Light detection device and electronic apparatus

Abstract

A light detection device according to one embodiment of the present disclosure comprises: a first semiconductor layer; a plurality of pixels including a first pixel having a first photoelectric conversion element and a second photoelectric conversion element; and a pixel separation region having a first electrode. The first pixel has a first separation region, a second separation region, and an overflow path provided between the first separation region and the second separation region so as to be in contact with the first photoelectric conversion element and the second photoelectric conversion element. The first separation region has a second electrode provided between the first electrode and the overflow path and comprising a material having a work function different from the work function of the first electrode.

Description

Photodetector and electronic equipment

[0001] The present disclosure relates to photodetection devices and electronic equipment.

[0002] A device has been proposed that has an inter-pixel separator including a protrusion that protrudes toward the center of the pixel, and that performs photoelectric conversion of incident light (Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2018-201015

[0004] There is a demand for improved performance in light-detecting devices.

[0005] It is desirable to provide a photodetector device with good performance.

[0006] A photodetector according to an embodiment of the present disclosure includes a first semiconductor layer, a plurality of pixels including a first pixel having a first photoelectric conversion element and a second photoelectric conversion element arranged in a first direction in the first semiconductor layer, and a pixel isolation region arranged in the first semiconductor layer around the pixel and having a first electrode. The first pixel includes a first isolation region arranged between the first photoelectric conversion element and the second photoelectric conversion element, a second isolation region arranged in a second direction intersecting the first direction with respect to the first isolation region, and an overflow path arranged between the first isolation region and the second isolation region so as to contact the first photoelectric conversion element and the second photoelectric conversion element. The first isolation region includes a second electrode arranged between the first electrode and the overflow path and made of a material having a work function different from that of the first electrode. An electronic device according to an embodiment of the present disclosure includes an optical system and a photodetector configured to receive light transmitted through the optical system. The photodetector device includes a first semiconductor layer, a plurality of pixels including a first pixel having a first photoelectric conversion element and a second photoelectric conversion element arranged in a first direction in the first semiconductor layer, and a pixel isolation region arranged in the first semiconductor layer around the pixel and having a first electrode. The first pixel includes a first isolation region arranged between the first photoelectric conversion element and the second photoelectric conversion element, a second isolation region arranged in a second direction intersecting the first direction with respect to the first isolation region, and an overflow path arranged between the first isolation region and the second isolation region so as to contact the first photoelectric conversion element and the second photoelectric conversion element. The first isolation region has a second electrode arranged between the first electrode and the overflow path and made of a material having a work function different from that of the first electrode.

[0007] FIG. 1 is a block diagram illustrating an example of a schematic configuration of an imaging device that is an example of a photodetector according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating an example of an arrangement of pixels in the imaging device according to an embodiment of the present disclosure. FIG. 3 is a diagram illustrating an example of a circuit configuration of a pixel in the imaging device according to an embodiment of the present disclosure. FIG. 4A is a diagram illustrating another example of a circuit configuration of a pixel in the imaging device according to an embodiment of the present disclosure. FIG. 4B is a diagram illustrating another example of a circuit configuration of a pixel in the imaging device according to an embodiment of the present disclosure. FIG. 5A is a diagram illustrating another example of a circuit configuration of a pixel in the imaging device according to an embodiment of the present disclosure. FIG. 5B is a diagram illustrating another example of a circuit configuration of a pixel in the imaging device according to an embodiment of the present disclosure. FIG. 6 is a diagram illustrating an example of a planar configuration of a pixel in the imaging device according to an embodiment of the present disclosure. FIG. 7 is a diagram illustrating an example of a cross-sectional configuration of a pixel in the imaging device according to an embodiment of the present disclosure. FIG. 8 is a diagram illustrating an example of a cross-sectional configuration of a pixel in the imaging device according to an embodiment of the present disclosure. FIG. 9 is a diagram illustrating another example of a configuration of a pixel in the imaging device according to an embodiment of the present disclosure. FIG. 10 is a diagram illustrating another example of a configuration of a pixel in the imaging device according to an embodiment of the present disclosure. FIG. 11A is a diagram illustrating an example of a manufacturing method of an imaging device according to an embodiment of the present disclosure. FIG. 11B is a diagram illustrating an example of a manufacturing method of an imaging device according to an embodiment of the present disclosure. FIG. 11C is a diagram illustrating an example of a manufacturing method of an imaging device according to an embodiment of the present disclosure. FIG. 11D is a diagram illustrating an example of a manufacturing method of an imaging device according to an embodiment of the present disclosure. FIG. 12 is a diagram illustrating an example of a cross-sectional configuration of an imaging device according to an embodiment of the present disclosure. FIG. 13 is a diagram illustrating another example of a cross-sectional configuration of an imaging device according to an embodiment of the present disclosure. FIG. 14 is a diagram illustrating an example of a planar configuration of a pixel of an imaging device according to Modification 1 of the present disclosure. FIG. 15 is a diagram illustrating an example of a cross-sectional configuration of a pixel of an imaging device according to Modification 1 of the present disclosure. FIG. 16 is a diagram illustrating an example of a cross-sectional configuration of a pixel of an imaging device according to Modification 1 of the present disclosure. FIG. 17 is a diagram illustrating an example of a configuration of an imaging device according to Modification 2 of the present disclosure. FIG. 18 is a diagram illustrating an example of a configuration of an imaging device according to Modification 2 of the present disclosure. FIG. 19 is a diagram illustrating an example of a configuration of an imaging device according to Modification 3 of the present disclosure. FIG. 20 is a diagram illustrating an example of a configuration of an imaging device according to Modification 3 of the present disclosure.FIG. 21 is a diagram for explaining a configuration example of an imaging device according to Modification 4 of the present disclosure. FIG. 22 is a diagram for explaining a configuration example of an imaging device according to Modification 4 of the present disclosure. FIG. 23 is a diagram for explaining a configuration example of an imaging device according to Modification 5 of the present disclosure. FIG. 24 is a diagram for explaining another configuration example of an imaging device according to Modification 5 of the present disclosure. FIG. 25 is a diagram for explaining another configuration example of an imaging device according to Modification 5 of the present disclosure. FIG. 26 is a block diagram showing an example of the configuration of an electronic device having an imaging device. FIG. 27 is a block diagram showing an example of a schematic configuration of a vehicle control system. FIG. 28 is an explanatory diagram showing an example of installation positions of an outside-vehicle information detection unit and an imaging unit. FIG. 29 is a diagram showing an example of a schematic configuration of an endoscopic surgery system. FIG. 30 is a block diagram showing an example of the functional configuration of a camera head and a CCU.

[0008] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be made in the following order: 1. Embodiment 2. Modification 3. Application Example 4. Application Example

[0009] 1 is a block diagram showing an example of a schematic configuration of an imaging device that is an example of a photodetection device according to an embodiment of the present disclosure. The photodetection device is a device that can detect incident light. The imaging device 1 that is a photodetection device has a plurality of pixels P each having a photoelectric conversion unit (photoelectric conversion element) and is configured to photoelectrically convert incident light to generate a signal. The imaging device 1 can receive light that has passed through an optical system (not shown) that includes an optical lens and generate a signal.

[0010] The imaging device 1 is configured, for example, using a semiconductor substrate (e.g., a silicon substrate) on which a plurality of pixels P are provided. The photoelectric conversion unit of each pixel P of the imaging device 1 is, for example, a photodiode (PD) and is configured to be able to photoelectrically convert light. The imaging device 1 has, as an imaging area, a region (pixel unit 100) in which a plurality of pixels P are two-dimensionally arranged in a matrix. The pixel unit 100 of the imaging device 1 can also be referred to as a pixel array in which a plurality of pixels P are arranged. The photoelectric conversion unit of each pixel P can also be referred to as a photoelectric conversion region.

[0011] The imaging device 1 captures incident light (image light) from a subject to be measured via an optical system including an optical lens. The imaging device 1 captures an image of the subject formed by the optical lens. The imaging device 1 can generate pixel signals by photoelectrically converting the received light (e.g., visible light, infrared light, etc.). The imaging device 1, which is a photodetector, is a device that can receive incident light and generate a signal, and can also be called a light-receiving device.

[0012] The imaging device 1 (photodetector) may be configured as an image sensor, for example. The imaging device 1 may be, for example, a complementary metal oxide semiconductor (CMOS) image sensor. The imaging device 1 may have a structure (a stacked structure) formed by stacking multiple semiconductor layers. The imaging device 1 may be used in various electronic devices, such as digital still cameras, video cameras, and mobile phones.

[0013] 1 , the imaging device 1 includes a pixel unit 100, a pixel driving unit 105, a signal processing unit 112, a control unit 113, and a processing unit 114. The imaging device 1 is also provided with, for example, a plurality of control lines Lread and a plurality of signal lines VSL.

[0014] The control lines Lread are signal lines capable of transmitting signals for controlling the pixels P, and are connected to the pixel driving unit 105 and the pixels P of the pixel unit 100. In the example shown in FIG. 1 , in the pixel unit 100, a plurality of control lines Lread are wired for each pixel row made up of a plurality of pixels P arranged in the horizontal direction (row direction). The control lines Lread are configured to transmit control signals for reading out signals from the pixels P.

[0015] The plurality of control lines Lread for each pixel row of the imaging device 1 include, for example, wiring for transmitting signals that control transfer transistors, wiring for transmitting signals that control selection transistors, wiring for transmitting signals that control reset transistors, etc. The control lines Lread can also be said to be drive lines (pixel drive lines) that transmit signals that drive the pixels P.

[0016] The signal line VSL is a signal line capable of transmitting a signal from the pixel P, and is connected to the pixel P of the pixel unit 100 and the signal processing unit 112. In the pixel unit 100, for example, a signal line VSL is wired for each pixel column made up of a plurality of pixels P aligned in the vertical direction (column direction). The signal line VSL is a vertical signal line and is configured to transmit a signal output from the pixel P.

[0017] The pixel driving unit 105 is configured to be able to drive each pixel P of the pixel unit 100. The pixel driving unit 105 is a driving circuit and is configured by a plurality of circuits including, for example, a buffer, a shift register, an address decoder, etc. The pixel driving unit 105 generates a signal for driving the pixel P and outputs the signal to each pixel P of the pixel unit 100 via a control line Lread. The pixel driving unit 105 is controlled by the control unit 113 and controls the pixels P of the pixel unit 100.

[0018] The pixel driving unit 105 generates signals for controlling the pixels P, such as signals for controlling the transfer transistors, selection transistors, and reset transistors of the pixels P, and supplies these signals to each pixel P via a control line Lread. The pixel driving unit 105 can control the reading of pixel signals from each pixel P. The pixel driving unit 105 can also be referred to as a pixel control unit configured to be able to control each pixel P. The pixel driving unit 105 and the control unit 113 can also be referred to collectively as a pixel control unit.

[0019] The signal processing unit 112 is configured to be able to perform signal processing of input pixel signals. The signal processing unit 112 is a signal processing circuit and includes, for example, a load circuit, an AD (Analog-Digital) conversion circuit, a horizontal selection switch, etc. The load circuit is, for example, configured by a current source capable of supplying current to the amplification transistor of the pixel P. The load circuit, together with the amplification transistor of the pixel P, forms, for example, a source follower circuit.

[0020] The signal processing unit 112 may have an amplifier circuit configured to be able to amplify signals read out from the pixels P via the signal lines VSL. A load circuit, an amplifier circuit, an AD conversion circuit, etc. are provided for each of the multiple signal lines VSL, for example. A load circuit, an amplifier circuit, an AD conversion circuit, etc. may be provided for each pixel column of the pixel unit 100.

[0021] The signals output from each pixel P selected and scanned by the pixel driving unit 105 are input to the signal processing unit 112 via signal lines VSL. The signal processing unit 112 can perform signal processing such as AD conversion of the signals from the pixel P and CDS (Correlated Double Sampling). The signals from each pixel P transmitted through each of the signal lines VSL are subjected to signal processing by the signal processing unit 112 and output to the processing unit 114.

[0022] The processing unit 114 is configured to be able to perform signal processing on the input signal. The processing unit 114 is a processing circuit, and is configured, for example, by a circuit that performs various types of signal processing on pixel signals. The processing unit 114 may include a processor and a memory. The processing unit 114 performs signal processing on pixel signals input from the signal processing unit 112 and outputs the processed pixel signals. The processing unit 114 can perform various types of signal processing, for example, noise reduction processing, gradation correction processing, etc.

[0023] The control unit 113 is configured to be able to control each unit of the imaging device 1. The control unit 113 receives an externally provided clock, data instructing an operation mode, etc., and can also output data such as internal information of the imaging device 1. The control unit 113 is a control circuit, and has, for example, a timing generator configured to be able to generate various timing signals.

[0024] The control unit 113 controls the driving of the pixel driving unit 105, the signal processing unit 112, etc. based on various timing signals (pulse signals, clock signals, etc.) generated by the timing generator. The control unit 113 and the processing unit 114 may be configured integrally.

[0025] The pixel driving unit 105, the signal processing unit 112, the control unit 113, the processing unit 114, etc. may be provided on a single semiconductor substrate or may be provided separately on multiple semiconductor substrates. Some or all of the signal processing unit 112, the control unit 113, and the processing unit 114 may be configured integrally.

[0026] 2 is a diagram showing an example of the arrangement of pixels in an imaging device according to an embodiment. A pixel P of the imaging device 1 includes a photoelectric conversion unit 12, a lens 31, and a filter 32. As shown in FIG. 2 , the incident direction of light from a subject is defined as the Z-axis direction, the left-right direction on the paper surface perpendicular to the Z-axis direction is defined as the X-axis direction, and the up-down direction on the paper surface perpendicular to the Z-axis and X-axis directions is defined as the Y-axis direction. In the following figures, directions may be indicated based on the directions of the arrows in FIG. 2 .

[0027] A pixel P of the imaging device 1 may have a plurality of photoelectric conversion units 12 (in the example shown in FIG. 2 , a first photoelectric conversion unit 12 a, a second photoelectric conversion unit 12 b, a third photoelectric conversion unit 12 c, and a fourth photoelectric conversion unit 12 d). In each pixel P of the imaging device 1, for example, a plurality of photoelectric conversion units 12 are arranged adjacent to each other.

[0028] 2, for example, the second photoelectric conversion unit 12b is provided next to the first photoelectric conversion unit 12a. Furthermore, the fourth photoelectric conversion unit 12d is provided next to the third photoelectric conversion unit 12c. It can be said that a pixel having the first photoelectric conversion unit 12a, a pixel having the second photoelectric conversion unit 12b, a pixel having the third photoelectric conversion unit 12c, and a pixel having the fourth photoelectric conversion unit 12d are provided.

[0029] In the imaging device 1, for example, a lens 31 and a filter 32 are provided on the side where light from an optical system such as an imaging lens is incident. The lens 31 (lens unit) is a lens that collects light and is an optical member also known as an on-chip lens. The lens 31 is provided above the first to fourth photoelectric conversion units 12a to 12d, for example, for each pixel P or for each set of pixels P.

[0030] Light from a subject to be measured is incident on the lens 31 via an optical system such as an imaging lens. The lens 31 guides the incident light to the photoelectric conversion unit 12 of the pixel P. The first to fourth photoelectric conversion units 12a to 12d of the pixel P each perform photoelectric conversion on the light incident via the lens 31 and the filter 32.

[0031] The filter 32 is configured to selectively transmit light in a specific wavelength range from the incident light. The filter 32 is an RGB color filter, a filter that transmits infrared light, etc. The filter 32 is provided above the first to fourth photoelectric conversion units 12 a to 12 d, for example, for each pixel P or for each set of pixels P.

[0032] The plurality of pixels P provided in the pixel section 100 of the imaging device 1 include, for example, pixels (R pixels) provided with filters 32 that transmit red (R) light, pixels (G pixels) provided with filters 32 that transmit green (G) light, and pixels (B pixels) provided with filters 32 that transmit blue (B) light. In the pixel section 100, a plurality of R pixels, a plurality of G pixels, and a plurality of B pixels are repeatedly arranged.

[0033] The R, G, and B pixels are arranged according to a Bayer array, for example. The R, G, and B pixels can generate R, G, and B component pixel signals, respectively. The imaging device 1 can obtain RGB pixel signals. Note that the arrangement of the pixels P is not limited to the above example and can be set arbitrarily.

[0034] As an example, the R pixels, G pixels, and B pixels may each be arranged in 2×2 pixel units. In the pixel unit 100, for example, four adjacent R pixels, four adjacent G pixels, and four adjacent B pixels may be arranged repeatedly. It can also be said that the R pixels, G pixels, and B pixels are each periodically arranged in 2 rows and 2 columns.

[0035] The filter 32 provided in the pixel P of the pixel unit 100 is not limited to a primary color (RGB) color filter, but may be a complementary color filter such as Cy (cyan), Mg (magenta), or Ye (yellow). A filter corresponding to W (white), i.e., a filter that transmits light of the entire wavelength range of incident light, may also be provided. The filter 32 may also be a filter that transmits infrared light.

[0036] It should be noted that the filter 32 may be omitted as needed in the imaging device 1. The filter 32 may not be provided in some or all of the pixels P of the imaging device 1. For example, the filter 32 may not be provided in pixels that receive white (W) light and perform photoelectric conversion.

[0037] In the imaging device 1, for example, one lens 31 may be provided for four photoelectric conversion units 12 (first to fourth photoelectric conversion units 12a to 12d). In the imaging device 1, the first to fourth photoelectric conversion units 12a to 12d receive light that has passed through different regions of an optical system such as an imaging lens, and perform pupil division.

[0038] The imaging device 1 can generate, for example, a signal (first pixel signal) based on charges converted by the first photoelectric conversion unit 12a, a signal (second pixel signal) based on charges converted by the second photoelectric conversion unit 12b, a signal (third pixel signal) based on charges converted by the third photoelectric conversion unit 12c, and a signal (fourth pixel signal) based on charges converted by the fourth photoelectric conversion unit 12d.

[0039] Phase difference data (phase difference information) can be obtained by using the first to fourth pixel signals. The phase difference data makes it possible to perform phase difference AF (autofocus). The pixels P (R pixels, G pixels, B pixels, etc.) of the imaging device 1 are pixels that can be used for phase difference detection and can also be called phase difference pixels (or phase difference detection pixels).

[0040] 3 is a diagram illustrating an example of a circuit configuration of a pixel of an image pickup device according to an embodiment. Each pixel P of the image pickup device 1 includes a plurality of photoelectric conversion units 12 (first to fourth photoelectric conversion units 12a to 12d in FIG. 3), a plurality of transistors TG (transistors TG1 to TG4 in FIG. 3), a floating diffusion FD, and a readout circuit 20.

[0041] The photoelectric conversion unit 12 is configured to receive light and generate a signal. The photoelectric conversion unit 12 is a light receiving unit (light receiving element) and is configured to be able to generate electric charges through photoelectric conversion. In the example shown in Fig. 3, the first photoelectric conversion unit 12a, the second photoelectric conversion unit 12b, the third photoelectric conversion unit 12c, and the fourth photoelectric conversion unit 12d are each a photodiode (PD).

[0042] The first photoelectric conversion unit 12 a, the second photoelectric conversion unit 12 b, the third photoelectric conversion unit 12 c, and the fourth photoelectric conversion unit 12 d each convert incident light into an electric charge. Each of the first photoelectric conversion unit 12 a to the fourth photoelectric conversion unit 12 d performs photoelectric conversion to generate an electric charge according to the amount of received light.

[0043] The transistors TG (transistors TG1, TG2, TG3, and TG4 in FIG. 3) are transfer transistors, and are configured to be able to transfer charges photoelectrically converted by the photoelectric conversion unit 12 to the floating diffusion FD. The transistors TG electrically connect or disconnect the photoelectric conversion unit 12 and the floating diffusion FD. In the example shown in FIG. 3, the transistors TG1 to TG4 are controlled by different signals.

[0044] The transistor TG1 is controlled by a signal STG1 to electrically connect or disconnect the first photoelectric conversion unit 12a and the floating diffusion FD. The transistor TG1 can transfer the charge that is photoelectrically converted and accumulated in the first photoelectric conversion unit 12a to the floating diffusion FD.

[0045] The transistor TG2 is controlled by a signal STG2 to electrically connect or disconnect the second photoelectric conversion unit 12b and the floating diffusion FD. The transistor TG2 can transfer the charge that is photoelectrically converted and accumulated in the second photoelectric conversion unit 12b to the floating diffusion FD.

[0046] The transistor TG3 is controlled by a signal STG3 to electrically connect or disconnect the third photoelectric conversion unit 12c and the floating diffusion FD. The transistor TG3 can transfer the charge that is photoelectrically converted and accumulated in the third photoelectric conversion unit 12c to the floating diffusion FD.

[0047] The transistor TG4 is controlled by a signal STG4 to electrically connect or disconnect the fourth photoelectric conversion unit 12d and the floating diffusion FD. The transistor TG4 can transfer the charge that is photoelectrically converted and accumulated in the fourth photoelectric conversion unit 12d to the floating diffusion FD.

[0048] The floating diffusion FD is an accumulation unit configured to be able to accumulate transferred charges. The floating diffusion FD can accumulate charges photoelectrically converted by the photoelectric conversion unit 12. The floating diffusion FD can also be considered a holding unit capable of holding the transferred charges. The floating diffusion FD accumulates the transferred charges and converts them into a voltage according to the capacitance of the floating diffusion FD.

[0049] The readout circuit 20 is configured to be able to output signals based on the photoelectrically converted charges, including a first pixel signal based on the charges generated by the first photoelectric conversion unit 12 a, a second pixel signal based on the charges generated by the second photoelectric conversion unit 12 b, a third pixel signal based on the charges generated by the third photoelectric conversion unit 12 c, and a fourth pixel signal based on the charges generated by the fourth photoelectric conversion unit 12 d.

[0050] The readout circuit 20 is also configured to be capable of outputting a pixel signal corresponding to the sum of the charges photoelectrically converted by the first to fourth photoelectric conversion units 12 a to 12 d. The readout circuit 20 can read out a pixel signal based on the sum of the charges from two or more photoelectric conversion units 12, for example.

[0051] 3, the readout circuit 20 includes, for example, a transistor AMP, a transistor SEL, and a transistor RST. The transistor AMP is configured to generate and output a signal based on the charge accumulated in the floating diffusion FD. The transistor AMP is an amplifying transistor and can generate and output a signal based on the charge converted by the photoelectric conversion unit 12.

[0052] 3, the gate of the transistor AMP is electrically connected to the floating diffusion FD, and the voltage converted by the floating diffusion FD is input to the gate of the transistor AMP. The drain of the transistor AMP is connected to, for example, a power supply line to which a power supply voltage (power supply voltage VDD in the example shown in FIG. 3) is supplied.

[0053] The source of the transistor AMP is connected to a signal line VSL via a transistor SEL. The transistor AMP is configured to generate a signal based on the charge accumulated in the floating diffusion FD, i.e., a signal based on the voltage of the floating diffusion FD, and output the signal to the signal line VSL.

[0054] The transistor SEL is configured to be able to control the output of a pixel signal. The transistor SEL is electrically connected in series to the transistor AMP, for example, as in the example shown in Figure 3. The transistor SEL is controlled by a signal SSEL and is configured to be able to output a signal from the transistor AMP to a signal line VSL. The transistor SEL is a selection transistor and can control the output timing of the pixel signal.

[0055] The transistor SEL is configured to be able to output a signal based on the charge converted by the photoelectric conversion unit 12. The transistor SEL can output pixel signals (first pixel signal to fourth pixel signal, etc.) of the pixel P to the signal line VSL. The transistor SEL may be electrically connected between the transistor AMP and a power supply line to which the power supply voltage VDD is applied. The transistor SEL may also be omitted as necessary.

[0056] The transistor RST is configured to be able to reset the voltage of the floating diffusion FD. In the example shown in Fig. 3, the transistor RST is electrically connected to a power supply line to which a power supply voltage VDD is applied, and is configured to reset the charge of the pixel P. The transistor RST is a reset transistor.

[0057] The transistor RST is controlled by a signal SRST and can reset the charge accumulated in the floating diffusion FD and reset the potential of the floating diffusion FD. The transistor RST electrically connects the power supply line and the floating diffusion FD and can discharge the charge accumulated in the floating diffusion FD. The transistor RST can also discharge the charge accumulated in the photoelectric conversion unit 12 via the transistor TG.

[0058] 4A is a diagram illustrating another example of a circuit configuration of a pixel of an imaging device according to an embodiment. The readout circuit 20 may include a transistor FDG, as shown in the example of FIG. The transistor FDG is configured, for example, to be capable of electrically connecting the floating diffusion FD and the transistor RST. For example, the transistor FDG is controlled by a signal SFDG to electrically connect or disconnect the floating diffusion FD and the transistor RST.

[0059] When the transistor FDG is turned on, the capacitance added to the floating diffusion FD of the pixel P increases, and the conversion efficiency (gain) when converting electric charge to voltage is switched. The transistor FDG is a switching transistor used to set the conversion efficiency. The transistor FDG can change the conversion efficiency by switching the capacitance connected to the gate of the transistor AMP.

[0060] The transistor FDG may be electrically connected in series with the transistor RST or electrically connected in parallel with the transistor RST. As shown in the example of FIG. 4B , the transistor FDG may be configured to be able to electrically connect the floating diffusion FD and the capacitance element C1. For example, the transistor FDG is controlled by a signal SFDG to electrically connect or disconnect the floating diffusion FD and the capacitance element C1. By switching the connection state of the capacitance element C1, it is possible to change the conversion efficiency.

[0061] The above-mentioned transistor TG (transfer transistor), transistor AMP (amplification transistor), transistor SEL (selection transistor), transistor RST (reset transistor), and transistor FDG (switching transistor) are each a MOS transistor (MOSFET) having gate, source, and drain terminals.

[0062] 3 and the like, the transistors TG1 to TG4, the transistor AMP, the transistor SEL, the transistor RST, and the transistor FDG are each configured as an NMOS transistor. The transistor of the pixel P may be configured as a PMOS transistor. The transistor of the pixel P may be configured as a 3D transistor, for example, a FinFET.

[0063] 5A or 5B, the transistor RST and the transistor AMP may be electrically connected to different power supply lines. For example, the drain of the transistor AMP may be electrically connected to a power supply line that supplies a power supply voltage VDD1, and the drain of the transistor RST may be electrically connected to a power supply line that supplies a power supply voltage VDD2. The drain potential of the transistor RST and the drain potential of the transistor AMP can be controlled separately (independently).

[0064] The pixel driving unit 105 (see FIG. 1) of the imaging device 1 supplies control signals to the gates of the transistors TG1 to TG4, the transistor SEL, the transistor RST, the transistor FDG, etc. of each pixel P via the control line Lread described above, turning the transistors on (conducting state) or off (non-conducting state).

[0065] The multiple control lines Lread for each pixel row of the imaging device 1 include, for example, a wiring for transmitting a signal STG1 that controls transistor TG1, a wiring for transmitting a signal STG2 that controls transistor TG2, a wiring for transmitting a signal STG3 that controls transistor TG3, and a wiring for transmitting a signal STG4 that controls transistor TG4.

[0066] The control lines Lread include, for example, a wiring for transmitting a signal SSEL that controls the transistor SEL, a wiring for transmitting a signal SRST that controls the transistor RST, and a wiring for transmitting a signal SFDG that controls the transistor FDG.

[0067] The transistors TG1 to TG4, transistor SEL, transistor RST, transistor FDG, etc. are controlled to be turned on and off by a pixel driving unit 105. The pixel driving unit 105 controls the readout circuit 20 of each pixel P to output a pixel signal from each pixel P to a signal line VSL. The pixel driving unit 105 can control the reading out of the pixel signal of each pixel P to the signal line VSL.

[0068] The imaging device 1 may have a configuration in which a plurality of pixels P share one readout circuit 20. For example, in the imaging device 1, the readout circuit 20 may be provided for a plurality of pixels P. A readout circuit 20 is arranged for each of a plurality of pixels P, and the plurality of pixels P share one readout circuit 20. As an example, a 2×2 pixel array consisting of four adjacent pixels P may share one readout circuit 20.

[0069] Fig. 6 is a diagram showing an example of the planar configuration of a pixel of an imaging device according to an embodiment. Figs. 7 and 8 are diagrams showing an example of the cross-sectional configuration of a pixel of an imaging device. Fig. 7 shows an example of the configuration of a pixel in the direction of line A-A' shown in Fig. 6. Fig. 8 shows an example of the configuration of a pixel in the direction of line B-B' shown in Fig. 6.

[0070] Each pixel P of the imaging device 1 has, for example, the structure shown in Figures 6 to 8. The pixel P has a first photoelectric conversion unit 12a to a fourth photoelectric conversion unit 12d, a transistor TG1 to a transistor TG4, a floating diffusion FD, and an overflow path 70.

[0071] The imaging device 1 is configured using a substrate 201 including a semiconductor layer 101. The substrate 201 is configured, for example, by a semiconductor substrate such as a Si (silicon) substrate. Note that the substrate 201 (base material) may also be configured using an SOI (silicon on insulator) substrate, a SiGe (silicon germanium) substrate, other compound semiconductor materials, or the like. In the examples shown in FIGS. 6 to 8 , the substrate 201 is configured to include the semiconductor layer 101 and a wiring layer 111.

[0072] 7 and 8, the semiconductor layer 101 has opposing surfaces 11S1 and 11S2. The surface 11S2 is the surface opposite to the surface 11S1. The surface 11S1 of the semiconductor layer 101 is, for example, an element formation surface on which elements such as transistors are formed. A gate electrode, a gate insulating film (e.g., a gate oxide film), etc. are provided on the surface 11S1 of the semiconductor layer 101. The surface 11S2 of the semiconductor layer 101 is, for example, a light-receiving surface (light incident surface).

[0073] In the semiconductor layer 101, a plurality of photoelectric conversion units 12 (photoelectric conversion elements) are provided along a surface 11S1 and a surface 11S2 of the semiconductor layer 101. The photoelectric conversion units 12 can also be referred to as a photoelectric conversion layer. For example, a plurality of first to fourth photoelectric conversion units 12a to 12d are embedded in the semiconductor layer 101. The first to fourth photoelectric conversion units 12a to 12d are provided between the surface 11S1 and the surface 11S2 of the semiconductor layer 101.

[0074] 7 and 8, the semiconductor layer 101 has a well 25. The well 25 is, for example, a p-type semiconductor region, or a p-type well (p-well). In the example shown in FIGS. 7 and 8, the well 25, which is a p-type well region, is provided in the semiconductor layer 101.

[0075] The first photoelectric conversion unit 12a includes a semiconductor region 15a. The second photoelectric conversion unit 12b includes a semiconductor region 15b. The third photoelectric conversion unit 12c includes a semiconductor region 15c. The fourth photoelectric conversion unit 12d includes a semiconductor region 15d. The semiconductor regions 15a to 15d are, for example, n-type semiconductor regions provided in a well 25.

[0076] In the example shown in FIG. 6 etc., the first photoelectric conversion unit 12a and the second photoelectric conversion unit 12b are arranged side by side in the X-axis direction in the semiconductor layer 101. The first photoelectric conversion unit 12a and the third photoelectric conversion unit 12c are arranged side by side in the Y-axis direction in the semiconductor layer 101. The third photoelectric conversion unit 12c and the fourth photoelectric conversion unit 12d are arranged side by side in the X-axis direction in the semiconductor layer 101. The second photoelectric conversion unit 12b and the fourth photoelectric conversion unit 12d are arranged side by side in the Y-axis direction in the semiconductor layer 101.

[0077] The transistors TG1, TG2, TG3, TG4, floating diffusion FD, etc. are provided on the surface 11S1 side of the semiconductor layer 101. The floating diffusion FD includes, for example, an n-type semiconductor region.

[0078] On the surface 11S1 side of the semiconductor layer 101, for example, a semiconductor region (not shown) of the same conductivity type as the well 25 is provided as a well contact region for the well 25. In addition, a contact (well contact) electrically connected to the well contact region can be provided in the wiring layer 111.

[0079] The well contact region is electrically connected to, for example, a reference potential line in the wiring layer 111 via a contact. A reference potential is applied to the well contact region and the well 25. As an example, a GND potential (ground potential) is applied to the well contact region and the well 25 via the contact.

[0080] Each of the transistors TG1 to TG4 has a gate electrode 45 and a gate insulating film 46. The transistors TG1 to TG4 have, for example, a planar gate structure. Each of the transistors TG1 to TG4 is configured as, for example, a planar transistor.

[0081] The gate electrode 45 of each of the transistors TG1 to TG4 is made of, for example, polysilicon. The gate electrode 45 may be made of a metal material or a metal compound. The gate electrode 45 may be made of, for example, tungsten (W), titanium nitride (TiN), tantalum nitride (TaN), or the like. Sidewalls may be provided on the side surfaces of the gate electrode 45.

[0082] The gate insulating film 46 is configured by, for example, a single layer film made of one of silicon oxide (SiO), silicon oxynitride (SiON), hafnium oxide (HfO), etc., or a laminated film made of two or more of these. The gate insulating film 46 may be formed using a high-dielectric-constant material having a higher dielectric constant than that of silicon oxide, such as a hafnium-based insulating film.

[0083] The transistors TG1 to TG4 may have a vertical gate structure. For example, at least a portion of each of the gate electrode 45 and the gate insulating film 46 is provided within the semiconductor layer 101. The transistors TG1 to TG4 have the gate electrode 45 provided by digging into the semiconductor layer 101, and can also be called vertical transistors.

[0084] The imaging device 1 has a pixel isolation region 91, which is an isolation region (isolation portion) provided around the pixel P. The pixel isolation region 91 is configured using, for example, a trench (groove portion). In the example shown in FIGS. 6 to 8 , the pixel isolation region 91 has an electrode 95 and is provided so as to penetrate the semiconductor layer 101.

[0085] The pixel isolation region 91 is provided between adjacent pixels P in the semiconductor layer 101, and separates the pixels P (or the photoelectric conversion units 12). At least a part of the pixel isolation region 91 is provided on the boundary between adjacent pixels P. It can also be said that the pixel P has a structure partitioned by the pixel isolation region 91.

[0086] The pixel isolation region 91 has, for example, a full trench isolation (FTI) structure and is formed so as to penetrate the semiconductor layer 101. In the examples shown in Figures 6 to 8, the pixel isolation region 91 is provided so as to surround the first to fourth photoelectric conversion units 12a to 12d, the transistors TG1 to TG4, the floating diffusion FD, etc.

[0087] The pixel isolation region 91 is formed in a lattice shape in plan view so as to surround the first to fourth photoelectric conversion units 12a to 12d of each pixel P (see FIGS. 2, 6, etc.). An electrode 95 is provided in the pixel isolation region 91. The pixel isolation region 91 can also be referred to as an inter-pixel isolation portion or an inter-pixel isolation wall.

[0088] The electrode 95 can be provided so as to be embedded (filled) in the trench of the pixel isolation region 91. The electrode 95 is, for example, a semiconductor region or a conductor region containing impurities, and is formed using polysilicon (Poly-Si). As an example, the electrode 95 is a p-type region, and is made of polysilicon doped (added) with impurities.

[0089] The electrode 95 may contain, for example, a high concentration of impurities (dopants) and may be configured as a conductor region (conductive portion). For example, the electrode 95 has an impurity concentration higher than the impurity concentration of the well 25. The electrode 95 may be formed in the pixel isolation region 91 so as to reach the surface 11S2 of the semiconductor layer 101. Note that the electrode 95 may also be configured using other conductive materials (for example, metal materials).

[0090] The electrode 95 of the pixel isolation region 91 is electrically connected to, for example, wires and vias of the wiring layer, and is given a predetermined potential (voltage). The pixel isolation region 91 is formed, for example, by a trench filled with a conductive material, and is given a negative bias voltage via wires of the wiring layer 111. This makes it possible to reduce dark current on the side surface (sidewall) of the pixel isolation region 91.

[0091] Furthermore, a plurality of isolation regions 92 (isolation regions 92a, 92b, 92c, and 92d in the example shown in FIG. 6 and other figures) are provided in each pixel P of the imaging device 1. The isolation regions 92 have, for example, electrodes 96 and are provided between a plurality of adjacent photoelectric conversion units 12.

[0092] The separation region 92a is provided between the adjacent first and second photoelectric conversion units 12a and 12b in the semiconductor layer 101. The separation region 92b is provided between the adjacent third and fourth photoelectric conversion units 12c and 12d in the semiconductor layer 101. The separation region 92b is provided so as to be aligned with the separation region 92a in the Y-axis direction, for example, as in the example shown in FIG.

[0093] The isolation region 92c is provided between the adjacent first and third photoelectric conversion units 12a and 12c in the semiconductor layer 101. The isolation region 92d is provided between the adjacent second and fourth photoelectric conversion units 12b and 12d in the semiconductor layer 101. The isolation region 92d is provided so as to be aligned with the isolation region 92c in the X-axis direction, for example, as in the example shown in FIG.

[0094] The isolation regions 92a, 92b, 92c, and 92d are configured using, for example, trenches (grooves) and have an FTI structure. As an example, the isolation regions 92a to 92d are provided so as to penetrate the semiconductor layer 101 and separate elements from one another. Note that each of the isolation regions 92a to 92d may be provided from the surface 11S1 side of the semiconductor layer 101 to between the surfaces 11S1 and 11S2 of the semiconductor layer 101.

[0095] The isolation regions 92a and 92b have a shape extending in the Y-axis direction in a plan view, for example. The isolation regions 92c and 92d have a shape extending in the X-axis direction in a plan view, for example. The isolation regions 92a to 92d and the pixel isolation region 91 can be formed continuously and integrally, as in the example shown in Figure 6. The isolation regions 92a to 92d can also be said to be structural parts that protrude from the pixel isolation region 91 toward the center of the pixel P.

[0096] An electrode 96 is provided in each of the isolation regions 92a to 92d. The electrode 96 can be provided so as to be embedded in the trenches of the isolation regions 92a to 92d. The electrode 96 is, for example, a semiconductor region or a conductor region containing impurities, and is formed using polysilicon. As an example, the electrode 96 is an n-type region, and is made of polysilicon doped with impurities.

[0097] The electrode 96 may contain, for example, a high concentration of impurities and may be configured as a conductive region. For example, the electrode 96 has an impurity concentration higher than the impurity concentration of the well 25. The electrode 96 may be formed in the isolation region 92 so as to reach the surface 11S2 of the semiconductor layer 101. Note that the electrode 96 may also be configured using other conductive materials (such as metal materials).

[0098] 7 and other figures, the electrode 96 is provided in the semiconductor layer 101 between the electrode 95 and the overflow path 70. The electrodes 96 in the isolation regions 92a to 92d are provided so as to be in contact with the electrode 95 in the pixel isolation region 91. In the example shown in FIG. 6 and other figures, the electrode 96 is embedded in each of the isolation regions 92a to 92d and is in contact with the electrode 95 in the pixel isolation region 91.

[0099] The electrode 96 may be made of a material having a work function different from that of the electrode 95. The electrode 96 may be made of, for example, a material having a work function smaller than that of the electrode 95. As an example, the electrode 96 is formed as an n-type region having a different conductivity type from that of the electrode 95, and is joined to the electrode 95 which is a p-type region. The electrodes 95 and 96 may be provided in contact with each other with band bending, for example.

[0100] In the imaging device 1, for example, the electrode 95 is made of p-type polysilicon, and the electrode 96 is made of n-type polysilicon. The material of the electrode 96 can be selected depending on, for example, the material, work function, electron affinity, carriers (signal charges), etc. of the electrode 95. The work function can be measured and analyzed by, for example, spreading resistance measurement, photoelectron spectroscopy, etc.

[0101] The overflow path 70 is provided, for example, between adjacent photoelectric conversion units 12. The overflow path 70 is a region formed using impurities, for example, an n-type semiconductor region. The overflow path 70 can be provided so as to be adjacent to the multiple photoelectric conversion units 12. As in the example shown in FIG. 6 etc., the overflow path 70 is formed between the multiple isolation regions 92 so as to be in contact with the multiple photoelectric conversion units 12.

[0102] The overflow path 70 can be formed between the first to fourth photoelectric conversion units 12 a to 12 d in the semiconductor layer 101. The overflow path 70 is provided, for example, below the floating diffusion FD and in contact with the first to fourth photoelectric conversion units 12 a to 12 d. The isolation regions 92 a to 92 d are provided in the semiconductor layer 101 so as to sandwich the overflow path 70 therebetween.

[0103] In the imaging device 1, the overflow path 70 is provided, so that overflowing charges can be transferred (moved) between the first to fourth photoelectric conversion units 12a to 12d. For example, even if charges exceed the amount of charge (saturation charge amount) that can be stored in one photoelectric conversion unit 12, the overflowing charges can be stored in another photoelectric conversion unit 12. Signals corresponding to the charges photoelectrically converted by the multiple photoelectric conversion units 12 can be obtained.

[0104] The imaging device 1 has an insulating film 80 provided on the semiconductor layer 101. For example, as shown in FIG. 6 and other examples, the insulating film 80 is provided so as to follow the side surfaces of the electrodes 95 in the pixel isolation region 91 and the side surfaces of the electrodes 96 in the isolation regions 92a to 92d. The insulating film 80 is formed between the electrodes 96 in the isolation regions 92a to 92d and the overflow path 70.

[0105] The insulating film 80 is configured, for example, by a single layer film made of one of an oxide film (e.g., a silicon oxide film), a nitride film (e.g., a silicon nitride film), an oxynitride film, etc., or a laminated film made of two or more of these. The insulating film 80 may be configured using an insulating material such as aluminum oxide (AlO), or may be configured using other materials.

[0106] As described above, in the imaging device 1 according to the present embodiment, the electrode 96 is provided between the electrode 95 and the overflow path 70. This makes it possible to set the electric potential in the overflow path 70 via the electrode 95 and the electrode 96. For example, by controlling the voltage supplied to the electrode 95, it becomes possible to adjust the electric potential of the overflow path 70.

[0107] Overflow path 70 is supplied with a potential (voltage) that corresponds to, for example, the voltage applied to electrode 95 and the built-in potentials of electrodes 95 and 96. As an example, when a negative bias voltage is applied to electrode 95, the built-in potential of the PN junction formed by electrodes 95 and 96, i.e., a potential that corresponds to the difference in work function between electrodes 95 and 96, is supplied to overflow path 70. In other words, a potential that is positive with respect to the potential of electrode 95 can be applied to overflow path 70.

[0108] In the imaging device 1, the supply of a negative voltage to the electrode 95 can control the potential of the overflow path 70 while suppressing dark current in the pixel isolation region 91. It is possible to reduce the variation in characteristics of the overflow path 70 caused by the impurity concentration, distribution, and formation position of each of the photoelectric conversion unit 12 and the overflow path 70.

[0109] The built-in potentials of the electrodes 95 and 96 can be adjusted by, for example, the materials and impurity concentrations constituting the electrodes 95 and 96. By adjusting the voltage applied to the electrode 95, the potential of the overflow path 70 can be appropriately determined.

[0110] 9 and 10 are diagrams showing another example of the configuration of a pixel of an imaging device according to an embodiment. FIGS. 9 and 10 show an example of a cross-sectional configuration of a pixel of the imaging device. The imaging device 1 may have an isolation region 93. The isolation region 93 is formed, for example, by a trench. The isolation region 93 has an STI (Shallow Trench Isolation) structure and is provided on the surface 11S1 side of the semiconductor layer 101.

[0111] An insulating film (insulator) such as an oxide film (e.g., a silicon oxide film) or a nitride film (e.g., a silicon nitride film) is provided in the trench of the isolation region 93. Other insulating materials may be embedded in the isolation region 93. A portion of the insulating film 80 may be formed in the isolation region 93. The isolation region 93 can also be considered a portion of the pixel isolation region 91 (or the isolation region 92).

[0112] 9 and 10 , the pixel isolation region 91 may be provided from the surface 11S1 side of the semiconductor layer 101 to between the surfaces 11S1 and 11S2 of the semiconductor layer 101. In addition, the isolation region 92 (isolation region 92c and isolation region 92d in FIG. 9 ) may be provided from the surface 11S1 side of the semiconductor layer 101 to between the surfaces 11S1 and 11S2 of the semiconductor layer 101.

[0113] 11A to 11D are diagrams showing an example of a method for manufacturing an image pickup device according to an embodiment. First, as shown in Fig. 11A, a trench having an FTI structure is formed as a pixel isolation region 91 in a semiconductor layer 101. Then, an electrode 95 is formed by embedding the electrode in the pixel isolation region 91.

[0114] Next, as shown in Fig. 11B, a portion of the semiconductor layer 101 is selectively removed by lithography and dry etching. Then, an insulating film 80 is formed in the removed portion as shown in Fig. 11B. Furthermore, a trench with an FTI structure is formed as an isolation region 92 in the semiconductor layer 101. Then, as shown in Fig. 11C, an electrode 96 is formed by burying it in the isolation region 92.

[0115] Next, as shown in Fig. 11D , the photoelectric conversion unit 12, overflow path 70, floating diffusion FD, etc. of each pixel P are formed on the semiconductor layer 101. Thereafter, the transistor TG, wiring layer 111, etc. are formed on the semiconductor layer 101. By the manufacturing method described above, the imaging device 1 shown in Fig. 9 and the like can be manufactured. Note that the manufacturing method described above is merely an example, and other manufacturing methods may also be adopted.

[0116] 12 is a diagram illustrating an example of a cross-sectional configuration of an image pickup device according to an embodiment. The image pickup device 1 includes, for example, a semiconductor layer 101, a wiring layer 111, a wiring layer 121, a semiconductor layer 102, a wiring layer 122, a wiring layer 131, and a semiconductor layer 103, as shown in the example of FIG.

[0117] The imaging device 1 has, for example, the above-described semiconductor layer 101 and wiring layer 111 as a first layer (first hierarchical level). The imaging device 1 has, as a second layer (second hierarchical level), a semiconductor layer 102 and wiring layers 121 and 122. The imaging device 1 also has, as a third layer (third hierarchical level), a semiconductor layer 103 and wiring layer 131. The imaging device 1 has a configuration in which the first to third layers are stacked in the Z-axis direction.

[0118] 12, provided from the light incident side are a semiconductor layer 101, a wiring layer 111, a wiring layer 121, a semiconductor layer 102, a wiring layer 122, a wiring layer 131, and a semiconductor layer 103. The semiconductor layer 101, the semiconductor layer 102, and the semiconductor layer 103 are each formed of a semiconductor substrate (for example, a silicon substrate, an SOI (Silicon On Insulator) substrate, etc.).

[0119] As an example, the imaging device 1 may be configured with a substrate 201 including a semiconductor layer 101 and a wiring layer 111, a substrate 202 including a semiconductor layer 102, a wiring layer 121, and a wiring layer 122, and a substrate 203 including a semiconductor layer 103 and a wiring layer 131. The semiconductor layer 102 has opposing surfaces 12S1 and 12S2. The surface 12S2 of the semiconductor layer 102 is the surface opposite to the surface 12S1.

[0120] The semiconductor layer 103 also has opposing surfaces 13S1 and 13S2. The surface 13S2 of the semiconductor layer 103 is the surface opposite to the surface 13S1. The surfaces 11S1, 12S1, and 13S1 are, for example, element formation surfaces on which elements such as transistors are formed. A gate electrode, a gate insulating film (e.g., a gate oxide film), etc. may be provided on each of the surfaces 11S1, 12S1, and 13S1.

[0121] 12 illustrates the transistor TG, transistor AMP, transistor SEL, transistor RST, etc. of the pixel P. The transistor TG and a floating diffusion FD are formed on the surface 11S1 side of the semiconductor layer 101. The transistors (transistors AMP, SEL, RST, etc.) of the readout circuit 20 are provided on the surface 12S1 side of the semiconductor layer 102.

[0122] A wiring layer 111 is provided on the surface 11S1 side of the semiconductor layer 101. The above-mentioned lens 31 and filter 32 are provided on the surface 11S2 side of the semiconductor layer 101. The lens 31, filter 32, etc. are provided on the side where light from the optical system is incident, and the wiring layer 111 is provided on the side opposite to the side where the light is incident. The lens 31 and filter 32 are stacked on the semiconductor layer 101 in a thickness direction perpendicular to the surface 11S2 of the semiconductor layer 101.

[0123] The lens 31 and the filter 32 are provided on the surface 11S2 side of the semiconductor layer 101, for example, for each pixel P or for each set of pixels P. As an example, the filter 32 is formed between the lens 31 and the semiconductor layer 101. The first to fourth photoelectric conversion units 12a to 12d perform photoelectric conversion on light incident via the lens 31 and the filter 32, respectively.

[0124] A wiring layer 121 is provided on the surface 12S1 side of the semiconductor layer 102, and a wiring layer 122 is provided on the surface 12S2 side of the semiconductor layer 102. A wiring layer 131 is provided on the surface 13S1 side of the semiconductor layer 103. The wiring layers 111, 121, 122, and 131 each include, for example, a conductor film and an insulating film, and have a plurality of wirings and vias (VIAs) and the like.

[0125] Each of the wiring layers 111, 121, 122, and 131 includes, for example, two or more layers of wiring, or three or more layers of wiring. The wiring layers 111, 121, 122, and 131 have a configuration in which a plurality of wirings are stacked with an insulating film interposed therebetween as an interlayer insulating film (interlayer insulating layer).

[0126] The wiring of each of the wiring layers 111, 121, 122, and 131 is formed using a metal material such as aluminum (Al), tungsten (W), or copper (Cu). Note that the wiring of each of the wiring layers 111, 121, 122, and 131 may be formed using polysilicon or other conductive materials. The interlayer insulating film is formed using, for example, silicon oxide, silicon nitride, or silicon oxynitride.

[0127] As described above, for example, the first to fourth photoelectric conversion units 12a to 12d, transistors TG1 to TG4, floating diffusion FD, etc. of each pixel P are provided in the semiconductor layer 101 and the wiring layer 111. The transistors (transistors AMP, SEL, RST, etc.) of the readout circuit 20 are provided in the semiconductor layer 102 and the wiring layer 121.

[0128] Fig. 13 is a diagram showing another example of the cross-sectional configuration of the imaging device according to the embodiment. In the example shown in Fig. 13, a semiconductor layer 101, a wiring layer 111, a semiconductor layer 102, a wiring layer 121, a wiring layer 131, and a semiconductor layer 103 are provided from the light incident side. The semiconductor layer 101, the semiconductor layer 102, and the semiconductor layer 103 are formed of a semiconductor substrate (silicon substrate, SOI substrate, etc.). For example, the semiconductor layer 102 may be formed of a silicon layer on a BOX (Buried Oxide) layer of an SOI substrate.

[0129] 13 , the semiconductor layer 101 and the semiconductor layer 102 are provided so that the surface 11S1 and the surface 12S2 face each other. The semiconductor layer 101 and the semiconductor layer 102 are stacked so that the wiring layer 111 faces the semiconductor layer 102. Furthermore, the semiconductor layer 102 and the semiconductor layer 103 are stacked so that the surface 12S1 and the surface 13S1 face each other, for example.

[0130] In the imaging device 1, the above-described signal processing unit 112, control unit 113, processing unit 114, etc. are provided, for example, in the semiconductor layer 103 and wiring layer 131. In the imaging device 1, for example, as in the examples shown in Fig. 12 or 13, the photoelectric conversion unit 12 and the readout circuit 20 can be arranged on separate layers. This allows the imaging device 1 to have a structure that is advantageous for miniaturizing pixels.

[0131] [Actions and Effects] The photodetector device according to the present embodiment includes a first semiconductor layer (semiconductor layer 101), a plurality of pixels (pixels P) including a first pixel having a first photoelectric conversion element and a second photoelectric conversion element (e.g., first photoelectric conversion unit 12 a and second photoelectric conversion unit 12 b) arranged in a first direction (e.g., the X-axis direction) in the first semiconductor layer, and a pixel isolation region (pixel isolation region 91) arranged around the pixel in the first semiconductor layer and having a first electrode (electrode 95). The first pixel includes a first isolation region (isolation region 92 a) arranged between the first photoelectric conversion element and the second photoelectric conversion element, a second isolation region (isolation region 92 b) arranged in a second direction (e.g., the Y-axis direction) intersecting the first direction with respect to the first isolation region, and an overflow path (overflow path 70) arranged between the first isolation region and the second isolation region so as to contact the first photoelectric conversion element and the second photoelectric conversion element. The first isolation region has a second electrode (electrode 96) provided between the first electrode and the overflow path and made of a material having a work function different from that of the first electrode.

[0132] In the photodetector (imaging device 1) according to this embodiment, the separation region 92 has an electrode 96 provided between the electrode 95 and the overflow path 70, and made of a material having a work function different from that of the electrode 95. This makes it possible to set the potential of the overflow path 70. This makes it possible to realize a photodetector with good performance.

[0133] Next, a modified example of the present disclosure will be described. In the following, the same components as those in the above embodiment will be denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0134] 2. Modifications (2-1. Modification 1) Fig. 14 is a diagram showing an example of the planar configuration of a pixel of an imaging device according to Modification 1 of the present disclosure. Figs. 15 and 16 are diagrams showing an example of the cross-sectional configuration of a pixel of the imaging device. Fig. 15 shows an example of the configuration of a pixel in the direction of line A-A' shown in Fig. 14. Fig. 16 shows an example of the configuration of a pixel in the direction of line B-B' shown in Fig. 14.

[0135] Of the multiple isolation regions 92 in each pixel P, some isolation regions 92 may be made of different materials from the other isolation regions 92. For example, as in the examples schematically shown in Figures 14 to 16, the isolation regions 92a and 92b may be made of a different material from the isolation regions 92c and 92d. The isolation regions 92a and 92b are configured as regions of a different conductivity type from the isolation regions 92c and 92d, for example.

[0136] The isolation regions 92a and 92b may each be a p-type region, and the isolation regions 92c and 92d may each be an n-type region. As an example, the isolation regions 92a and 92b may be made of p-type polysilicon, and the isolation regions 92c and 92d may be made of n-type polysilicon.

[0137] In the imaging device 1 according to this modification, a variety of potentials (potential distributions) can be formed in the overflow path 70. For example, it is possible to adjust the potential of each path between the multiple photoelectric conversion units 12, and it becomes possible to control the direction of overflow (i.e., the direction of charge transfer).

[0138] (2-2. Modification 2) Figures 17 and 18 are diagrams for explaining an example configuration of an imaging device according to Modification 2. Figure 18 shows an example configuration of a pixel in the direction of line A-A' shown in Figure 17. As in the example schematically shown in Figures 17 and 18, the imaging device 1 may be configured to be able to supply different voltages to the electrode 95 in the pixel isolation region 91 and the electrode 96 in the isolation region 92.

[0139] The electrode 95 in the pixel isolation region 91 and the electrode 96 in the isolation region 92 are electrically connected to, for example, different wirings, vias, etc. As an example, the electrode 95 in the pixel isolation region 91 may be electrically connected to a wiring to which a voltage V1 is supplied, and the electrode 96 in the isolation region 92 may be electrically connected to a wiring to which a voltage V2 is supplied.

[0140] In the imaging device 1, the potential of the electrode 95 and the potential of the electrode 96 can be controlled separately (independently), which improves the degree of freedom in setting the potential of the overflow path 70. Note that the imaging device 1 may be configured to be able to separately (independently) control the potential of each electrode 96 of the multiple separation regions 92 (for example, the potential of the electrode 96 in separation region 92a, the potential of the electrode 96 in separation region 92d, etc.).

[0141] 19 and 20 are diagrams for explaining an example configuration of an imaging device according to Modification 3. Fig. 20 shows an example configuration of pixels in the direction of line A-A' shown in Fig. 19. The electrode 95 in the pixel isolation region 91 or the electrode 96 in the isolation region 92 may be made of a metal material.

[0142] 19 and 20 , for example, the electrode 95 of the pixel isolation region 91 is made of a metal material. The electrode 95 (or the electrode 96) may be formed using a metal material such as aluminum (Al), tungsten (W), or copper (Cu). The electrode 95 (or the electrode 96) may be made of a metal compound (metal oxide, metal nitride, etc.), or may be made of other conductive materials.

[0143] The electrodes 96 of the separation regions 92a to 92d can be made of a material having a work function different from the work function of the metal material that makes up the electrode 95. In the case of the imaging device 1 according to this modification, it is also possible to reduce dark current and adjust the potential of the overflow path 70 by applying a negative bias voltage to the electrode 95. The same effects as those of the above-described embodiment can be obtained.

[0144] (2-4. Modification 4) FIGS. 21 and 22 are diagrams for explaining an example configuration of an imaging device according to Modification 4. FIG. 22 shows an example configuration of a pixel in the direction of line A-A' shown in FIG. 21. A portion of the pixel isolation region 91 and a portion of the electrode 95 may each be provided between a plurality of adjacent photoelectric conversion units 12, as in the example shown in FIG. 21. A portion of the electrode 95 may be provided so as to contact the electrode 96 between a plurality of adjacent photoelectric conversion units 12.

[0145] 21 and 22 , parts of the electrode 95 are provided between the first photoelectric conversion unit 12 a and the second photoelectric conversion unit 12 b and between the first photoelectric conversion unit 12 a and the third photoelectric conversion unit 12 c. Other parts of the electrode 95 are provided between the second photoelectric conversion unit 12 b and the fourth photoelectric conversion unit 12 d and between the third photoelectric conversion unit 12 c and the fourth photoelectric conversion unit 12 d.

[0146] In the imaging device 1 according to this modification, a pixel isolation region 91 having an electrode 95 is provided in a partial region between adjacent photoelectric conversion units 12. For example, a negative bias voltage is supplied to the electrode 95 in the pixel isolation region 91. This makes it possible to effectively suppress the generation of dark current in the region between adjacent photoelectric conversion units 12.

[0147] (2-5. Modification 5) In the above-described embodiment and modification, an example configuration of the imaging device 1 has been described, but this is merely an example, and the configuration of the imaging device 1 is not limited to the above-described example. For example, the number and arrangement of the photoelectric conversion units 12, transistors TG, floating diffusions FD, etc. are not limited to the example shown in the drawings, and can be changed as appropriate.

[0148] Fig. 23 is a diagram illustrating an example configuration of an imaging device according to Modification 5. For example, as in the example shown in Fig. 23, multiple transistors TG (transistors TG1 to TG4 in Fig. 23) may be provided away from the central region of a pixel P. Furthermore, each pixel P may have multiple floating diffusions FD. In the example shown in Fig. 23, four floating diffusions FD are arranged corresponding to the transistors TG1 to TG4.

[0149] 24 and 25 are diagrams illustrating another example configuration of an imaging device according to Modification 5. FIG. 25 shows an example configuration of a pixel in the direction of line A-A' shown in FIG. 24. As in the example shown in FIG. 24, a pixel P of the imaging device 1 may have two photoelectric conversion units 12 (a first photoelectric conversion unit 12a and a second photoelectric conversion unit 12b). Furthermore, for example, a pixel P may be configured to include four or more photoelectric conversion units 12. In the case of this modification, the same effects as those of the above-described embodiment can be obtained.

[0150] 3. Application Examples The imaging device 1 and the like can be applied to any type of electronic device equipped with an imaging function, for example, a camera system such as a digital still camera or video camera, a mobile phone with an imaging function, etc. Fig. 26 shows a schematic configuration of an electronic device 1000.

[0151] The electronic device 1000 includes, for example, a lens group 1001, an imaging device 1, a DSP (Digital Signal Processor) circuit 1002, a frame memory 1003, a display unit 1004, a recording unit 1005, an operation unit 1006, and a power supply unit 1007, which are interconnected via a bus line 1008.

[0152] The lens group 1001 captures incident light (image light) from a subject and forms an image on the imaging surface of the imaging device 1. The imaging device 1 converts the amount of incident light formed on the imaging surface by the lens group 1001 into an electrical signal on a pixel-by-pixel basis and supplies the signal as a pixel signal to the DSP circuit 1002.

[0153] The DSP circuit 1002 is a signal processing circuit that processes signals supplied from the imaging device 1. The DSP circuit 1002 outputs image data obtained by processing the signals from the imaging device 1. The frame memory 1003 temporarily stores the image data processed by the DSP circuit 1002 on a frame-by-frame basis.

[0154] The display unit 1004 is composed of a panel-type display device such as a liquid crystal panel or an organic EL (Electro Luminescence) panel, and records image data of moving images or still images captured by the imaging device 1 on a recording medium such as a semiconductor memory or a hard disk.

[0155] The operation unit 1006, in response to a user's operation, outputs operation signals for various functions of the electronic device 1000. The power supply unit 1007 supplies various types of power to the DSP circuit 1002, frame memory 1003, display unit 1004, recording unit 1005, and operation unit 1006 as needed.

[0156] 4. Application Examples (Application Examples to Mobile Bodies) The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of mobile body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, or a robot.

[0157] FIG. 27 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology according to the present disclosure can be applied.

[0158] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 27, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional components of the integrated control unit 12050 are a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (Interface) 12053.

[0159] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

[0160] The body system control unit 12020 controls the operation of various devices equipped in the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0161] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture images outside the vehicle and receives the captured images. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, characters on the road surface, etc. based on the received images.

[0162] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0163] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

[0164] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the outside-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the distance between vehicles, maintaining vehicle speed, vehicle collision warning, vehicle lane departure warning, etc.

[0165] In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle obtained by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0166] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the outside information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside information detection unit 12030, and perform cooperative control aimed at preventing glare, such as switching from high beams to low beams.

[0167] The audio / video output unit 12052 transmits at least one of audio and video output signals to an output device capable of visually or audibly notifying information to vehicle occupants or the outside of the vehicle. In the example of Fig. 27, the output devices are exemplified by an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.

[0168] FIG. 28 is a diagram showing an example of the installation position of the imaging unit 12031.

[0169] In FIG. 28, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0170] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided on the front nose and the imaging unit 12105 provided on the top of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 provided on the top of the windshield inside the vehicle cabin is mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0171] 28 shows an example of the imaging ranges of the imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 12101 to 12104, an overhead image of the vehicle 12100 viewed from above can be obtained.

[0172] At least one of the image capturing units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the image capturing units 12101 to 12104 may be a stereo camera made up of multiple image capturing elements, or may be an image capturing element having pixels for phase difference detection.

[0173] For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 can calculate the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the change in this distance over time (relative speed with respect to the vehicle 12100), thereby extracting as a preceding vehicle, in particular, the three-dimensional object that is the closest three-dimensional object on the path of the vehicle 12100 and traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or higher). Furthermore, the microcomputer 12051 can set a vehicle-to-vehicle distance to be maintained in advance in front of the preceding vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. In this way, cooperative control can be performed for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation.

[0174] For example, the microcomputer 12051 classifies and extracts three-dimensional object data regarding three-dimensional objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from the imaging units 12101 to 12104, and can use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines a collision risk that indicates the risk of collision with each obstacle, and when the collision risk is equal to or greater than a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drive system control unit 12010.

[0175] At least one of the image capturing units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether a pedestrian is present in the images captured by the image capturing units 12101 to 12104. Such pedestrian recognition is performed, for example, by extracting feature points from the images captured by the image capturing units 12101 to 12104 as infrared cameras and performing pattern matching on a series of feature points that indicate the outline of an object to determine whether the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the image capturing units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular outline on the recognized pedestrian for emphasis. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating the pedestrian at a desired position.

[0176] An example of a mobile object control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to, for example, the image capturing unit 12031 of the above-described configuration. Specifically, for example, the image capturing device 1 or the like can be applied to the image capturing unit 12031. By applying the technology according to the present disclosure to the image capturing unit 12031, it becomes possible to obtain high-resolution captured images. It becomes possible to perform high-precision control using captured images in the mobile object control system.

[0177] (Application Example to Endoscopic Surgery System) The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

[0178] FIG. 29 is a diagram showing an example of a schematic configuration of an endoscopic surgery system to which the technology according to the present disclosure (the present technology) can be applied.

[0179] 29 shows an operator (doctor) 11131 performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgery system 11000. As shown in the figure, the endoscopic surgery system 11000 is composed of an endoscope 11100, other surgical tools 11110 such as an insufflation tube 11111 and an energy treatment tool 11112, a support arm device 11120 that supports the endoscope 11100, and a cart 11200 on which various devices for endoscopic surgery are mounted.

[0180] The endoscope 11100 is composed of a lens barrel 11101, a region of a predetermined length from the tip of which is inserted into a body cavity of a patient 11132, and a camera head 11102 connected to the base end of the lens barrel 11101. In the example shown, the endoscope 11100 is configured as a so-called rigid scope having a rigid lens barrel 11101, but the endoscope 11100 may also be configured as a so-called flexible scope having a flexible lens barrel.

[0181] An opening into which an objective lens is fitted is provided at the tip of the lens barrel 11101. A light source device 11203 is connected to the endoscope 11100, and light generated by the light source device 11203 is guided to the tip of the lens barrel by a light guide extending inside the lens barrel 11101, and is irradiated via the objective lens toward an object to be observed inside the body cavity of the patient 11132. The endoscope 11100 may be a direct-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0182] An optical system and an image sensor are provided inside the camera head 11102, and light reflected from the object of observation (observation light) is collected by the optical system onto the image sensor. The observation light is photoelectrically converted by the image sensor to generate an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. The image signal is sent to a camera control unit (CCU) 11201 as RAW data.

[0183] The CCU 11201 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and comprehensively controls the operations of the endoscope 11100 and the display device 11202. Furthermore, the CCU 11201 receives an image signal from the camera head 11102 and performs various types of image processing on the image signal, such as development processing (demosaic processing), to display an image based on the image signal.

[0184] Under the control of the CCU 11201, the display device 11202 displays an image based on an image signal that has been subjected to image processing by the CCU 11201.

[0185] The light source device 11203 is composed of a light source such as an LED (Light Emitting Diode), and supplies the endoscope 11100 with irradiation light when photographing the surgical site, etc.

[0186] The input device 11204 is an input interface for the endoscopic surgery system 11000. A user can input various information and instructions to the endoscopic surgery system 11000 via the input device 11204. For example, the user inputs an instruction to change the imaging conditions (type of irradiation light, magnification, focal length, etc.) of the endoscope 11100.

[0187] The treatment tool control device 11205 controls the driving of the energy treatment tool 11112 for cauterizing tissue, incising, sealing blood vessels, etc. The insufflation device 11206 inflates the body cavity of the patient 11132 through the insufflation tube 11111 in order to ensure a clear field of view for the endoscope 11100 and a working space for the surgeon. The recorder 11207 is a device capable of recording various types of information related to the surgery. The printer 11208 is a device capable of printing various types of information related to the surgery in various formats such as text, images, or graphs.

[0188] The light source device 11203, which supplies illumination light to the endoscope 11100 when photographing the surgical site, can be configured from a white light source, such as an LED, a laser light source, or a combination of these. When the white light source is configured from a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, allowing the light source device 11203 to adjust the white balance of the captured image. In this case, it is also possible to time-share images corresponding to each RGB by irradiating the object of observation with laser light from each RGB laser light source and controlling the drive of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, color images can be obtained without providing a color filter to the image sensor.

[0189] Furthermore, the light source device 11203 may be controlled to change the intensity of light it outputs at predetermined time intervals. By controlling the driving of the image sensor of the camera head 11102 in synchronization with the timing of the change in light intensity to acquire images in a time-division manner and combining the images, it is possible to generate an image with a high dynamic range that is free from so-called blocked-up shadows and blown-out highlights.

[0190] The light source device 11203 may also be configured to supply light in a predetermined wavelength band corresponding to special light observation. Special light observation, for example, utilizes the wavelength dependence of light absorption in body tissues to irradiate light in a narrower band than the light irradiated during normal observation (i.e., white light) to capture high-contrast images of specific tissues, such as blood vessels on the surface of mucous membranes, in what is known as narrow band imaging. Alternatively, special light observation may involve fluorescence observation, in which images are obtained using fluorescence generated by irradiating excitation light. Fluorescence observation may involve irradiating excitation light onto body tissues and observing the fluorescence from the tissues (autofluorescence observation), or may involve locally injecting a reagent such as indocyanine green (ICG) into the body tissue and irradiating the tissues with excitation light corresponding to the fluorescent wavelength of the reagent to obtain a fluorescent image. The light source device 11203 may be configured to supply narrow band light and / or excitation light corresponding to such special light observation.

[0191] FIG. 30 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG.

[0192] The camera head 11102 has a lens unit 11401, an imaging unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. The CCU 11201 has a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are connected to each other via a transmission cable 11400 so that they can communicate with each other.

[0193] The lens unit 11401 is an optical system provided at the connection portion with the lens barrel 11101. Observation light taken in from the tip of the lens barrel 11101 is guided to the camera head 11102 and enters the lens unit 11401. The lens unit 11401 is composed of a combination of multiple lenses including a zoom lens and a focus lens.

[0194] The imaging unit 11402 is composed of an imaging element. The imaging element constituting the imaging unit 11402 may be a single (so-called single-chip type) or multiple (so-called multi-chip type). When the imaging unit 11402 is composed of a multi-chip type, for example, each imaging element may generate an image signal corresponding to each of RGB, and a color image may be obtained by combining these signals. Alternatively, the imaging unit 11402 may be configured to have a pair of imaging elements for acquiring image signals for the right eye and the left eye corresponding to 3D (dimensional) display. The 3D display allows the surgeon 11131 to more accurately grasp the depth of the biological tissue at the surgical site. Note that when the imaging unit 11402 is composed of a multi-chip type, multiple lens units 11401 may be provided corresponding to each imaging element.

[0195] Furthermore, the imaging unit 11402 does not necessarily have to be provided in the camera head 11102. For example, the imaging unit 11402 may be provided inside the lens barrel 11101, immediately after the objective lens.

[0196] The driving unit 11403 is configured by an actuator, and moves the zoom lens and focus lens of the lens unit 11401 by a predetermined distance along the optical axis under the control of the camera head control unit 11405. This allows the magnification and focus of the image captured by the imaging unit 11402 to be adjusted appropriately.

[0197] The communication unit 11404 is configured by a communication device for transmitting and receiving various types of information to and from the CCU 11201. The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 to the CCU 11201 via the transmission cable 11400 as RAW data.

[0198] Furthermore, the communication unit 11404 receives a control signal for controlling the driving of the camera head 11102 from the CCU 11201 and supplies the control signal to the camera head control unit 11405. The control signal includes information on the imaging conditions, such as information specifying the frame rate of the captured image, information specifying the exposure value at the time of imaging, and / or information specifying the magnification and focus of the captured image.

[0199] The image capturing conditions such as the frame rate, exposure value, magnification, and focus may be appropriately specified by the user, or may be automatically set by the control unit 11413 of the CCU 11201 based on the acquired image signal. In the latter case, the endoscope 11100 is equipped with a so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function.

[0200] The camera head control unit 11405 controls the driving of the camera head 11102 based on a control signal received from the CCU 11201 via the communication unit 11404 .

[0201] The communication unit 11411 is configured by a communication device for transmitting and receiving various information to and from the camera head 11102. The communication unit 11411 receives an image signal transmitted from the camera head 11102 via the transmission cable 11400.

[0202] Furthermore, the communication unit 11411 transmits to the camera head 11102 a control signal for controlling the driving of the camera head 11102. The image signal and the control signal can be transmitted by electrical communication, optical communication, or the like.

[0203] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102 .

[0204] The control unit 11413 performs various controls related to the imaging of the surgical site, etc. by the endoscope 11100 and the display of the captured image obtained by imaging the surgical site, etc. For example, the control unit 11413 generates a control signal for controlling the driving of the camera head 11102.

[0205] Furthermore, the control unit 11413 displays the captured image showing the surgical site, etc., on the display device 11202 based on the image signal subjected to image processing by the image processing unit 11412. At this time, the control unit 11413 may recognize various objects in the captured image using various image recognition technologies. For example, the control unit 11413 can recognize surgical tools such as forceps, specific biological parts, bleeding, mist generated when using the energy treatment tool 11112, etc., by detecting the shape and color of the edges of objects included in the captured image. When displaying the captured image on the display device 11202, the control unit 11413 may use the recognition results to superimpose various surgical support information on the image of the surgical site. By superimposing the surgical support information and presenting it to the surgeon 11131, the burden on the surgeon 11131 can be reduced and the surgeon 11131 can proceed with the surgery reliably.

[0206] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable for electrical signal communication, an optical fiber for optical communication, or a composite cable of these.

[0207] In the illustrated example, communication is performed wired using a transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may also be performed wirelessly.

[0208] The above describes an example of an endoscopic surgery system to which the technology according to the present disclosure can be applied. Of the above-described configurations, the technology according to the present disclosure can be suitably applied to, for example, the imaging unit 11402 provided in the camera head 11102 of the endoscope 11100. By applying the technology according to the present disclosure to the imaging unit 11402, it is possible to provide a high-definition endoscope 11100.

[0209] Although the present disclosure has been described above by way of embodiments, modifications, application examples, and applied examples, the present technology is not limited to the above-described embodiments, etc., and various modifications are possible. For example, although the modifications described above have been described as modifications of the above-described embodiments, the configurations of the modifications can be combined as appropriate.

[0210] In the above embodiments, an imaging device has been described as an example. However, the photodetector of the present disclosure may be, for example, a device that receives incident light and converts the light into an electric charge. The output signal may be a signal of image information or a signal of ranging information. The photodetector (imaging device) may be applied to an image sensor, a ranging sensor, etc. Note that the present disclosure is not limited to a back-illuminated image sensor, but may also be applied to a front-illuminated image sensor.

[0211] The photodetector according to the present disclosure may also be applied as a distance measuring sensor capable of measuring distances using a time-of-flight (TOF) method. The photodetector (image capture device) may also be applied as a sensor capable of detecting events, such as an event-driven sensor (also known as an event vision sensor (EVS), an event-driven sensor (EDS), or a dynamic vision sensor (DVS)).

[0212] According to one embodiment of the present disclosure, a photodetector device includes a first semiconductor layer, a plurality of pixels including a first pixel having a first photoelectric conversion element and a second photoelectric conversion element arranged in a first direction in the first semiconductor layer, and a pixel isolation region having a first electrode. The first pixel includes a first isolation region arranged between the first photoelectric conversion element and the second photoelectric conversion element, a second isolation region arranged in a second direction intersecting the first direction with respect to the first isolation region, and an overflow path. The first isolation region includes a second electrode arranged between the first electrode and the overflow path and made of a material having a work function different from that of the first electrode. This makes it possible to set the potential of the overflow path. This makes it possible to realize a photodetector device with good performance.

[0213] Note that the effects described in this specification are merely examples and are not limited to those described, and other effects may also be present. The present disclosure may also have the following configuration: (1) A photodetector device comprising: a first semiconductor layer; a plurality of pixels including a first pixel having a first photoelectric conversion element and a second photoelectric conversion element arranged to be aligned in a first direction in the first semiconductor layer; and a pixel isolation region arranged in the first semiconductor layer around the pixel and having a first electrode, wherein the first pixel has: a first isolation region arranged between the first photoelectric conversion element and the second photoelectric conversion element; a second isolation region arranged to be aligned in a second direction intersecting the first direction with respect to the first isolation region; and an overflow path arranged between the first isolation region and the second isolation region so as to contact the first photoelectric conversion element and the second photoelectric conversion element, and the first isolation region has a second electrode arranged between the first electrode and the overflow path and made of a material having a work function different from that of the first electrode. (2) The photodetector according to (1), wherein the second electrode is made of a material having a work function smaller than that of the first electrode. (3) The photodetector according to (1) or (2), wherein the first electrode is made of a first conductivity type region provided in the first semiconductor layer, and the second electrode is made of a second conductivity type region provided in the first semiconductor layer. (4) The photodetector according to any one of (1) to (3), wherein the overflow path is made of a semiconductor region of a second conductivity type. (5) The photodetector according to any one of (1) to (4), further comprising a first insulating film provided in the first semiconductor layer between the overflow path and the second electrode. (6) The photodetector according to any one of (1) to (5), wherein at least one of the first electrode and the second electrode is made of polysilicon. (7) The photodetector according to any one of (1) to (6), wherein the first electrode or the second electrode is made of a metal material.(8) The photodetector according to any one of (1) to (7), wherein the first isolation region and the second isolation region each have the second electrode and are provided on either side of the overflow path. (9) The photodetector according to any one of (1) to (8), wherein the second electrode is provided so as to be in contact with the first electrode. (10) The photodetector according to any one of (1) to (9), wherein a portion of the first electrode is provided so as to be in contact with the second electrode between the first photoelectric conversion element and the second photoelectric conversion element. (11) The photodetector according to any one of (1) to (10), further comprising a second insulating film provided between the first electrode and the second electrode in the first semiconductor layer. (12) The photodetector according to any one of (1) to (11), further comprising: a third photoelectric conversion element arranged to be aligned in the second direction with respect to the first photoelectric conversion element; and a fourth photoelectric conversion element arranged to be aligned in the second direction with respect to the second photoelectric conversion element, wherein the second isolation region is provided between the third photoelectric conversion element and the fourth photoelectric conversion element. (13) The photodetector according to (12), further comprising: a third isolation region arranged between the first photoelectric conversion element and the third photoelectric conversion element, the third isolation region having a third electrode, the third electrode being constituted by a first conductivity type region provided in the first semiconductor layer, and the second electrode being constituted by a second conductivity type region provided in the first semiconductor layer. (14) The photodetector according to any one of (1) to (13), wherein the first pixel has a floating diffusion provided in the first semiconductor layer, and the overflow path is provided in the first semiconductor layer below the floating diffusion. (15) The photodetector according to any one of (1) to (14), wherein the pixel isolation region is provided so as to penetrate the first semiconductor layer, and the first electrode is embedded in the pixel isolation region. (16) The photodetector according to any one of (1) to (15), wherein the first isolation region is provided so as to penetrate the first semiconductor layer, and the second electrode is embedded in the first isolation region.(17) The photodetector according to any one of (1) to (16), wherein the pixel isolation region, the first isolation region, and the second isolation region are provided continuously. (18) The photodetector according to any one of (1) to (17), further comprising a readout circuit capable of outputting a signal based on charges photoelectrically converted by the first photoelectric conversion element and a signal based on charges photoelectrically converted by the second photoelectric conversion element. (19) The photodetector according to (18), further comprising a second semiconductor layer stacked on the first semiconductor layer, wherein the second semiconductor layer has at least a part of the readout circuit. (20) An electronic device comprising: an optical system; and a photodetector that receives light transmitted through the optical system, wherein the photodetector comprises: a first semiconductor layer; a plurality of pixels including a first pixel having a first photoelectric conversion element and a second photoelectric conversion element arranged to be aligned in a first direction in the first semiconductor layer; and a pixel isolation region arranged in the first semiconductor layer around the pixel and having a first electrode, wherein the first pixel comprises: a first isolation region arranged between the first photoelectric conversion element and the second photoelectric conversion element; a second isolation region arranged to be aligned in a second direction intersecting the first direction with respect to the first isolation region; and an overflow path arranged between the first isolation region and the second isolation region so as to contact the first photoelectric conversion element and the second photoelectric conversion element, wherein the first isolation region has a second electrode arranged between the first electrode and the overflow path and made of a material having a work function different from that of the first electrode.

[0214] This application claims priority based on Japanese Patent Application No. 2024-018493, filed on February 9, 2024, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0215] Those skilled in the art will recognize that various modifications, combinations, subcombinations, and variations may occur depending on design requirements and other factors, and are intended to be within the scope of the appended claims and their equivalents.

Claims

1. A photodetector comprising: a first semiconductor layer; a plurality of pixels including a first pixel having a first photoelectric conversion element and a second photoelectric conversion element arranged in a first direction in the first semiconductor layer; and a pixel isolation region arranged in the first semiconductor layer around the pixel and having a first electrode, wherein the first pixel has: a first isolation region arranged between the first photoelectric conversion element and the second photoelectric conversion element; a second isolation region arranged in a second direction intersecting the first direction with respect to the first isolation region; and an overflow path arranged between the first isolation region and the second isolation region so as to contact the first photoelectric conversion element and the second photoelectric conversion element, and the first isolation region has a second electrode arranged between the first electrode and the overflow path and made of a material having a work function different from that of the first electrode.

2. The photodetector according to claim 1, wherein the second electrode is made of a material having a work function smaller than that of the first electrode.

3. The photodetector device according to claim 1, wherein the first electrode is formed by a region of a first conductivity type provided in the first semiconductor layer, and the second electrode is formed by a region of a second conductivity type provided in the first semiconductor layer.

4. The photodetector according to claim 1, wherein the overflow path is formed of a semiconductor region of the second conductivity type.

5. The photodetector according to claim 1, further comprising a first insulating film provided in the first semiconductor layer between the overflow path and the second electrode.

6. The photodetector according to claim 1, wherein at least one of the first electrode and the second electrode is made of polysilicon.

7. The photodetector according to claim 1, wherein the first electrode or the second electrode is made of a metal material.

8. The photodetector according to claim 1, wherein the first isolation region and the second isolation region each have the second electrode and are provided on either side of the overflow path.

9. The photodetector according to claim 1, wherein the second electrode is provided so as to be in contact with the first electrode.

10. The photodetector according to claim 1, wherein a portion of the first electrode is provided between the first photoelectric conversion element and the second photoelectric conversion element so as to be in contact with the second electrode.

11. The photodetector according to claim 1, further comprising a second insulating film provided in the first semiconductor layer between the first electrode and the second electrode.

12. The photodetector device according to claim 1, further comprising: a third photoelectric conversion element arranged to be aligned in the second direction with respect to the first photoelectric conversion element; and a fourth photoelectric conversion element arranged to be aligned in the second direction with respect to the second photoelectric conversion element, wherein the second isolation region is arranged between the third photoelectric conversion element and the fourth photoelectric conversion element.

13. The photodetector device according to claim 12, further comprising a third isolation region provided between the first photoelectric conversion element and the third photoelectric conversion element and having a third electrode, wherein the third electrode is formed by a region of a first conductivity type provided in the first semiconductor layer, and the second electrode is formed by a region of a second conductivity type provided in the first semiconductor layer.

14. The photodetector device according to claim 1, wherein the first pixel has a floating diffusion provided in the first semiconductor layer, and the overflow path is provided in the first semiconductor layer below the floating diffusion.

15. The photodetector according to claim 1, wherein the pixel isolation region is provided so as to penetrate the first semiconductor layer, and the first electrode is embedded in the pixel isolation region.

16. The photodetector according to claim 1, wherein the first isolation region is provided so as to penetrate the first semiconductor layer, and the second electrode is embedded in the first isolation region.

17. The photodetector according to claim 1, wherein the pixel isolation region, the first isolation region, and the second isolation region are provided contiguously.

18. The photodetector according to claim 1, further comprising a readout circuit capable of outputting a signal based on the charge photoelectrically converted by the first photoelectric conversion element and a signal based on the charge photoelectrically converted by the second photoelectric conversion element.

19. The photodetector device according to claim 18, further comprising a second semiconductor layer stacked on the first semiconductor layer, the second semiconductor layer having at least a part of the readout circuit.

20. An electronic device comprising: an optical system; and a photodetector that receives light transmitted through the optical system, wherein the photodetector has: a first semiconductor layer; a plurality of pixels including a first pixel having a first photoelectric conversion element and a second photoelectric conversion element arranged to be aligned in a first direction in the first semiconductor layer; and a pixel isolation region arranged in the first semiconductor layer around the pixel and having a first electrode, wherein the first pixel includes: a first isolation region arranged between the first photoelectric conversion element and the second photoelectric conversion element; a second isolation region arranged to be aligned in a second direction intersecting the first direction with respect to the first isolation region; and an overflow path arranged between the first isolation region and the second isolation region so as to contact the first photoelectric conversion element and the second photoelectric conversion element, wherein the first isolation region has a second electrode arranged between the first electrode and the overflow path and made of a material having a work function different from that of the first electrode.

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