelectric conversion layer according to the first embodiment. FIG. 7 is a diagram showing an example of a transmission spectrum of a color filter according to the first embodiment. FIG. 8 is a cross-sectional view showing another example of a cross-sectional structure of a visible pixel and a near-infrared pixel according to the first embodiment. FIG. 9 is a cross-sectional view showing yet another example of a cross-sectional structure of a visible pixel and a near-infrared pixel according to the first embodiment. FIG. 10 is a plan view showing another example of a planar layout of a visible pixel and a near-infrared pixel according to the first embodiment. FIG. 11 is a plan view showing yet another example of the planar layout of visible light pixels and near-infrared light pixels according to Embodiment 1. FIG. 12 is a plan view showing an example of the planar layout of visible light pixels and near-infrared light pixels according to Modification 1 of Embodiment 1. FIG. 13 is a cross-sectional view showing an example of the cross-sectional structure of visible light pixels and near-infrared light pixels according to Modification 1 of Embodiment 1. FIG. 14 is a plan view showing another example of the planar layout of visible light pixels and near-infrared light pixels according to Modification 1 of Embodiment 1. FIG. 15 is a plan view showing an example of the planar layout of visible light pixels and near-infrared light pixels according to Modification 2 of Embodiment 1. FIG. 16 is a cross-sectional view showing an example of the cross-sectional structure of visible light pixels and near-infrared light pixels according to Modification 2 of Embodiment 1. FIG. 17 is a plan view showing another example of the planar layout of visible light pixels and near-infrared light pixels according to Modification 2 of Embodiment 1. FIG. 18 is a block diagram showing an example of the configuration of a camera system according to Embodiment 2. FIG. 19 is a diagram showing an example of the transmission spectrum of a double band-pass filter and an emission spectrum of a near-infrared light source according to Embodiment 2.

[0010] (How an Aspect of the Present Disclosure Was Achieved) Before describing specific embodiments of the present disclosure, how an aspect of the present disclosure was achieved will be described. The present inventors have discovered that the following problems arise in conventional imaging devices that include a photoelectric conversion layer and a photodiode and capture images using visible light and near-infrared light.

[0011] Patent Literature 1 discloses an imaging device in which a photoelectric conversion layer converts visible light into electric charges and a photodiode converts near-infrared light into electric charges. In the imaging device disclosed in Patent Literature 1, a transparent electrode that transmits near-infrared light is used for the pixel electrode that collects the signal charge generated by photoelectric conversion in the photoelectric conversion layer. However, because a transparent electrode is used for the pixel electrode in an imaging device with such a configuration, near-infrared light that transmits through the pixel electrode adversely affects a detection circuit unit such as a transistor formed on the substrate, resulting in increased noise. Furthermore, visible light that is not absorbed by the photoelectric conversion layer also transmits through the pixel electrode, resulting in further increased noise and a decrease in the visible light sensitivity of the photoelectric conversion layer.

[0012] Furthermore, Patent Document 2 discloses an imaging device in which a photoelectric conversion layer converts near-infrared light into electric charges and a photodiode converts visible light into electric charges. In the imaging device disclosed in Patent Document 2, an aperture is provided in a pixel electrode that collects signal charges generated by photoelectric conversion in the photoelectric conversion layer, and visible light passing through the aperture is converted into electric charges by the photodiode. However, while an imaging device with such a configuration uses a photoelectric conversion layer sensitive to near-infrared light, it is difficult to realize a photoelectric conversion layer sensitive only to near-infrared light, resulting in the photoelectric conversion layer being sensitive to visible light as well. As a result, a portion of the visible light reaching the photodiode is absorbed by the photoelectric conversion layer, reducing its sensitivity to visible light imaging. Furthermore, the signal charges generated by photoelectric conversion in the photoelectric conversion layer contain components generated by not only near-infrared light but also visible light, reducing the wavelength separation between visible light and near-infrared light. In such a case, when data captured using near-infrared light is used for authentication, authentication accuracy may be reduced.

[0013] Furthermore, Patent Document 3 discloses an imaging device in which a photoelectric conversion layer converts near-infrared light into electric charges and a photodiode converts visible light into electric charges. In the imaging device disclosed in Patent Document 3, pixel electrodes that collect signal charges generated by photoelectric conversion in the photoelectric conversion layer and photodiodes are arranged at different positions in a planar view, and visible light transmitted through the photoelectric conversion layer is converted into electric charges by the photodiodes. In an imaging device configured in this manner, similar to the imaging device disclosed in Patent Document 2, reduced sensitivity for imaging visible light and reduced wavelength separation between visible light and near-infrared light occur. Furthermore, the imaging device disclosed in Patent Document 3 uses transparent or semitransparent electrodes for the pixel electrodes, and similar to the imaging device disclosed in Patent Document 1, visible light passing through the pixel electrodes also results in increased noise and reduced visible light sensitivity in the photoelectric conversion layer.

[0014] The present disclosure has been made in consideration of such problems, and aims to provide an imaging device and camera system that can capture both visible light and near-infrared light, and that can improve sensitivity and reduce noise.

[0015] (Summary of the Present Disclosure) As an overview of the present disclosure, examples of an imaging device and a camera system according to the present disclosure are described below.

[0016] For example, an imaging device according to a first aspect of the present disclosure includes at least one first pixel, at least one second pixel adjacent to the at least one first pixel in a planar view, and a photoelectric conversion layer extending continuously across the at least one first pixel and the at least one second pixel and shared by the at least one first pixel and the at least one second pixel, the photoelectric conversion layer absorbing visible light. The at least one first pixel includes a first pixel electrode that collects first signal charges generated in the photoelectric conversion layer, the first pixel electrode having light-shielding properties against visible light and near-infrared light. The at least one second pixel includes a photodiode that generates second signal charges by absorbing the near-infrared light that has passed through the photoelectric conversion layer.

[0017] This allows the first pixel to capture visible light and the second pixel to capture near-infrared light. In this case, the photodiode of the second pixel absorbs near-infrared light that has passed through the photoelectric conversion layer, so the photodiode's light absorption does not affect the visible light absorption by the photoelectric conversion layer, improving the sensitivity of the first pixel. Furthermore, a photoelectric conversion layer that absorbs visible light can easily be designed to have characteristics that make it less likely to absorb near-infrared light, making it easier for the photodiode to receive near-infrared light, improving the sensitivity of the second pixel. Furthermore, because a light-shielding electrode is used as the pixel electrode of the first pixel, the pixel electrode blocks light, reducing the impact of that light on the pixel circuit and suppressing noise. Therefore, the imaging device can capture both visible light and near-infrared light, improving sensitivity and reducing noise. Furthermore, because at least a portion of the visible light reaching the photodiode is absorbed by the photoelectric conversion layer, the wavelength separation of near-infrared light in the second pixel is improved.

[0018] Furthermore, for example, an imaging device according to a second aspect of the present disclosure may be the imaging device according to the first aspect, and in the imaging device according to the second aspect, the at least one second pixel may include a color filter located above a surface of the photoelectric conversion layer on which light is incident, and which transmits components of at least a portion of the wavelength band of the near-infrared light and blocks components of at least a portion of the wavelength band of the visible light.

[0019] This allows the color filter to further reduce the visible light incident on the photodiode, further improving the wavelength separation of near-infrared light in the second pixel.

[0020] Furthermore, for example, an imaging device according to a third aspect of the present disclosure is the imaging device according to the second aspect, and in the imaging device according to the third aspect, the combined average transmittance of the color filter and the photoelectric conversion layer of the at least one second pixel for the entire wavelength band of visible light may be 6% or less.

[0021] This allows the color filter and the photoelectric conversion layer to reduce the transmittance over the entire wavelength band of visible light, further improving the wavelength separation of near-infrared light in the second pixel.

[0022] Furthermore, for example, an imaging device according to a fourth aspect of the present disclosure may be the imaging device according to the second or third aspect, and in the imaging device according to the fourth aspect, the color filter of the at least one second pixel may be a black color filter that absorbs the entire wavelength band of visible light.

[0023] This allows the color filter to absorb the entire wavelength band of visible light, further improving the wavelength separation of near-infrared light in the second pixel.

[0024] Furthermore, for example, an imaging device according to a fifth aspect of the present disclosure is the imaging device according to the second or third aspect, and in the imaging device according to the fifth aspect, the color filter of the at least one second pixel may be a blue color filter that transmits blue light or a green color filter that transmits green light.

[0025] The blue or green color filter absorbs red light. Therefore, red light, which is often difficult to absorb in a photoelectric conversion layer that absorbs visible light, is absorbed by the color filter, and the light that passes through the color filter and the photoelectric conversion layer absorbs the entire wavelength range of visible light. This further improves the wavelength separation of near-infrared light in the second pixel.

[0026] Furthermore, for example, an imaging device according to a sixth aspect of the present disclosure may be an imaging device according to any one of the first to fifth aspects, and may further include a plurality of pixel groups, each including the at least one first pixel and the at least one second pixel, and the plurality of pixel groups may be arranged two-dimensionally in the planar view.

[0027] This improves the visibility of the image obtained by imaging, and also improves the ease of processing when performing authentication or other processing using the data obtained by imaging.

[0028] Furthermore, for example, an imaging device according to a seventh aspect of the present disclosure is the imaging device according to the sixth aspect, wherein each of the plurality of pixel groups may further include a third pixel and a fourth pixel, and the photoelectric conversion layer may be continuous across the at least one first pixel, the at least one second pixel, the third pixel, and the fourth pixel, or may be shared by the at least one first pixel, the at least one second pixel, the third pixel, and the fourth pixel, and the third pixel is a second pixel electrode that collects third signal charges generated in the photoelectric conversion layer and has light-shielding properties against the visible light and the near-infrared light. the fourth pixel may include a third pixel electrode that collects fourth signal charges generated in the photoelectric conversion layer and that has light-blocking properties against the visible light and the near-infrared light; each of the at least one first pixel, the third pixel, and the fourth pixel may include a color filter that is located above a surface of the photoelectric conversion layer on which light is incident and that blocks a portion of the wavelength band of the visible light; and the color filter of the at least one first pixel, the color filter of the third pixel, and the color filter of the fourth pixel may block light of different wavelength bands of the visible light.

[0029] This makes it possible to arrange color filters in a Bayer array, improving the ease of processing when performing authentication and other processes using data obtained by imaging.

[0030] Also, for example, an imaging device according to an eighth aspect of the present disclosure may be an imaging device according to any one of the first to seventh aspects, and may further include a pixel array including a plurality of pixels, wherein the at least one first pixel may include a plurality of first pixels, the at least one second pixel may include a plurality of second pixels, and the plurality of pixels may include the plurality of first pixels and the plurality of second pixels, and a proportion of the plurality of second pixels among all pixels included in the pixel array may be less than 25%.

[0031] This makes it possible to suppress a decrease in resolution when capturing visible light, even in an imaging device that can capture near-infrared light using the second pixels.

[0032] Furthermore, for example, an imaging device according to a ninth aspect of the present disclosure is an imaging device according to any one of the first to eighth aspects, and in the imaging device according to the ninth aspect, the photoelectric conversion layer may have sensitivity in a wavelength band of 400 nm or more and 600 nm or less, and the sensitivity of the photoelectric conversion layer may gradually decrease as the wavelength becomes longer than 600 nm.

[0033] Human luminosity peaks at 555 nm and decreases as wavelengths become longer than 600 nm. Therefore, by making the sensitivity of the photoelectric conversion layer also decrease as wavelengths become longer than 600 nm, like human luminosity, it is possible to make images captured using visible light into images with natural coloring that is closer to what people actually see.

[0034] Furthermore, for example, an imaging device according to a tenth aspect of the present disclosure may be an imaging device according to any one of the first to ninth aspects, further comprising a metal grid or an air gap located between the first pixel electrode and the photodiode in the planar view and above the light-incident surface of the photoelectric conversion layer.

[0035] This makes it possible to suppress the incidence of light on the pixel circuit by the light-shielding structure between the pixel electrode and the photodiode in a plan view, thereby reducing noise.

[0036] Furthermore, for example, an imaging device according to an eleventh aspect of the present disclosure may be an imaging device according to any one of the first to tenth aspects, and may further include a substrate including the photodiode, on which the photoelectric conversion layer is stacked, and a metal layer located between the photoelectric conversion layer and the substrate in the stacking direction and between the first pixel electrode and the photodiode in the planar view.

[0037] This makes it possible to suppress the incidence of light into the pixel circuit by the metal layer between the pixel electrode and the photodiode in a plan view, thereby reducing noise.

[0038] Furthermore, for example, an imaging device according to a twelfth aspect of the present disclosure may be an imaging device according to any one of the first to eleventh aspects, further comprising a shield electrode located between the first pixel electrode and the photodiode in the planar view and having a light-blocking property against the visible light and the near-infrared light.

[0039] This makes it possible to suppress the incidence of light into the pixel circuit by the shield electrode between the pixel electrode and the photodiode in a plan view, thereby reducing noise.

[0040] Also, for example, an imaging device according to a thirteenth aspect of the present disclosure may be the imaging device according to the twelfth aspect, further comprising: a substrate including the photodiode, the substrate on which the photoelectric conversion layer is laminated; and a via connected to the shield electrode, the via being located between the shield electrode and the substrate and between the first pixel electrode and the photodiode in the planar view, and having light-blocking properties against the visible light and the near-infrared light.

[0041] This makes it possible to prevent light that has entered the photoelectric conversion layer of the second pixel obliquely from entering the pixel circuit of the first pixel by the via, thereby reducing noise.

[0042] Also, for example, an imaging device according to a fourteenth aspect of the present disclosure is an imaging device according to any one of the first to thirteenth aspects, and in the imaging device according to the fourteenth aspect, the at least one first pixel may further include a first microlens, the at least one second pixel may further include a second microlens, and the curvature of the second microlens may be smaller than the curvature of the first microlens.

[0043] As a result, in the second pixel, in which the photodiode absorbs near-infrared light that has passed through the photoelectric conversion layer to generate the second signal charge, the focal length of the microlens is longer than that of the first pixel, in which the photodiode absorbs visible light to generate the first signal charge. This makes it easier for the microlens to focus light at a position corresponding to the photoelectric conversion layer of the first pixel that generates the signal charge and the photodiode of the second pixel. This improves the sensitivity of the first pixel and the second pixel.

[0044] Furthermore, for example, an imaging device according to a fifteenth aspect of the present disclosure is an imaging device according to any one of the first to thirteenth aspects, and in the imaging device according to the fifteenth aspect, the at least one first pixel may further include a first microlens, the at least one second pixel may further include a second microlens, and the first pixel electrode may be biased in a predetermined direction from the center of the first microlens in the planar view.

[0045] This allows the detection result of the first pixel to be used for phase difference detection.

[0046] Furthermore, for example, a camera system according to a sixteenth aspect of the present disclosure includes an imaging device according to any one of the first to fifteenth aspects and a double band-pass filter having transmission bands in the wavelength band of visible light and the wavelength band of near-infrared light, and the visible light and the near-infrared light that have passed through the double band-pass filter are incident on the photoelectric conversion layer.

[0047] This improves the wavelength separation between visible light and near-infrared light in the first and second pixels.

[0048] Also, for example, a camera system according to a seventeenth aspect of the present disclosure includes an imaging device according to any one of the first to fifteenth aspects and a light source that emits the near-infrared light, and the imaging device detects reflected light generated when the near-infrared light emitted by the light source is reflected by an object.

[0049] This allows the object to be irradiated with near-infrared light according to the sensitivity characteristics of the second pixel, thereby improving the wavelength separation of near-infrared light in the second pixel.

[0050] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component arrangements and connection forms, steps, and step orders shown in the following embodiments are merely examples and are not intended to limit the present disclosure. The various aspects described in this specification can be combined with each other as long as no contradiction occurs. Furthermore, among the components in the following embodiments, components not recited in independent claims are described as optional components. In each drawing, components having substantially the same functions are designated by common reference symbols, and redundant descriptions may be omitted or simplified.

[0051] Furthermore, the various elements shown in the drawings are merely shown schematically to facilitate understanding of the present disclosure, and the dimensional ratios and appearances may differ from the actual objects. In other words, each drawing is a schematic diagram and is not necessarily an accurate depiction. Therefore, for example, the scales of the drawings do not necessarily match.

[0052] Furthermore, in this specification, terms indicating the relationship between elements, such as parallel or coincident, terms indicating the shape of elements, such as circular or rectangular, and numerical ranges are not expressions that only express a strict meaning, but are expressions that also include a substantially equivalent range, for example, a difference of about a few percent.

[0053] Furthermore, in this specification, the terms "upper" and "lower" do not refer to the upward (vertically upward) and downward (vertically downward) directions in absolute spatial recognition, but are used as terms defined by a relative positional relationship based on the stacking order in the stacked structure. Specifically, the light incident side of the imaging device is referred to as "upper," and the side opposite the light incident side is referred to as "lower." Similarly, the "upper surface" and "lower surface" of each component refer to the surface of the imaging device on the light incident side as the "upper surface" and the surface opposite the light incident side as the "lower surface." Note that the terms "upper," "lower," "upper surface," and "lower surface" are used solely to specify the relative arrangement of components and are not intended to limit the orientation of the imaging device during use. Furthermore, the terms "upper" and "lower" apply not only to cases where two components are arranged with a gap between them and another component is present between them, but also to cases where two components are arranged closely together and in contact with each other. In this specification, the term "plan view" refers to a view from a direction perpendicular to the top surface of the semiconductor substrate (in other words, the thickness direction of the semiconductor substrate).

[0054] In this specification and the drawings, the X-axis, Y-axis, and Z-axis represent the three axes of a three-dimensional Cartesian coordinate system. In the following embodiments, the Z-axis direction is the thickness direction of the semiconductor substrate and the stacking direction in which the semiconductor substrate and the photoelectric conversion layer stacked on the semiconductor substrate are aligned. The negative side of the Z-axis is defined as "downward," and the positive side of the Z-axis is defined as "upward."

[0055] In this specification, when a transistor is disposed on a certain surface of a semiconductor substrate, it means that the gate, source, and drain of the transistor are disposed with the certain surface sandwiched therebetween.

[0056] In this specification, not only visible light but also invisible light such as ultraviolet light and near-infrared light will be referred to as "light" for convenience.

[0057] First Embodiment An imaging device according to a first embodiment will be described.

[0058] [Overall Configuration] First, the overall configuration of the imaging device according to this embodiment will be described.

[0059] FIG. 1 is a block diagram showing an example of the configuration of an imaging device 100 according to this embodiment.

[0060] As shown in FIG. 1 , the imaging device 100 includes a semiconductor substrate 40, a peripheral circuit 15, visible light pixels 24, and near-infrared light pixels 29 formed on the semiconductor substrate 40. The semiconductor substrate 40 is an example of a substrate. The imaging device 100 is, for example, an image sensor realized by a single-chip integrated circuit. Note that the configuration formed on the semiconductor substrate 40 includes not only a configuration formed in or on the semiconductor substrate 40, but also a stacked configuration formed at least either above or below the semiconductor substrate 40. Furthermore, although the visible light pixels 24 and the near-infrared light pixels 29 are each shown as a single block in FIG. 1 , a plurality of visible light pixels 24 and a plurality of near-infrared light pixels 29 may be two-dimensionally arranged on the semiconductor substrate 40.

[0061] The visible light pixels 24 are pixels that are sensitive to at least a portion of the wavelength band of visible light and are used to capture an image of visible light incident on the imaging device 100. The near-infrared light pixels 29 are pixels that are sensitive to at least a portion of the wavelength band of near-infrared light and are used to capture an image of near-infrared light incident on the imaging device 100. In this specification, the wavelength of near-infrared light is 680 nm or more and 3000 nm or less. The wavelength of visible light is 380 nm or more and less than 680 nm. The near-infrared light pixels 29 may be sensitive to at least a portion of the wavelength band of 680 nm or more and 1700 nm or less, or may be sensitive to at least a portion of the wavelength band of 700 nm or more and 1000 nm or less.

[0062] The peripheral circuit 15 is electrically connected to the visible light pixels 24 and the near-infrared light pixels 29 and is a circuit for driving the visible light pixels 24 and the near-infrared light pixels 29 and acquiring signals from the visible light pixels 24 and the near-infrared light pixels 29. The peripheral circuit 15 may include a load circuit, a signal processing circuit, an output circuit, a control circuit, and a power supply that supplies a predetermined voltage to the visible light pixels 24 and the near-infrared light pixels 29. The peripheral circuit 15 may drive the visible light pixels 24 and the near-infrared light pixels 29 using a global shutter system or a rolling shutter system. At least a portion of the peripheral circuit 15 may be disposed on a semiconductor substrate different from the semiconductor substrate 40. In other words, at least a portion of the peripheral circuit 15 does not have to be formed on the semiconductor substrate 40.

[0063] [Circuit Configuration] Next, a description will be given of the circuit configurations of the visible light pixels 24, near-infrared light pixels 29, and peripheral circuit 15 according to this embodiment. First, a description will be given of the circuit configurations of the visible light pixels 24 and the peripheral circuit 15 connected to the visible light pixels 24. Figure 2 is a schematic diagram showing an exemplary circuit configuration of the visible light pixels 24 and the circuit connected to the visible light pixels 24 according to this embodiment.

[0064] As shown in FIG. 2 , the imaging device 100 includes a plurality of visible light pixels 24, and peripheral circuits 15 connected to the plurality of visible light pixels 24, including a voltage supply circuit 19, a vertical scanning circuit 25, a horizontal signal readout circuit 20, a plurality of column signal processing circuits 30, a plurality of load circuits 28, and a plurality of differential amplifiers 32.

[0065] A plurality of visible light pixels 24 are arranged two-dimensionally on the semiconductor substrate 40. Specifically, the plurality of visible light pixels 24 are arranged in row and column directions. While FIG. 2 shows a circuit configuration of two rows and two columns of visible light pixels 24, the actual arrangement of the visible light pixels 24 may differ from the arrangement shown in FIG. 2. For example, a plurality of pixels including visible light pixels 24 and near-infrared light pixels 29 are arranged in row and column directions on the semiconductor substrate 40 to form a photosensitive region. In other words, near-infrared light pixels 29 may be included in the rows and columns of visible light pixels 24. Note that, as in the planar layout shown in FIG. 11 (described later), there may be rows and columns in which only visible light pixels 24 are aligned in one direction. The number of visible light pixels 24 is not particularly limited. In this specification, the row direction and column direction refer to the directions in which the rows and columns extend, respectively. That is, in FIG. 2 and FIG. 3 (described later), the vertical direction on the paper surface is the column direction, and the horizontal direction is the row direction.

[0066] Each visible light pixel 24 includes a photoelectric conversion unit 10A, a charge detection circuit that detects signal charge generated by the photoelectric conversion unit 10A, and a charge accumulation node 34 electrically connected to the photoelectric conversion unit 10A and the charge detection circuit. The charge accumulation node 34 accumulates the signal charge generated by the photoelectric conversion unit 10A, and the charge detection circuit of the visible light pixel 24 detects the signal charge accumulated in the charge accumulation node 34. The charge detection circuit of the visible light pixel 24 includes an amplification transistor 21, a reset transistor 22, and an address transistor 23. The circuit configurations of the multiple visible light pixels 24 are, for example, the same as each other.

[0067] The photoelectric conversion unit 10A includes a photoelectric conversion layer 3, a pixel electrode 2, and a counter electrode 4. The entire photoelectric conversion unit 10A does not need to be an independent element for each visible light pixel 24, and a portion of the photoelectric conversion unit 10A may span multiple visible light pixels 24. The photoelectric conversion layer 3 generates positive and negative charges through photoelectric conversion in response to incident light. The positive and negative charges are typically hole-electron pairs. One of the holes and electrons generated in the photoelectric conversion layer 3 is used as a signal charge. In the photoelectric conversion unit 10A, the signal charge generated by the photoelectric conversion layer 3 photoelectrically converting light containing a visible light component is collected by the pixel electrode 2.

[0068] The pixel electrode 2 is connected to the gate of the amplification transistor 21, and the signal charge collected by the pixel electrode 2 is stored in a charge storage node 34 located between the pixel electrode 2 and the gate of the amplification transistor 21. The signal charge is, for example, a hole. That is, the charge storage node 34 is electrically connected to the pixel electrode 2 and stores the holes generated in the photoelectric conversion layer 3. In the following, unless otherwise specified, a case will be described in which the signal charge is a hole. Note that the signal charge may also be an electron.

[0069] A voltage for applying a predetermined bias voltage is supplied to the counter electrode 4 via the counter electrode signal line 26. When the imaging device 100 is in operation, a predetermined bias voltage is applied to the counter electrode signal line 26. By applying the predetermined bias voltage to the counter electrode 4, one of the positive and negative charges generated by photoelectric conversion can be selectively stored as a signal charge in the charge storage node 34. Specifically, by applying a bias voltage to the counter electrode 4 such that the potential of the counter electrode 4 is higher than the potential of the pixel electrode 2, positive holes, which are signal charges, move to the pixel electrode 2 and are stored in the charge storage node 34.

[0070] The voltage supply circuit 19 is electrically connected to the counter electrode 4 via the counter electrode signal line 26. The voltage supply circuit 19 applies a predetermined bias voltage to the counter electrode 4, thereby creating a potential difference between the pixel electrode 2 and the counter electrode 4.

[0071] The amplification transistor 21, the reset transistor 22, and the address transistor 23 are, for example, field effect transistors (FETs) formed on a semiconductor substrate 40. In the example shown in FIG. 2, each of the amplification transistor 21, the reset transistor 22, and the address transistor 23 is an N-channel MOSFET (Metal Oxide Semiconductor FET). Which of the two diffusion regions of the FET corresponds to the source and drain is determined by the polarity of the FET and the level of the potential at that time. Therefore, which is the source and which is the drain may vary depending on the operating state of the FET.

[0072] As shown in FIG. 2 , the gate of the amplifier transistor 21 is electrically connected to the pixel electrode 2. The signal charge generated by the photoelectric conversion unit 10A is accumulated in a charge accumulation node 34 between the pixel electrode 2 and the gate of the amplifier transistor 21. The charge accumulation node 34 is connected to the pixel electrode 2, the gate of the amplifier transistor 21, and one of the source and drain of the reset transistor 22. The charge accumulation node 34 functions as at least a part of a charge accumulation region that accumulates the signal charge of the visible light pixel 24, and the potential of the charge accumulation node 34 corresponds to the amount of signal charge accumulated in the charge accumulation region. The charge accumulation node 34 includes wiring that connects the pixel electrode 2, the amplifier transistor 21, and the reset transistor 22. The signal charge accumulated in the charge accumulation node 34 is applied to the gate of the amplifier transistor 21 as a voltage corresponding to the amount of signal charge.

[0073] One of the source and drain of the amplifying transistor 21 is connected to a power supply wiring 31 that supplies a predetermined power supply voltage to each visible light pixel 24 when the imaging device 100 is in operation. The predetermined power supply voltage is, for example, 3.3 V, but is not particularly limited to this. The amplifying transistor 21 outputs a signal voltage that corresponds to the amount of signal charge generated by the photoelectric conversion unit 10A. The other of the source and drain of the amplifying transistor 21 is connected to one of the source and drain of the address transistor 23.

[0074] A vertical signal line 27 is connected to the other of the source and drain of the address transistor 23. As shown in Fig. 2, a vertical signal line 27 is provided for each column of the visible light pixels 24, and a load circuit 28 and a column signal processing circuit 30 are connected to each vertical signal line 27. The load circuit 28 forms a source follower circuit together with the amplification transistor 21, for example.

[0075] An address signal line 36 is connected to the gate of the address transistor 23. An address signal line 36 is provided for each row of the visible light pixels 24. The address signal line 36 is connected to the vertical scanning circuit 25, which applies a row selection signal to the address signal line 36 that controls the on and off of the address transistor 23. This causes the row to be read out to be scanned in the vertical direction (i.e., the column direction), and the row to be read out is selected. By controlling the on and off of the address transistor 23 via the address signal line 36, the vertical scanning circuit 25 can read out the output of the amplification transistor 21 of the selected visible light pixel 24 to the corresponding vertical signal line 27.

[0076] The signal voltage from the visible light pixel 24 output to the vertical signal line 27 via the address transistor 23 is input to a corresponding one of the plurality of column signal processing circuits 30 provided for each column of the plurality of visible light pixels 24 corresponding to the vertical signal line 27.

[0077] The column signal processing circuits 30 perform noise suppression signal processing typified by correlated double sampling, analog-to-digital conversion (AD conversion), etc. The column signal processing circuits 30 are connected to the horizontal signal readout circuit 20. The horizontal signal readout circuit 20 sequentially reads out signals from the multiple column signal processing circuits 30 to a horizontal common signal line.

[0078] A reset signal line 37, which is connected to the vertical scanning circuit 25, is connected to the gate of the reset transistor 22. Like the address signal lines 36, the reset signal line 37 is provided for each row of multiple visible light pixels 24. The vertical scanning circuit 25 can select the visible light pixels 24 to be reset row by row by applying a row selection signal to the address signal line 36. The vertical scanning circuit 25 can also turn on the reset transistor 22 in the selected row by applying a reset signal that controls the on / off of the reset transistor 22 to the gate of the reset transistor 22 via the reset signal line 37. Turning on the reset transistor 22 resets the potential of the charge storage node 34. In other words, the reset transistor 22 resets the potential of the gate of the amplification transistor 21 and the pixel electrode 2.

[0079] 2 , the other of the source and drain of the reset transistor 22 is connected to one of feedback lines 33 provided for each column of multiple visible light pixels 24. That is, in this example, the voltage of the feedback line 33 is supplied to the charge storage node 34 as a reset voltage for initializing the signal charge generated in the photoelectric conversion unit 10A. Here, the above-mentioned feedback line 33 is connected to the output terminal of a corresponding one of differential amplifiers 32 provided for each column of multiple visible light pixels 24.

[0080] Now, let us focus on one of the columns of multiple visible light pixels 24. As shown in FIG. 2 , the inverting input terminal of the differential amplifier 32 is connected to the vertical signal line 27 of that column. The output terminal of the differential amplifier 32 is also connected to one or more visible light pixels 24 belonging to that column via a feedback line 33. During operation of the imaging device 100, a predetermined input voltage is supplied to the non-inverting input terminal of the differential amplifier 32. By selecting one of the one or more visible light pixels 24 belonging to that column and turning on the address transistor 23 and reset transistor 22, a feedback path can be formed that negatively feeds back the output of that one visible light pixel 24. The formation of the feedback path causes the voltage of the vertical signal line 27 to converge to the input voltage to the non-inverting input terminal of the differential amplifier 32. In other words, the formation of the feedback path resets the voltage of the charge storage node 34 to a voltage that makes the voltage of the vertical signal line 27 the same magnitude as the input voltage. The input voltage can be any voltage within the range of the power supply voltage and the ground voltage. For example, the input voltage is within the range of 0 V to 3.3 V. The differential amplifier 32 is also called a feedback amplifier.

[0081] 2, the formation of a feedback path causes the AC component of the thermal noise to be fed back to the other of the source and drain of the reset transistor 22. In the configuration illustrated in FIG. 2, the feedback path is formed until just before the reset transistor 22 is turned off, so it is possible to reduce the reset noise that occurs when the reset transistor 22 is turned off.

[0082] Next, a description will be given of the circuit configuration of the near-infrared light pixels 29 and the peripheral circuit 15 connected to the near-infrared light pixels 29. Fig. 3 is a schematic diagram showing an exemplary circuit configuration of the near-infrared light pixels 29 and the circuits connected to the near-infrared light pixels 29 according to this embodiment. In the following description of the circuits connected to the near-infrared light pixels 29 and the near-infrared light pixels 29, differences from the description of the circuit configuration of the visible light pixels 24 and the circuits connected to the visible light pixels 24 will be mainly described, and description of commonalities will be omitted or simplified.

[0083] 3 , the imaging device 100 includes a plurality of near-infrared pixels 29 and peripheral circuits 15 connected to the plurality of near-infrared pixels 29, including a vertical scanning circuit 25, a horizontal signal readout circuit 20, a plurality of column signal processing circuits 30, a plurality of load circuits 28, and a plurality of differential amplifiers 32. The peripheral circuits 15 connected to the plurality of near-infrared pixels 29 have a configuration in which the voltage supply circuit 19 is removed from the peripheral circuits 15 connected to the plurality of visible pixels 24. At least some of the vertical scanning circuit 25, horizontal signal readout circuit 20, a plurality of column signal processing circuits 30, a plurality of load circuits 28, and a plurality of differential amplifiers 32 may be shared by the plurality of visible pixels 24 and the plurality of near-infrared pixels 29. In other words, at least one of the vertical scanning circuit 25, horizontal signal readout circuit 20, column signal processing circuits 30, load circuits 28, and differential amplifiers 32 may be a single circuit connected to both the near-infrared pixels 29 and the visible pixels 24. Furthermore, the near-infrared light pixels 29 and the visible light pixels 24 may share at least a portion of wiring such as signal lines that are connected to peripheral circuits.

[0084] The plurality of near-infrared light pixels 29 are arranged two-dimensionally on the semiconductor substrate 40. Specifically, the plurality of near-infrared light pixels 29 are arranged in row and column directions. While FIG. 3 shows a circuit configuration of two rows and two columns of near-infrared light pixels 29, the actual arrangement of the near-infrared light pixels 29 may differ from the arrangement shown in FIG. 3. For example, as described above, a plurality of pixels including visible light pixels 24 and near-infrared light pixels 29 are arranged in row and column directions on the semiconductor substrate 40. Note that, as in the planar layout shown in FIG. 11 described later, there may be rows and columns in which only a plurality of near-infrared light pixels 29 are aligned in one direction. Furthermore, the number of near-infrared light pixels 29 is not particularly limited.

[0085] The near-infrared pixel 29 includes a photodiode 10B, a charge detection circuit that detects signal charge generated by the photodiode 10B, and a charge accumulation node 35 provided in the charge detection circuit. The charge detection circuit of the near-infrared pixel 29 includes an amplification transistor 21, a reset transistor 22, an address transistor 23, and a transfer transistor 18. The charge accumulation node 35 accumulates the signal charge generated by the photodiode 10B, and the charge detection circuit of the near-infrared pixel 29 detects the signal charge accumulated in the charge accumulation node 35. The near-infrared pixel 29 has a circuit configuration in which the photoelectric conversion unit 10A and the charge accumulation node 34 of the visible light pixel 24 are replaced with a photodiode 10B and a charge accumulation node 35, respectively, and a transfer transistor 18 is added. Furthermore, the circuit configurations of multiple near-infrared pixels 29 are, for example, the same as each other.

[0086] The photodiode 10B is a photoelectric conversion element that receives incident light and generates a signal charge through photoelectric conversion. The signal charge generated by the photodiode 10B is transferred to the charge accumulation node 35 by the transfer transistor 18.

[0087] The transfer transistor 18 is, for example, a field effect transistor formed on a semiconductor substrate 40. In the example shown in Fig. 3, the transfer transistor 18 is an N-channel MOSFET.

[0088] As shown in FIG. 3 , one of the source and drain of the transfer transistor 18 is connected to the photodiode 10B. The other of the source and drain of the transfer transistor 18 is connected to the charge accumulation node 35. A transfer signal line 38 is connected to the gate of the transfer transistor 18. The transfer signal line 38 is provided for each row of the near-infrared light pixels 29. The transfer signal line 38 is connected to the vertical scanning circuit 25. The vertical scanning circuit 25 can turn on the transfer transistor 18 by applying a transfer control signal, which controls the on / off of the transfer transistor 18, to the gate of the transfer transistor 18 via the transfer signal line 38. When the transfer transistor 18 is turned on, the signal charge generated in the photodiode 10B is transferred to the charge accumulation node 35.

[0089] The signal charge generated by the photodiode 10B is accumulated in a charge accumulation node 35. The charge accumulation node 35 is connected to the other of the source and drain of the transfer transistor 18, the gate of the amplification transistor 21, and one of the source and drain of the reset transistor 22. The charge accumulation node 35 functions as at least a part of a charge accumulation region that accumulates the signal charge of the near-infrared pixel 29, and the potential of the charge accumulation node 35 corresponds to the amount of signal charge accumulated in the charge accumulation region. The signal charge accumulated in the charge accumulation node 35 is applied to the gate of the amplification transistor 21 as a voltage according to the amount of signal charge. Reading the output of the amplification transistor 21 in the near-infrared pixel 29 and resetting the potential of the charge accumulation node 35 are performed in the same manner as the operations described for the visible light pixel 24.

[0090] [Plane Layout and Device Structure of Pixels] Next, the planar layout and device structure of the visible light pixel 24 and the near-infrared light pixel 29 according to this embodiment will be described.

[0091] 4 is a plan view showing an example of the planar layout of the visible light pixel 24 and the near-infrared light pixel 29 according to the present embodiment. Note that in FIG. 4, components other than the pixel electrode 2 and the photodiode 10B are omitted from the illustration.

[0092] In Fig. 4 , the boundary between two adjacent pixels (specifically, two adjacent visible light pixels 24 or an adjacent visible light pixel 24 and a near-infrared light pixel 29) is indicated by a dashed line or a two-dot chain line. In Fig. 4 , the two-dot chain line also indicates the boundary between adjacent pixel groups PG. In other words, the pixel group PG is made up of pixels in an area surrounded by the two-dot chain line. These points are also the same in other planar layout diagrams described below. In addition, Fig. 4 shows at least some of the pixels included in the imaging device 100, and does not necessarily show all of the pixels included in the imaging device 100. This is also the same in other planar layout diagrams described below.

[0093] In the example shown in FIG. 4 , the multiple visible light pixels 24 include visible light pixels 24a, 24b, and 24c, each including a color filter (specifically, color filter 60A, described later) that blocks light of different wavelength bands within visible light. In this embodiment, the visible light pixel 24a is an example of at least one first pixel, the near-infrared light pixel 29 is an example of at least one second pixel, the visible light pixel 24b is an example of a third pixel, and the visible light pixel 24c is an example of a fourth pixel. Note that, in this specification, the visible light pixels 24 may be described separately as the visible light pixels 24a, 24b, and 24c, as necessary. Furthermore, when the term "visible light pixel 24" is used without any particular distinction, the description applies to all visible light pixels 24, including the visible light pixels 24a, 24b, and 24c. Furthermore, the pixel electrodes 2 of the visible light pixels 24 may also be distinguished from one another by referring to the pixel electrode 2 of the visible light pixel 24a as the pixel electrode 2a, the pixel electrode 2 of the visible light pixel 24b as the pixel electrode 2b, and the pixel electrode 2 of the visible light pixel 24c as the pixel electrode 2c. In Fig. 4, to make it easier to distinguish between the visible light pixels 24a, 24b, and 24c, the pixel electrode 2a of the visible light pixel 24a is given a diagonal line pattern, the pixel electrode 2b of the visible light pixel 24b is given a dotted pattern, and the pixel electrode 2c of the visible light pixel 24c is given a vertical line pattern.

[0094] For example, one of the visible light pixels 24a, 24b, and 24c is a blue pixel including a blue color filter, another is a green pixel including a green color filter, and the remaining one is a red pixel including a red color filter. As a specific example, the visible light pixel 24a is a blue pixel, the visible light pixel 24b is a green pixel, and the visible light pixel 24c is a red pixel. Note that the visible light pixel 24 does not need to include a color filter, in which case the visible light pixel 24 is a black and white pixel.

[0095] FIG. 4 illustrates a planar layout of a pixel array PA included in the imaging device 100. The pixel array PA is composed of a plurality of pixels. The plurality of pixels constituting the pixel array PA includes a plurality of visible light pixels 24a, a plurality of visible light pixels 24b, a plurality of visible light pixels 24c, and a plurality of near-infrared light pixels 29. The number of pixels constituting the pixel array PA is not particularly limited. The plurality of pixels constituting the pixel array PA are formed on a semiconductor substrate 40 and are arranged two-dimensionally in a planar view. The pixel array PA forms a photosensitive region on the semiconductor substrate 40. The distance between two adjacent pixels among the plurality of pixels constituting the pixel array PA may be, for example, approximately 2 μm. The distance between two adjacent pixels is also referred to as the "pixel pitch." In the example illustrated in FIG. 4, two adjacent pixels are aligned in a row direction or a column direction. In FIG. 4, the row direction is the X-axis direction, and the column direction is the Y-axis direction.

[0096] The region corresponding to each pixel, separated by the boundary between two adjacent pixels shown in the figure, is, for example, a region for receiving light for each pixel to generate signal charge, and does not necessarily include all of the components of each pixel. In the example shown in Figure 4, the shape of the region corresponding to each pixel is square, but it may be other shapes such as rectangular or octagonal. Since the multiple pixels that make up the pixel array PA are regularly arranged in units of pixel pitch, the boundary between two adjacent pixels is determined by, for example, the pixel pitch.

[0097] Furthermore, for example, when the pixel electrode 2 or the photodiode 10B is disposed at the center of the pixel, the boundary between two adjacent pixels is the position of a side of a square whose center coincides with the center of the pixel electrode 2 or the photodiode 10B and whose side length is the pixel pitch. Furthermore, the boundary between two adjacent pixels is, for example, a position equidistant from the center of the two adjacent pixel electrodes 2, or a position equidistant from the center of each of the adjacent pixel electrodes 2 and the photodiode 10B. Furthermore, when the adjacent pixels include color filters of different colors, the boundary between two adjacent pixels is, for example, the position of the boundary of the color filters.

[0098] 4, the pixel array PA includes a plurality of pixel groups PG, each including a visible light pixel 24a, 24b, and 24c and a near-infrared light pixel 29. In the example shown in FIG. 4, the pixel group PG is composed of four pixels, one each of the visible light pixel 24a, 24b, and 24c and the near-infrared light pixel 29. The pixel arrangement in the plurality of pixel groups PG is the same as each other, and is the smallest unit of repetition of the pixel arrangement in the pixel array PA. The plurality of pixel groups PG are arranged two-dimensionally in a planar view. The two-dimensional arrangement of the plurality of pixel groups PG forms, for example, a Bayer array in which some of the pixel groups are replaced with near-infrared light pixels 29. The number of the plurality of pixel groups PG is not particularly limited.

[0099] 4, in a plan view, the near-infrared pixel 29 is adjacent to the visible light pixel 24a and the visible light pixel 24c. The visible light pixel 24 adjacent to the near-infrared pixel 29 is the visible light pixel 24 that includes the pixel electrode 2 that is closest to the photodiode 10B of the near-infrared pixel 29 in a plan view. In addition, the visible light pixel 24b is adjacent to the visible light pixel 24a and the visible light pixel 24c, and is positioned diagonally opposite the near-infrared pixel 29 within the pixel group PG.

[0100] 5 is a cross-sectional view showing an example of the cross-sectional structure of the visible light pixel 24 and the near-infrared light pixel 29 according to the present embodiment. For ease of viewing, hatching indicating the cross section of the insulating layer 50 is omitted in FIG.

[0101] As shown in Fig. 5, the visible light pixel 24 and the near-infrared light pixel 29 are formed on a semiconductor substrate 40. Fig. 5 shows the cross-sectional structure of one visible light pixel 24a out of the multiple visible light pixels 24, but the cross-sectional structures of the visible light pixels 24b and 24c are the same as that of the visible light pixel 24a. As shown in Fig. 5, the visible light pixel 24 includes a pixel electrode 2, a photoelectric conversion layer 3, a counter electrode 4, a color filter 60A, and a microlens 61. The near-infrared light pixel 29 also includes a photoelectric conversion layer 3, a photodiode 10B, a color filter 60B, and a microlens 61.

[0102] In the configuration shown in FIG. 5 , a transistor group 45 including a plurality of transistors is formed on a semiconductor substrate 40. Specifically, the transistor group 45 is formed on the upper surface of the semiconductor substrate 40. The plurality of transistors included in the transistor group 45 include, for example, the amplification transistor 21, reset transistor 22, address transistor 23, and transfer transistor 18 in the above-described visible light pixel 24 and near-infrared light pixel 29. FIG. 5 only illustrates impurity regions formed in the semiconductor substrate 40 that function as sources or drains of the plurality of transistors included in the transistor group 45, and does not illustrate details. Furthermore, the number of impurity regions in the transistor group 45 is not limited to the example shown in FIG. 5 . This also applies to the transistor groups 45 in the subsequent cross-sectional views.

[0103] In the semiconductor substrate 40, an impurity region FD is formed as one of the impurity regions in the transistor group 45, in which signal charges collected by the pixel electrode 2 are accumulated. The impurity region FD functions as, for example, one of the source and drain of the reset transistor 22 of the visible light pixel 24.

[0104] The semiconductor substrate 40 is not limited to a substrate made entirely of semiconductor. The semiconductor substrate 40 may be an insulating substrate having a semiconductor layer formed on the surface on which the photosensitive region is formed. Here, an example will be described in which a P-type silicon (Si) substrate is used as the semiconductor substrate 40. In this case, the impurity regions in the transistor group 45 are N-type regions in which N-type impurities are diffused. The semiconductor substrate 40 may also be provided with an element isolation region for electrical isolation between pixels.

[0105] Furthermore, a photodiode 10B is formed on the semiconductor substrate 40 at a position different from the transistor group 45 in plan view. The photodiode 10B is, for example, a buried photodiode formed on a silicon substrate. In this case, the photodiode 10B formed on the silicon substrate absorbs, for example, near-infrared light components in a wavelength band of 1100 nm or less. The photodiode 10B overlaps the photoelectric conversion layer 3 in plan view and generates signal charges by absorbing near-infrared light that has passed through the photoelectric conversion layer 3. The signal charges generated by the photodiode 10B are an example of second signal charges.

[0106] An insulating layer 50 is disposed above the semiconductor substrate 40. The insulating layer 50 is formed of an insulating material such as silicon oxide. As shown in FIG. 5 , a plurality of metal layers 55 are disposed within the insulating layer 50. The plurality of metal layers 55 are formed of a metal such as copper and have light-blocking properties against visible light and near-infrared light. Note that in this specification, "having light-blocking properties" and "light-blocking" do not simply mean that no light passes through, but rather that the metal layer 55 substantially blocks light. For example, the metal layer 55 does not transmit 90% or more of incident visible light and near-infrared light. The metal layer 55 does not necessarily need to transmit 99% or more of incident visible light and near-infrared light.

[0107] At least one of the plurality of metal layers 55 is a wiring layer that may include, for example, wiring that connects the visible light pixels 24 and near-infrared light pixels 29 to peripheral circuits, such as the above-mentioned vertical signal line 27. The number of metal layers 55 arranged in the insulating layer 50 can be set arbitrarily and is not limited to the example shown in FIG.

[0108] At least one of the multiple metal layers 55 is located between the photoelectric conversion layer 3 and the semiconductor substrate 40 in the stacking direction, and between the pixel electrode 2a and the photodiode 10B in a plan view. As a result, in a plan view, the metal layer 55 overlaps a portion of the transistor group 45 formed on the semiconductor substrate 40, covering the portion of the transistor group 45 from above with the metal layer 55, thereby suppressing light from being incident on the transistor group 45. This makes it possible to suppress noise generation due to light absorption by the transistor group 45. The multiple metal layers 55 include, for example, a metal layer 55 covering a portion of the transistor group 45 in the visible light pixel 24 and a metal layer 55 covering a portion of the transistor group 45 in the near-infrared light pixel 29 in a plan view.

[0109] A plurality of vias are disposed in the insulating layer 50. The plurality of vias include, for example, a via 56 connecting the pixel electrode 2 and the impurity region FD, a via (not shown) connecting the metal layer 55, and a via (not shown) connecting the metal layer 55 and the transistor group 45. Each of the plurality of vias is a plug formed from a metal such as aluminum, copper, or tungsten, a metal nitride, or polysilicon doped with impurities to provide conductivity. The plurality of vias has a light-blocking property against, for example, visible light and near-infrared light. The plurality of vias reflect, for example, visible light and near-infrared light.

[0110] As shown in Fig. 5 , in the visible light pixel 24, a photoelectric conversion layer 3 is disposed above an insulating layer 50 with a pixel electrode 2 interposed therebetween. In the example shown in Fig. 5 , in the visible light pixel 24, a pixel electrode 2, a photoelectric conversion layer 3, a counter electrode 4, a passivation layer 65, a color filter 60A, and a microlens 61 are stacked in this order from the semiconductor substrate 40 side, with the insulating layer 50 interposed therebetween. In the near-infrared light pixel 29, a photoelectric conversion layer 3 is disposed above the insulating layer 50 without a pixel electrode 2 interposed therebetween. In the example shown in Fig. 5 , in the near-infrared light pixel 29, a photoelectric conversion layer 3, a counter electrode 4, a passivation layer 65, a color filter 60B, and a microlens 61 are stacked in this order from the semiconductor substrate 40 side, with the insulating layer 50 interposed therebetween.

[0111] 5, the photoelectric conversion layer 3, the counter electrode 4, and the passivation layer 65 are continuous across the visible light pixel 24a and the near-infrared light pixel 29, and are shared by the visible light pixel 24a and the near-infrared light pixel 29. Although not shown in Fig. 5, the photoelectric conversion layer 3, the counter electrode 4, and the passivation layer 65 are also continuous across the visible light pixel 24b and the visible light pixel 24c, and are shared by the visible light pixel 24a, the near-infrared light pixel 29, the visible light pixel 24b, and the visible light pixel 24c. The photoelectric conversion layer 3, the counter electrode 4, and the passivation layer 65 may also be continuous across all of the multiple pixels constituting the pixel array PA, and be shared by the multiple pixels.

[0112] The pixel electrode 2 is an electrode that collects signal charges generated in the photoelectric conversion layer 3. The signal charges collected by the pixel electrode 2 a are an example of first signal charges. The pixel electrode 2 is spatially separated from the pixel electrodes 2 of other adjacent visible light pixels 24, and is thereby electrically isolated from the pixel electrodes 2 of other visible light pixels 24.

[0113] The pixel electrode 2 is located below the photoelectric conversion layer 3, that is, on the opposite side to the light incident side. In this embodiment, the light incident side of the imaging device 100 is the opposite side to the semiconductor substrate 40 side of the photoelectric conversion layer 3. Therefore, the pixel electrode 2 is located between the semiconductor substrate 40 and the photoelectric conversion layer 3. In a planar view, the pixel electrode 2 overlaps with a part of the transistor group 45. In addition, in a planar view, the pixel electrode 2 does not overlap with the photodiode 10B, and the pixel electrode 2 and the photodiode 10B are spaced apart. Note that in a planar view, the pixel electrode 2 may overlap with a part of the photodiode 10B.

[0114] The pixel electrode 2 has a light-blocking property against visible light and near-infrared light. The pixel electrode 2 may reflect visible light and near-infrared light transmitted through the photoelectric conversion layer 3. The pixel electrode 2 is formed from a metal such as aluminum, copper, or tungsten, a metal nitride, or polysilicon doped with impurities to provide conductivity. For example, a TaN electrode having a thickness of 100 nm can be formed as the pixel electrode 2 to achieve sufficient light-blocking properties. However, the pixel electrode 2 is not limited to a TaN electrode as long as it has light-blocking properties. For example, the pixel electrode 2 does not transmit 90% or more of incident visible light and near-infrared light. The pixel electrode 2 does not need to transmit 99% or more of incident visible light and near-infrared light.

[0115] The photoelectric conversion layer 3 absorbs visible light. The photoelectric conversion layer 3 is located above the pixel electrode 2 and the photodiode 10B. Visible light and near-infrared light that have passed through the microlens 61, the color filter 60A or 60B, the passivation layer 65, and the counter electrode 4 are incident on the photoelectric conversion layer 3. The photoelectric conversion layer 3, for example, absorbs the entire wavelength range of visible light and transmits at least a portion of the wavelength range of near-infrared light. The photoelectric conversion layer 3 is formed from an organic material or an inorganic material such as amorphous silicon. The photoelectric conversion layer 3 may include multiple layers, and the multiple layers may include layers composed of organic materials and layers composed of inorganic materials.

[0116] The counter electrode 4 is located above the photoelectric conversion layer 3 and is disposed opposite the pixel electrode 2. The counter electrode 4 transmits visible light and near-infrared light. The counter electrode 4 is, for example, a transparent electrode formed from a transparent conductive material. In this specification, "transparent" means that at least a portion of the light in the wavelength band to be detected is transmitted, and it is not essential that the counter electrode 4 transmits light over the entire wavelength band of visible light and near-infrared light. For example, the counter electrode 4 transmits at least a portion of the light of the wavelength to which the photoelectric conversion layer 3 is sensitive and at least a portion of the light of the wavelength to which the photodiode 10B is sensitive. Transparent electrodes include, for example, ITO, IZO, AZO, FTO, SnO ２ , TiO ２ , ZnO ２Transparent conducting oxides (TCOs) such as the above can be used.

[0117] Although not shown, the imaging device 100 may further include at least one of an electron blocking layer and a hole blocking layer. The electron blocking layer and the hole blocking layer are, for example, continuous across all of the pixels constituting the pixel array PA and are shared by the multiple pixels.

[0118] The electron blocking layer is provided to reduce dark current caused by electrons injected from the pixel electrode 2, and suppresses electrons from being injected from the pixel electrode 2 into the photoelectric conversion layer 3. The electron blocking layer is located below the photoelectric conversion layer 3, and is provided, for example, on the pixel electrode 2 and the insulating layer 50. In the visible light pixel 24, the electron blocking layer is located between the pixel electrode 2 and the photoelectric conversion layer 3, and in the near-infrared light pixel 29, the electron blocking layer is located between the photodiode 10B and the photoelectric conversion layer 3.

[0119] The electron blocking layer may be made of an organic material such as α-NPD (N,N'-Di(1-naphthalyl)-N,N'-diphenylbenzidine) or 9,9'-[1,1'-biphenyl]-4,4'-diylbis[3,6-bis(1,1-dimethyl ethyl)]-9H-carbazole, or an organic-metal compound, or an inorganic material such as NiO.

[0120] The electron blocking layer transmits near-infrared light and may have a thickness of, for example, 2 nm to 50 nm.

[0121] The hole-blocking layer is provided to reduce dark current caused by holes injected from the counter electrode 4, and suppresses holes from being injected from the counter electrode 4 into the photoelectric conversion layer 3. The hole-blocking layer is located between the photoelectric conversion layer 3 and the counter electrode 4.

[0122] The hole-blocking layer may be made of an organic material such as copper phthalocyanine, PTCDA (3,4,9,10-Perylenetetracarboxylic dianhydride), an acetylacetonate complex, BCP (Bathocuproine), or Alq (Tris(8-quinolinolate)aluminum), or an organic-metal compound, or an inorganic material such as MgAg or MgO. The hole-blocking layer may be made of an acceptor organic semiconductor material, which will be described later as the photoelectric conversion material of the photoelectric conversion layer 3.

[0123] The hole-blocking layer transmits visible light and near-infrared light. The hole-blocking layer preferably has high transmittance for visible light and near-infrared light so as not to interfere with the light absorption of the photoelectric conversion layer 3 and the photodiode 10B, and a material that does not absorb light in the visible light wavelength band may be selected. The thickness of the hole-blocking layer may also be reduced. The thickness of the hole-blocking layer depends on the configuration of the photoelectric conversion layer 3, the thickness of the counter electrode, and the like, but may be, for example, 2 nm to 50 nm.

[0124] The electron blocking layer and the hole blocking layer may also be transparent to visible and near infrared light.

[0125] When electrons are used as signal charges, the positions of the electron blocking layer and the hole blocking layer are reversed. In this case, the electron blocking layer prevents electrons from the counter electrode 4 from being injected into the photoelectric conversion layer 3, and the hole blocking layer prevents holes from the pixel electrode 2 from being injected into the photoelectric conversion layer 3.

[0126] The passivation layer 65 is an insulating protective film that protects the underlying layers. The passivation layer 65 transmits visible light and near-infrared light. The passivation layer 65 is made of, for example, SiON or AlO.

[0127] The color filters 60A and 60B are located above the photoelectric conversion layer 3. In other words, the color filters 60A and 60B are located closer to the light incident side than the photoelectric conversion layer 3.

[0128] The color filter 60A overlaps with the pixel electrode 2 in a plan view. In the visible light pixel 24, light transmitted through the color filter 60A enters the photoelectric conversion layer 3. The color filter 60A blocks components of a certain wavelength band of visible light and transmits components of other wavelength bands of visible light. The color filter 60A is, for example, a red, green, or blue color filter that blocks components of a certain wavelength band of visible light. The color filter 60A may transmit or block near-infrared light.

[0129] The color filter 60B overlaps the photodiode 10B in a planar view. In the near-infrared light pixel 29, light transmitted through the color filter 60B and the photoelectric conversion layer 3 enters the photodiode 10B. The color filter 60B transmits components of at least a portion of the wavelength band of near-infrared light and blocks components of at least a portion of the wavelength band of visible light. The color filter 60B is, for example, a black color filter, but it may also be a green or blue color filter. The black color filter may be a single black color filter, or may be a filter formed by stacking multiple color filters of different colors (e.g., blue and green) to essentially function as a black color filter. The color filter 60B, for example, does not transmit 90% or more of light in at least a portion of the wavelength band of visible light. Note that the near-infrared light pixel 29 does not necessarily include the color filter 60B.

[0130] The color filters 60A and 60B are formed as on-chip color filters by patterning, for example, using a photosensitive resin in which a dye or a pigment is dispersed, etc. The color filters 60A and 60B are formed, for example, by a patterning process at the same time.

[0131] The microlens 61 is located above the photoelectric conversion layer 3. The microlens 61 is provided individually for the visible light pixel 24 and the near-infrared light pixel 29. The pixel electrode 2 is located on the optical axis of the microlens 61 of the visible light pixel 24. For example, in a plan view, the center of the pixel electrode 2 and the center of the microlens 61 of the visible light pixel 24 coincide with each other. The photodiode 10B is located on the optical axis of the microlens 61 of the near-infrared light pixel 29. For example, in a plan view, the center of the photodiode 10B and the center of the microlens 61 of the near-infrared light pixel 29 coincide with each other. The microlens 61 is formed, for example, as an on-chip microlens. The microlens 61 is made of a material such as an ultraviolet-sensitive material.

[0132] A general semiconductor manufacturing process can be used to manufacture the imaging device 100. In particular, when a silicon substrate is used as the semiconductor substrate 40, the imaging device 100 can be manufactured using various silicon semiconductor processes.

[0133] As described above, the imaging device 100 according to the present embodiment includes a visible light pixel 24a, a near-infrared light pixel 29 adjacent to the visible light pixel 24a in a planar view, and a photoelectric conversion layer 3 that is continuous across the visible light pixel 24a and the near-infrared light pixel 29 and shared by the visible light pixel 24a and the near-infrared light pixel 29, and that absorbs visible light. The visible light pixel 24a includes a pixel electrode 2a that collects first signal charges generated in the photoelectric conversion layer 3, and that has light-blocking properties against visible light and near-infrared light. The near-infrared light pixel 29 includes a photodiode 10B that generates second signal charges by absorbing near-infrared light that has transmitted through the photoelectric conversion layer 3.

[0134] This allows the visible light pixel 24a to capture visible light, and the near-infrared light pixel 29 to capture near-infrared light. In this case, the photodiode 10B of the near-infrared light pixel 29 absorbs near-infrared light that has passed through the photoelectric conversion layer 3. Therefore, the light absorption by the photodiode 10B does not affect the absorption of visible light by the photoelectric conversion layer 3, thereby improving the sensitivity of the visible light pixel 24a. Furthermore, the photoelectric conversion layer 3, which absorbs visible light, can easily be designed to have characteristics that make it difficult to absorb near-infrared light, making it easier for the photodiode 10B to receive near-infrared light, thereby improving the sensitivity of the near-infrared light pixel 29. Furthermore, because a light-shielding electrode is used as the pixel electrode 2a of the visible light pixel 24a, the pixel electrode 2a blocks light, reducing the impact of that light on the pixel circuit and suppressing noise. Therefore, the imaging device 100 can capture both visible light and near-infrared light, improving sensitivity and reducing noise. Furthermore, because the visible light component of the light that reaches the photodiode 10B is absorbed by the photoelectric conversion layer 3, the wavelength separation of near-infrared light in the near-infrared light pixel 29 is improved. In other words, it becomes difficult for the near-infrared light pixel 29 to detect components in wavelength bands other than near-infrared light. Therefore, for example, when data captured using near-infrared light by the imaging device 100 is used for authentication such as face authentication, authentication accuracy is improved.

[0135] [Characteristics of Photoelectric Conversion Layer and Color Filter] Next, the characteristics of the photoelectric conversion layer 3 and the color filters 60A and 60B will be described. In this embodiment, in the visible light pixel 24, the photoelectric conversion layer 3 absorbs visible light that has passed through the color filter 60A, generating signal charges. The signal charges are collected by the pixel electrode 2 and read out as signals. In the near-infrared light pixel 29, the photodiode 10B absorbs near-infrared light that has passed through the color filter 60B and the photoelectric conversion layer 3, generating signal charges. The signal charges are transferred by the transfer transistor 18 and read out as signals. The photoelectric conversion layer 3 and the color filters 60A and 60B have the light absorption and transmission characteristics required to generate the signal charges described above.

[0136] First, the light absorption characteristics of the photoelectric conversion layer 3 will be described. The photoelectric conversion layer 3 has the property of absorbing visible light and transmitting near-infrared light. The photoelectric conversion layer 3 may also absorb components of a partial wavelength band of near-infrared light. Fig. 6 is a diagram showing an example of the absorption spectrum of the photoelectric conversion layer 3. Fig. 6 shows the absorption spectrum of the photoelectric conversion layer 3 formed by co-evaporating fullerene C60 and subphthalocyanine at a volume ratio of 4:1 to a film thickness of 500 nm.

[0137] 6, the photoelectric conversion layer 3 has a high absorptance in the wavelength band of 400 nm or more and 600 nm or less, with the absorptance in this wavelength band being 80% or more. The absorptance of the photoelectric conversion layer 3 gradually decreases as the wavelength becomes longer than 600 nm. The absorptance of the photoelectric conversion layer 3 is 50% or less in the wavelength band of 680 nm or more. Furthermore, the absorptance of the photoelectric conversion layer 3 is zero at 800 nm, and there is a wavelength band of near-infrared light in which the photoelectric conversion layer 3 does not absorb.

[0138] Because the photoelectric conversion layer 3 absorbs light to perform photoelectric conversion, the light absorptance of the photoelectric conversion layer 3 is positively correlated with the sensitivity of the photoelectric conversion layer 3. Therefore, the photoelectric conversion layer 3 having the absorption spectrum shown in FIG. 6 has sensitivity in the wavelength band of 400 nm to 600 nm, and has a characteristic of being more sensitive in the wavelength band of 400 nm to 600 nm than in the wavelength band longer than 600 nm. Furthermore, the photoelectric conversion layer 3 having the absorption spectrum shown in FIG. 6 has a characteristic of gradually decreasing sensitivity as the wavelength becomes longer than 600 nm. Human luminosity peaks near 555 nm, decreases at wavelengths longer than 555 nm, and becomes almost zero at wavelengths of 680 nm or longer. Furthermore, if red light is defined as light in the wavelength band from 600 nm to 680 nm, human luminosity is high near 600 nm and low near 680 nm. Therefore, in the case of the imaging device 100, if the sensitivity of the red pixel is high at 600 nm and decreases as the wavelength approaches 600 nm to 680 nm, it becomes possible to output an image with a natural color tone that is closer to the actual appearance. Therefore, by having the photoelectric conversion layer 3 have a characteristic in which the sensitivity gradually decreases as the wavelength becomes longer than 600 nm, it is possible to make an image captured using visible light into an image with a natural color tone that is closer to the actual appearance.

[0139] The absorption spectrum of the photoelectric conversion layer 3 is not limited to the example shown in FIG. 6 and can be adjusted by the photoelectric conversion material constituting the photoelectric conversion layer 3 and the thickness of the photoelectric conversion layer 3 .

[0140] The photoelectric conversion layer 3 includes, for example, a donor semiconductor material and an acceptor semiconductor material as photoelectric conversion materials. The photoelectric conversion layer 3 is fabricated using, for example, an organic semiconductor material. The photoelectric conversion layer 3 can be fabricated by, for example, a wet method such as a coating method using spin coating or a dry method such as a vacuum deposition method.

[0141] The photoelectric conversion layer 3 is, for example, a mixed film with a bulk heterostructure containing a donor semiconductor material such as a donor organic semiconductor material and an acceptor semiconductor material such as an acceptor organic semiconductor material. Alternatively, the photoelectric conversion layer 3 may have a laminated structure in which a layer composed of a donor semiconductor material and a layer composed of an acceptor semiconductor material are laminated. Furthermore, the photoelectric conversion layer 3 does not necessarily have a structure in which multiple layers are clearly laminated, and may be, for example, a layer having a region in which the content ratio of the donor semiconductor material is higher than the content ratio of the acceptor semiconductor material and a region in which the content ratio of the acceptor semiconductor material is higher than the content ratio of the donor semiconductor material.

[0142] Examples of donor organic semiconductor materials include triarylamine compounds, benzidine compounds, pyrazoline compounds, styrylamine compounds, hydrazone compounds, triphenylmethane compounds, carbazole compounds, polysilane compounds, thiophene compounds, phthalocyanine compounds, naphthalocyanine compounds, subphthalocyanine compounds, cyanine compounds, merocyanine compounds, oxonol compounds, polyamine compounds, indole compounds, pyrrole compounds, pyrazole compounds, polyarylene compounds, fused aromatic carbocyclic compounds (e.g., naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, and fluoranthene derivatives), and metal complexes having a nitrogen-containing heterocyclic compound as a ligand.

[0143] Examples of the acceptor organic semiconductor material include fullerenes (e.g., C60 fullerene and C70 fullerene), fullerene derivatives (e.g., PCBM (phenyl C ６１ butyric acid methyl ester) and ICBA (indene C ６０bis-adducts), fused aromatic carbocyclic compounds (for example, naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, and fluoranthene derivatives), 5- to 7-membered heterocyclic compounds containing a nitrogen atom, an oxygen atom, or a sulfur atom (for example, pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline, tetrazole, pyrazole, imidazoline, Examples of the metal complex include a metal complex having, as a ligand, one of: tetrazolindene, thiazole, oxazole, indazole, benzimidazole, benzotriazole, benzoxazole, benzothiazole, carbazole, purine, triazolopyridazine, triazolopyrimidine, tetrazaindene, oxadiazole, imidazopyridine, pyrrolidine, pyrrolopyridine, thiadiazolopyridine, dibenzazepine, and tribenzazepine), a polyarylene compound, a fluorene compound, a cyclopentadiene compound, a silyl compound, and a nitrogen-containing heterocyclic compound.

[0144] The donor organic semiconductor material and the acceptor organic semiconductor material are not limited to the above examples. Low-molecular-weight organic compounds and high-molecular-weight organic compounds may be used as the donor organic semiconductor material and the acceptor organic semiconductor material constituting the photoelectric conversion layer 3, as long as they are organic compounds that can be formed into a film as a photoelectric conversion layer by either a dry method or a wet method.

[0145] The photoelectric conversion layer 3 may also contain semiconductor materials other than those mentioned above as donor semiconductor materials and acceptor semiconductor materials. The photoelectric conversion layer 3 may also contain, as semiconductor materials, for example, silicon semiconductors, compound semiconductors, quantum dots, perovskite materials, carbon nanotubes, or a mixture of two or more of these.

[0146] At least one of the photoelectric conversion materials contained in the photoelectric conversion layer 3 has an absorption peak in the wavelength band of visible light, for example. For example, the donor semiconductor material contained in the photoelectric conversion layer 3 has an absorption peak in the wavelength band of visible light. The absorption peak may be present in a wavelength band of 500 nm or more and 600 nm or less. This makes it easier to increase the sensitivity of the visible light pixel 24 to green wavelengths, for which human visibility is high. For example, the subphthalocyanine described above in FIG. 6 has an absorption peak around 555 nm.

[0147] The thickness of the photoelectric conversion layer 3 is, for example, 50 nm or more, or may be 200 nm or more, or 400 nm or more. The thickness of the photoelectric conversion layer 3 is, for example, 1000 nm or less.

[0148] Next, the light transmission characteristics of the color filters 60A and 60B will be described. Fig. 7 shows an example of the transmission spectra of the color filters. Fig. 7 shows the transmission spectra of blue, green, red, and black color filters, each having a film thickness of 800 nm.

[0149] The color filter 60A may be, for example, a blue, green, or red color filter. The visible light pixel 24 detects light of the color of the color filter used as the color filter 60A. The color filter 60B may be, for example, a blue, green, or black color filter.

[0150] In the example shown in Figure 7, each of the blue, green, red, and black color filters transmits components of at least some wavelength bands of near-infrared light. The blue color filter transmits blue light and blocks visible light in other wavelength bands. The green color filter transmits green light and blocks visible light in other wavelength bands. The red color filter transmits red light and blocks visible light in other wavelength bands. The black color filter absorbs the entire wavelength band of visible light and blocks visible light in all wavelength bands. The transmittance of light in the wavelength bands blocked by the color filters is, for example, 10% or less.

[0151] In the near-infrared light pixel 29, light transmitted through the color filter 60B and the photoelectric conversion layer 3 is incident on the photodiode 10B. The total average transmittance of the color filter 60B and the photoelectric conversion layer 3 for the entire wavelength band of visible light is, for example, 6% or less. This total average transmittance is the average transmittance for the entire wavelength band of visible light when visible light passes through the color filter 60B and the photoelectric conversion layer 3, and can also be calculated by multiplying the transmittance of the color filter 60B by the transmittance of the photoelectric conversion layer 3. When the total average transmittance of the color filter 60B and the photoelectric conversion layer 3 for the entire wavelength band of visible light is 6% or less, the incidence of visible light on the photodiode 10B is suppressed, improving the wavelength separation of near-infrared light in the near-infrared light pixel 29. In other words, it is possible to capture near-infrared light while suppressing visible light components. Therefore, for example, when data captured using near-infrared light is used for facial recognition, authentication accuracy can be improved.

[0152] In the example of the photoelectric conversion layer 3 shown in FIG. 6 , the transmittance is 64% at 680 nm, which is the wavelength in the visible light wavelength band with the lowest absorption in the photoelectric conversion layer 3. Also, in the example shown in FIG. 7 , at 680 nm, the transmittance of the green color filter is 10%, the transmittance of the blue color filter is 5%, and the transmittance of the black color filter is 2%. Therefore, the total transmittance of the green color filter and the photoelectric conversion layer 3 for light at 680 nm is 6.4%. The total transmittance of the blue color filter and the photoelectric conversion layer 3 for light at 680 nm is 3.2%. The total transmittance of the black color filter and the photoelectric conversion layer 3 for light at 680 nm is 1.3%. Thus, by using any one of green, blue, and black color filters as the color filter 60B, the total transmittance of the color filter 60B and the photoelectric conversion layer 3 is 7% or less even at 680 nm, where the transmittance is highest, and can be reduced to 1% or less on average across the entire visible light wavelength band.

[0153] The transmission spectrum of the color filter is not limited to the example shown in FIG. 7, and can be adjusted by the composition of the photosensitive resin used to form the color filter, the thickness of the color filter, and the like.

[0154] [Another Example of Pixel Cross-Sectional Structure] Next, a description will be given of another example of the cross-sectional structure of the visible light pixel 24 and the near-infrared light pixel 29 according to the present embodiment. In the following description of the cross-sectional structure of the visible light pixel 24 and the near-infrared light pixel 29, differences from the description of the cross-sectional structure of the visible light pixel 24 and the near-infrared light pixel 29 shown in FIG. 5 above will be mainly described, and description of commonalities will be omitted or simplified.

[0155] 8 is a cross-sectional view showing another example of the cross-sectional structure of the visible light pixel 24 and the near-infrared light pixel 29 according to the present embodiment. For ease of viewing, hatching indicating the cross section of the insulating layer 50 is omitted in FIG.

[0156] The example shown in Figure 8 differs from the example shown in Figure 5 mainly in that the visible light pixel 24a and the near-infrared light pixel 29 include microlenses 61A and 61B with different curvatures, and that the near-infrared light pixel 29 includes a color filter 60A.

[0157] 8, the visible light pixel 24a includes a microlens 61A instead of the above-described microlens 61, and the near-infrared light pixel 29 includes a microlens 61B instead of the above-described microlens 61. Although not shown, the visible light pixel 24b and the visible light pixel 24c also include a microlens 61A instead of the above-described microlens 61.

[0158] The curvature of the microlens 61B is smaller than that of the microlens 61A. As a result, the focal length of the microlens 61B is longer than that of the microlens 61A. Therefore, the microlens 61A makes it easier for visible light to be focused on the photoelectric conversion layer 3 located above the semiconductor substrate 40, and the microlens 61B makes it easier for near-infrared light to be focused on the photodiode 10B formed on the semiconductor substrate 40, thereby increasing the sensitivity of each pixel. In addition, stray light is less likely to be generated, which improves the wavelength separation ability of each pixel.

[0159] In the example shown in FIG. 8 , the near-infrared light pixel 29 includes a color filter 60A instead of the above-described color filter 60B. The color filter 60A is continuous across the visible light pixel 24a and the near-infrared light pixel 29. In this case, the color filter 60A across the visible light pixel 24a and the near-infrared light pixel 29 is, for example, a blue or green color filter. As a result, even if the photoelectric conversion layer 3 has a low absorptance in a partial wavelength band of red light, the blue or green color filter blocks red light, making it easier for the photoelectric conversion layer 3 and the color filter 60A to block the entire wavelength band of visible light incident on the photodiode 10B. Furthermore, by using the same color filter 60A for the visible light pixel 24a and the near-infrared light pixel 29, the number of types of materials used for patterning the color filter can be reduced.

[0160] 9 is a cross-sectional view showing yet another example of the cross-sectional structure of the visible light pixel 24 and the near-infrared light pixel 29 according to the present embodiment. For ease of viewing, hatching indicating the cross sections of the insulating layers 51 and 52 and the insulating film 75 is omitted in FIG.

[0161] The example shown in FIG. 9 differs from the example shown in FIG. 5 mainly in that a transistor group 45 is formed on the lower surface of the semiconductor substrate 40 .

[0162] 9 , a transistor group 45 is formed on the lower surface of the semiconductor substrate 40. Therefore, some of the transistors in the transistor group 45 can be disposed below the photodiode 10B, which increases the area of ​​the photodiode 10B in a plan view and makes it possible to increase the sensitivity of the near-infrared light pixel 29.

[0163] 9 , an insulating layer 51 is disposed between the semiconductor substrate 40 and the pixel electrode 2 and photoelectric conversion layer 3, and an insulating layer 52 is disposed below the semiconductor substrate 40. The impurity region FD is connected to the pixel electrode 2 via a via 71 disposed in the insulating layer 51, a through via 72 penetrating the semiconductor substrate 40, and a wiring 73 disposed in the insulating layer 52. An insulating film 75 is disposed between the through via 72 and the semiconductor substrate 40, separating the through via 72 from the semiconductor substrate 40. Although not shown, one or more wiring layers are disposed in the insulating layer 52, which may include wiring such as the above-mentioned vertical signal line 27 that connects the visible light pixels 24 and near-infrared light pixels 29 to peripheral circuits.

[0164] [Another Example of Planar Layout of Pixels] Next, a description will be given of another example of the planar layout of the visible light pixels 24 and the near-infrared light pixels 29 according to the present embodiment. In the following description of the planar layout of the visible light pixels 24 and the near-infrared light pixels 29, differences from the description of the planar layout of the visible light pixels 24 and the near-infrared light pixels 29 shown in FIG. 4 above will be mainly described, and description of commonalities will be omitted or simplified.

[0165] 10 is a plan view showing another example of the planar layout of the visible light pixel 24 and the near-infrared light pixel 29 according to the present embodiment. Note that in FIG. 10, components other than the pixel electrode 2 and the photodiode 10B are omitted from the illustration.

[0166] FIG. 10 illustrates a pixel array PA1 that differs from the pixel array PA in the planar layout of the visible light pixels 24 and near-infrared light pixels 29. Like the pixel array PA, the pixel array PA1 is composed of a plurality of pixels, including a plurality of visible light pixels 24a, a plurality of visible light pixels 24b, a plurality of visible light pixels 24c, and a plurality of near-infrared light pixels 29. The number of pixels constituting the pixel array PA1 is not particularly limited. The pixel array PA1 differs from the pixel array PA primarily in the proportion of near-infrared light pixels 29 among the plurality of pixels constituting the pixel array PA1. The proportion of near-infrared light pixels 29 among the plurality of pixels constituting the pixel array PA1 is less than 25%, and in the example shown in FIG. 10, is 6.25%. In other words, in the pixel array PA1, the number of visible light pixels 24 is more than three times the number of near-infrared light pixels 29, and in the example shown in FIG. 10, it is 15 times the number of near-infrared light pixels 29. This enables near-infrared light imaging while suppressing a decrease in the resolution of the visible light image.

[0167] 10 , the pixel array PA1 includes a plurality of pixel groups PG1, each of which includes visible light pixels 24a, 24b, and 24c and a near-infrared light pixel 29. In the example shown in FIG. 10 , the pixel group PG1 consists of 16 pixels, including four visible light pixels 24a, seven visible light pixels 24b, four visible light pixels 24c, and one near-infrared light pixel 29. The arrangement of the pixels in the plurality of pixel groups PG1 is the same as each other. The plurality of pixel groups PG1 are arranged two-dimensionally in a planar view. By arranging the plurality of pixel groups PG1 two-dimensionally, for example, a Bayer array is formed in which some of the pixel groups are replaced with near-infrared light pixels 29.

[0168] 11 is a plan view showing yet another example of the planar layout of the visible light pixel 24 and the near-infrared light pixel 29 according to the present embodiment. Note that in FIG. 11, components other than the pixel electrode 2 and the photodiode 10B are omitted from the illustration.

[0169] FIG. 11 shows a pixel array PA2 that differs from the pixel array PA in the planar layout of the visible light pixels 24 and near-infrared light pixels 29. Like the pixel array PA, the pixel array PA2 is composed of a plurality of pixels, including a plurality of visible light pixels 24a, a plurality of visible light pixels 24b, a plurality of visible light pixels 24c, and a plurality of near-infrared light pixels 29. The number of pixels constituting the pixel array PA2 is not particularly limited. The pixel array PA2 differs from the pixel array PA mainly in the shape of the region corresponding to the visible light pixels 24. In the pixel array PA2, the shape of the region corresponding to the visible light pixels 24 is octagonal. In the pixel array PA2, one near-infrared light pixel 29 is located at the center of four visible light pixels 24 arranged in two rows and two columns. Furthermore, in the pixel array PA2, the region corresponding to the near-infrared light pixels 29 is smaller than the region corresponding to the visible light pixels 24.

[0170] In the pixel array PA2, a pixel group (the dash-dot lines indicating the boundaries of the pixel groups are omitted in FIG. 11 ) consisting of four visible light pixels 24 arranged in two rows and two columns and one near-infrared pixel 29 located at the center of the four visible light pixels 24 is arranged two-dimensionally in a planar view. In the example shown in FIG. 11 , there is a location at the center of the four visible light pixels 24 arranged in two rows and two columns where no near-infrared pixel 29 is located, but a near-infrared pixel 29 may also be located in that location. In this case, a pixel group consisting of one visible light pixel 24 and one near-infrared pixel 29 adjacent to that one visible light pixel 24 is arranged two-dimensionally in a planar view.

[0171] [Modification 1] The following describes Modification 1 of Embodiment 1. Note that in the following description of Modification 1, differences from Embodiment 1 will be mainly described, and descriptions of commonalities will be omitted or simplified.

[0172] Fig. 12 is a plan view showing an example of the planar layout of the visible light pixel 24 and the near-infrared light pixel 29 according to this modified example. Fig. 13 is a cross-sectional view showing an example of the cross-sectional structure of the visible light pixel 24 and the near-infrared light pixel 29 according to this modified example. Note that in Fig. 12, components other than the pixel electrode 2, the photodiode 10B, and the shield electrode 5 are omitted. Also, Fig. 12 shows one pixel group PG as a representative. Also, in Fig. 13, for ease of viewing, hatching indicating the cross section of the insulating layer 50 is omitted.

[0173] As shown in Figures 12 and 13, the imaging device of this modified example differs from the imaging device 100 of embodiment 1 mainly in that it further includes a shield electrode 5, a via 57, and a light-shielding structure 80.

[0174] 12 , the shield electrode 5 is located, in a plan view, between the pixel electrodes 2 of two adjacent visible light pixels 24, and between the photodiode 10B of a near-infrared light pixel 29 and the pixel electrode 2 of the visible light pixel 24 adjacent to that near-infrared light pixel 29. In the example shown in FIG. 12 , the shield electrode 5 surrounds each of the pixel electrodes 2 and the photodiode 10B in a lattice shape in a plan view. In a plan view, the shield electrode 5 is spaced apart from the pixel electrode 2 and the photodiode 10B and does not overlap with the pixel electrode 2 and the photodiode 10B. Note that, in a plan view, the shield electrode 5 may overlap with a portion of the photodiode 10B.

[0175] The shield electrode 5 is, for example, continuously formed collectively in the photosensitive region where the pixel array PA is arranged. Note that the shield electrode 5 may be divided and provided corresponding to one or more pixels included in the pixel array PA.

[0176] The shield electrode 5 is connected to, for example, a voltage supply circuit or ground (not shown) and is maintained at a predetermined potential. The shield electrode 5 has, for example, the same potential within the pixel array PA. The shield electrode 5 and the pixel electrodes 2 are electrically separated. The potential of the shield electrode 5 is, for example, a fixed potential, but may be variable.

[0177] The shield electrode 5 suppresses electrical color mixing between adjacent visible light pixels 24. It also suppresses the movement of signal charges generated in the photoelectric conversion layer 3 of the near-infrared light pixels 29 adjacent to the visible light pixels 24 to the visible light pixels 24. When the signal charges are holes, the potential of the shield electrode 5 is set, for example, higher than the potential of the charge storage node 34 when the signal charges are reset. This suppresses the movement of signal charges to adjacent visible light pixels 24, enables signal charges generated near the shield electrode 5 to be extracted with high efficiency, and improves sensitivity. The potential of the shield electrode 5 may also be set lower than the potential of the charge storage node 34 when the signal charges are reset. This also allows the signal charges to be collected by the shield electrode 5, suppressing the movement of signal charges to adjacent visible light pixels 24.

[0178] 13 , the shield electrode 5 is located below the photoelectric conversion layer 3, that is, on the side opposite to the light incident side. The shield electrode 5 is also located above the semiconductor substrate 40. Therefore, the shield electrode 5 is located between the semiconductor substrate 40 and the photoelectric conversion layer 3. In addition, the shield electrode 5 overlaps with a part of the transistor group 45 in a plan view.

[0179] The shield electrode 5 has a light-shielding property against visible light and near-infrared light. Covering a portion of the transistor group 45 from above with the light-shielding shield electrode 5 prevents light from entering the transistor group 45, thereby suppressing noise generation due to light absorption by the transistor group 45. The shield electrode 5 may reflect visible light and near-infrared light transmitted through the photoelectric conversion layer 3. The shield electrode 5 is formed from a metal such as aluminum, copper, or tungsten, a metal nitride, or polysilicon doped with impurities to provide conductivity. The shield electrode 5 does not transmit, for example, 90% or more of incident visible light and near-infrared light. The shield electrode 5 may not transmit 99% or more of incident visible light and near-infrared light.

[0180] 12 , the shield electrode 5 is disposed at a position including the boundary between two adjacent pixels in a plan view. In the example shown in FIG. 12 , the width of the shield electrode 5 between the photodiode 10B of the near-infrared pixel 29 and the pixel electrode 2 of the visible light pixel 24 adjacent to the near-infrared pixel 29 is wider than the width of the portion between the pixel electrodes 2 of the two adjacent visible light pixels 24 in a plan view. In the example shown in FIG. 12 , in a portion of the shield electrode 5 between the photodiode 10B of the near-infrared pixel 29 and the pixel electrode 2 of the visible light pixel 24 adjacent to the near-infrared pixel 29 in a plan view, the width Lb from the boundary between the two adjacent pixels toward the photodiode 10B of the near-infrared pixel 29 is longer than the width La from the boundary toward the pixel electrode 2 of the visible light pixel 24. This increases the proportion of the light-shielding shield electrode 5 disposed in the region corresponding to the near-infrared pixel 29 where the light-shielding pixel electrode 2 is not disposed. Therefore, in the near-infrared light pixel 29, the incidence of light on the transistor group 45 is further suppressed.

[0181] The shield electrode 5 is formed on the same plane as the pixel electrode 2, for example, using the same material as the pixel electrode 2, in the same process. Note that different materials may be used for the shield electrode 5 and the pixel electrode 2. Furthermore, the process of forming the shield electrode 5 and the process of forming the pixel electrode 2 may be separated.

[0182] 13 , the via 57 is connected to the shield electrode 5. The via 57 is a plug formed of a metal such as aluminum, copper, or tungsten, a metal nitride, or polysilicon doped with impurities to provide conductivity. In the example shown in FIG. 13 , the via 57 connects the shield electrode 5 to a metal layer 55. For example, the metal layer 55 connected to the via 57 is a wiring layer, and the shield electrode 5 is connected to a voltage supply circuit or ground (not shown) via the via 57 and the metal layer 55. In the example shown in FIG. 13 , the via 57 is connected to the metal layer 55 closest to the semiconductor substrate 40 among the multiple metal layers 55.

[0183] As shown in FIG. 13 , the via 57 is located between the shield electrode 5 and the semiconductor substrate 40 in the stacking direction. The via 57 is also located between the pixel electrode 2a and the photodiode 10B in a planar view. Although not shown, the number of vias 57 connected to the shield electrode 5 is not limited to one, and multiple vias 57 may be connected to the shield electrode 5. For example, multiple vias 57 may be arranged side by side between the pixel electrode 2a and the photodiode 10B in a planar view. Furthermore, for example, a via 57 may also be arranged between the photodiode 10B of the near-infrared pixel 29 and the pixel electrode 2 of a visible light pixel 24 other than the visible light pixel 24a adjacent to the near-infrared pixel 29 in a planar view. Furthermore, for example, a via 57 may also be arranged between the pixel electrodes 2 of two adjacent visible light pixels 24 in a planar view.

[0184] The via 57 has a light-blocking property against visible light and near-infrared light. This blocks light incident obliquely on the near-infrared light pixel 29, preventing the light from entering the portion of the transistor group 45 on the visible light pixel 24a side, thereby suppressing noise generation due to light absorption by the transistor group 45. Furthermore, near-infrared light passing between the pixel electrode 2a and the shield electrode 5 is prevented from entering the photodiode 10B, thereby suppressing color mixing between pixels. The via 57 may also reflect near-infrared light transmitted through the photoelectric conversion layer 3. This increases the amount of near-infrared light incident on the photodiode 10B, thereby improving the sensitivity of the near-infrared light pixel 29.

[0185] As shown in FIG. 13 , the light-shielding structure 80 is located above the photoelectric conversion layer 3, i.e., closer to the light incident side than the photoelectric conversion layer 3. In the example shown in FIG. 13 , the light-shielding structure 80 is formed on each of the passivation layer 65 and the color filter 60A. The light-shielding structure 80 blocks visible light and near-infrared light. The light-shielding structure 80 may reflect visible light and near-infrared light. The light-shielding structure 80 is, for example, a metal grid or an air gap. When the light-shielding structure 80 is an air gap, the surface in contact with the air gap reflects visible light and near-infrared light, thereby blocking visible light and near-infrared light. Note that the light-shielding structure 80 may be formed on either the passivation layer 65 or the color filter 60A. 13, both the visible light pixel 24a and the near-infrared light pixel 29 include the color filter 60A, but the near-infrared light pixel 29 may include the above-mentioned color filter 60B instead of the color filter 60A. In this case, the light-shielding structure 80 is formed, for example, between the color filter 60A and the color filter 60B.

[0186] 13 , the light-shielding structure 80 is located between the pixel electrode 2a and the photodiode 10B in a plan view. This allows the light-shielding structure 80 to cover a portion of the transistor group 45 from above, preventing light from entering the transistor group 45, thereby suppressing noise generation due to light absorption by the transistor group 45. The light-shielding structure 80 may also be located between the photodiode 10B of the near-infrared pixel 29 and the pixel electrode 2 of a visible light pixel 24 other than the visible light pixel 24a adjacent to the near-infrared pixel 29 in a plan view. For example, the light-shielding structure 80 may also be located between the pixel electrodes 2 of two adjacent visible light pixels 24 in a plan view. Although not shown, the light-shielding structure 80 extends, for example, along the boundary between two adjacent pixels in a plan view (specifically, the boundary between the visible light pixel 24a and the near-infrared pixel 29 in the example shown in FIG. 13 ). Furthermore, the light-shielding structure 80 blocks and reflects light that is obliquely incident near the boundary between two adjacent pixels, thereby improving wavelength separation and sensitivity in each pixel.

[0187] 13 , at least one of the plurality of metal layers 55 is located between the pixel electrode 2 and the shield electrode 5 in a plan view. This causes a portion of the transistor group 45 in the visible light pixel 24 to be covered by the metal layer 55. Also, in the example shown in FIG. 13 , at least one of the plurality of metal layers 55 is located between the photodiode 10B and the shield electrode 5 in a plan view. This causes a portion of the transistor group 45 in the near-infrared light pixel 29 to be covered by the metal layer 55. Also, the transistor group 45 may be completely covered by a metal structure group that is light-blocking to visible light and near-infrared light in a plan view. This metal structure group includes, for example, at least one of the pixel electrode 2, the shield electrode 5, a metal grid, and the metal layer 55.

[0188] 13 , the metal layer 55 located between the pixel electrode 2 and the shield electrode 5 in a plan view, and the metal layer 55 located between the photodiode 10B and the shield electrode 5 in a plan view, may be located below the center between the upper surface of the semiconductor substrate 40 and the lower surface of the photoelectric conversion layer 3 in the stacking direction. This prevents light that is obliquely incident on the visible light pixel 24 and the near-infrared light pixel 29 from entering the transistor group 45.

[0189] 12, the shield electrode 5 is formed continuously and collectively to surround the pixel electrode 2 and the photodiode 10B in plan view, but this is not limiting. For example, the shield electrode 5 may be separated into multiple parts as shown in FIG. 14. FIG. 14 is a plan view showing another example of the planar layout of the visible light pixel 24 and the near-infrared light pixel 29 according to this modified example. Note that in FIG. 14, only the pixel electrode 2, the photodiode 10B, and the shield electrode 5 are shown. In addition, FIG. 14 shows one pixel group PG as a representative.

[0190] As shown in FIG. 14 , the multiple separated shield electrodes 5 are arranged along the boundary between two adjacent pixels. The multiple shield electrodes 5 are arranged to surround the pixel electrodes 2 and photodiodes 10B, respectively. In the example shown in FIG. 14 , the multiple shield electrodes 5 are arranged not only between the pixel electrodes 2 of two adjacent visible light pixels 24 and between the photodiode 10B of a near-infrared light pixel 29 and the pixel electrode 2 of the visible light pixel 24 adjacent to the near-infrared light pixel 29 in plan view, but also between the pixel electrodes 2 arranged diagonally and between the photodiode 10B and the pixel electrode 2 arranged diagonally. Note that the number and arrangement of the multiple shield electrodes 5 are not limited to the example shown in FIG. 14 . Furthermore, in the example shown in FIG. 14 , each of the multiple shield electrodes 5 has a square shape in plan view, but may have other shapes in plan view. Although not shown, a via 57 is connected to each of the multiple shield electrodes 5.

[0191] [Modification 2] The following describes Modification 2 of Embodiment 1. Note that in the following description of Modification 2, differences from the above-described Embodiment 1 and Modification 1 will be mainly described, and descriptions of commonalities will be omitted or simplified.

[0192] Fig. 15 is a plan view showing an example of the planar layout of the visible light pixel 24 and the near-infrared light pixel 29 according to this modified example. Fig. 16 is a cross-sectional view showing an example of the cross-sectional structure of the visible light pixel 24 and the near-infrared light pixel 29 according to this modified example. Note that in Fig. 15, components other than the pixel electrode 2, the photodiode 10B, and the microlens 61 are omitted. In Fig. 15, the microlens 61 is indicated by a dashed line. In Fig. 16, for ease of viewing, hatching indicating the cross section of the insulating layer 50 is omitted.

[0193] As shown in Figures 15 and 16, the imaging device of this modified example differs from the imaging devices of embodiment 1 and modified example 1 of embodiment 1 mainly in that there are visible light pixels 24 and near-infrared light pixels 29 that share a microlens 61.

[0194] 15 , the imaging device according to this modification includes a pixel array PA3 configured with a plurality of pixels including visible light pixels 24 and near-infrared light pixels 29. The pixel array PA3 differs from the pixel arrays according to the first embodiment and the first modification of the first embodiment in that the plurality of pixels configuring the pixel array PA3 include a visible light pixel 24d and a near-infrared light pixel 29a that share a microlens 61, and a visible light pixel 24e and a near-infrared light pixel 29b that share a microlens 61. In this modification, the visible light pixels 24d and 24e are examples of first pixels, and the near-infrared light pixels 29a and 29b are examples of second pixels. Note that, in this specification, the visible light pixel 24 may be distinguished as the visible light pixels 24d and 24e, and the near-infrared light pixel 29 may be distinguished as the near-infrared light pixels 29a and 29b, as necessary. Furthermore, the pixel electrodes 2 of the visible light pixels 24 may be described separately, with the pixel electrode 2 of the visible light pixel 24d being referred to as pixel electrode 2d and the pixel electrode 2 of the visible light pixel 24e being referred to as pixel electrode 2e. Similarly, the photodiode 10B of the near-infrared light pixel 29 may be described separately, with the photodiode 10B of the near-infrared light pixel 29a being referred to as photodiode 10Ba and the photodiode 10B of the near-infrared light pixel 29b being referred to as photodiode 10Bb. In the example shown in FIG. 15 , the visible light pixels 24d and 24e are pixels that include color filters of the same color as the visible light pixel 24b, and dot patterns are applied to the pixel electrodes 2d and 2e. The visible light pixels 24d and 24e may also be pixels that include color filters of the same color as the visible light pixel 24a or 24c.

[0195] 15 , the plurality of pixels constituting pixel array PA3 include visible light pixel 24d and near-infrared light pixel 29a, visible light pixel 24e and near-infrared light pixel 29b, and visible light pixels 24a, 24b, and 24c. Visible light pixel 24d and near-infrared light pixel 29a, and visible light pixel 24e and near-infrared light pixel 29b each share microlens 61, and therefore the size of the area corresponding to the pixel is half that of visible light pixels 24a, 24b, and 24c, which are visible light pixels 24 other than visible light pixels 24d and 24e. The plurality of pixels constituting pixel array PA3 may also include near-infrared light pixel 29 having a corresponding area the same size as the visible light pixels 24a, 24b, and 24c.

[0196] 15 , pixel electrodes 2d and 2e and photodiodes 10Ba and 10Bb are each biased in a predetermined direction from the center of microlens 61 in a plan view. In the example shown in Fig. 15 , pixel electrode 2d and photodiode 10Bb are biased in the negative direction of the X axis from the center of microlens 61 in a plan view, and the entirety is shifted in the negative direction of the X axis from the center of microlens 61. In addition, in the example shown in Fig. 15 , pixel electrode 2e and photodiode 10Ba are biased in the positive direction of the X axis, which is the direction opposite to the negative direction of the X axis, from the center of microlens 61 in a plan view, and the entirety is shifted in the positive direction of the X axis from the center of microlens 61.

[0197] The pixel electrodes 2d and 2e are symmetrical in terms of their relative positions with respect to the center of the microlens 61 in a planar view. The signals output by the visible light pixel 24d and the visible light pixel 24e can be used for phase difference detection. Phase difference detection is performed, for example, by a processing circuit in a camera system and is used for autofocusing and the like. In this case, autofocusing is possible using visible light, which captures high-resolution images. Furthermore, the photodiodes 10Ba and 10Bb are symmetrical in terms of their relative positions with respect to the center of the microlens 61 in a planar view. The signals output by the near-infrared light pixel 29a and the near-infrared light pixel 29b can be used for phase difference detection. In this case, autofocusing is possible using near-infrared light. The pixel electrodes 2d and 2e and the photodiodes 10Ba and 10Bb may be offset from the center of the microlens 61 not only in the X-axis direction but also in the Y-axis direction, for example.

[0198] 16, the cross-sectional structure of the visible light pixel 24d and the near-infrared light pixel 29a below the microlens 61 is the same as, for example, the example shown in FIG. 13. As shown in FIG. 16, in a plan view, a shield electrode 5 is disposed between the pixel electrode 2d and the photodiode 10Ba, thereby suppressing the movement of signal charges generated in the photoelectric conversion layer 3 of the near-infrared light pixel 29a adjacent to the visible light pixel 24d to the visible light pixel 24d. This improves the accuracy of phase difference detection using signals output by the visible light pixel 24d and the near-infrared light pixel 29a. Note that the cross-sectional structures of the visible light pixel 24d and the near-infrared light pixel 29a are not limited to the example shown in FIG. 16. The cross-sectional structure of the visible light pixel 24d and the near-infrared light pixel 29a below the microlens 61 may be the same as the example shown in FIG. 5, FIG. 8, or FIG. 9. Furthermore, while Figure 16 shows the cross-sectional structures of the visible light pixel 24d and the near-infrared light pixel 29a, the cross-sectional structures of the visible light pixel 24e and the near-infrared light pixel 29b are structures in which the positions of the visible light pixel 24d and the near-infrared light pixel 29a are reversed (i.e., structures inverted along the X-axis).

[0199] In the example shown in FIG. 15 , one visible light pixel 24d and one near-infrared light pixel 29a, and one visible light pixel 24e and one near-infrared light pixel 29b each share a microlens 61, but this is not limited to this. FIG. 17 is a plan view showing another example of the planar layout of the visible light pixel 24 and the near-infrared light pixel 29 according to this modification. In FIG. 17 , components other than the pixel electrode 2, the photodiode 10B, and the microlenses 61 and 61C are omitted. In FIG. 17 , the microlenses 61 and 61C are indicated by dashed dotted lines. In FIG. 17 , components other than the visible light pixel 24d and the visible light pixel 24e are shown without distinction as visible light pixels 24, but the visible light pixels 24 other than the visible light pixel 24d and the visible light pixel 24e may be the visible light pixels 24a, 24b, or 24c.

[0200] 17 , the imaging device according to this modification may include a pixel array PA4 instead of the pixel array PA3. The pixels constituting the pixel array PA4 include a plurality of visible light pixels 24, including visible light pixels 24d and 24e, and a near-infrared light pixel 29. The visible light pixels 24d and 24e and the near-infrared light pixel 29 share a microlens 61C. Note that the pixels constituting the pixel array PA4 may also include a near-infrared light pixel 29 that does not share a microlens with the visible light pixels 24d and 24e.

[0201] In the example shown in Fig. 17, the length in the X-axis direction of microlens 61C is longer than that of microlens 61, being twice that of microlens 61. In the example shown in Fig. 17, the size of the area corresponding to visible light pixels 24d and 24e is half that of the visible light pixels 24 other than visible light pixels 24d and 24e, and the size of the area corresponding to near-infrared pixel 29 is the same as that of the visible light pixels 24 other than visible light pixels 24d and 24e. In the example shown in Fig. 17, the area corresponding to near-infrared pixel 29 can be made larger than that of near-infrared pixels 29a and 29b shown in Fig. 15, thereby improving sensitivity to near-infrared light.

[0202] As shown in FIG. 17 , the pixel electrodes 2d and 2e are each offset in a predetermined direction from the center of the microlens 61C in a planar view. In the example shown in FIG. 17 , the pixel electrode 2d is offset from the center of the microlens 61C in the negative direction of the X axis in a planar view, and the entire electrode is offset from the center of the microlens 61C in the negative direction of the X axis. In addition, in the example shown in FIG. 17 , the pixel electrode 2e is offset from the center of the microlens 61C in the positive direction of the X axis, which is the opposite direction to the negative direction of the X axis, and the entire electrode is offset from the center of the microlens 61C in the positive direction of the X axis. The pixel electrodes 2d and 2e are arranged symmetrically with respect to the center of the microlens 61C in a planar view. The signals output by the visible light pixel 24d and the visible light pixel 24e can be used for phase difference detection.

[0203] (Embodiment 2) Next, a description will be given of embodiment 2. In embodiment 2, a camera system including an imaging device according to embodiment 1, modification 1 of embodiment 1, or modification 2 of embodiment 1 will be described.

[0204] FIG. 18 is a block diagram showing an example of the configuration of a camera system 500 according to this embodiment.

[0205] The camera system 500 includes the image capture device 100A, a near-infrared light source 501, a lens optical system 502, an ISP (Image Signal Processor) 503, a signal processing circuit 504, edge processing circuits 505, 506, and a double bandpass filter (DBF). The camera system 500 may be, for example, a smartphone, a digital camera, a video camera, or an in-vehicle camera. The camera system 500 is configured to process data based on light of two wavelength bands acquired by the image capture device 100A and output the data to an external device. The ISP 503, the signal processing circuit 504, the edge processing circuit 505, and the edge processing circuit 506 may each be configured as separate circuits, or at least one of the ISP 503, the signal processing circuit 504, the edge processing circuit 505, and the edge processing circuit 506 may share at least a portion of the circuitry. The camera system 500 may perform centralized processing or distributed processing.

[0206] The near-infrared light source 501 emits near-infrared light P1 toward the subject P2. The near-infrared light source 501 is an example of a light source. The subject P2 is an example of an object. The near-infrared light source 501 emits near-infrared light P1 in a wavelength band that is not absorbed by the photoelectric conversion layer 3, for example.

[0207] The imaging device 100A receives reflected light P3 generated when near-infrared light P1 emitted from the near-infrared light source 501 hits and reflects off a subject P2, via a lens optical system 502 and a double band-pass filter DBF, and detects the reflected light P3. The imaging device 100A outputs, for example, data based on visible light and data based on near-infrared light in two systems. The imaging device 100A is, for example, an imaging device according to the above-described first embodiment, first modification of the first embodiment, or second modification of the first embodiment.

[0208] The lens optical system 502 may include, for example, a lens group including at least one of an autofocus lens and a zoom lens, and an aperture. The lens optical system 502 focuses light onto the imaging surface of the imaging device 100A. The imaging surface of the imaging device 100A is, for example, the photosensitive region described above. The double bandpass filter DBF is located on the light incident side of the imaging device 100A and has transmission bands in the visible light wavelength band and the near-infrared light wavelength band. The double bandpass filter DBF also has a light-blocking region in a wavelength band between the transmission band of the visible light wavelength band and the transmission band of the near-infrared light wavelength band. Visible light and near-infrared light that have passed through the double bandpass filter DBF are incident on the photoelectric conversion layer 3. This improves the wavelength separation between visible light and near-infrared light in the visible light pixel 24 and the near-infrared light pixel 29. The double bandpass filter DBF is, for example, a thin-film stacked filter.

[0209] 18 , the double bandpass filter DBF is disposed between the image capturing device 100A and the lens optical system 502, and reflected light P3 transmitted through the lens optical system 502 is incident on the double bandpass filter DBF. There are no particular limitations on the double bandpass filter DBF as long as it is disposed closer to the light incident side than the photoelectric conversion layer 3. For example, the double bandpass filter DBF may be disposed on the light incident side of the lens optical system 502. Alternatively, the double bandpass filter DBF may be disposed inside the image capturing device 100A.

[0210] Here, a description will be given of the transmission spectrum of the double bandpass filter DBF and the emission spectrum of the near-infrared light source 501. Fig. 19 is a diagram showing an example of the transmission spectrum of the double bandpass filter DBF and the emission spectrum of the near-infrared light source 501 according to this embodiment. In Fig. 19, the transmission spectrum of the double bandpass filter DBF is shown by a solid line, and the emission spectrum of the near-infrared light source 501 is shown by a dashed line.

[0211] In the example shown in FIG. 19 , the double bandpass filter DBF has transmission bands in the visible light wavelength band of 400 nm to 650 nm and the near-infrared light wavelength band including 940 nm. The boundary wavelength on the long wavelength side of the visible light transmission band of the double bandpass filter DBF is, for example, 630 nm to 670 nm. This makes it difficult for wavelengths around 680 nm, which have low luminosity, to reach the photoelectric conversion layer 3, making it possible to output images with natural coloring that is closer to the actual appearance. This also further improves the wavelength separation of near-infrared light in the near-infrared light pixel 29. The boundary wavelength on the short wavelength side of the visible light transmission band of the double bandpass filter DBF is, for example, 380 nm to 420 nm.

[0212] In the example shown in FIG. 19 , the near-infrared light P1 emitted by the near-infrared light source 501 has a narrow-band emission peak at 940 nm within the near-infrared transmission range of the double bandpass filter DBF. This allows blocking of ambient light and other wavelength bands other than the wavelength of the near-infrared light P1 emitted by the near-infrared light source 501, thereby improving robustness in sensing. The near-infrared light source 501 is, for example, a vertical cavity surface emitting laser (VCSEL) illumination that emits near-infrared light P1 having a narrow-band emission peak around 940 nm. The half-width of the emission peak of the near-infrared light P1 is, for example, 70 nm or less. The half-width of the emission peak of the near-infrared light P1 may be 50 nm or less. The near-infrared light source 501 is not particularly limited and may be an LED (Light Emitting Diode) illumination or a laser diode illumination. The center of the near-infrared transmission range of the double bandpass filter DBF and the emission peak of the near-infrared light P1 emitted by the near-infrared light source 501 are not limited to around 940 nm and may be designed according to the purpose. The center of the near-infrared transmission range of the double bandpass filter DBF and the emission peak of the near-infrared light P1 emitted by the near-infrared light source 501 may be around 850 nm, for example. The near-infrared transmission range of the double bandpass filter DBF and the emission band of the near-infrared light P1 emitted by the near-infrared light source 501 may include a wavelength band of 850 nm or more and 940 nm or less.

[0213] 18 , the ISP 503 processes the data based on visible light. This results in a full-color image. The full-color image is transmitted to, for example, an external display 509a and displayed on the external display 509a. The full-color image is also transmitted to an external device and / or the cloud 508a after being processed by, for example, the edge processing circuit 506.

[0214] The signal processing circuit 504 processes data based on the near-infrared light. This results in an image using near-infrared light. The signal processing circuit 504 may be configured to calculate the distance to the subject from the data based on the near-infrared light. In this case, the image capture device 100A has a circuit configuration for performing distance measurement using, for example, a time-of-flight (TOF) method. The image using near-infrared light is transmitted to, for example, an external display 509b and displayed on the external display 509b. The image using near-infrared light is also transmitted to an external device and / or the cloud 508a after being processed by, for example, the edge processing circuit 505. It is also possible to add the full-color image and the image using near-infrared light and display them on the external display 509c. In the example shown in FIG. 18 , the images are output from the camera system 500 separately to the external displays 509a, 509b, and 509c, but they may also be output to a single external display.

[0215] Sensing can also be performed using data based on visible light and data based on near-infrared light. Because data based on visible light and data based on near-infrared light can be obtained with a single imaging device 100A, there is no image misalignment, and image processing can be facilitated. Examples of sensing include authentication, such as facial recognition, shape recognition using machine vision, and sensing at specific near-infrared wavelengths, such as moisture detection. Sensing may be performed, for example, by a processing circuit in the camera system 500 (not shown), or by an external device and / or the cloud 508a.

[0216] (Other Embodiments) While the imaging device and camera system according to the present disclosure have been described above based on the embodiments, the present disclosure is not limited to these embodiments. Various modifications conceivable by those skilled in the art without departing from the spirit of the present disclosure are also included within the scope of the present disclosure. Furthermore, the components of the embodiments and modifications of the embodiments may be combined in any manner without departing from the spirit of the present disclosure.

[0217] For example, in the above embodiment, the transfer transistor 18, the amplification transistor 21, the reset transistor 22, and the address transistor 23 are each an N-channel MOSFET, but this is not limiting. At least one of the transfer transistor 18, the amplification transistor 21, the reset transistor 22, and the address transistor 23 may be a P-channel MOSFET. Furthermore, at least one of the transfer transistor 18, the amplification transistor 21, the reset transistor 22, and the address transistor 23 may not be a field-effect transistor, but may be another transistor such as a bipolar transistor.

[0218] The imaging device and camera system according to the present disclosure can be used as a camera for smartphones, tablets, laptops, medical cameras, robots, security cameras, cameras mounted on vehicles, and the like.

[0219] 2, 2a, 2b, 2c, 2d, 2e Pixel electrode 3 Photoelectric conversion layer 4 Counter electrode 5 Shield electrode 10A Photoelectric conversion section 10B, 10Ba, 10Bb Photodiode 15 Peripheral circuit 18 Transfer transistor 19 Voltage supply circuit 20 Horizontal signal readout circuit 21 Amplification transistor 22 Reset transistor 23 Address transistor 24, 24a, 24b, 24c, 24d, 24e Visible light pixel 25 Vertical scanning circuit 26 Counter electrode signal line 27 Vertical signal line 28 Load circuit 29, 29a, 29b Near-infrared light pixel 30 Column signal processing circuit 31 Power supply wiring 32 Differential amplifier 33 Feedback line 34, 35 Charge storage node 36 Address signal line 37 Reset signal line 38 Transfer signal line 40 Semiconductor substrate 45 REFERENCE SIGNS LIST Transistor group 50, 51, 52 Insulating layer 55 Metal layer 56, 57, 71 Via 60A, 60B Color filter 61, 61A, 61B, 61C Microlens 65 Passivation layer 72 Through via 73 Wiring 75 Insulating film 80 Light-shielding structure 100, 100A Imaging device 500 Camera system 501 Near-infrared light source 502 Lens optical system 503 ISP 504 Signal processing circuit 505, 506 Edge processing circuit 508a External device and / or cloud 509a, 509b, 509c External display DBF Double band-pass filter FD Impurity region PA, PA1, PA2, PA3, PA4 Pixel array PG, PG1 Pixel group

Claims

1. An imaging device comprising: at least one first pixel; at least one second pixel adjacent to the at least one first pixel in a planar view; and a photoelectric conversion layer continuous across the at least one first pixel and the at least one second pixel and shared by the at least one first pixel and the at least one second pixel, the photoelectric conversion layer absorbing visible light, wherein the at least one first pixel includes a first pixel electrode that collects first signal charges generated in the photoelectric conversion layer, the first pixel electrode having a light-shielding property against the visible light and near-infrared light, and the at least one second pixel includes a photodiode that generates second signal charges by absorbing the near-infrared light that has passed through the photoelectric conversion layer.

2. The imaging device described in claim 1, wherein at least one of the second pixels is located above a surface of the photoelectric conversion layer on which light is incident and includes a color filter that transmits at least a portion of the wavelength band components of the near-infrared light and blocks at least a portion of the wavelength band components of the visible light.

3. The imaging device according to claim 2, wherein the combined average transmittance of the color filter and the photoelectric conversion layer of the at least one second pixel for the entire wavelength band of visible light is 6% or less.

4. The imaging device according to claim 2, wherein the color filter of the at least one second pixel is a black color filter that absorbs the entire wavelength band of the visible light.

5. The imaging device according to claim 2, wherein the color filter of the at least one second pixel is a blue color filter that transmits blue light or a green color filter that transmits green light.

6. The imaging device of claim 1, further comprising a plurality of pixel groups each including the at least one first pixel and the at least one second pixel, the plurality of pixel groups being arranged two-dimensionally in the planar view.

7. Each of the plurality of pixel groups further includes a third pixel and a fourth pixel, the photoelectric conversion layer is continuous across the at least one first pixel, the at least one second pixel, the third pixel, and the fourth pixel, and is shared by the at least one first pixel, the at least one second pixel, the third pixel, and the fourth pixel, the third pixel, and the fourth pixel, the third pixel includes a second pixel electrode that collects a third signal charge generated in the photoelectric conversion layer, the second pixel electrode having a light-shielding property against the visible light and the near-infrared light, the fourth pixel includes a third pixel electrode that collects a fourth signal charge generated in the photoelectric conversion layer, the third pixel electrode having a light-shielding property against the visible light and the near-infrared light, each of the at least one first pixel, the third pixel, and the fourth pixel includes a color filter that is located above a surface of the photoelectric conversion layer on which light is incident, and that blocks components of a partial wavelength band of the visible light, The imaging device according to claim 6 , wherein the color filter of the at least one first pixel, the color filter of the third pixel, and the color filter of the fourth pixel block light of different wavelength bands of the visible light.

8. The imaging device of claim 1, further comprising a pixel array including a plurality of pixels, wherein the at least one first pixel includes a plurality of first pixels, the at least one second pixel includes a plurality of second pixels, the plurality of pixels includes the plurality of first pixels and the plurality of second pixels, and a proportion of the plurality of second pixels among all pixels included in the pixel array is less than 25%.

9. The imaging device according to claim 1, wherein the photoelectric conversion layer has sensitivity in a wavelength band of 400 nm or more and 600 nm or less, and the sensitivity of the photoelectric conversion layer gradually decreases as the wavelength becomes longer than 600 nm.

10. The imaging device of claim 1, further comprising a metal grid or an air gap located between the first pixel electrode and the photodiode in the planar view and above the light-incident surface of the photoelectric conversion layer.

11. The imaging device of claim 1, further comprising: a substrate including the photodiode, the substrate having the photoelectric conversion layer stacked thereon; and a metal layer located between the photoelectric conversion layer and the substrate in the stacking direction, and between the first pixel electrode and the photodiode in the planar view.

12. The imaging device according to claim 1, further comprising a shield electrode located between the first pixel electrode and the photodiode in the planar view, the shield electrode having a light blocking property against the visible light and the near-infrared light.

13. The imaging device of claim 12, further comprising: a substrate including the photodiode, the substrate having the photoelectric conversion layer laminated thereon; and a via connected to the shield electrode, the via being located between the shield electrode and the substrate and between the first pixel electrode and the photodiode in the planar view, the via having light-shielding properties against the visible light and the near-infrared light.

14. The imaging device of claim 1, wherein the at least one first pixel further includes a first microlens, and the at least one second pixel further includes a second microlens, and the curvature of the second microlens is smaller than the curvature of the first microlens.

15. The imaging device of claim 1, wherein the at least one first pixel further includes a first microlens, the at least one second pixel further includes a second microlens, and the first pixel electrode is biased in a predetermined direction from the center of the first microlens in the planar view.

16. A camera system comprising: an imaging device according to any one of claims 1 to 15; and a double bandpass filter having a transmission range in each of the wavelength bands of visible light and near-infrared light, wherein the visible light and near-infrared light that have passed through the double bandpass filter are incident on the photoelectric conversion layer.

17. A camera system comprising: an imaging device according to any one of claims 1 to 15; and a light source that emits near-infrared light, wherein the imaging device detects reflected light generated when the near-infrared light emitted by the light source is reflected by an object.

Images