Light detection device and electronic equipment

Abstract

A light detection device according to an embodiment of the present disclosure comprises: a photoelectric conversion element that photoelectrically converts light; a floating diffusion; a first transistor capable of transferring charges converted by the photoelectric conversion element to the floating diffusion; a first wiring electrically connected to the floating diffusion; and a second wiring that is provided around the first wiring and that is capable of transmitting a first voltage.

Description

Optical Detection Device and Electronic Device

[0001] The present disclosure relates to an optical detection device and an electronic device.

[0002] An imaging device including a plurality of pixels each having a photodiode, a transfer transistor, and a floating diffusion has been proposed (Patent Document 1).

[0003] International Publication No. 2020 / 262582

[0004] In a device that detects light, it is desirable to be able to transfer signal charges appropriately.

[0005] There is a desire to provide an optical detection device capable of improving charge transfer.

[0006] The optical detection device according to an embodiment of the present disclosure includes a photoelectric conversion element that photoelectrically converts light, a floating diffusion, a first transistor capable of transferring the charges converted by the photoelectric conversion element to the floating diffusion, a first wiring electrically connected to the floating diffusion, and a second wiring provided around the first wiring and capable of transmitting a first voltage. The electronic device according to an embodiment of the present disclosure includes an optical system and an optical detection device that receives the light transmitted through the optical system. The optical detection device has a photoelectric conversion element that photoelectrically converts light, a floating diffusion, a first transistor capable of transferring the charges converted by the photoelectric conversion element to the floating diffusion, a first wiring electrically connected to the floating diffusion, and a second wiring provided around the first wiring and capable of transmitting a first voltage.

[0007] Figure 1 is a block diagram showing an example of the schematic configuration of an imaging device, which is an example of a photodetector according to an embodiment of the present disclosure. Figure 2 is a diagram showing an example of the pixel section of an imaging device according to an embodiment of the present disclosure. Figure 3 is a diagram showing an example of the circuit configuration of a pixel in an imaging device according to an embodiment of the present disclosure. Figure 4 is a diagram illustrating an example of the cross-sectional configuration of an imaging device according to an embodiment of the present disclosure. Figure 5 is a diagram illustrating an example of the cross-sectional configuration of an imaging device according to an embodiment of the present disclosure. Figure 6A is a diagram illustrating an example of the potential distribution in a pixel of an imaging device according to an embodiment of the present disclosure. Figure 6B is a diagram illustrating an example of the potential distribution in a pixel of an imaging device according to an embodiment of the present disclosure. Figure 7 is a timing chart showing an example of operation of an imaging device according to an embodiment of the present disclosure. Figure 8 is a timing chart showing another example of operation of an imaging device according to an embodiment of the present disclosure. Figure 9 is a diagram illustrating another example of the configuration of an imaging device according to an embodiment of the present disclosure. Figure 10 is a diagram illustrating another example of the configuration of an imaging device according to an embodiment of the present disclosure. Figure 11 is a diagram illustrating another example of the configuration of an imaging device according to an embodiment of the present disclosure. Figure 12A is a diagram illustrating an example of the planar configuration of an imaging device according to an embodiment of the present disclosure. Figure 12B is a diagram illustrating an example of a planar configuration of an imaging device according to an embodiment of the present disclosure. Figure 13 is a diagram illustrating another configuration example of an imaging device according to an embodiment of the present disclosure. Figure 14 is a diagram illustrating an example of a configuration example of an imaging device according to Modification 1 of the present disclosure. Figure 15 is a diagram illustrating another configuration example of an imaging device according to Modification 1 of the present disclosure. Figure 16 is a diagram illustrating another configuration example of an imaging device according to Modification 1 of the present disclosure. Figure 17 is a diagram illustrating another configuration example of an imaging device according to Modification 1 of the present disclosure. Figure 18 is a diagram illustrating an example of the pixel circuit configuration of an imaging device according to Modification 2 of the present disclosure. Figure 19 is a diagram illustrating an example of the cross-sectional configuration of an imaging device according to Modification 2 of the present disclosure. Figure 20 is a diagram illustrating another example of the pixel circuit configuration of an imaging device according to Modification 2 of the present disclosure. Figure 21 is a diagram illustrating another example of the pixel circuit configuration of an imaging device according to Modification 2 of the present disclosure. Figure 22 is a diagram illustrating another example of the pixel circuit configuration of an imaging device according to Modification 2 of the present disclosure.Figure 23 is a block diagram showing an example of the configuration of an electronic device having an imaging device. Figure 24 is a block diagram showing an example of a schematic configuration of a vehicle control system. Figure 25 is an explanatory diagram showing an example of the installation position of an external information detection unit and an imaging unit. Figure 26 is a diagram showing an example of a schematic configuration of an endoscopic surgery system. Figure 27 is a block diagram showing an example of the functional configuration of a camera head and a CCU.

[0008] The embodiments of this disclosure will be described in detail below with reference to the drawings. The description will be in the following order: 1. Embodiments 2. Modifications 3. Application Examples 4. Application Examples

[0009] <1. Embodiments> Figure 1 is a block diagram showing an example of the schematic configuration of an imaging device, which is an example of a light detection device according to an embodiment of the present disclosure. Figure 2 is a diagram showing an example of the pixel section of an imaging device according to an embodiment. A light detection device is a device capable of detecting incident light. An imaging device 1, which is an example of a light detection device, has a plurality of pixels P including a photoelectric conversion unit, and is configured to generate a signal by photoelectric conversion of incident light.

[0010] The imaging device 1, for example, receives light transmitted through an optical system (not shown) and generates a signal. The imaging device 1 is constructed using a substrate (for example, a semiconductor substrate such as a Si (silicon) substrate or an SOI (silicon on insulator) substrate) on which each pixel P is provided with a photoelectric conversion unit. The imaging device 1 may also have a structure (layered structure) in which multiple substrates are stacked.

[0011] The photoelectric conversion unit of a pixel P is, for example, a photodiode (PD) and is configured to convert light into photoelectric energy. Each photoelectric conversion unit (photoelectric conversion element) of a pixel P can also be called a photoelectric conversion region. The imaging device 1 has a region (pixel section 100) where a plurality of pixels P are provided, as shown in the example in Figure 1 or Figure 2. The imaging device 1 has, for example, a pixel section 100 in which a plurality of pixels P are arranged in a matrix in two dimensions as an imaging area.

[0012] The imaging device 1 captures incident light (image light) from the subject to be measured through an optical system including an optical lens and an aperture (aperture diaphragm). The imaging device 1 captures an image of the subject formed by the optical lens. The imaging device 1 can generate pixel signals by photoelectric conversion of the received light (e.g., visible light, infrared light, or ultraviolet light). The imaging device 1, being a light detection device, is a device capable of receiving light and generating signals, and can also be called a light receiving device.

[0013] The imaging device 1 (light detection device) is configured, for example, as an image sensor. The imaging device 1 is, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The imaging device 1 can be used in various electronic devices such as digital still cameras, video cameras, and mobile phones.

[0014] As shown in Figure 2, the direction of incidence of light from the subject being measured is defined as the Z-axis direction, the left-right direction perpendicular to the Z-axis direction is defined as the X-axis direction, and the up-down direction perpendicular to both the Z-axis and X-axis directions is defined as the Y-axis direction. In subsequent figures, directions may also be indicated based on the direction of the arrows in Figure 2.

[0015] [Outline Configuration of the Imaging Device] The imaging device 1, as an example, includes a pixel section 100, a pixel control unit 105, a signal processing unit 112, a control unit 113, and a processing unit 114, as shown in Figure 1. The imaging device 1 is also provided with, for example, a plurality of control lines Lread and a plurality of signal lines VSL. The pixel section 100 is a pixel array in which a plurality of pixels P are arranged. The number and arrangement of pixels P provided in the pixel section 100 (i.e., the pixel array) can be changed as appropriate.

[0016] The control line Lread is a signal line capable of transmitting signals to control pixels P, and is connected to the pixel control unit 105 and the pixels P of the pixel unit 100. Multiple control lines Lread are wired to the pixel unit 100 for each pixel row, which is composed of multiple pixels P arranged horizontally (in the row direction). The control line Lread is configured to transmit control signals for reading signals from the pixels P.

[0017] The multiple control lines Lread for each pixel row of the imaging device 1 include, for example, wiring that transmits signals to control the transfer transistor, wiring that transmits signals to control the selection transistor, wiring that transmits signals to control the reset transistor, wiring that transmits signals to control the switching transistor, etc. The control lines Lread can also be called drive lines (or pixel drive lines) that transmit signals to drive the pixels P.

[0018] The signal line VSL is a signal line capable of transmitting signals from pixels P, and is connected to the pixels P of the pixel unit 100 and the signal processing unit 112. In the pixel unit 100, for example, one or more signal lines VSL are wired for each pixel row, which is composed of multiple pixels P arranged vertically (in the column direction). The signal line VSL is electrically connected to the pixels P and is configured to transmit signals output from the pixels P.

[0019] In the imaging device 1, multiple signal lines VSL may be provided for a single pixel row. For example, the imaging device 1 has multiple signal lines VSL for each pixel row containing multiple pixels P. The number and arrangement of control lines Lread and signal lines VSL provided in the imaging device 1 are not limited to the illustrated example and can be changed as appropriate.

[0020] The pixel control unit 105 is configured to control each pixel P of the pixel unit 100. The pixel control unit 105 is a control circuit and is composed of multiple circuits, such as a buffer, a shift register, and an address decoder. The pixel control unit 105 generates a signal for controlling the pixels P and outputs it to each pixel P of the pixel unit 100 via the control line Lread. The pixel control unit 105 is controlled by the control unit 113 and controls the pixels P of the pixel unit 100.

[0021] The pixel control unit 105 generates signals for controlling pixels P, such as signals to control the transfer transistor, signals to control the selection transistor, signals to control the reset transistor, and signals to control the switching transistor, and supplies these signals to each pixel P via the control line Lread. The pixel control unit 105 can perform control to read out pixel signals from each pixel P. The pixel control unit 105 can also be described as a pixel drive unit (pixel drive circuit) configured to drive each pixel P.

[0022] The signal processing unit 112 is configured to perform signal processing on the input pixel signal. 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 composed of, for example, a current source capable of supplying current to the amplification transistor of the pixel P. As an example, the load circuit together with the amplification transistor of the pixel P constitutes a source follower circuit.

[0023] The signal processing unit 112 may have an amplification circuit configured to amplify the signal read from the pixel P via the signal line VSL. The load circuit, amplification circuit, and AD conversion circuit, etc., are provided, for example, for each of the multiple signal lines VSL. In the imaging device 1, the load circuit, amplification circuit, and AD conversion circuit, etc., may be provided for each pixel row of the pixel section 100.

[0024] The signals output from each pixel P selected and scanned by the pixel control unit 105 are input to the signal processing unit 112 via the signal line VSL. The signal processing unit 112 can perform signal processing such as AD conversion and CDS (Correlated Double Sampling) of the pixel P signals. The signals from each pixel P transmitted via each signal line VSL are processed by the signal processing unit 112 and output to the processing unit 114.

[0025] The processing unit 114 is configured to acquire signals from each pixel P and perform signal processing. The processing unit 114 is a processing circuit and consists of, for example, circuits that perform various signal processing on the input pixel signals. The processing unit 114 is configured to include, as an example, an arithmetic circuit, a memory circuit, and the like.

[0026] The processing unit 114 can perform signal processing on the pixel signals input from the signal processing unit 112 and output the processed pixel signals. The processing unit 114 can perform various signal processing such as noise reduction, interpolation, and gradation correction. The processing unit 114 may include a processor and memory.

[0027] The control unit 113 is configured to control each part of the imaging device 1. The control unit 113 receives data such as a clock and operating mode commands from an external source, and can output data such as internal information of the imaging device 1. The control unit 113 is a control circuit and, for example, has a timing generator configured to generate various timing signals.

[0028] The control unit 113 controls the operation of the pixel control unit 105 and 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 may include circuits such as a PLL (Phase Locked Loop) and a DAC (Digital to Analog Converter). The control unit 113 and the processing unit 114 may be configured as an integrated unit.

[0029] The pixel unit 100, pixel control unit 105, signal processing unit 112, control unit 113, processing unit 114, etc., described above may be provided on a single substrate or divided and provided on multiple substrates. The pixel control unit 105, signal processing unit 112, control unit 113, processing unit 114, etc., may be provided, for example, as peripheral circuits in the peripheral area of ​​the pixel unit 100. Note that some or all of the signal processing unit 112, control unit 113, and processing unit 114 may be configured as a single unit.

[0030] [Pixel Configuration] Figure 3 shows an example of the circuit configuration of a pixel in an imaging device according to an embodiment. A pixel P includes a photoelectric conversion unit 11, a transistor TG, a floating diffusion FD, and a readout circuit 15. The photoelectric conversion unit 11 is configured to receive light and generate a signal. The readout circuit 15 is configured to output a signal based on the photoelectrically converted charge.

[0031] The photoelectric conversion unit 11 is configured to generate electric charge through photoelectric conversion. In the example shown in Figure 3, the photoelectric conversion unit 11 is a photodiode (PD) that converts incident light into electric charge. The photoelectric conversion unit 11 can generate an electric charge corresponding to the amount of light received by performing photoelectric conversion. The photoelectric conversion unit 11 is a photoelectric conversion element and can also be called a light receiving element.

[0032] The transistor TG is configured to transfer the charge photoelectrically converted in the photoelectric conversion unit 11 to the floating diffusion FD. The transistor TG is controlled by the signal VTG and electrically connects or disconnects the photoelectric conversion unit 11 and the floating diffusion FD. The transistor TG is a transfer transistor. The transistor TG can transfer the charge converted and stored in the photoelectric conversion unit 11 to the floating diffusion FD.

[0033] The floating diffusion FD is a storage unit and is configured to store the transferred charge. The floating diffusion FD can store the charge photoelectrically converted by the photoelectric conversion unit 11. The floating diffusion FD stores the transferred charge and converts it into a voltage corresponding to the capacitance of the floating diffusion FD. The floating diffusion FD can also be described as a storage unit capable of holding charge.

[0034] Pixel P has a capacitance C1, which will be described later, as shown by the dotted line in Figure 3. Capacitor C1 is added to the floating diffusion FD and used to control the potential (electric potential) in the floating diffusion FD. Capacitor C1 is composed of, for example, wiring capacitance.

[0035] The readout circuit 15 includes, for example, a transistor AMP, a transistor SEL, and a transistor RST. The readout circuit 15 can read out pixel signals based on the charge photoelectrically converted by the photoelectric conversion unit 11. The readout circuit 15 may also include a floating diffusion FD. The readout circuit 15 may also include a transistor TG.

[0036] The transistor AMP is configured to generate and output a signal based on the charge stored in the floating diffusion FD. The transistor AMP is an amplifying transistor. The transistor AMP can generate and output a signal based on the charge converted in the photoelectric conversion unit 11 (i.e., the photoelectric conversion region).

[0037] 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. The drain of the transistor AMP is connected to a power supply line to which, for example, a power supply voltage (power supply voltage VDD in the example shown in FIG. 3) is supplied.

[0038] The source of the transistor AMP is connected to the signal line VSL via, for example, the transistor SEL. The transistor AMP is configured to generate a signal based on the charge accumulated in the floating diffusion FD, that is, a signal based on the voltage of the floating diffusion FD, and output it to the signal line VSL.

[0039] The transistor SEL is configured to be able to control the output of the signal of the pixel. The transistor SEL is electrically connected in series with the transistor AMP, for example, as in the example shown in FIG. 3. The transistor SEL is controlled by the signal VSEL and is configured to be able to output the signal from the transistor AMP to the signal line VSL. The transistor SEL is a selection transistor. The transistor SEL can control the output timing of the signal of the pixel.

[0040] The transistor SEL is configured to be able to output a signal based on the charge converted by the photoelectric conversion unit 11. The transistor SEL can output the pixel signal of the pixel P to the signal line VSL. Note that the transistor SEL may be electrically connected in series between the power supply line to which the power supply voltage (power supply voltage VDD in the example shown in FIG. 3) is applied and the transistor AMP. If necessary, the transistor SEL may be omitted.

[0041] 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 the power supply line to which the power supply voltage VDD is applied and is configured to be able to execute the reset of the charge of the pixel P. The transistor RST is a reset transistor.

[0042] The transistor RST is controlled by the signal VRST, resets the charge accumulated in the floating diffusion FD, and can reset the voltage of the floating diffusion FD. The transistor RST electrically connects the power supply line and the floating diffusion FD, and discharges the charge accumulated in the floating diffusion FD. Note that the transistor RST can reset the charge accumulated in the photoelectric conversion unit 11 via the transistor TG.

[0043] The above-described transistor TG (transfer transistor), transistor AMP (amplification transistor), transistor SEL (selection transistor), and transistor RST (reset transistor) are each, for example, a MOS transistor (MOSFET) having gate, source, and drain terminals.

[0044] In the example shown in FIG. 3, the transistor TG, transistor AMP, transistor SEL, and transistor RST are each composed of an NMOS transistor. Note that the transistors of the pixel P may be composed of PMOS transistors as required.

[0045] The pixel control unit 105 (see FIG. 1) of the imaging device 1 supplies a control signal to the gates of the transistors TG, SEL, RST, etc. of each pixel P via the above-described control line Lread, and turns the transistors on (conducting state) or off (non-conducting state).

[0046] As an example, the plurality of control lines Lread for each pixel row of the imaging device 1 include a wiring for transmitting a signal VTG for controlling the transistor TG, a wiring for transmitting a signal VSEL for controlling the transistor SEL, a wiring for transmitting a signal VRST for controlling the transistor RST, and the like.

[0047] Transistors TG, SEL, and RST are switched on and off by the pixel control unit 105. The pixel control unit 105 controls the readout circuit 15 for each pixel P, causing each pixel P to output a pixel signal to the signal line VSL. The pixel control unit 105 can perform control to read the pixel signal of each pixel P to the signal line VSL.

[0048] The imaging device 1 may have a configuration in which multiple pixels P share one readout circuit 15. The readout circuit 15 is provided for multiple pixels P, for example. In the imaging device 1, a readout circuit 15 is provided for each of the multiple pixels P, and one readout circuit 15 may be shared by multiple pixels P. As an example, a 2x2 pixel array, composed of four adjacent pixels P, may share one readout circuit 15.

[0049] [Configuration of the Imaging Device] Figure 4 is a diagram illustrating an example of the cross-sectional configuration of an imaging device according to an embodiment. The imaging device 1 is configured using a substrate 201 including a semiconductor layer 101, as shown in Figure 4. The substrate 201 has a semiconductor layer 101 and a wiring layer 111. The wiring layer 111 is provided stacked on the semiconductor layer 101 in the Z-axis direction. For example, the semiconductor layer 101 and the wiring layer 111 are provided from the side where light is incident.

[0050] The substrate 201 is constructed using, for example, a semiconductor substrate such as a silicon substrate or an SOI substrate. The substrate 201 may be constructed using a SiGe (silicon germanium) substrate or a SiC (silicon carbide) substrate, or it may be constructed using other materials. The substrate 201 may be constructed using a compound semiconductor material of group III-V, etc.

[0051] As shown in Figure 4, the semiconductor layer 101 has opposing surfaces 11S1 and 11S2. Surface 11S2 is the surface opposite to surface 11S1. For example, surface 11S2 is the light-receiving surface (light incident surface). Surface 11S1 of the semiconductor layer 101 is an element-forming surface on which elements such as transistors and capacitive elements are formed. Surface 11S1 is provided with a electrode film, a gate insulating film (for example, a gate oxide film), etc.

[0052] A wiring layer 111 is provided on the surface 11S1 side of the semiconductor layer 101. The wiring layer 111 includes, for example, a conductive film and an insulating film, and has a plurality of wirings and a plurality of vias. The wiring layer 111 has a configuration in which a plurality of wirings are stacked with an insulating film acting as an interlayer insulating film (interlayer insulating layer). The wiring layer 111 is configured as a multilayer wiring layer and may include two or more or three or more layers of wiring.

[0053] The wiring of the wiring layer 111 is formed using a metallic material such as aluminum (Al), copper (Cu), or tungsten (W). The wiring of the wiring layer 111 may also be made of polysilicon (Poly-Si) or other conductive materials. The interlayer insulating film may be formed using silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), or other insulating materials.

[0054] The substrate 201, which includes the semiconductor layer 101, is provided with a photoelectric conversion unit 11, a transistor TG, a floating diffusion FD, a readout circuit 15 (see also Figure 3), and the like. Each pixel P of the imaging device 1 has, for example, the structure shown in Figure 4. The pixel control unit 105, signal processing unit 112, control unit 113, processing unit 114 (see Figure 1), etc., are provided on the substrate 201 or on a substrate separate from the substrate 201.

[0055] As shown in Figure 4, the semiconductor layer 101 has a semiconductor region 40. The semiconductor region 40 is, for example, a p-type semiconductor region and is provided as a p-type well (p-well). As an example, the semiconductor layer 101 is provided with a semiconductor region 40 which is a p-type well region. The semiconductor region 40 may be an n-type semiconductor region which is an n-type well region, if necessary.

[0056] In the semiconductor layer 101, a plurality of photoelectric conversion units 11 are provided along the surfaces 11S1 and 11S2 of the semiconductor layer 101. For example, a plurality of photoelectric conversion units 11 are embedded in the semiconductor layer 101. The photoelectric conversion units 11 are provided between the surfaces 11S1 and 11S2 of the semiconductor layer 101.

[0057] Each pixel P has a photoelectric conversion unit 11, which is a photoelectric conversion element and can also be called a photoelectric conversion region. The photoelectric conversion unit 11 (photoelectric conversion element) is provided on the semiconductor layer 101 and includes a semiconductor region 13. The semiconductor region 13 is, for example, an n-type semiconductor region provided within a semiconductor region 40 (i.e., a well).

[0058] On the surface 11S1 side of the semiconductor layer 101, for example, as shown in the example in Figure 4, a transistor TG (transfer transistor), a floating diffusion FD, a transistor RST (reset transistor), a transistor AMP (amplifier transistor), and a transistor SEL (selection transistor) are provided.

[0059] Transistor TG has a gate electrode 31, and transistor RST has a gate electrode 32. Transistor AMP has a gate electrode 33, and transistor SEL has a gate electrode 34. In the example shown in Figure 4, transistors TG, RST, AMP, and SEL each have a gate insulating film 38. Gate electrodes 31 to 34 are each provided on the gate insulating film 38.

[0060] The gate electrodes 31 to 34 are each constructed, for example, using polysilicon (Poly-Si). Each of the gate electrodes 31 to 34 may be constructed using a metallic material or a metallic compound material. For example, the gate electrodes 31 to 34 may be constructed using tungsten (W), tantalum nitride (TaN), titanium nitride (TiN), etc. Sidewalls may be provided on each of the sides of the gate electrodes 31 to 34.

[0061] The gate insulating film 38 is composed of a single layer film made of one of the following materials: silicon oxide, silicon oxynitride, hafnium oxide (HfO), etc., or a multilayer film made of two or more of these materials. The gate insulating film 38 may be made using an insulating material having a high dielectric constant (relative dielectric constant). For example, the gate insulating film 38 may be formed using a high dielectric constant material having a higher dielectric constant than silicon oxide, such as a hafnium-based insulating film.

[0062] For example, the transistor TG has a planar gate structure and is configured as a planar transistor. The gate electrode 31 of transistor TG receives the control signal VTG described above via contacts (also called vias) and wiring provided in the wiring layer 111, as schematically shown in Figure 4.

[0063] The transistor TG may have a vertical gate structure. For example, the gate electrode 31 of the transistor TG is provided such that a portion of the gate electrode 31 is located within the semiconductor layer 101. A portion of both the gate electrode 31 and the gate insulating film 38 of the transistor TG may be provided within the semiconductor layer 101 so as to reach the photoelectric conversion unit 11.

[0064] A floating diffusion FD is composed of, for example, a semiconductor region 41 provided in a semiconductor layer 101. The semiconductor region 41 is provided in a semiconductor region 40 (i.e., a well). The semiconductor region 41 is a semiconductor region of a different conductivity type than the semiconductor region 40 and is formed on the surface 11S1 side of the semiconductor layer 101.

[0065] The semiconductor region 41 is a region formed using impurities, for example, an n-type semiconductor region. The semiconductor region 41 can also be called an n-type diffusion region or an n-type conductive region. The semiconductor region 41 may have an impurity concentration higher than that of the semiconductor region 40, for example, and may be configured as an n+-type semiconductor region. The semiconductor region 41 as a floating diffusion FD can also be called a floating diffusion region.

[0066] The semiconductor region 41 stores the charge transferred from the photoelectric conversion unit 11 via the region beneath the gate electrode 31 and gate insulating film 38 of the transistor TG. The semiconductor region 41 is also, for example, one of the source region and drain region of the transistor TG. Furthermore, in the example shown in Figure 4, the semiconductor region 41 is also one of the source region and drain region of the transistor RST.

[0067] The floating diffusion FD, i.e., the semiconductor region 41, is electrically connected to the wiring L1 provided on the wiring layer 111, as shown in the example in Figure 4, and is electrically connected to the gate electrode 33 of the transistor AMP via the wiring L1. The wiring L1 can be called a floating diffusion wiring (FD wiring). The floating diffusion FD may include the wiring L1.

[0068] The signal VRST described above is input to the gate electrode 32 of transistor RST via contacts and wiring (not shown) provided in the wiring layer 111. Transistor RST has a semiconductor region 42 provided in the semiconductor region 40, which is the other of the source region and drain region of transistor RST. In the example shown in Figure 4, the semiconductor region 42 is also one of the source region and drain region of transistor AMP.

[0069] The semiconductor region 42 is a semiconductor region of a different conductivity type than the semiconductor region 40, and is formed on the surface 11S1 side of the semiconductor layer 101. The semiconductor region 42 is, for example, an n-type semiconductor region, or it may be configured as an n+-type semiconductor region. The semiconductor region 42 is electrically connected, for example, to a power line (wiring) to which a power supply voltage (e.g., power supply voltage VDD) is supplied.

[0070] The transistor AMP has a gate electrode 33, a semiconductor region 42, and another semiconductor region 43. The semiconductor region 42 is one of the source region and drain region of the transistor AMP, for example, the drain region. The semiconductor region 43 is the other of the source region and drain region of the transistor AMP, for example, the source region.

[0071] The transistor SEL has a gate electrode 34, a semiconductor region 43, and another semiconductor region 44. The semiconductor region 43 is either the source region or the drain region of the transistor SEL. The semiconductor region 44 is the other either the source region or the drain region of the transistor SEL. The semiconductor region 43 is also, for example, the source region of the transistor AMP.

[0072] Semiconductor region 43 and semiconductor region 44 are, for example, n-type semiconductor regions. Each of semiconductor region 43 and semiconductor region 44 may be configured as an n+-type semiconductor region, for example. Semiconductor region 44 is electrically connected to the signal line VSL described above, for example, as shown in the example in Figure 4.

[0073] The imaging device 1 has wiring L2, as shown in the example in Figure 4. Wiring L2 is capable of transmitting a predetermined voltage and is provided around wiring L1, which is an FD wiring. Wiring L2 is arranged adjacent to wiring L1 such that a capacitance is formed between wiring L1 and wiring L2. Wiring L2 is provided, for example, along wiring L1 via an insulating film.

[0074] The wiring L2 is provided, for example, around the wiring L1, facing the wiring L1. As an example, the wiring L2 extends in the X-axis direction (or Y-axis direction) along the wiring L1 in the wiring layer 111, and is provided facing the wiring L1. The wiring L2 may be arranged adjacent to the wiring L1 in the thickness direction of the wiring layer 111 (i.e., the Z-axis direction), or adjacent to the wiring L1 in the X-axis direction or the Y-axis direction.

[0075] The imaging device 1 has a capacitance C1 configured using wiring L1 and wiring L2, as schematically shown in Figure 5. Capacitor C1 includes, for example, at least a portion of wiring L1 and at least a portion of wiring L2, and is configured as a wiring capacitance. Capacitor C1 has, for example, an insulating film 20 provided between wiring L2 and wiring L1. In the example shown in Figure 4 or Figure 5, wiring L2 and wiring L1 are stacked with the insulating film 20, which is part of the wiring layer 111, in between.

[0076] In the imaging device 1, a capacitance C1 formed by wirings L2 and L1 and an insulating film 20 is added to the semiconductor region 41, which is a floating diffusion FD. Capacitor C1 is formed, for example, as a wiring capacitance that includes a part of wiring L1 and a part of wiring L2 as electrodes. It can also be said that capacitance C1 is connected between wiring L2 and wiring L1. Note that the arrangement of wirings L2 and L1 is not limited to the illustrated example and can be changed as appropriate.

[0077] Wiring L2 and wiring L1 are each formed using a metallic material such as aluminum (Al), copper (Cu), tungsten (W), cobalt (Co), or ruthenium (Ru). Wiring L2 and wiring L1 may each be made of silicon (Si), polysilicon (Poly-Si), or other conductive material. Wiring L2 may be made of the same material as wiring L1, or it may be made of a different material than wiring L1.

[0078] The insulating film 20 is, for example, silicon oxide (SiO ２ ), silicon nitride (e.g., Si ３ N ４ The insulating film 20 is constructed using insulating materials such as silicon oxide (ZrO) or silicon oxynitride (SiON). The insulating film 20 may be constructed using a high dielectric constant material having a dielectric constant higher than that of silicon oxide. For example, the insulating film 20 may be made of zirconium oxide (ZrO). ２ ), or aluminum oxide (Al ２ O ３ ) may be formed using

[0079] The insulating film 20 may be composed of a compound containing at least one of the elements titanium (Ti), tantalum (Ta), bismuth (Bi), hafnium (Hf), strontium (Sr), germanium (Ge), etc. The insulating film 20 may be composed of the same material as the surrounding insulating film, or it may be composed of a different material.

[0080] The thickness d1 of the insulating film 20 (in Figure 5, the thickness in the Z-axis direction of the insulating film 20 (film thickness)) may be, for example, in the range of 0.1 nm to 20 nm. The thickness d1 of the insulating film 20 may also be in the range of 1 nm to 20 nm. Furthermore, the thickness d1 of the insulating film 20 may be set to a size of 20 nm or more.

[0081] Wiring L2 is provided around wiring L1, which is FD wiring, as described above, as wiring that can be used for potential control of the floating diffusion FD. Wiring L2 is configured to utilize capacitive coupling between wiring L1 and wiring L2, and to apply a voltage to the floating diffusion FD via capacitor C1 that corresponds to the voltage of wiring L2.

[0082] When the floating diffusion FD is electrically floating, its potential changes due to capacitive coupling by capacitor C1 in response to the voltage (potential) applied to the wiring L2. For example, the potential of the floating diffusion FD can be temporarily changed in accordance with the change in the voltage of the wiring L2 and the capacitance value of capacitor C1.

[0083] The imaging device 1 can adjust the potential in the floating diffusion FD (i.e., the semiconductor region 41) by controlling the voltage supplied to the wiring L2, thereby assisting the transfer of signal charge by the transistor TG. This makes it possible to properly transfer charge from the photoelectric conversion unit 11 to the floating diffusion FD.

[0084] In the example shown in Figure 4 or Figure 5, wiring L2 is provided as part of the wiring that transmits the signal VFD2 and is configured to transmit the voltage of the signal VFD2. The voltage of wiring L2, i.e., the voltage value (signal level) of the signal VFD2, is controlled, for example, by the pixel control unit 105 (see Figure 1). The pixel control unit 105 (control circuit) generates the signal VFD2 as a control signal for wiring L2 and supplies it to wiring L2 via the control line Lread described above.

[0085] The pixel control unit 105 is configured to change the voltage of the signal VFD2 supplied to the wiring L2. The voltage value of the signal VFD2 can be switched between, for example, voltage VH and voltage VL, which is lower than voltage VH. Voltage VH has a voltage value different from the power supply voltage VDD, and is set to, for example, a voltage higher than the power supply voltage VDD (= VDD + α). The value of voltage VH may be VDD + 0.1V, VDD + 0.2V, VDD + 0.5V, or VDD + 1.0V, etc.

[0086] The pixel control unit 105 is configured to apply a voltage VH to the wiring L2 and to perform control to transfer charge from the photoelectric conversion unit 11 to the floating diffusion FD. For example, the pixel control unit 105 transitions the voltage of the signal VFD2 from voltage VL to voltage VH, and turns the transistor TG from the off state to the on state. This temporarily increases the potential of the floating diffusion FD, making it possible to promote the movement of charge from the photoelectric conversion unit 11.

[0087] Furthermore, the pixel control unit 105 may change the voltage of the signal VFD2 from voltage VH to voltage VL after the transistor TG has transitioned from the ON state to the OFF state. For example, after a predetermined time has elapsed since the transistor TG was turned from the ON state to the OFF state, the voltage of the wiring L2 is switched from voltage VH to voltage VL. By doing so, charge transfer can be performed appropriately, and it is possible to suppress the accumulation of signal charge within the photoelectric conversion unit 11.

[0088] Figures 6A and 6B are diagrams illustrating an example of the potential distribution in the pixels of an imaging device according to an embodiment. As described above, the pixel control unit 105 of the imaging device 1 can temporarily raise the potential of the floating diffusion FD by supplying a voltage VH (= VDD + α) to the wiring L2, as schematically shown by the arrow in Figure 6A.

[0089] Therefore, in the imaging device 1 according to this embodiment, charge transfer via the transistor TG can be assisted, and the occurrence of residual charge in the photoelectric conversion unit 11 can be suppressed. The deterioration of the linearity of the pixel signal due to residual signal charge can be suppressed. It becomes possible to realize an imaging device 1 capable of improved charge transfer.

[0090] Furthermore, according to the technology disclosed herein, it is not necessary to set the potential of the photoelectric conversion unit 11 to a very low value in order to secure a potential gradient for charge transfer. Instead, as schematically shown by the dashed arrow in Figure 6B, it is possible to adjust the potential of the photoelectric conversion unit 11 and increase the Qs (saturation charge amount) of the photoelectric conversion unit 11. This makes it possible to improve the amount of charge stored in the photoelectric conversion unit 11 and the floating diffusion FD.

[0091] Figure 7 is a timing chart showing an example of operation of an imaging device according to an embodiment. The timing chart in Figure 7 shows the control signals (signal VSEL, signal VRST, signal VTG, signal VFD2) supplied to the pixel P of the imaging device 1, the voltage VFD of the floating diffusion FD, and the voltage of the signal line VSL, with time on the horizontal axis. In Figure 7, transistors that receive a high-level control signal are turned ON, and transistors that receive a low-level control signal are turned OFF.

[0092] At time t1, signals VRST and VTG become high. When signal VRST becomes high, transistor RST of pixel P shown in Figure 3 becomes ON. Also, when signal VTG becomes high, transistor TG becomes ON. As a result, during the period from time t1 to time t2, the floating diffusion FD and the photoelectric conversion unit 11 are electrically connected to the power line to which the power supply voltage VDD is supplied.

[0093] During the period from time t1 to time t2, the charge in the floating diffusion FD and the photoelectric conversion unit 11 is discharged, and the voltages in the floating diffusion FD and the photoelectric conversion unit 11 are reset. Also, at time t2, the signals VRST and VTG become low levels. The photoelectric conversion unit 11 of the pixel P converts the incident light into electricity and stores the generated charge.

[0094] At time t3, signals VSEL and VRST both reach high levels. When signal VSEL reaches a high level, transistor SEL of pixel P turns on. Also, when signal VRST reaches a high level, transistor RST turns on. During the period from time t3 to time t4, the charge in the floating diffusion FD is discharged, and the voltage of the floating diffusion FD is reset.

[0095] During the period from time t4 to time t5 (i.e., the P-phase (Pre-charge phase) period after reset), a signal (referred to as signal Sp) corresponding to the voltage of the floating diffusion FD after reset is output to the signal line VSL by transistor AMP (and transistor SEL). Signal Sp is a signal indicating the reset level (reference level).

[0096] At time t5, the signal VFD2 becomes high level. As the voltage of signal VFD2 changes from a low level (voltage VL) to a high level (voltage VH = (VDD + α)), the potential of the floating diffusion FD temporarily increases due to capacitive coupling by capacitance C1. Also at time t5, the signal VTG becomes high level.

[0097] When the signal VTG reaches a high level, the transistor TG turns on, and the photoelectric conversion unit 11 and the floating diffusion FD are electrically connected. As a result, the charge that has been photoelectrically converted and stored in the photoelectric conversion unit 11 is transferred to the floating diffusion FD. In this case, the charge transfer is assisted by potential control by the signal VFD2, enabling efficient charge transfer.

[0098] At time t6, the signal VSEL becomes high, turning on the transistor SEL. Also at time t6, the signals VTG and VFD2 become low. The signal VFD2 transitions from high level (voltage VH) to low level (voltage VL).

[0099] During the period from time t7 to time t8 (i.e., the D phase (Data phase) period after charge has been transferred from the photoelectric conversion unit 11 to the floating diffusion FD), a signal corresponding to the voltage of the floating diffusion FD after charge transfer is output as signal Sd to the signal line VSL by the transistor AMP.

[0100] The signals Sp and Sd, sequentially read from each pixel P, are input to the signal processing unit 112 (see Figure 1) via the signal line VSL. The signal processing unit 112 (signal processing circuit) performs signal processing such as AD conversion on signals Sp and Sd. As an example, the signal processing unit 112 can perform CDS (correlated double sampling) processing, which subtracts signal Sp from signal Sd, and obtain the pixel signal after CDS processing.

[0101] Figure 8 is a timing chart showing another example of operation of the imaging device according to the embodiment. The operation example of the imaging device 1 will be further explained with reference to the timing chart in Figure 8. During the period from time t11 to time t15 shown in Figure 8, reset operations, signal Sp readout operations, etc., are performed, similar to the period from time t1 to time t5 shown in Figure 7.

[0102] The pixel control unit 105 may, as shown in the example in Figure 8, transition the signal VTG from a high level to a low level at time t16, and then transition the signal VFD2 from a high level to a low level at time t17. For example, after the signal VTG transitions from a high level to a low level and a predetermined time (e.g., several nssec) has elapsed, the signal VFD2 falls from a high level (VH) to a low level (VL).

[0103] By turning off transistor TG and then lowering the voltage of signal VFD2, charge transfer can be reliably completed, and it is possible to suppress the remaining signal charge in the photoelectric conversion unit 11. In addition, during the period from time t18 to time t19 shown in Figure 8, the signal Sd readout operation and other operations are performed in the same way as in the period from time t7 to time t8 shown in Figure 7.

[0104] Figures 9 to 11 are diagrams illustrating another configuration example of the imaging device according to the embodiment. As shown in the example in Figure 9, the wiring L2 may be provided adjacent to the wiring L1, which is an FD wiring, in the Z-axis direction. The wiring L2 may be arranged adjacent to the wiring L1 in the X-axis direction (or Y-axis direction), as shown in the example in Figure 10. The wiring L2 may be provided so as to sandwich at least a part of the wiring L1, as shown in the example in Figure 11.

[0105] Figures 12A and 12B are diagrams illustrating an example of the planar configuration of an imaging device according to an embodiment. For example, as shown in Figure 12A, wiring L2 is provided adjacent to wiring L1, which is FD wiring, in a plan view (i.e., when viewed in the XY plane). Alternatively, as shown in Figure 12B, wiring L2 may be provided sandwiching a part of wiring L1 in a plan view.

[0106] Figure 13 is a diagram illustrating another configuration example of the imaging device according to the embodiment. The wiring L2 may be provided so as to surround at least a part of the wiring L1. In the example shown in Figure 13, the wiring L2 is provided in the wiring layer 111 so as to surround the wiring L1 that is electrically connected to the semiconductor region 41. Note that the arrangement and shape of the wiring L2 are not limited to the illustrated example and can be changed as appropriate.

[0107] [Function and Effects] The light detection device according to this embodiment comprises a photoelectric conversion element (photoelectric conversion unit 11) that converts light into photoelectric energy, a floating diffusion (floating diffusion FD), a first transistor (transistor TG) capable of transferring the charge converted by the photoelectric conversion element to the floating diffusion, a first wiring (wiring L1) electrically connected to the floating diffusion, and a second wiring (wiring L2) provided around the first wiring and capable of transmitting a first voltage (for example, voltage VH).

[0108] The photodetector (imaging device 1) according to this embodiment includes a wiring L1 electrically connected to a floating diffusion FD, and a wiring L2 provided around the wiring L1 that can transmit a predetermined voltage (e.g., voltage VH). This makes it possible to realize a photodetector capable of improving charge transfer.

[0109] Next, modified examples of the present disclosure will be described. In the following, components similar to those in the above embodiments will be denoted by the same reference numerals, and their descriptions will be omitted as appropriate.

[0110] <2. Modifications> (2-1. Modification 1) In the embodiments described above, an example of the configuration of the imaging device was explained, but the configuration of the imaging device is not limited to the example described above. Figure 14 is a diagram illustrating an example of the configuration of an imaging device according to Modification 1 of the present disclosure. The imaging device 1 has, for example, a substrate 201 and a substrate 202, as shown in the example in Figure 14.

[0111] The imaging device 1, as an example, has a configuration in which a substrate 201 as a first layer (first tier) and a substrate 202 as a second layer (second tier) are stacked in the Z-axis direction. The substrate 202 is made of a semiconductor substrate such as a Si substrate or an SOI substrate. However, the substrate 202 may be made of other semiconductor materials.

[0112] In the example shown in Figure 14, substrate 201 has a semiconductor layer 101 and a wiring layer 111. Substrate 202 has a semiconductor layer 102 and a wiring layer 121. For example, the semiconductor layer 101, wiring layer 111, semiconductor layer 102, and wiring layer 121 are arranged from the side where light is incident. Substrate 201 (first layer) can also be called the first circuit layer. Substrate 202 (second layer) can also be called the second circuit layer.

[0113] The semiconductor layer 102 of the substrate 202 has opposing surfaces 12S1 and 12S2. Surface 12S2 is the surface opposite to surface 12S1. Surface 12S1 of the semiconductor layer 102 is an element formation surface on which elements such as transistors are formed. A gate electrode, a gate insulating film, etc., are provided on surface 12S1 of the semiconductor layer 102. The element formation surface of the semiconductor layer 102 is the surface on which various circuit elements are provided, and can also be called a circuit surface.

[0114] A wiring layer 111 is provided on the surface 11S1 side of the semiconductor layer 101. A wiring layer 121 is provided on the surface 12S1 side of the semiconductor layer 102. The wiring layer 111 is located on the surface 12S2 side of the semiconductor layer 102. On the surface 11S2 side of the semiconductor layer 101, at least one of a lens and a filter may be provided, for example.

[0115] The lens (lens unit) is an optical component also called an on-chip lens. The lens is provided above the photoelectric conversion unit 11, for example, for each pixel P or for each of several pixels P (i.e., for each predetermined number of pixels P). Light from the subject to be measured is incident on the lens, for example, through an optical system such as an imaging lens. The lens guides the incident light towards the photoelectric conversion unit 11 side of the pixel P.

[0116] The filters include primary color (RGB) filters, complementary color (CMY) filters, and filters that transmit infrared light. The filters are provided, for example, above the photoelectric conversion unit 11 for each pixel P or for each set of pixels P. As an example, the filters are formed between the lens and the semiconductor layer 101. For example, the photoelectric conversion unit 11 of a pixel P converts the light incident on it through the lens and filter into photoelectric energy.

[0117] The wiring layers 111 and 121 each include, for example, a conductive film and an insulating film, and have a plurality of wirings and a plurality of vias. Each of the wiring layers 111 and 121 has a configuration in which a plurality of wirings are laminated with an insulating film acting as an interlayer insulating film. Each of the wiring layers 111 and 121 is configured as a multilayer wiring layer and may include two or more or three or more layers of wiring.

[0118] As an example, substrates 201 and 202 are stacked so that their surfaces 11S1 and 12S2 face each other. That is, substrates 201 and 202 are joined so that the surface of semiconductor layer 101 and the back surface of semiconductor layer 102 face each other. Semiconductor layer 101 and semiconductor layer 102 are stacked so that the wiring layer 111 faces semiconductor layer 102.

[0119] In the imaging device 1, for example, each circuit element of the pixel P is provided on multiple substrates. As an example, as shown in Figure 14, among the multiple circuit elements of the pixel P, the photoelectric conversion unit 11, the transistor TG (transfer transistor), and the floating diffusion FD are provided on the substrate 201.

[0120] Among the multiple circuit elements of pixel P, transistors RST (reset transistor), AMP (amplifier transistor), and SEL (selection transistor) are provided on substrate 202. The circuits of substrate 201 and substrate 202 are electrically connected, for example, via through-electrodes provided to penetrate the semiconductor layer 102.

[0121] Furthermore, the substrate 202 is provided with, for example, at least some of the pixel control unit 105, signal processing unit 112, control unit 113, and processing unit 114 (see Figure 1) described above. The imaging device 1 may have a structure in which three or more substrates are stacked. The signal processing unit 112, control unit 113, and processing unit 114, etc., may be provided on a single substrate or may be provided on multiple substrates.

[0122] The wiring L2 is provided on the substrate 201, for example, as shown in the example in Figure 14. The wiring L2 is arranged around the wiring L1, which is an FD wiring, in the wiring layer 111 of the substrate 201. The capacitance C1 includes the wiring L1, the wiring L2, and the insulating film 20, and is formed in the wiring layer 111 as a wiring capacitance.

[0123] Furthermore, as shown in the example in Figure 15, the wiring L2 may be provided on the substrate 202. In the example shown in Figure 15, the wiring L2 is arranged around the wiring L1 in the wiring layer 121 of the substrate 202. The capacitance C1 has the wiring L1, the wiring L2, and the insulating film 20, and is formed in the wiring layer 121 as a wiring capacitance.

[0124] Furthermore, wiring L2 may be provided adjacent to wiring L1 in the Z-axis direction, or adjacent in the X-axis direction or the Y-axis direction. Also, for example, wiring L2 may be provided so as to sandwich at least a part of wiring L1. Wiring L2 may be provided so as to surround at least a part of wiring L1.

[0125] In the case of the imaging device 1 according to this modified example, the presence of wiring L2 allows for potential adjustment of the floating diffusion FD. This assists charge transfer by transistor TG and suppresses residual charge in the photoelectric conversion unit 11. This makes it possible to realize a photodetector (imaging device) capable of improving charge transfer.

[0126] The wiring L2 may be provided on both the substrate 201 and the substrate 202. The imaging device 1 may have, for example, the wiring L2 (wiring L2a) provided on the substrate 201 and the wiring L2 (wiring L2b) provided on the substrate 202, as shown in the example in Figure 16. The wiring L2a and the wiring L2b may be electrically connected to each other, for example, via through electrodes.

[0127] In the example shown in Figure 16, wiring L2a is provided around a portion of wiring L1, which is FD wiring, in wiring layer 111, and wiring L2b is provided around another portion of wiring L1 in wiring layer 121. The imaging device 1 has a capacitance C1 (capacity C1a) that includes a portion of wiring L1 and wiring L2a, and a capacitance C1 (capacity C1b) that includes the other portion of wiring L1 and wiring L2b.

[0128] Figure 17 is a diagram illustrating another configuration example of the imaging device according to Modification 1. The wiring layer 111 has a plurality of electrodes 81 (electrodes 81a and 81b in Figure 17), and the wiring layer 121 has a plurality of electrodes 82 (electrodes 82a and 82b in Figure 17). Electrodes 81 and 82 are electrodes formed using copper (Cu), for example.

[0129] Electrodes 81 and 82 are electrodes used for joining metal electrodes, and can also be called joining electrodes. Electrodes 81 and 82 may be made of metal materials other than copper (Cu), such as nickel (Ni), cobalt (Co), gold (Au), tin (Sn), etc., or may be made of other materials.

[0130] As an example, substrates 201 and 202 are bonded together by a bond between metal electrodes made of Cu (electrode 81, electrode 82), i.e., a Cu-Cu bond. In the imaging device 1, the circuit provided on substrate 201 and the circuit provided on substrate 202 are electrically connected via electrodes 81 and 82.

[0131] As an example, substrates 201 and 202 are stacked such that surfaces 11S1 and 12S1, on which elements such as transistors are formed by electrode bonding, face each other. That is, substrates 201 and 202 are bonded so that the surface of semiconductor layer 101 and the surface of semiconductor layer 102 face each other. Alternatively, substrates 201 and 202 may be stacked using bumps.

[0132] The imaging device 1 includes, for example, wiring L2a provided on substrate 201 and wiring L2b provided on substrate 202. The imaging device 1 may also have capacitors C1a and C1b. Wiring L2a and wiring L2b are electrically connected to each other, for example, via electrodes 81b and 82b. Note that the imaging device 1 may have only one of wiring L2a or wiring L2b.

[0133] (2-2. Modification 2) Figure 18 is a diagram showing an example of the pixel circuit configuration of the imaging device according to Modification 2. Figure 19 is a diagram showing an example of the cross-sectional configuration of the imaging device according to Modification 2. The readout circuit 15 of the imaging device 1 may be configured to change the conversion gain (i.e., conversion efficiency) when converting electric charge to voltage.

[0134] The readout circuit 15 may have a transistor FDG, as shown in Figure 18, and be configured to allow changing the conversion gain. The transistor FDG is a switching transistor and can be used to set the conversion gain. The transistor FDG is electrically connected, for example, between the floating diffusion FD and the transistor RST.

[0135] In the example shown in Figure 18, transistor FDG is configured to be electrically connectable to the floating diffusion FD and transistor RST. Transistor FDG is controlled, for example, by the signal VFDG to electrically connect or disconnect the floating diffusion FD and transistor RST. The pixel control unit 105 can control transistor FDG by supplying the signal VFDG to transistor FDG via the control line Lread.

[0136] In the readout circuit 15, when transistor FDG is turned ON, the capacitance added to the floating diffusion FD of pixel P increases, and the conversion gain (conversion efficiency) when converting charge to voltage is switched. Transistor FDG can change the conversion gain by switching the capacitance connected to the gate of transistor AMP.

[0137] The transistor FDG is provided on the surface 11S1 side of the semiconductor layer 101, for example, as shown in the example in Figure 19. The imaging device 1 may have a structure in which a plurality of substrates, for example, substrate 201 and substrate 202, are stacked. The transistor FDG may be provided on substrate 202. The transistor FDG may be electrically connected in series with the transistor RST, or electrically connected in parallel with the transistor RST.

[0138] Figure 20 shows another example of the pixel circuit configuration of the imaging device according to Modification 2. Transistor AMP and transistor RST may be electrically connected to different power lines. For example, as shown in the example in Figure 20, one of the source and drain of transistor AMP, for example the drain of transistor AMP, is electrically connected to the power line to which the power supply voltage VDD1 is supplied.

[0139] Furthermore, in the example shown in Figure 20, one of the sources and drains of transistor RST is electrically connected to the power line to which the power supply voltage VDD2 is supplied. With this configuration, the voltage supplied to transistor RST and the voltage supplied to transistor AMP can be controlled individually (independently).

[0140] Figures 21 and 22 show another example of the pixel circuit configuration of the imaging device according to Modification 2. The imaging device 1 may have a configuration in which multiple pixels P share one readout circuit 15. The readout circuit 15 is provided, for example, for multiple pixels P. In the imaging device 1, a readout circuit 15 is arranged for each of the multiple pixels P, and one readout circuit 15 may be shared by multiple pixels P.

[0141] As an example, as shown in Figure 21 or Figure 22, a readout circuit 15 is arranged for every two pixels P (referred to as pixel Pa and pixel Pb). Pixel Pa and pixel Pb share one readout circuit 15. For example, in the pixel section 100 of the imaging device 1, adjacent pixels Pa and Pb share one readout circuit 15.

[0142] In the example shown in Figure 21 or Figure 22, the transistors TG of pixel Pa and pixel Pb are controlled by different signals. The transistor TG1 of pixel Pa is controlled by the signal VTG1 and electrically connects or disconnects the photoelectric conversion unit 11a and the floating diffusion FD. The transistor TG1 can transfer the charge that has been photoelectrically converted and stored in the photoelectric conversion unit 11a to the floating diffusion FD.

[0143] Furthermore, the transistor TG2 of the pixel Pb is controlled by the signal VTG2 to electrically connect or disconnect the photoelectric conversion unit 11b and the floating diffusion FD. Transistor TG2 can transfer the charge that has been photoelectrically converted and stored in the photoelectric conversion unit 11b to the floating diffusion FD. The readout circuit 15 may also have a transistor FDG, as shown in the example in Figure 22.

[0144] The imaging device 1 may have a configuration in which four pixels P share one readout circuit 15. For example, a 2x2 pixel arrangement, composed of four adjacent pixels P, may share one readout circuit 15. Alternatively, the imaging device 1 may have a configuration in which five or more pixels P, for example eight pixels P, share one readout circuit 15.

[0145] <3. Examples of Application> The above-described imaging device 1 can be applied to any type of electronic device equipped with an imaging function, such as camera systems like digital still cameras and video cameras, or mobile phones with imaging capabilities. Figure 23 shows a schematic configuration of the electronic device 1000.

[0146] 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, all of which are interconnected via a bus line 1008.

[0147] The lens group 1001 captures incident light (image light) from the 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 it as a pixel signal to the DSP circuit 1002.

[0148] 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 holds the image data processed by the DSP circuit 1002 in frame units.

[0149] The display unit 1004 consists of, for example, a panel-type display device such as a liquid crystal panel or an organic EL (Electro Luminescence) panel, and records the video or still image data captured by the imaging device 1 onto a recording medium such as a semiconductor memory or a hard disk.

[0150] The operation unit 1006 outputs operation signals for various functions possessed by the electronic device 1000 in accordance with user operations. The power supply unit 1007 appropriately supplies various power sources to the DSP circuit 1002, frame memory 1003, display unit 1004, recording unit 1005, and operation unit 1006.

[0151] <4. Application Examples> (Application Examples to Mobile Devices) The technology relating to this disclosure (this technology) can be applied to various products. For example, the technology relating to this disclosure may be implemented as a device mounted on any type of mobile device such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, ships, and robots.

[0152] Figure 24 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology described herein may be applied.

[0153] The vehicle control system 12000 comprises a plurality of electronic control units connected via a communication network 12001. In the example shown in Figure 24, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. The functional configuration of the integrated control unit 12050 is shown in the figure, which includes a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface 12053.

[0154] The drivetrain control unit 12010 controls the operation of devices related to the vehicle's drivetrain according to various programs. For example, the drivetrain control unit 12010 functions as a control device for a drivetrain generating device that generates driving force for the vehicle, such as an internal combustion engine or a drive motor; a drivetrain transmission mechanism that transmits driving force to the wheels; a steering mechanism that adjusts the steering angle of the vehicle; and a braking device that generates braking force for the vehicle.

[0155] The body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window system, or various lamps such as headlights, reverse lights, brake lights, turn signals, or fog lights. In this case, the body system control unit 12020 may receive radio waves transmitted from a portable device that replaces a key or signals from various switches. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock system, power window system, lamps, etc.

[0156] The external information detection unit 12030 detects information from outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the external information detection unit 12030. The external information detection unit 12030 causes the imaging unit 12031 to capture images of the outside of the vehicle and receives the captured images. Based on the received images, the external information detection unit 12030 may perform object detection processing such as detecting people, cars, obstacles, signs, or characters on the road surface, or distance detection processing.

[0157] The imaging unit 12031 is a light 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.

[0158] The in-vehicle information detection unit 12040 detects information inside the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver status detection unit 12041 that detects the driver's state. The driver status detection unit 12041 includes, for example, a camera that captures images of the driver, and the in-vehicle information detection unit 12040 may calculate the driver's level of fatigue or concentration, or determine whether the driver is drowsy, based on the detection information input from the driver status detection unit 12041.

[0159] The microcomputer 12051 can calculate control target values ​​for the drive force generator, steering mechanism, or braking device based on information inside and outside the vehicle acquired by the external information detection unit 12030 or the internal 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 ADAS (Advanced Driver Assistance System) functions, including collision avoidance or impact mitigation, following driving based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

[0160] Furthermore, the microcomputer 12051 can perform cooperative control for purposes such as autonomous driving, where the vehicle drives autonomously without driver intervention, by controlling the drive force generating device, steering mechanism, or braking device, etc., based on information about the vehicle's surroundings acquired by the external information detection unit 12030 or the internal information detection unit 12040.

[0161] Furthermore, the microcomputer 12051 can output control commands to the body system control unit 12020 based on external information acquired by the external information detection unit 12030. For example, the microcomputer 12051 can control the headlights according to the position of a preceding or oncoming vehicle detected by the external information detection unit 12030, and perform coordinated control aimed at reducing glare, such as switching from high beams to low beams.

[0162] The audio-image output unit 12052 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying information to the vehicle's occupants or to those outside the vehicle. In the example shown in Figure 24, the output devices are exemplified as 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 onboard display and a head-up display.

[0163] Figure 25 shows an example of the installation position of the imaging unit 12031.

[0164] In Figure 25, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0165] The imaging units 12101, 12102, 12103, 12104, and 12105 are installed, for example, on the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle 12100. The imaging unit 12101 installed on the front nose and the imaging unit 12105 installed on the upper part of the windshield inside the vehicle mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 installed on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 installed on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 installed on the upper part of the windshield inside the vehicle is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, or lanes.

[0166] Figure 25 shows an example of the imaging range of imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of imaging unit 12101 located on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of imaging units 12102 and 12103 located on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of imaging unit 12104 located on the rear bumper or back door. For example, by superimposing the image data captured by imaging units 12101 to 12104, an overhead view image of the vehicle 12100 can be obtained.

[0167] At least one of the imaging units 12101 to 12104 may have a function for acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera consisting of multiple image sensors, or an image sensor having pixels for phase difference detection.

[0168] For example, the microcomputer 12051, based on distance information obtained from the imaging units 12101 to 12104, can determine the distance to each object within the imaging range 12111 to 12114 and the temporal change of this distance (relative speed to the vehicle 12100). In particular, it can extract the closest object on the vehicle 12100's path that is traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or more) as the preceding vehicle. Furthermore, the microcomputer 12051 can set a predetermined distance to be maintained before the preceding vehicle and perform automatic braking control (including follow-and-stop control) and automatic acceleration control (including follow-and-start control), etc. In this way, cooperative control aimed at autonomous driving, where the vehicle drives autonomously without driver intervention, can be performed.

[0169] For example, the microcomputer 12051 can use distance information obtained from imaging units 12101 to 12104 to classify and extract three-dimensional object data related to three-dimensional objects, such as motorcycles, passenger cars, large vehicles, pedestrians, utility poles, and other three-dimensional objects, and use this data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies 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 the collision risk, which indicates the degree of risk of collision with each obstacle. If the collision risk is above a set value and there is a possibility of collision, the microcomputer 12051 can provide driving assistance to avoid collisions by outputting a warning to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or evasive steering via the drive system control unit 12010.

[0170] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared light. For example, the microcomputer 12051 can recognize pedestrians by determining whether or not pedestrians are present in the images captured by the imaging units 12101 to 12104. Such pedestrian recognition is performed, for example, by a procedure to extract feature points from the images captured by the imaging units 12101 to 12104 as infrared cameras, and a procedure to perform pattern matching on a series of feature points that indicate the contour of an object to determine whether or not it is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the imaging units 12101 to 12104 and recognizes a pedestrian, the audio-image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio-image output unit 12052 may also control the display unit 12062 to display an icon indicating a pedestrian at a desired position.

[0171] The above describes an example of a mobile control system to which the technology described herein can be applied. The technology described herein can be applied to, for example, the imaging unit 12031 of the configuration described above. Specifically, for example, the imaging device 1 can be applied to the imaging unit 12031. By applying the technology described herein to the imaging unit 12031, it becomes possible to obtain high-definition captured images. This makes it possible to perform high-precision control using captured images in the mobile control system.

[0172] (Examples of application to endoscopic surgical systems) The technology described herein (the technology) can be applied to various products. For example, the technology described herein may be applied to endoscopic surgical systems.

[0173] Figure 26 is a diagram showing an example of a schematic configuration of an endoscopic surgical system to which the technology described herein (the technology) may be applied.

[0174] Figure 26 illustrates a surgeon (physician) 11131 performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgical system 11000. As shown in the figure, the endoscopic surgical system 11000 consists of an endoscope 11100, other surgical instruments 11110 such as an insufflation tube 11111 and an energy treatment device 11112, a support arm device 11120 for supporting the endoscope 11100, and a cart 11200 equipped with various devices for endoscopic surgery.

[0175] The endoscope 11100 consists of a barrel 11101, the tip of which is inserted into the body cavity of the patient 11132 for a predetermined length, and a camera head 11102 connected to the base end of the barrel 11101. In the illustrated example, the endoscope 11100 is shown as a so-called rigid endoscope having a rigid barrel 11101, but the endoscope 11100 may also be configured as a so-called flexible endoscope having a flexible barrel.

[0176] An opening into which an objective lens is fitted is provided at the tip of the microscope tube 11101. A light source device 11203 is connected to the endoscope 11100, and the light generated by the light source device 11203 is guided to the tip of the microscope tube by a light guide extending inside the microscope tube 11101, and is irradiated through the objective lens towards the object to be observed inside the body cavity of the patient 11132. The endoscope 11100 may be a straight-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0177] The camera head 11102 contains an optical system and an image sensor. Reflected light from the object being observed (observation light) is focused onto the image sensor by the optical system. The image sensor converts the observation light into electrical signals, generating an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. This image signal is transmitted as RAW data to the camera control unit (CCU) 11201.

[0178] The CCU 11201 is composed of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and other components, and comprehensively controls the operation 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 image processing operations on that image signal, such as development processing (demosaic processing), to display the image based on that image signal.

[0179] The display device 11202 displays an image based on an image signal that has been processed by the CCU 11201, under control from the CCU 11201.

[0180] The light source device 11203 consists of a light source such as an LED (Light Emitting Diode) and supplies illumination light to the endoscope 11100 when photographing the surgical area, etc.

[0181] The input device 11204 is an input interface for the endoscopic surgical system 11000. The user can input various types of information and instructions to the endoscopic surgical system 11000 via the input device 11204. For example, the user can input instructions to change the imaging conditions (type of light, magnification, focal length, etc.) of the endoscope 11100.

[0182] The treatment instrument control device 11205 controls the drive of the energy treatment instrument 11112 for purposes such as tissue cauterization, incision, or blood vessel sealing. The insufflation device 11206 injects gas into the body cavity of the patient 11132 via the insufflation tube 11111 to inflate the body cavity for the purpose of securing a field of view by the endoscope 11100 and securing the operator's workspace. The recorder 11207 is a device capable of recording various information related to the surgery. The printer 11208 is a device capable of printing various information related to the surgery in various formats such as text, images, or graphs.

[0183] The light source device 11203 that supplies illumination light to the endoscope 11100 when photographing the surgical area can be configured as a white light source consisting of, for example, an LED, a laser light source, or a combination thereof. When the white light source is configured as a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, so the white balance of the captured image can be adjusted in the light source device 11203. In this case, it is also possible to capture images corresponding to each of the RGB colors in time-division by irradiating the observation target with laser light from each of the RGB laser light sources in time-division and controlling the drive of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, a color image can be obtained without providing a color filter on the image sensor.

[0184] Furthermore, the light source device 11203 may be controlled to change the intensity of the light it outputs at predetermined time intervals. By controlling the drive of the image sensor of the camera head 11102 in synchronization with the timing of the change in light intensity, images can be acquired in time-division order, and these images can be combined to generate high dynamic range images without so-called black crushing and white clipping.

[0185] Furthermore, the light source device 11203 may be configured to supply light in a predetermined wavelength band corresponding to special light observation. In special light observation, for example, by utilizing the wavelength dependence of light absorption in body tissue and irradiating with narrow-band light compared to the irradiation light used in normal observation (i.e., white light), so-called narrow-band imaging is performed to image predetermined tissues such as blood vessels on the surface of mucosa with high contrast. Alternatively, in special light observation, fluorescence observation may be performed to obtain an image from fluorescence generated by irradiation with excitation light. In fluorescence observation, excitation light is irradiated onto body tissue and fluorescence from the body tissue is observed (autofluorescence observation), or a reagent such as indocyanine green (ICG) is injected into body tissue and excitation light corresponding to the fluorescence wavelength of the reagent is irradiated onto the body tissue to obtain a fluorescence image. The light source device 11203 may be configured to supply narrow-band light and / or excitation light corresponding to such special light observation.

[0186] Figure 27 is a block diagram showing an example of the functional configuration of the camera head 11102 and CCU 11201 shown in Figure 26.

[0187] The camera head 11102 includes 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 includes 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.

[0188] The lens unit 11401 is an optical system provided at the connection point 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 then incident on the lens unit 11401. The lens unit 11401 is composed of a combination of multiple lenses, including a zoom lens and a focus lens.

[0189] The imaging unit 11402 is composed of image sensors. The imaging unit 11402 may consist of one image sensor (a so-called single-chip type) or multiple image sensors (a so-called multi-chip type). If the imaging unit 11402 is composed of multiple chips, for example, each image sensor may generate image signals corresponding to RGB, and these may be combined to obtain a color image. Alternatively, the imaging unit 11402 may be configured to have a pair of image sensors for acquiring image signals for the right eye and left eye, respectively, corresponding to 3D (Dimensional) display. By performing 3D display, the surgeon 11131 can more accurately grasp the depth of the biological tissue in the surgical area. In addition, if the imaging unit 11402 is composed of multiple chips, multiple lens units 11401 may also be provided corresponding to each image sensor.

[0190] Furthermore, the imaging unit 11402 does not necessarily have to be located on the camera head 11102. For example, the imaging unit 11402 may be located inside the lens barrel 11101, directly behind the objective lens.

[0191] The drive unit 11403 is composed of actuators and, under control from the camera head control unit 11405, moves the zoom lens and focus lens of the lens unit 11401 along the optical axis by a predetermined distance. This allows the magnification and focus of the image captured by the imaging unit 11402 to be adjusted as appropriate.

[0192] The communication unit 11404 is composed of communication devices for sending and receiving various types of information with the CCU 11201. The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 as RAW data to the CCU 11201 via the transmission cable 11400.

[0193] Furthermore, the communication unit 11404 receives a control signal from the CCU 11201 to control the drive of the camera head 11102 and supplies it to the camera head control unit 11405. The control signal includes information about imaging conditions, such as information to specify the frame rate of the captured image, information to specify the exposure value at the time of imaging, and / or information to specify the magnification and focus of the captured image.

[0194] The imaging conditions such as frame rate, exposure value, magnification, and focus may be specified by the user as appropriate, or they 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 will be equipped with so-called AE (Auto Exposure), AF (Auto Focus), and AWB (Auto White Balance) functions.

[0195] The camera head control unit 11405 controls the drive of the camera head 11102 based on the control signal received from the CCU 11201 via the communication unit 11404.

[0196] The communication unit 11411 is comprised of a communication device for sending and receiving various types of information with the camera head 11102. The communication unit 11411 receives image signals transmitted from the camera head 11102 via the transmission cable 11400.

[0197] Furthermore, the communication unit 11411 transmits control signals to the camera head 11102 to control the driving of the camera head 11102. Image signals and control signals can be transmitted by telecommunications, optical communications, etc.

[0198] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102.

[0199] The control unit 11413 performs various controls related to imaging the surgical area, etc., by the endoscope 11100, and the display of the images obtained from imaging the surgical area, etc. For example, the control unit 11413 generates a control signal to control the driving of the camera head 11102.

[0200] Furthermore, the control unit 11413 displays the captured image showing the surgical area, etc., on the display device 11202 based on the image signal processed by the image processing unit 11412. At this time, the control unit 11413 may recognize various objects in the captured image using various image recognition technologies. For example, the control unit 11413 can recognize surgical instruments such as forceps, specific biological sites, bleeding, mist when using the energy treatment device 11112, etc., by detecting the shape and color of the edges of objects included in the captured image. When the control unit 11413 displays the captured image on the display device 11202, it may use the recognition results to superimpose various surgical support information onto the image of the surgical area. 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.

[0201] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable compatible with electrical signal communication, an optical fiber compatible with optical communication, or a composite cable thereof.

[0202] In the illustrated example, communication was performed via a wired connection using a transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may be performed wirelessly.

[0203] The above describes an example of an endoscopic surgical system to which the technology described herein may be applied. The technology described herein can be suitably applied, for example, to the imaging unit 11402 provided on the camera head 11102 of the endoscope 11100. By applying the technology described herein to the imaging unit 11402, it becomes possible to provide a high-definition endoscope 11100.

[0204] Although the present disclosure has been described above with reference to embodiments, modifications, application examples, and application examples, the present technology is not limited to the above embodiments, and various modifications are possible. For example, although the above modifications were described as modifications of the above embodiments, the configurations of each modification can be combined as appropriate.

[0205] In the embodiments described above, an imaging device was used as an example; however, the light detection device of this disclosure may be any device that receives incident light and converts the light into an electric charge. The output signal may be an image information signal or a distance measurement information signal. The light detection device (imaging device) can be applied to an image sensor, a distance measurement sensor, etc. Furthermore, this disclosure is not limited to back-illuminated image sensors, but is also applicable to front-illuminated image sensors.

[0206] The light detection device relating to this disclosure can also be used as a distance measuring sensor capable of measuring distance using the Time of Flight (TOF) method. The light detection device (imaging device) can also be used as a sensor capable of detecting events, for example, an event-driven sensor (also known as an EVS (Event Vision Sensor), EDS (Event Driven Sensor), DVS (Dynamic Vision Sensor), etc.).

[0207] One embodiment of the photodetector in this disclosure comprises a photoelectric conversion element that converts light into photoelectric energy, a floating diffusion element, a first transistor capable of transferring the charge converted by the photoelectric conversion element to the floating diffusion element, a first wiring electrically connected to the floating diffusion element, and a second wiring provided around the first wiring and capable of transmitting a first voltage. This makes it possible to realize a photodetector capable of improving charge transfer.

[0208] The effects described herein are merely illustrative and not limited to those described herein; other effects may also exist. Furthermore, this disclosure may also take the following configurations: (1) A photodetector comprising: a photoelectric conversion element for photoelectric conversion of light; a floating diffusion; a first transistor capable of transferring the charge converted by the photoelectric conversion element to the floating diffusion; a first wiring electrically connected to the floating diffusion; and a second wiring provided around the first wiring and capable of transmitting a first voltage. (2) The photodetector according to (1), wherein the second wiring is provided around the first wiring so as to face the first wiring. (3) The photodetector according to (1) or (2), having a capacitance including at least a portion of the second wiring and at least a portion of the first wiring. (4) The photodetector according to (3), wherein the second wiring is capable of supplying a voltage corresponding to the first voltage to the floating diffusion via the capacitance. (5) The photodetector according to (3) or (4), wherein the capacitance includes an insulating film provided between the first wiring and the second wiring, and the second wiring is provided along the first wiring via the insulating film. (6) The photodetector according to any one of (1) to (5), further comprising a semiconductor layer including the photoelectric conversion element and the floating diffusion, and a wiring layer including the first wiring and the second wiring, wherein the wiring layer has an insulating film provided between the first wiring and the second wiring, and the first wiring and the second wiring are laminated with the insulating film in between. (7) The photodetector according to any one of (1) to (6), wherein the second wiring is provided so as to surround at least a portion of the first wiring. (8) The photodetector according to any one of (1) to (7), further comprising a second transistor capable of outputting a first signal based on the charge accumulated in the floating diffusion.(9) The photodetector according to any one of (1) to (8), further comprising a third transistor capable of resetting the voltage of the floating diffusion, wherein the third transistor is electrically connected to a power line to which a second voltage is supplied, and the second wiring is capable of transmitting the first voltage which is different from the second voltage. (10) The photodetector according to (9), wherein the second wiring is capable of transmitting the first voltage which is higher than the second voltage. (11) The photodetector according to any one of (1) to (10), further comprising an insulating film provided between the first wiring and the second wiring, wherein the thickness of the insulating film is 0.1 nm or more and 20 nm or less. (12) The photodetector according to any one of (1) to (11), further comprising: a first layer having the photoelectric conversion element, the floating diffusion, and the first transistor; a second layer stacked with the first layer and having a second transistor capable of outputting a first signal based on the charge accumulated in the floating diffusion, wherein the second wiring is provided around the first wiring in the first layer. (13) The photodetector according to any one of (1) to (12), further comprising: a first layer having the photoelectric conversion element, the floating diffusion, and the first transistor; a second layer stacked with the first layer and having a second transistor capable of outputting a first signal based on the charge accumulated in the floating diffusion, wherein the second wiring is provided around the first wiring in the second layer.(14) The photodetector according to any one of (1) to (13), further comprising: a first layer having the photoelectric conversion element, the floating diffusion, and the first transistor; a second layer stacked with the first layer and having a second transistor capable of outputting a first signal based on the charge accumulated in the floating diffusion; and a third wiring capable of transmitting the first voltage, wherein the floating diffusion is electrically connected to the gate of the second transistor in the second layer via the first wiring, the second wiring is provided around the first wiring in the first layer, and the third wiring is provided around the first wiring in the second layer. (15) The photodetector according to any one of (1) to (14), further comprising a control circuit capable of controlling the voltage supplied to the second wiring. (16) The photodetector according to any one of (1) to (15), further comprising a control circuit, wherein the control circuit is capable of applying the first voltage to the second wiring and performing control to transfer charge from the photoelectric conversion element to the floating diffusion. (17) The photodetector according to (16), further comprising a third transistor capable of resetting the voltage of the floating diffusion, wherein the third transistor is electrically connected to a power line to which a second voltage is applied, and the control circuit is capable of applying the first voltage higher than the second voltage to the second wiring and performing control to transfer charge from the photoelectric conversion element to the floating diffusion. (18) The photodetector according to any one of (1) to (17), wherein the second wiring is capable of transmitting a third voltage lower than the first voltage. (19) The photodetector according to (18), further comprising a control circuit, wherein the control circuit is capable of performing control to supply a first voltage to the second wiring when the first transistor is ON, and to supply a third voltage to the second wiring after the first transistor is turned OFF.(20) Electronic device comprising an optical system and a photodetector that receives light transmitted through the optical system, wherein the photodetector comprises a photoelectric conversion element that converts light into photoelectric energy, a floating diffusion, a first transistor capable of transferring the charge converted by the photoelectric conversion element to the floating diffusion, a first wiring electrically connected to the floating diffusion, and a second wiring provided around the first wiring and capable of transmitting a first voltage.

[0209] This application claims priority based on Japanese Patent Application No. 2024-221079, filed with the Japan Patent Office on 17 December 2024, and all contents of that application are incorporated herein by reference.

[0210] Those skilled in the art will understand that various modifications, combinations, subcombinations, and changes can be conceived depending on design requirements and other factors, and that these fall within the scope of the attached claims and their equivalents.

Claims

1. A photodetector comprising: a photoelectric conversion element for converting light into photoelectric energy; a floating diffusion element; a first transistor capable of transferring the charge converted by the photoelectric conversion element to the floating diffusion element; a first wiring electrically connected to the floating diffusion element; and a second wiring provided around the first wiring and capable of transmitting a first voltage.

2. The photodetector according to claim 1, wherein the second wiring is provided around the first wiring so as to face the first wiring.

3. The photodetector according to claim 1, having a capacitance that includes at least a portion of the second wiring and at least a portion of the first wiring.

4. The photodetector according to claim 3, wherein the second wiring is capable of supplying a voltage corresponding to the first voltage to the floating diffusion via the capacitance.

5. The photodetector according to claim 3, wherein the capacitance includes an insulating film provided between the first wiring and the second wiring, and the second wiring is provided along the first wiring via the insulating film.

6. The photodetector according to claim 1, further comprising a semiconductor layer including the photoelectric conversion element and the floating diffusion, and a wiring layer including the first wiring and the second wiring, wherein the wiring layer has an insulating film provided between the first wiring and the second wiring, and the first wiring and the second wiring are laminated with the insulating film in between.

7. The photodetector according to claim 1, wherein the second wiring is provided so as to surround at least a portion of the first wiring.

8. The photodetector according to claim 1, further comprising a second transistor capable of outputting a first signal based on the charge accumulated in the floating diffusion.

9. The photodetector according to claim 1, further comprising a third transistor capable of resetting the voltage of the floating diffusion, wherein the third transistor is electrically connected to a power line to which a second voltage is supplied, and the second wiring is capable of transmitting the first voltage which is different from the second voltage.

10. The photodetector according to claim 9, wherein the second wiring is capable of transmitting the first voltage which is higher than the second voltage.

11. The photodetector according to claim 1, further comprising an insulating film provided between the first wiring and the second wiring, wherein the thickness of the insulating film is 0.1 nm or more and 20 nm or less.

12. The photodetector according to claim 1, further comprising: a first layer having the photoelectric conversion element, the floating diffusion, and the first transistor; and a second layer stacked with the first layer, having a second transistor capable of outputting a first signal based on the charge accumulated in the floating diffusion, wherein the second wiring is provided around the first wiring in the first layer.

13. The photodetector according to claim 1, further comprising: a first layer having the photoelectric conversion element, the floating diffusion, and the first transistor; and a second layer stacked with the first layer, having a second transistor capable of outputting a first signal based on the charge accumulated in the floating diffusion, wherein the second wiring is provided around the first wiring in the second layer.

14. The photodetector according to claim 1, further comprising: a first layer having the photoelectric conversion element, the floating diffusion, and the first transistor; a second layer stacked with the first layer and having a second transistor capable of outputting a first signal based on the charge accumulated in the floating diffusion; and a third wiring capable of transmitting the first voltage, wherein the floating diffusion is electrically connected to the gate of the second transistor in the second layer via the first wiring, the second wiring is provided around the first wiring in the first layer, and the third wiring is provided around the first wiring in the second layer.

15. The photodetector according to claim 1, further comprising a control circuit capable of controlling the voltage supplied to the second wiring.

16. The photodetector according to claim 1, further comprising a control circuit, wherein the control circuit is capable of applying the first voltage to the second wiring and performing control to transfer charge from the photoelectric conversion element to the floating diffusion.

17. The photodetector according to claim 16, further comprising a third transistor capable of resetting the voltage of the floating diffusion, wherein the third transistor is electrically connected to a power line to which a second voltage is supplied, and the control circuit is capable of supplying the first voltage, which is higher than the second voltage, to the second wiring, and of performing control to transfer charge from the photoelectric conversion element to the floating diffusion.

18. The photodetector according to claim 1, wherein the second wiring is capable of transmitting a third voltage lower than the first voltage.

19. The photodetector according to claim 18, further comprising a control circuit, wherein the control circuit is capable of performing control to supply a first voltage to the second wiring when the first transistor is ON, and to supply a third voltage to the second wiring after the first transistor is turned OFF.

20. An electronic device comprising an optical system and a photodetector that receives light transmitted through the optical system, wherein the photodetector comprises a photoelectric conversion element that converts light into photoelectric energy, a floating diffusion, a first transistor capable of transferring the charge converted by the photoelectric conversion element to the floating diffusion, a first wiring electrically connected to the floating diffusion, and a second wiring provided around the first wiring and capable of transmitting a first voltage.

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