Patent Application
20240290809
The present disclosure relates to a solid-state image sensor and a manufacturing method thereof, and an electronic device, and particularly, to a solid-state image sensor configured to be capable of suppressing dark currents in a solid-state image sensor including a compound semiconductor and a manufacturing method thereof, and an electronic device.
Conventionally, solid-state image sensors including compound semiconductors, such as InGaAs, as photoelectric conversion layers have been known (for example, see Patent Literature 1). In such solid-state image sensors, P-type diffusion regions including P-type impurities, such as Zn (zinc), dispersed therein are formed for each pixel as pixel electrodes for reading out signal discharges generated in a photoelectric conversion portion.
However, there is a concern about the deterioration of dark currents due to the strong electric field generated by the P-type diffusion regions as pixel electrodes.
The present disclosure has been made in view of such circumstances and is intended to suppress dark currents in the solid-state image sensors including compound semiconductors.
A solid-state image sensor of the first aspect of the present disclosure includes a photoelectric conversion layer containing a compound semiconductor, pixel electrodes that take out electric charges generated in the photoelectric conversion layer for each pixel, and a pixel separation portion disposed between the pixel electrodes of each pixel.
A method for manufacturing a solid-state image sensor of the second aspect of the present disclosure includes forming a pixel separation portion at a pixel boundary between a light incidence surface and an opposite surface of a photoelectric conversion layer containing a compound semiconductor, and forming a pixel electrode that take out an electric charge generated in the photoelectric conversion layer for each pixel inside the pixel separation portion.
An electronic device of the third aspect of the present disclosure includes a solid-state image sensor that includes a photoelectric conversion layer containing a compound semiconductor, pixel electrodes that take out electric charges generated in the photoelectric conversion layer for each pixel, and a pixel separation portion disposed between the pixel electrodes of each pixel.
In the first and third aspects of the present disclosure, a photoelectric conversion layer containing a compound semiconductor, pixel electrodes that take out electric charges generated in the photoelectric conversion layer for each pixel, and a pixel separation portion disposed between the pixel electrodes of each pixel is disposed.
In the second aspect of the present disclosure, a pixel separation portion is formed at a pixel boundary between a light incidence surface and an opposite surface of a photoelectric conversion layer containing a compound semiconductor, and pixel electrodes that take out an electric charge generated in the photoelectric conversion layer for each pixel is formed inside the pixel separation portion.
The solid-state image sensor and electronic device may be independent devices or may be modules incorporated into other devices.
Modes for embodying the technique of the present disclosure (hereinafter referred to as embodiments) will be described below with reference to the accompanying drawings. Description will be given in the following order.
In the drawings referred to in the following description, the same or similar portions will be denoted by the same or similar reference signs, and redundant descriptions will be omitted. The drawings are schematic, and relationships between thicknesses and plan view dimensions, ratios of thicknesses of respective layers, and the like differ from the actual ones. In addition, drawings may include portions where dimensional relationships and ratios differ between the drawings in some cases.
In addition, it is to be understood that definitions of directions, such as upward and downward, in the following description are merely definitions provided for the sake of brevity and are not intended to limit the technical ideas of the present disclosure. For example, when an object is observed after being rotated by 90 degrees, up-down is converted into and interpreted as left-right, and when an object is observed after being rotated by 180 degrees, up-down is interpreted as being inverted.
The pixel array region 1 is configured so that pixels Px are disposed two-dimensionally in a matrix, and the pixel array region 1 illustrated in
The pixel array region 1 is configured by laminating a sensor substrate 10 and a circuit board 30. The dash-dotted line of
The sensor substrate 10 is a substrate that photoelectrically converts light incident on the upper surface (the surface opposite to the circuit board 30 side) of
The sensor substrate 10 has a semiconductor layer 11. For example, the semiconductor layer 11 is configured by laminating, from the circuit board 30 side, a pixel electrode (a pixel electrode layer) 12, a photoelectric conversion layer 13, and a barrier layer 14.
The pixel electrode 12 is a semiconductor layer that functions as a lower electrode (a first electrode) of the two electrodes that sandwich the photoelectric conversion layer 13 above and below and is for reading out the signal charges generated in the photoelectric conversion layer 13 for each pixel Px to the circuit board 30. The upper surface, which is one surface of the pixel electrode 12, is connected to the photoelectric conversion layer 13, and the lower surface, which is the other surface on the opposite side, is connected to the contact electrode 17. The pixel electrode 12 is formed by a diffused region of a P-type impurity formed by diffusing a P-type impurity, such as Zn (zinc), in the same compound semiconductor material as the photoelectric conversion layer 13 or a compound semiconductor material with a larger band gap. As the same compound as the photoelectric conversion layer 13, for example, InGaAs (indium gallium arsenide) or the like may be used as will be described later. For example, as a compound semiconductor material with a larger band gap than the compound semiconductor material of the photoelectric conversion layer 13, InP (indium phosphide) may be used.
The impurity concentration of the pixel electrode 12 formed in the P-type diffusion region is formed so as to gradually decrease from the contact electrode 17 side toward the photoelectric conversion layer 13 side. For example, the impurity concentration of the pixel electrode 12 has a high concentration region 21 with a first concentration (P++) that is the highest concentration, a middle concentration region 22 with a second concentration (P+) that is lower than the first concentration, and a low concentration region 23 with a third concentration (P−) that is lower than the second concentration from the side closer to the contact electrode 17. For example, the thickness of the pixel electrode 12 is about 100 nm to 500 nm.
At the pixel boundary portion of the same layer as the pixel electrodes 12, a pixel separation portion 24 is formed, and the pixel electrodes 12 are electrically separated for each pixel Px. Although illustration is omitted, when the pixel array region 1 is viewed in plan view, the pixel separation portion 24 is formed in a grid pattern and disposed to surround rectangular pixel regions. This enables the signal charges generated in the photoelectric conversion layer 13 to be read out for each pixel. The pixel separation portion 24 may be formed by a metal film, such as titanium (Ti), tungsten (W), or titanium nitride (TiN), or an oxide film, such as silicon oxide (SiO2).
The photoelectric conversion layer 13 is a layer that absorbs light with a predetermined wavelength and generates signal charges and, for example, is constituted of a compound semiconductor material, such as a III-V semiconductor. As illustrated in
The barrier layer 14 is a semiconductor layer that is disposed to be connected to the upper electrode 15 on the light incidence surface side and prevents the backflow of signal charges generated by the photoelectric conversion layer 13, and, for example, is disposed on the entire surface of the pixel array region 1 in common to all pixels Px. The barrier layer 14 is disposed between and in contact with the photoelectric conversion layer 13 and the upper electrode 15. The barrier layer 14 is a region in which electric charges discharged from the upper electrode 15 move and, for example, is composed of a compound semiconductor containing an N-type impurity. For example, when holes are read out from the pixel electrode 12 as signal charges, electrons move into this barrier layer 14. For example, N-type InP (indium phosphide) may be used as the compound semiconductor material of the barrier layer 14. The thickness of the barrier layer 14 may be, for example, about 10 nm to 400 nm, and preferably 100 nm or less. By reducing the thickness of the barrier layer 14, the light absorbed by the barrier layer 14 is reduced, and the sensitivity of the photoelectric conversion layer 13 can be improved.
On the upper side (light incidence surface side) of the barrier layer 14, the upper electrode 15 is disposed, for example, as an electrode common to the pixels Px. The upper electrode 15 is the upper side electrode (second electrode) of the two electrodes that sandwich the photoelectric conversion layer 13 above and below. The upper electrode 15 discharges charges that are not used as signal charges among the charges generated in the photoelectric conversion layer 13 (cathode). For example, when holes are read out from the pixel electrode 12 as signal charges, electrons can be discharged through this upper electrode 15. For example, a predetermined bias voltage Va will be applied to this upper part electrode 15. The upper electrode 15 is composed of a conductive film that can transmit incident light, such as infrared light, and indium tin oxide (ITO) or ITiO (In2O3—TiO2) can be used, for example.
On the upper side of the upper electrode 15, a passivation film 16 is formed. Examples of materials used for the passivation film 16 include silicon nitride (SiN), hafnium oxide (HfO2), aluminum oxide (Al2O3), zirconium oxide (ZrO2), tantalum oxide (Ta2Ta5), titanium oxide (TiO2), and the like. The passivation film 16 also functions as an anti-reflection film.
On the circuit board 30 side of the semiconductor layer 11, a contact electrode 17 and a passivation film 18 are formed in the same layer. The contact electrode 17 is at least connected to the high concentration region 21 of the pixel electrode 12 on the upper surface on the semiconductor layer 11 side and connected to the pad electrode 19 on the lower surface on the circuit board 30 side. Similar to the passivation film 16 described above, the passivation film 18 is formed of silicon nitride (SiN), hafnium oxide (HfO2), aluminum oxide (Al2O3), zirconium oxide (ZrO2), tantalum oxide (Ta2Ta5), titanium oxide (TiO2), or the like. For example, the pad electrode 19 is formed of copper (Cu) in the interlayer insulation film 20. The pad electrode 19 is electrically connected to a pad electrode 32 of the circuit board 30 by metal joining, such as Cu—Cu joining. The interlayer insulation film 20 is also connected to the interlayer insulation film 34 on the circuit board 30 side by oxide film joining in a planar region other than the Cu—Cu joined region.
For example, the contact electrode 17 is made of a single material of any of titanium (Ti), tungsten (W), titanium nitride (TiN), platinum (Pt), gold (Au), germanium (Ge), palladium (Pd), zinc (Zn), nickel (Ni), or aluminum (Al), or an alloy containing at least one of them. The contact electrode 17 may be a single film of such constituent materials, or may be a laminated film in which two or more of the constituent materials are combined. For example, the contact electrode 17 is composed of a laminated film of titanium and tungsten.
For example, the interlayer insulation film 20 is composed of an inorganic insulation material. Examples of inorganic insulation materials include silicon nitride (SiN), aluminum oxide (Al2O3), silicon oxide (SiO2), hafnium oxide (HfO2), and the like.
For example, the circuit board 30 has a semiconductor substrate 31 made of a single crystal material, such as a single crystal silicon (Si). On the semiconductor substrate 31, a readout circuit of pixels Px, specifically, a capacitive element, a reset transistor, an amplification transistor, a selection transistor, and the like are formed. Details of the pixel circuit will be described later with reference to
On the sensor substrate 10 side of the semiconductor substrate 31, a pad electrode 32 and a contact electrode 33 electrically connecting the pad electrode 32 and the semiconductor substrate 31 are formed, and the layer from the joint surface to the semiconductor substrate 31 other than the pad electrode 32 and the pad electrode 32 are filled with an interlayer insulation film 34.
As the material of the contact electrode 33, the same type of materials for the contact electrode 17 described above may be used. However, the materials for the contact electrode 33 may differ from those for the contact electrode 17. For example, the interlayer insulation film 34 is composed of an inorganic insulation material. Examples of inorganic insulation materials include silicon nitride (SiN), aluminum oxide (Al2O3), silicon oxide (SiO2), hafnium oxide (HfO2), and the like.
The operation of the pixels Px will be described. For example, in the pixels Px, when light with wavelengths within the visible region and the infrared region is incident on the photoelectric conversion layer 13 through the passivation film 16 and upper part electrode 15, this light is photoelectrically converted in the photoelectric conversion layer 13. At this time, when a predetermined voltage is applied to, for example, the contact electrode 17, a potential gradient occurs in the photoelectric conversion layer 13, and either charge (e.g., a hole) of a pair of a hole and an electron generated by photoelectric conversion moves to the pixel electrode 12 as a signal charge and is collected from the pixel electrode 12 to the contact electrode 17. This signal charge moves to the pixel circuit of the semiconductor substrate 31 through the pad electrodes 19 and 32 and is read out for each pixel Px.
For example, each pixel Px in the pixel array region 1 with the above pixel structure receives light with wavelengths within the visible region and the short infrared region and outputs the obtained signal.
In pixels Px of the pixel array region 1, the P-type impurity concentration of the pixel electrode 12 formed so as to be separated for each pixel is formed so as to decrease step by step from the contact electrode 17 side toward the photoelectric conversion layer 13 side. This allows a gradual formation of the electric field at the pixel electrode 12, as illustrated in the potential diagram in
In the pixel Px, the pixel separation portion 24 is disposed at the pixel boundaries in the same layer as the pixel electrode 12 to electrically separate the pixel electrodes 12 for each pixel Px. This allows the electric characteristics for each pixel Px to be separated, and pixel separation can be improved.
As described below, in the P-type impurity diffusion step of the pixel electrode 12, the P-type impurity is diffused not only in the depth direction of the sensor substrate 10 (longitudinal direction in the figure) but also in the lateral direction. However, the placement of the pixel separation portion 24 at the pixel boundaries produces the effect of preventing excessive diffusion in the lateral direction and can prevent leakage to adjacent pixels.
A method of manufacturing the pixel Px of
At first, as illustrated as Ain
Next, as illustrated as B in
Next, as illustrated as C in
Next, as illustrated as D in
Then, as illustrated as E in
Next, as illustrated as F in
As described above, the semiconductor layer 11 of the sensor substrate 10 can be formed, and the impurity concentration of the pixel electrode 12 is formed so as to decrease step by step from the contact electrode 17 side toward the photoelectric conversion layer 13 side.
In the formation step of the pixel electrode 12, if it were tried to diffuse a P-type impurity thickly in the depth direction by heat diffusion, the P-type impurities are also widely diffused in the lateral direction. However, the diffusion in the lateral direction is prevented by the pixel separation portion 24. That is, the placement of the pixel separation portion 24 at the pixel boundaries can prevent excessive diffusion in the lateral direction and prevent leakage to adjacent pixels.
Furthermore, forming the pixel separation portion 24 to have a substantially T-shaped cross-sectional structure consisting of the pixel separation plane portion 24A and the pixel separation wall 24B improves the uniformity of the impurity concentration of the low concentration region 23 in the region opened at the pixel separation plane portion 24A and improves the flatness of the surface of the pixel electrode 12 in contact with the photoelectric conversion layer 13. This reduces the variation in the characteristics of dark currents.
In
The pixel array region 1 of the second embodiment illustrated in
The pixel Px has a configuration similar to that in the first embodiment. The pixel Px reads out the signal charges (e.g., holes) generated in the photoelectric conversion layer 13, passing through the pixel electrode 12, and collected by the contact electrode 17 and outputs the signal charges as pixel signals. In contrast, the pixel Py is a drain pixel that discharges the signal charges (e.g., holes) generated in the photoelectric conversion layer 13, passing through the pixel electrode 12, and collected by the contact electrode 17 as unnecessary charges without outputting them as pixel signals.
Comparing the pixel Py and pixel Px as drain pixels, a large pixel separation portion 24 is formed in the plane direction in the pixel Py, and, as a result, the plane region of the pixel electrode 12 is smaller than the pixel electrode 12 of the pixel Px. That is, the pixel Px differs from the pixel Py in the formed regions of the pixel electrode 12 and pixel separation portion 24 in the planar direction.
According to the pixel array region 1 of the second embodiment configured as above, a pixel separation portion 24 is provided as in the first embodiment, and the impurity concentration of the pixel electrode 12 is formed so as to gradually decrease from the contact electrode 17 side toward the photoelectric conversion layer 13 side. This allows the electric field of the pixel electrode 12 to be formed gently in the substrate depth direction, thereby suppressing dark currents. Furthermore, the pixel separation portion 24 improves pixel separation. Moreover, in the second embodiment, alternately arranging the pixel Py, which is a drain pixel that does not output pixel signals, and the pixel Px, which is a normal pixel that outputs pixel signals, decreases crosstalk.
The pixel array region 1 of the second embodiment may be manufactured by a similar method to that in the first embodiment explained in
Suppose a method for manufacturing a pixel array region in which pixels Py and pixels Px are arranged alternately if the pixel separation portion 24 is not formed. If the pixel separation portion 24 is not formed, two-time processing (diffusion step) is necessary because the plane regions of the pixel electrode 12 differ between the pixel Py and pixel Px, and it is necessary to form different opened regions and to differentiate the degree of diffusion between the pixel Py and pixel Px.
In contrast, in the pixel array region 1 of the second embodiment, by forming the pixel separation portion 24, the pixel separation portion 24 can block the diffusion of P-type impurities in the lateral direction. Thus, there is no need to worry about differences in the degree of diffusion of P-type impurities in the lateral direction, and only one-time processing (diffusion step) is needed. That is, the pixel array region 1 of the second embodiment can reduce the steps and also improve diffusion controllability in the process.
In the pixel Px and pixel Py described above, the pixel separation portion 24 is formed to have a substantially T-shaped cross-sectional structure consisting of the pixel separation plane portion 24A and the pixel separation wall 24B. However, the pixel separation portion 24 may be formed only by a pixel separation wall 24B in the depth direction (longitudinal direction) while omitting the pixel separation plane portion 24A spreading in the planar direction. The pixel separation wall 24B is formed such that the depth (height) thereof be the same as or deeper than the depth of the pixel electrode 12. The effect described above can also be exhibited in this case because the pixel electrode 12 of each pixel (pixel Px or pixel Py) can be separated.
In the pixel Px and pixel Py described above, only the passivation film 16 is formed on the upper side of the upper electrode 15, which is the side of a light incidence surface. Meanwhile, a color filter layer that transmits either R (red), G (green), or B (blue) light (wavelength light) may be installed in a predetermined array, such as a Bayer layout. Furthermore, an on-chip lens may be formed on the upper surface of the passivation film 16 or the color filter layer.
The solid-state image sensor 100 of
As a configuration of the pixel array region 103 in which a plurality of pixels 102 are two-dimensionally arranged in a matrix, the configuration of the pixel array region 1 according to the first embodiment illustrated in
The control circuit 108 receives input clocks and data instructing an operation mode and the like and outputs data such as internal information of the solid-state image sensor 100. In other words, in response to a vertical synchronizing signal, a horizontal synchronizing signal, and a master clock signal, the control circuit 108 generates clock signals or control signals to be used as a standard for operation by the vertical drive circuit 104, the column signal processing circuit 105, the horizontal drive circuit 106, and other elements. The control circuit 108 outputs the generated clock signals or control signals to the vertical drive circuit 104, the column signal processing circuit 105, the horizontal drive circuit 106, and other elements.
The vertical drive circuit 104 includes, for example, a shift register, and selects a prescribed pixel drive line 110 and supplies a pulse for driving the pixels 102 to the selected pixel drive line 110 to drive the pixels 102 on a row-basis. In other words, the vertical drive circuit 104 selectively scans pixels 102 in the pixel array region 103 on a row-basis in the vertical direction sequentially and supplies a pixel signal based on signal charges generated according to the amount of received light in the photoelectric conversion portion of the pixels 102 to the column signal processing circuits 105 through a vertical signal line 109.
One column signal processing circuit 105 is arranged for each column of the pixels 102 and performs signal processing such as noise cancellation on a signal outputted from the pixels 102 corresponding to one row for each column. For example, the column signal processing circuits 105 perform signal processing, such as correlated double sampling (CDS) for canceling out fixed pattern noise unique to the pixels and AD conversion.
The horizontal drive circuit 106 is configured by, for example, a shift register, and sequentially selects each of the column signal processing circuits 105 by sequentially outputting horizontal scan pulses and outputs pixel signals from each of the column signal processing circuits 105 to the horizontal signal line 111.
The output circuit 107 performs signal processing on signals sequentially supplied from each column signal processing circuit 105 through the horizontal signal line 111 and outputs the processed signals. For example, the output circuit 107 may perform only buffering in some cases or may perform black level adjustment, column variation compensation, and various kinds of digital signal processing in other cases. An input/output terminal 113 exchanges signals with the outside.
The solid-state image sensor 100 configured as above is a CMOS image sensor called a column AD type sensor, in which one column signal processing circuit 105 that performs CDS processing and AD conversion processing is arranged for each pixel column. Furthermore, the solid-state image sensor 100 with the configuration of the pixel array region 1 described above as the pixel array region 103 is, for example, a CMOS image sensor that outputs a captured image obtained by receiving light with wavelengths within the visible region and the short infrared region.
The solid-state image sensor 100 adopting the configuration of the pixel array region 1 described above suppresses dark currents in each pixel 102 and can create a high-quality captured image.
Each pixel 102 includes a photoelectric conversion portion 121, a capacitance element 122, a reset transistor 123, an amplification transistor 124, and a selection transistor 125.
For example, the photoelectric conversion portion 121 is composed of a compound semiconductor, such as InGaAs, and generates electric charges (signal charges) according to the amount of light received. A predetermined bias voltage Va is applied to the photoelectric conversion portion 121. For example, this photoelectric conversion portion 121 corresponds to the photoelectric conversion layer 13 of
The capacitance element 122 accumulates electric charges generated in the photoelectric conversion portion 121. The capacitance element 122 may be configured to include at least one of, for example, a PN junction capacitance, a MOS capacitance, or a wiring capacitance.
When the reset transistor 123 is turned on in response to a reset signal RST, the charges accumulated in the capacitance element 122 are discharged to a source (ground), thereby resetting the potential of the capacitance element 122.
The amplification transistor 124 outputs pixel signals according to the accumulated potential of the capacitance element 122. That is, the amplification transistor 124 constitutes a source follower circuit with a load MOS (not illustrated) as a constant current source connected via the vertical signal line 109, and pixel signals indicating a level according to the charges accumulated in the capacitance element 122 is outputted from the amplification transistor 124 to the column signal processing circuit 105 via the selection transistor 125.
The selection transistor 125 is turned on when a pixel 102 is selected in response to a selection signal SEL, and the pixel signal of the pixel 102 is outputted to the column signal processing circuit 105 via the vertical signal line 109. Each signal line through which the selection signal SEL, and reset signal RST are transmitted corresponds to the pixel drive line 110 in
The technique of the present disclosure (present technique) is not limited to an application to a solid-state image sensor. In other words, the present technique can be generally applied to electronic devices using solid-state image sensors in image-capturing portions (photoelectric conversion portions) such as image-capturing devices, including a digital still camera and a video camera, a mobile terminal device with an image-capturing function, and a copy machine having a solid-state image sensor in an image reading unit. The solid-state image sensor may be formed as a one-chip or may be formed as a module in which an image-capturing unit and a signal processing unit or an optical system are collectively packaged and which has an image-capturing function.
An image-capturing device 200 of
The optical unit 201 captures incident light (image light) from a subject and forms an image on an image-capturing surface of the solid-state image sensor 202. The solid-state image sensor 202 converts an amount of incident light formed on the image-capturing surface by the optical unit 201 into electrical signals for each pixel and outputs the electrical signals as pixel signals. As this solid-state image sensor 202, a solid-state image sensor which has the configuration of the solid-state image sensor 100 of
The display unit 205 is constituted by a panel-type display device, such as a liquid crystal panel or an organic electro luminescence (EL) panel, and displays a moving image or a still image captured by the solid-state image sensor 202. The recording unit 206 records the moving image or the still image captured by the solid-state image sensor 202 on a recording medium, such as a hard disk or a semiconductor memory.
The operation unit 207 issues operation commands for various functions of the image-capturing device 200 on the basis of the operations of a user. The power source unit 208 appropriately supplies various power supplies serving as operation power supplies for the DSP circuit 203, the frame memory 204, the display unit 205, the recording unit 206, and the operation unit 207 to these supply targets.
As described above, using the solid-state image sensor 100 having the above-mentioned structure of the pixel array region 1 as the solid-state image sensor 202 can suppress dark currents and image quality deterioration, for example. Moreover, an increased S/N ratio and a high dynamic range can be achieved. Accordingly, high image quality can be achieved in the captured image in the image-capturing device 200, such as a video camera, a digital still camera, and further a camera module for a mobile device, including a mobile phone.
An image sensor including the above-mentioned solid-state image sensor 100 can be used in various cases for sensing light, such as visible light, infrared light, ultraviolet light, and X-ray, as will be described later.
The technique according to the present disclosure (the present technique) can be applied to various products. For example, the technique according to the present disclosure may be realized as a device equipped in any type of moving body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility device, an airplane, a drone, a ship, and a robot.
The vehicle control system 12000 includes a plurality of electronic control units connected thereto via a communication network 12001. In the example illustrated in
The drive system control unit 12010 controls the operation of an apparatus related to a drive system of a vehicle according to various programs. For example, the drive system control unit 12010 functions as a driving force generator for generating a driving force of a vehicle, such as an internal combustion engine or a driving motor, a driving force transmission mechanism for transmitting a driving force to wheels, a steering mechanism for adjusting a turning angle of a vehicle, and a control apparatus, such as a braking apparatus that generates a braking force of a vehicle.
The body system control unit 12020 controls the operation of various devices mounted in the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device of a keyless entry system, a smart key system, a power window device, or various lamps, such as a headlamp, a back lamp, a brake lamp, a turn signal, and a fog lamp. In this case, radio waves transmitted from a portable device that substitutes for a key or signals of various switches may be input to the body system control unit 12020. The body system control unit 12020 receives inputs of the radio waves or signals and controls a door lock device, a power window device, a lamp, and the like, of the vehicle.
The vehicle exterior information detection unit 12030 detects information on the outside of the vehicle having the vehicle control system 12000 mounted thereon. For example, an image-capturing unit 12031 is connected to the vehicle exterior information detection unit 12030. The vehicle exterior information detection unit 12030 causes the image-capturing unit 12031 to capture an image of the outside of the vehicle and receives the captured image. The vehicle exterior information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, and letters on the road on the basis of the received image.
The image-capturing unit 12031 is an optical sensor that receives light and outputs an electrical signal according to the amount of the received light. The image-capturing unit 12031 can also output the electrical signal as an image or ranging information. In addition, the light received by the image-capturing unit 12031 may be visible light or invisible light, such as infrared light.
The vehicle interior information detection unit 12040 detects information on the inside of the vehicle. For example, a driver's condition detection unit 12041 that detects a driver's condition is connected to the vehicle interior information detection unit 12040. The driver's condition detection unit 12041 includes, for example, a camera that captures an image of a driver, and the vehicle interior information detection unit 12040 may calculate the degree of fatigue or concentration of the driver or may determine whether or not the driver is dozing on the basis of detection information inputted from the driver's condition detection unit 12041.
The microcomputer 12051 can calculate a control target value of the driving force generation device, the steering mechanism, or the braking device on the basis of the information on the outside or the inside of the vehicle acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040 and output a control command to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control for the purpose of realizing functions of an advanced driver assistance system (ADAS) including collision avoidance or impact mitigation of a vehicle, following traveling based on inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane deviation warning, or the like.
Further, the microcomputer 12051 can perform cooperative control for the purpose of automated driving or the like, in which autonomous travel is performed without depending on the operations of the driver, by controlling the driving force generator, the steering mechanism, or the braking device and the like on the basis of information about the surroundings of the vehicle, the information being acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040.
In addition, the microcomputer 12051 can output a control command to the body system control unit 12020 on the basis of the information acquired by the vehicle exterior information detection unit 12030 outside the vehicle. For example, the microcomputer 12051 can perform cooperative control for the purpose of preventing glare, such as switching from a high beam to a low beam, by controlling the headlamp according to the position of a preceding vehicle or an oncoming vehicle detected by the vehicle exterior information detection unit 12030.
The sound/image output unit 12052 transmits an output signal of at least one of sound and an image to an output device capable of visually or audibly notifying a passenger or the outside of the vehicle of information. In the example of
In
The image-capturing units 12101, 12102, 12103, 12104, and 12105 are provided at positions such as a front nose, side-view mirrors, a rear bumper, a back door, and an upper portion of a windshield in a vehicle interior of the vehicle 12100, for example. The image-capturing unit 12101 provided on the front nose and the image-capturing unit 12105 provided in the upper portion of the windshield in the vehicle interior mainly acquire images of the front of the vehicle 12100. The image-capturing units 12102 and 12103 provided on the side-view mirrors mainly acquire images of a lateral side of the vehicle 12100. The image-capturing unit 12104 provided on the rear bumper or the back door mainly acquires images of the rear of the vehicle 12100. Front view images acquired by the image-capturing units 12101 and 12105 are mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, and the like.
At least one of the image-capturing units 12101 to 12104 may have a function for obtaining distance information. For example, at least one of the image-capturing units 12101 to 12104 may be a stereo camera constituted by a plurality of image sensors or may be an image-capturing element with pixels for phase difference detection.
For example, the microcomputer 12051 can extract, particularly, the closest three-dimensional object on a path along which the vehicle 12100 is traveling, which is a three-dimensional object traveling at a predetermined speed (for example, 0 km/h or higher) in the substantially same direction as the vehicle 12100, as a preceding vehicle by acquiring the distance to each of three-dimensional objects in the image-capturing ranges 12111 to 12114 and temporal change of this distance (a relative speed with respect to the vehicle 12100) on the basis of the distance information obtained from the image-capturing units 12101 to 12104. Furthermore, the microcomputer 12051 can set an inter-vehicle distance which should be secured in front of the vehicle in advance with respect to the preceding vehicle and can perform automated brake control (also including following stop control) or automated acceleration control (also including following start control). In this way, it is possible to perform cooperative control for the purpose of automated driving or the like in which a vehicle autonomously travels without depending on the operations of the driver.
For example, the microcomputer 12051 can classify and extract three-dimensional data regarding three-dimensional objects into two-wheeled vehicles, normal vehicles, large vehicles, pedestrians, and other three-dimensional objects such as electric poles based on distance information obtained from the image-capturing units 12101 to 12104 and can use the three-dimensional data to perform automated avoidance of obstacles. For example, the microcomputer 12051 differentiates the surrounding obstacles of the vehicle 12100 into obstacles that can be viewed by the driver of the vehicle 12100 and obstacles that are difficult to view. Then, the microcomputer 12051 determines a collision risk indicating the degree of risk of collision with each obstacle, and when the collision risk is equal to or higher than a set value and there is a possibility of collision, an alarm is outputted to the driver through the audio speaker 12061 or the display unit 12062, forced deceleration or avoidance steering is performed through the drive system control unit 12010, and thus it is possible to perform driving support for collision avoidance.
At least one of the image-capturing units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether a pedestrian exists in the captured image of the image-capturing units 12101 to 12104. Such pedestrian recognition is performed by, for example, a procedure in which feature points in the captured images of the image-capturing units 12101 to 12104 as infrared cameras are extracted and a procedure in which pattern-matching processing is performed on a series of feature points indicating an outline of an object to determine whether or not the object is a pedestrian. When the microcomputer 12051 determines that there is a pedestrian in the captured images of the image-capturing units 12101 to 12104 and the pedestrian is recognized, the sound/image output unit 12052 controls the display unit 12062 so that a rectangular outline for emphasis be superimposed and displayed with the recognized pedestrian. In addition, the sound/image output unit 12052 may control the display unit 12062 so that an icon indicating a pedestrian or the like can be displayed at a desired position.
An example of a vehicle control system to which the technique according to the present disclosure can be applied has been described above. The technique according to the present disclosure can be applied to the image-capturing unit 12031 among the configurations described above. Specifically, an image sensor (e.g., the solid-state image sensor 100) with a structure of the pixel array region 1 described above can be applied as the image-capturing unit 12031. By applying the technique according to the present disclosure to the image-capturing unit 12031, a clearer captured image can be obtained, or distance information can be obtained while compactizing the device. In addition, using the obtained captured images and distance information, driver's fatigue can be reduced and increase driver and vehicle safety.
The technique of the present disclosure can be applied not only to solid-state image sensors that detect the distribution of the incident light amount of light with wavelengths within the visible region and a short infrared region and capture an image but also to any solid-state image sensor that captures an image of the distribution of the incident amount of infrared rays, X rays, or particles, or, in a broad sense, any solid-state image sensor (physical quantity distribution detection device), such as a fingerprint detection sensor, that detects the distribution of pressures, electrostatic capacities, or other physical quantities and captures an image.
The embodiments of the present disclosure are not limited to the above-described embodiments, and various modifications can be made without departing from the essential spirit of the technique of the present disclosure.
In the examples described above, a case where the charges (signal charges) treated as signals in the photoelectric conversion layer 13 are holes is described. Nevertheless, the technique according to the present disclosure may be applied to a solid-state image sensor using electrons as signal charges. In this case, conductive types of the semiconductor layer 11, the semiconductor substrate 31, or the like are reversed, and the positive and negative of the bias voltage applied are reversed.
For example, a combination of all or part of the plurality of embodiments described above may be employed.
The advantageous effects described in the present specification are merely exemplary and are not limited, and other advantageous effects of those described in the present specification may be achieved.
The technique of the present disclosure can be configured as follows.
(1)
A solid-state image sensor, including:
The solid-state image sensor according to the above (1), wherein
The solid-state image sensor according to the above (1) or (2), wherein
The solid-state image sensor according to any one of the above (1) to (3), wherein
The solid-state image sensor according to any one of the above (1) to (4), wherein
The solid-state image sensor according to any one of the above (1) to (5), wherein
The solid-state image sensor according to any one of the above (1) to (6), including
The solid-state image sensor according to the above (7), wherein
The solid-state image sensor according to the above (7) or (8), wherein
A method for manufacturing a solid-state image sensor including:
An electronic device including a solid-state image sensor that includes:
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/027268 | 7/21/2021 | WO |
