Image sensor and electronic device

Abstract

The present disclosure provides an image sensor and an electronic device, by setting the image sensor to include a plurality of pixel groups arranged in an array in a substrate, each pixel group including at least two pixel subgroups, the at least two pixel subgroups arranged along a first direction, each pixel subgroup including at least three pixel units; a transfer transistor corresponding to each pixel unit, and the source of the transfer transistor connected to the pixel unit; a floating diffusion region corresponding to each pixel subgroup, and in the same pixel subgroup, the drain of the transfer transistor corresponding to each pixel unit connected to the floating diffusion region; a signal transmission group corresponding to each pixel group, and located between two adjacent pixel groups arranged along a second direction, the signal transmission group connected to the floating diffusion regions of two adjacent pixel subgroups arranged along the first direction. The present disclosure can effectively improve the area utilization and light sensing efficiency of the image sensor, help to reduce the size of the image sensor, and improve its performance.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor technology, and more particularly to an image sensor and electronic device. Background Technology

[0002] CMOS (Complementary Metal Oxide Semiconductor) image sensors typically include components such as pixel arrays, row drivers, column drivers, timing control logic, analog-to-digital converters, data bus output interfaces, and control interfaces, all integrated on the same silicon chip.

[0003] In related technologies, a CMOS image sensor has multiple pixel units arranged in an array within its pixel region, and these pixel units are isolated from each other by an isolation structure. Each pixel unit includes a photodiode and a CMOS pixel readout circuit; the photodiode is a key device for converting optical signals into electrical signals.

[0004] The low area utilization of the aforementioned pixel units is detrimental to the reduction in size and the improvement in performance of CMOS image sensors. Summary of the Invention

[0005] This disclosure provides an image sensor and electronic device that can effectively improve the area utilization and light-sensing efficiency of the image sensor, help reduce the size of the image sensor, and improve its performance.

[0006] In a first aspect, this disclosure provides an image sensor, comprising:

[0007] Multiple pixel groups are arranged in an array in a substrate, each pixel group includes at least two pixel subgroups, the at least two pixel subgroups are arranged along a first direction, and each pixel subgroup includes at least three pixel units;

[0008] Each transmission transistor is configured to correspond one-to-one with a pixel unit, and the source of the transmission transistor is connected to the pixel unit.

[0009] The floating diffusion region is set one-to-one with the pixel subgroup, and in the same pixel subgroup, the drain of the transmission transistor corresponding to each pixel unit is connected to the floating diffusion region.

[0010] The signal transmission group is configured in a one-to-one correspondence with the pixel group and is located between two adjacent pixel groups arranged along the second direction. The signal transmission group is connected to the floating diffusion area of ​​two adjacent pixel subgroups arranged along the first direction; the first direction and the second direction intersect.

[0011] Optionally, in the image sensor described above, the signal transmission group includes a variable capacitor, the first electrode of which is connected to the floating diffusion region of the corresponding pixel group.

[0012] In the image sensor described above, optionally, the signal transmission group includes a source follower, and the source follower and the variable capacitor are arranged at intervals along a first direction; the gate of the source follower is connected to the first terminal of the variable capacitor.

[0013] In the image sensor described above, optionally, the signal transmission group includes a reset transistor, which is located between the source follower and the variable capacitor along a first direction; the source of the reset transistor is connected to the floating diffusion region of the corresponding pixel group, the reset transistor and the source follower share a drain, and are connected to the voltage input terminal.

[0014] In the image sensor described above, optionally, the signal transmission group includes a selection transistor located on the side of the source follower away from the reset transistor; the drain of the selection transistor is connected to the source of the source follower, and the source of the selection transistor is connected to the voltage output terminal.

[0015] Optionally, the image sensor described above includes a first metal layer, a dielectric layer, and a second metal layer sequentially stacked on a substrate; the first electrode of the variable capacitor and the source electrode of the reset transistor are located in the substrate.

[0016] The second terminal of the variable capacitor, the gate of the source follower, the gate of the reset transistor, the gate of the select transistor, and the gate of the transmission transistor are all located in the first metal layer;

[0017] Interconnect structures are formed in the second metal layer, and multiple vias are provided in the dielectric layer. In the same pixel group, the interconnect structures are connected to the floating diffusion region, the first electrode of the variable capacitor, the source of the reset transistor, and the gate of the source follower through different vias.

[0018] In the image sensor described above, optionally, within the same pixel subgroup, each pixel unit absorbs a different color of light, and each pixel unit has the same cross-sectional area.

[0019] In the image sensor described above, optionally, in the same pixel group, pixel units of the same color are not adjacent, and each pixel unit of one color is surrounded by multiple pixel units of other colors.

[0020] In the image sensor described above, optionally, the cross-section of the pixel unit along the substrate is circular or regular polygonal.

[0021] In the image sensor described above, optionally, at least three pixel units in each pixel subgroup are arranged in a hexagonal close-packed pattern on the substrate, and the floating diffusion region is equidistant from each pixel unit.

[0022] In the image sensor described above, optionally, a pixel subgroup includes three pixel units, and the centers of the three pixel units are connected in sequence to form an equilateral triangle in the plane on the substrate surface, with the floating diffusion region located at the exact center of the equilateral triangle.

[0023] In the image sensor described above, optionally, a first doped region and a second doped region surrounding the periphery of the first doped region are provided in the substrate, the first doped region forming a pixel unit, and a heavily doped region is provided in the substrate between at least three closely packed pixel units, the heavily doped region forming a floating diffusion region.

[0024] The heavily doped region has the same ion doping type as the first doped region, and the ion doping concentration of the heavily doped region is greater than that of the first doped region.

[0025] Optionally, the image sensor described above may also include a row driving circuit, wherein the gates of the transmission transistors of the pixel group located in the same row are interconnected and connected to the row driving circuit.

[0026] Optionally, the image sensor described above may also include a column driving circuit, wherein the gates of the selection transistors of the pixel units located in the same column are interconnected and connected to the column driving circuit.

[0027] Secondly, this disclosure also provides an electronic device including the image sensor described above.

[0028] The image sensor and electronic device disclosed herein, by configuring the pixel group of the image sensor to include at least two pixel subgroups, and each pixel subgroup including at least three pixel units, allows the pixel units to receive optical signals and convert the optical signals into electrical signals, thereby realizing the photoelectric conversion of the image sensor. By setting transmission transistors and floating diffusion regions, the transmission transistors are configured one-to-one with the pixel units, and the transmission transistors control the electrical signal output of the pixel units; similarly, the floating diffusion regions are configured one-to-one with the pixel subgroups, and the floating diffusion regions control the electrical signal output of the pixel subgroups. Furthermore, by setting signal transmission groups that correspond one-to-one with the pixel groups, the signal transmission groups control the electrical signal output of the pixel groups. This effectively reduces the number and area occupied by signal transmission groups controlling the electrical signal transmission in the image sensor, improving the area utilization rate of the image sensor and contributing to its size reduction; simultaneously, it ensures the stability of the electrical signal transmission of the image sensor, improving its performance.

[0029] The structure of this disclosure, as well as its other inventive objectives and beneficial effects, will become more apparent from the description of the preferred embodiments taken in conjunction with the accompanying drawings. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the arrangement of photodiodes in an image sensor in related technologies;

[0032] Figure 2 This is a schematic diagram of the structure of the pixel subgroup and signal transmission group of the image sensor provided in the embodiments of this disclosure;

[0033] Figure 3 A schematic diagram showing the connection between the pixel group and the signal transmission group of an image sensor provided in an embodiment of this disclosure;

[0034] Figure 4 A schematic diagram showing the connection between the pixel subgroup and the signal transmission group of an image sensor provided in an embodiment of this disclosure;

[0035] Figure 5 This is a schematic diagram of the circuit connection of an image sensor provided in an embodiment of this disclosure;

[0036] Figure 6 This is a schematic diagram of the substrate structure of the image sensor provided in an embodiment of this disclosure;

[0037] Figure 7 This is a schematic diagram of the structure of a pixel group of an image sensor provided in an embodiment of the present disclosure;

[0038] Figure 8 This is a schematic diagram of the structure of a pixel subgroup of an image sensor provided in an embodiment of the present disclosure;

[0039] Figure 9 This is a schematic diagram showing the arrangement of pixel units in an image sensor provided in an embodiment of this disclosure;

[0040] Figure 10 A schematic diagram of another pixel group structure of the image sensor provided in an embodiment of this disclosure;

[0041] Figure 11 A schematic diagram of another pixel subgroup structure of the image sensor provided in this disclosure embodiment;

[0042] Figure 12 This is a schematic diagram of the structure of an image sensor provided in an embodiment of this disclosure;

[0043] Figure 13 This is a schematic diagram of the structure of an image sensor (lens not shown) provided in an embodiment of this disclosure.

[0044] Explanation of reference numerals in the attached figures:

[0045] 100, Substrate; 101, First doped region; 102, Second doped region; 103, Heavily doped region; 200, Pixel group; 201, Pixel subgroup; 202, Pixel unit; 202a, First pixel unit; 202b, Second pixel unit; 202c, Third pixel unit; 300, Transmission transistor; 400, Floating diffusion region; 500, Signal transmission group; 501, Variable capacitor; 502, Source follower; 503, Reset transistor; 504, Select transistor; 505, Interconnect structure; 506, Row driving circuit; 507, Column driving circuit; 600, Filter; 700, Lens; 1, Photodiode. Detailed Implementation

[0046] In the pixel region of a CMOS image sensor of related technology, multiple pixel units are formed in an array, and each pixel unit is isolated from the others by an isolation structure. Each pixel unit includes a photodiode and a CMOS pixel readout circuit; the photodiode is used to convert optical signals into electrical signals. Figure 1 This is a schematic diagram of the arrangement of photodiodes in an image sensor in related technologies, with reference to... Figure 1 As shown, the photodiode 1 in the related technology is usually arranged in a square close-packed form. Figure 1 The four photodiodes 1 enclosed by the dashed box can be divided into a photodiode unit. Within this unit, the distance between the centers of two adjacent photodiodes 1 is 'a', and the area occupied by one photodiode unit is 'a'. 2 The arrangement of photodiode 1 as described above results in it occupying a relatively large area.

[0047] Furthermore, in related technologies, the CMOS pixel readout circuit and photodiode are configured one-to-one, resulting in a relatively large space occupied by the CMOS pixel readout circuit. Therefore, the pixel unit area utilization rate of the aforementioned image sensor is low, limiting its performance. As the integration level of electronic devices gradually increases, the aforementioned image sensor cannot effectively meet the needs of electronic devices.

[0048] The image sensor and electronic device disclosed herein configure the pixel group of the image sensor to include at least two pixel subgroups, and each pixel subgroup includes at least three pixel units. This allows the pixel units to receive light signals and convert them into electrical signals, achieving photoelectric conversion of the image sensor. By configuring transmission transistors and floating diffusion regions, the transmission transistors are configured one-to-one with the pixel units, controlling the electrical signal output of the pixel units; similarly, the floating diffusion regions are configured one-to-one with the pixel subgroups, controlling the electrical signal output of the pixel subgroups. Furthermore, by configuring signal transmission groups one-to-one with the pixel groups, the signal transmission groups control the electrical signal output of the pixel groups. This effectively reduces the number of signal transmission groups controlling the electrical signal transmission in the image sensor and reduces its occupied area. Moreover, in this disclosure, the pixel units are arranged in a hexagonal close-packed configuration, and the cross-section of the pixel units along the substrate is circular or a regular polygon. This not only increases the pixel unit density but also reduces the occupied area of ​​the image sensor and improves its photosensitivity. Therefore, this disclosure can improve the area utilization of image sensors and help reduce their size; at the same time, it can ensure the stability of the electrical signal transmission of image sensors, improve their performance, and effectively meet the needs of highly integrated electronic devices.

[0049] To make the objectives, technical solutions, and advantages of this disclosure clearer, the technical solutions in the embodiments of this disclosure will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this disclosure. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this disclosure, and should not be construed as limiting this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure. The embodiments of this disclosure will be described in detail below with reference to the accompanying drawings.

[0050] Figure 2 This is a schematic diagram of the structure of the pixel subgroup and signal transmission group of the image sensor provided in the embodiments of this disclosure. Figure 3 This is a schematic diagram showing the connection between the pixel group and the signal transmission group of the image sensor provided in this embodiment of the disclosure. Figure 4 This is a schematic diagram showing the connection between the pixel subgroup and the signal transmission group of the image sensor provided in an embodiment of this disclosure. Figure 5 This is a schematic diagram of the circuit connection of an image sensor provided in an embodiment of this disclosure.

[0051] Reference Figures 2 to 5 As shown, this disclosure provides an image sensor, including:

[0052] Multiple pixel groups 200 are arranged in an array in the substrate 100. Each pixel group 200 includes at least two pixel subgroups 201, which are arranged along a first direction. Each pixel subgroup 201 includes at least three pixel units 202.

[0053] A transfer gate (TG) is provided in a one-to-one correspondence with a pixel unit 202, and the source of the transfer gate is connected to the pixel unit 202.

[0054] The floating diffusion region (FD) is set one-to-one with the pixel subgroup 201, and in the same pixel subgroup 201, the drain of the transmission transistor corresponding to each pixel unit 202 is connected to the floating diffusion region.

[0055] The signal transmission group 500 is configured in a one-to-one correspondence with the pixel group 200 and is located between two adjacent pixel groups 200 arranged along the second direction. The signal transmission group 500 is connected to the floating diffusion area of ​​two adjacent pixel subgroups 201 arranged along the first direction; the first direction and the second direction intersect.

[0056] It should be noted that the image sensor provided in this disclosure includes multiple pixel groups 200, which are arranged in an array on the substrate 100. That is, refer to... Figure 3 As shown, multiple pixel groups 200 are arranged in the substrate 100 along a first direction and a second direction. The first direction can be the direction shown by X in the figure, and the second direction can be the direction shown by Y in the figure. Pixel groups 200 arranged along the first direction can be adjacent to each other, and pixel groups 200 arranged along the second direction can be spaced apart. The gap between two adjacent pixel groups 200 arranged along the second direction can be used to arrange other components, including but not limited to the signal transmission group 500 mentioned above.

[0057] Each pixel group 200 includes at least two pixel subgroups 201, which are arranged along a first direction and can be adjacent to each other. Each pixel subgroup 201 includes at least three pixel units 202, which can also be arranged in an adjacent manner. This effectively reduces the area occupied by the pixel units 202.

[0058] It should be noted that "adjacent" in this disclosure only indicates the arrangement method and does not refer to surface contact. An isolation structure is also provided between each pair of adjacent pixel units 202 to electrically isolate them and prevent electrical interference. This isolation structure can be a back-side deep trench isolation (BDTI) located in the substrate 100.

[0059] The pixel unit 202 in this disclosure can be a photodiode (PD). The photodiode includes two doped structures with different doping types, and a PN junction can be formed between the two doped structures. When the image sensor acquires external ambient light, the light can be captured by the photodiode and undergo photoelectric conversion in the PN junction of the photodiode, thereby generating an electrical signal.

[0060] The image sensor also includes a transmission transistor, the source of which is connected to a pixel unit 202 in a one-to-one correspondence. The electrical signals generated by the pixel unit 202 can be output externally under the control of the transmission transistor. This one-to-one correspondence between the transmission transistor and the pixel unit 202 improves the controllability of the electrical signal output from the pixel unit 202.

[0061] The image sensor also includes a floating diffusion region and a signal transmission group 500. The floating diffusion region is located in the pixel subgroup 201 and is connected to the drain of the transmission transistor corresponding to each pixel unit 202 in the same pixel subgroup 201. In this way, the electrical signals generated by multiple pixel units 202 in the same pixel subgroup 201 can be collected in the floating diffusion region and then output to the outside through the floating diffusion region.

[0062] In this disclosure, the signal transmission group 500 is located between two adjacent pixel groups 200 arranged along the second direction. The signal transmission group 500 is connected to the floating diffusion region of each pixel subgroup 201 within the same pixel group 200. Electrical signals collected in the floating diffusion region can be output outwards under the control of the signal transmission group 500. In the above scheme, this disclosure divides the image sensor into pixel groups 200, pixel subgroups 201, and pixel units 202. The floating diffusion region collects and controls the electrical signals of the pixel subgroups 201, and the signal transmission group 500 collects and controls the electrical signals of the pixel groups 200. This effectively reduces the number of components controlling the output of electrical signals from the pixel units 202, improving the area utilization of the image sensor and ensuring its controllability.

[0063] Specifically, refer to Figures 2 to 5As shown, the signal transmission group 500 includes a variable capacitor (Dual Conversion Gain, abbreviated as DCG), the first terminal of which is connected to the floating diffusion region of the corresponding pixel group 200. This variable capacitor may include a high capacitor and a low capacitor. When the light incident on the image sensor is low, the amount of electrons in the electrical signal converted by the pixel unit 202 is low. In this case, the low capacitor of the variable capacitor applies a smaller capacitance to the floating diffusion region, allowing for a larger voltage fluctuation in the floating diffusion region, which is beneficial for reading the electrical signal from the floating diffusion region. However, when multiple transmission transistors are connected to the same floating diffusion region, the amount of electrons gathered in the floating diffusion region is larger. In this case, the high capacitor of the variable capacitor applies a larger capacitance to the floating diffusion region, ensuring a larger voltage change in the floating diffusion region to meet the needs of reading electrical signals with larger voltage spans. This ensures that the image sensor can complete photoelectric conversion even with high-intensity light.

[0064] The signal transmission group 500 also includes a source follower (SF) and a reset transistor (RST). The source follower and the variable capacitor are arranged at intervals along a first direction; the gate of the source follower is connected to the first terminal of the variable capacitor. The reset transistor is located midway between the source follower and the variable capacitor along the first direction; the source of the reset transistor is connected to the floating diffusion region of the corresponding pixel group 200, and the reset transistor shares a drain with the source follower and is connected to the voltage input terminal.

[0065] The arrangement of source followers and variable capacitors along a first direction, with the reset transistor positioned between them along the first direction, effectively improves the area utilization of the gap between adjacent pixel groups 200, preventing the signal transmission group 500 from occupying a large area. The gate of the source follower is connected to the floating diffusion region, and the source follower amplifies the electrical signal from the floating diffusion region. Upon receiving the reset signal RST, the reset transistor can electronically clear the floating diffusion region before the electrical signal is read, resetting it and preventing it from being in a biased state.

[0066] The signal transmission group 500 also includes a selector (SEL), which is located on the side of the source follower away from the reset transistor. The drain of the selector is connected to the source of the source follower, and the source of the selector is connected to the voltage output terminal. The selector is also located between two adjacent pixel groups 200, and is spaced apart from the aforementioned variable capacitor, source follower, and reset transistor along a first direction. The selector is controlled by the addressing signal SEL, which is used to address and control the electrical signal output of the pixel unit 202.

[0067] Reference Figure 3 and Figure 4 As shown, the image sensor includes a first metal layer, a dielectric layer, and a second metal layer sequentially stacked on a substrate 100; the first metal layer and the second metal layer are isolated by a dielectric layer located between them. The first electrode of the variable capacitor and the source electrode of the reset transistor are located in the substrate 100.

[0068] The second terminal of the variable capacitor, the gate of the source follower, the gate of the reset transistor, the gate of the select transistor, and the gate of the transfer transistor are all located in the first metal layer.

[0069] Interconnect structure 505 is formed in the second metal layer, and multiple vias are provided in the dielectric layer. In the same pixel group 200, interconnect structure 505 is connected to the floating diffusion region, the first electrode of the variable capacitor, the source of the reset transistor, and the gate of the source follower through different vias.

[0070] It should be noted that the source and drain of the reset transistor, as well as the source and drain of the source follower, are formed in the substrate 100. The source and drain of the reset transistor are located on opposite sides of the gate of the reset transistor in the orthogonal projection of the substrate 100, and the source and drain of the source follower are located on opposite sides of the gate of the source follower in the orthogonal projection of the substrate 100.

[0071] Figure 6 This is a schematic diagram of the substrate structure of the image sensor provided in an embodiment of this disclosure, with reference to... Figure 6 As shown, a first doped region 101 and a second doped region 102 surrounding the outer periphery of the first doped region 101 are provided in the substrate 100. The first doped region 101 and the second doped region 102 form a pixel unit 202. A heavily doped region 103 is provided in the substrate 100 between at least three closely packed pixel units 202. The heavily doped region 103 forms a floating diffusion region.

[0072] The heavily doped region 103 has the same ion doping type as the first doped region 101, and the ion doping concentration of the heavily doped region 103 is greater than that of the first doped region 101.

[0073] It should be noted that the first doped region 101 and the heavily doped region 103 can be N-type doped, and the ion doping concentration in the heavily doped region 103 is greater than that in the first doped region 101. The second doped region 102 can be P-type doped. The first doped region 101 forms the pixel unit 202, and a PN junction is formed between the first doped region 101 and the second doped region 102 for photoelectric conversion.

[0074] An active region of a transfer transistor is disposed between the floating diffusion region formed by the heavily doped region 103 and the pixel unit 202. The gate of the transfer transistor can control the output of electrical signals in the pixel unit 202 to the floating diffusion region. When the transfer transistor is turned on, electrons in the first doped region 101 will transfer to the heavily doped region 103. Figure 6 The middle arrow indicates the direction of electron flow when the transmission transistor is turned on.

[0075] The following describes the specific structure of pixel group 200 in the image sensor.

[0076] Figure 7 This is a schematic diagram of the structure of a pixel group of an image sensor provided in an embodiment of the present disclosure. Figure 8 This is a schematic diagram of the structure of a pixel subgroup of an image sensor provided in an embodiment of this disclosure. Figure 9 This is a schematic diagram of the pixel unit arrangement of an image sensor provided in an embodiment of this disclosure. Figure 10 This is a schematic diagram of another pixel group structure of the image sensor provided in an embodiment of this disclosure. Figure 11 This is a schematic diagram of another pixel subgroup structure of an image sensor provided in an embodiment of this disclosure.

[0077] Reference Figure 7 and Figure 8 As shown, within the same pixel subgroup 201, each pixel unit 202 absorbs a different color of light, and each pixel unit 202 has the same cross-sectional area. The same pixel subgroup 201 may include multiple pixel units 202. This disclosure uses an example of a pixel subgroup 201 comprising three pixel units 202, namely, a first pixel unit 202a, a second pixel unit 202b, and a third pixel unit 202c. The first pixel unit 202a can receive green light, the second pixel unit 202b can receive red light, and the third pixel unit 202c can receive blue light.

[0078] Each pixel unit 202 within the same pixel subgroup 201 absorbs light of a different color. When white light from the external environment enters the image sensor, it is processed by the image sensor's filter 600, which filters the white light into different colors. These different colors of light are then absorbed by the corresponding pixel units 202, completing the photoelectric conversion. This allows for effective photoelectric conversion of white light from the external environment, improving the photoelectric conversion efficiency.

[0079] Furthermore, the cross-sectional area of ​​each pixel unit 202 is equal, which ensures that the light incident amount of each pixel unit 202 is the same, so as to meet the relatively balanced photoelectric conversion among the pixel units 202 in the image sensor, and also facilitates the setting of the signal transmission group 500, reducing the fabrication difficulty of the image sensor.

[0080] Within the same pixel group 200, pixel units 202 of the same color are not adjacent, and each pixel unit 202 of one color is surrounded by multiple pixel units 202 of other colors. This ensures the rational arrangement of pixel units 202 that absorb different colors of light, guaranteeing that in the white light of the external environment, light of different colors can be absorbed and photoelectric conversion can be completed.

[0081] In this disclosure, the cross-sectional shape of the pixel unit 202 can be defined as follows: the cross-section of the pixel unit 202 along the substrate 100 is circular or a regular polygon. The cross-section along the substrate 100 can be understood as the shape of the pixel unit 202 being circular or a regular polygon in the cross-section along the surface direction of the substrate 100. (Refer to...) Figure 7 and Figure 8 As shown, the pixel unit 202 is circular in shape. Figure 10 and Figure 11 The pixel unit 202 shown is hexagonal in shape. Of course, in some embodiments, the pixel unit 202 may also be triangular or quadrilateral.

[0082] In this disclosure, reference is made to Figure 9 As shown, at least three pixel units 202 in each pixel subgroup 201 are arranged in a hexagonal close-packed pattern on the substrate 100, and the floating diffusion region is at the same distance from each pixel unit 202. Figure 9 The four pixel units 202 enclosed by the dashed line can form a combination of pixel units 202. In this combination of pixel units 202, the distance between the centers of two adjacent pixel units 202 is 'a', and the area of ​​the combination of pixel units 202 is √3 / 2a. 2 .and Figure 1 In contrast, the combination of pixel units 202 in this disclosure adopts a hexagonal close-packed form, which can effectively reduce the occupied area, thereby helping to improve the area utilization of the image sensor. Furthermore, in the field of memory technology, DRAM's 6F... 2 The capacitors in the architecture are also arranged in a hexagonal close-packed manner. Therefore, when the pixel unit is arranged in a hexagonal close-packed design, the manufacturing process of DRAM capacitors can be referenced. Combined with the DRAM process platform, the manufacturing of image sensors can be easily realized.

[0083] The floating diffusion region can be located at the junction of the three pixel units 202, and the floating diffusion region is equidistant from the center of each pixel unit 202. Specifically, in the plane on the surface of the substrate 100, the center lines connecting the three pixel units 202 form an equilateral triangle, and the floating diffusion region is located at the exact center of the equilateral triangle.

[0084] Combination Figure 2As shown, a single pixel unit 202 is a regular hexagon, and three pixel units 202 are arranged in a hexagonal close-packed configuration. The overlapping points of the endpoints of the three pixel units 202 are the junction points. This ensures that the movement paths of electrons from each pixel unit 202 to the floating diffusion region are approximately the same, guaranteeing the stability of electrical signal reception. Furthermore, it facilitates the placement of the transmission transistor in each pixel unit 202, reducing the fabrication complexity of the image sensor.

[0085] Combination Figure 7 and Figure 10 As shown, the image sensor of this disclosure also includes a row driving circuit 506 and a column driving circuit 507. The gates of the transmission transistors of pixel groups 200 located in the same row are interconnected and connected to the row driving circuit 506. The row driving circuit 506 can generate a row selection signal to control the transmission transistors of pixel units 202 located in a specific row to turn on or off. The gates of the selection transistors of pixel units 202 located in the same column are interconnected and connected to the column driving circuit 507. The column driving circuit 507 can generate an addressing signal to control the selection transistors of pixel units 202 located in a specific column to turn on or off. In this way, the electrical signal output of the pixel units 202 at the intersection of a specific row and a specific column can be controlled by the row driving circuit 506 and the column driving circuit 507.

[0086] Figure 12 This is a schematic diagram of the structure of the image sensor provided in an embodiment of this disclosure. Figure 13 This is a schematic diagram of the structure of an image sensor (lens not shown) provided in an embodiment of this disclosure.

[0087] Reference Figure 12 and Figure 13 As shown, the image sensor disclosed herein also includes a plurality of filters 600, which are disposed on the light-incident side of the pixel unit 202. Each filter 600 corresponds to one pixel unit 202 and has the same color. The filters 600 may be located on one side of the pixel group 200 along a third direction, which may be... Figure 12 and Figure 13 The direction indicated by Z in the middle.

[0088] The filter 600 is used to filter white light incident on the pixel unit 202, filtering the white light into light of a specific color. This specific color light can be absorbed by the pixel unit 202 corresponding to the filter 600 and undergo photoelectric conversion. For example, if the filter 600 is green, then the pixel unit 202 corresponding to the filter 600 can absorb green light.

[0089] The cross-sectional shape of the pixel unit 202 along the extension direction of the substrate 100 is the same as the shape of the corresponding filter 600. This ensures the shape compatibility between the pixel unit 202 and the filter 600, thereby ensuring that the light filtered by the filter 600 can be received by the pixel unit 202.

[0090] The image sensor disclosed herein also includes a plurality of lenses 700, which are located on the side of the filter 600 away from the pixel unit 202, with one lens 700 corresponding to one pixel unit 202. The cross-sectional shape of the pixel unit 202 along the extension direction of the substrate 100 is the same as the cross-sectional shape of the corresponding lens 700 along the extension direction of the substrate 100.

[0091] It should be noted that ambient light from the outside shines on the lens 700 from various angles, and the lens 700 converges the light. The converged light then shines on the filter 600, and after being filtered by the filter 600, it enters the substrate 100. Each pixel unit 202 converts the light signal into an electrical signal, and the electrical signal is output to the outside through the transmission transistor.

[0092] Secondly, embodiments of this disclosure also provide an electronic device including the image sensor described above. This electronic device may be a camera, video camera, or other imaging device that captures digital image data.

[0093] In the description of the embodiments of this disclosure, it should be understood that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection or an indirect connection through an intermediate medium, or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances. The terms "upper," "lower," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure. In the description of this disclosure, "a plurality of" means two or more, unless otherwise precisely specified.

[0094] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this disclosure described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit them. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this disclosure.

Claims

1. An image sensor, characterized in that, include: Multiple pixel groups are arranged in an array in a substrate, each pixel group includes at least two pixel subgroups, the at least two pixel subgroups are arranged along a first direction, and each pixel subgroup includes at least three pixel units; A transmission transistor is provided, corresponding to each pixel unit, and the source of the transmission transistor is connected to the pixel unit; A floating diffusion region is provided in a one-to-one correspondence with the pixel subgroup, and in the same pixel subgroup, the drain of the transmission transistor corresponding to each pixel unit is connected to the floating diffusion region; A signal transmission group is configured in one-to-one correspondence with the pixel group and is located between two adjacent pixel groups arranged along the second direction. The signal transmission group is connected to the floating diffusion region of two adjacent pixel subgroups arranged along the first direction. The first direction and the second direction intersect. The signal transmission group includes a variable capacitor, a source follower, and a reset transistor. The traces of the floating diffusion regions of two adjacent pixel subgroups converge and are connected to the first terminal of the same variable capacitor. The gate of the source follower is connected to the first terminal of the variable capacitor. The reset transistor shares a drain with the source follower and is connected to the voltage input terminal.

2. The image sensor according to claim 1, characterized in that, The source follower and the variable capacitor are arranged at intervals along the first direction.

3. The image sensor according to claim 2, characterized in that, The reset transistor is located midway between the source follower and the variable capacitor along the first direction; the source of the reset transistor is connected to the floating diffusion region corresponding to the pixel group.

4. The image sensor according to claim 3, characterized in that, The signal transmission group includes a selection transistor located on the side of the source follower away from the reset transistor; the drain of the selection transistor is connected to the source of the source follower, and the source of the selection transistor is connected to the voltage output terminal.

5. The image sensor according to claim 4, characterized in that, It includes a first metal layer, a dielectric layer, and a second metal layer sequentially stacked on the substrate; the first electrode of the variable capacitor and the source electrode of the reset transistor are located in the substrate; The second terminal of the variable capacitor, the gate of the source follower, the gate of the reset transistor, the gate of the select transistor, and the gate of the transmission transistor are all located in the first metal layer; An interconnect structure is formed in the second metal layer, and a plurality of vias are provided in the dielectric layer. In the same pixel group, the interconnect structure is connected to the floating diffusion region, the first terminal of the variable capacitor, the source of the reset transistor, and the gate of the source follower through different vias.

6. The image sensor according to any one of claims 1-5, characterized in that, Within the same subgroup of pixels, each pixel unit absorbs a different color of light, and each pixel unit has the same cross-sectional area.

7. The image sensor according to claim 6, characterized in that, Within the same pixel group, pixel units of the same color are not adjacent, and each pixel unit of one color is surrounded by a plurality of pixel units of the other colors.

8. The image sensor according to claim 6, characterized in that, The pixel unit has a circular or regular polygonal cross-section along the substrate.

9. The image sensor according to any one of claims 1-5, characterized in that, At least three pixel units in each pixel subgroup are arranged in a hexagonal close-packed configuration on the substrate, and the floating diffusion region is equidistant from each pixel unit.

10. The image sensor according to claim 9, characterized in that, A pixel subgroup includes three pixel units. In the plane on the substrate surface, the centers of the three pixel units are connected in sequence to form an equilateral triangle, and the floating diffusion region is located at the exact center of the equilateral triangle.

11. The image sensor according to any one of claims 1-5, characterized in that, The substrate has a first doped region and a second doped region surrounding the first doped region. The first doped region forms the pixel unit. The substrate between at least three closely packed pixel units has a heavily doped region, which forms the floating diffusion region. The heavily doped region has the same ion doping type as the first doped region, and the ion doping concentration of the heavily doped region is greater than that of the first doped region.

12. The image sensor according to any one of claims 1-5, characterized in that, It also includes a row driving circuit, wherein the gates of the transmission transistors of the pixel group located in the same row are interconnected and connected to the row driving circuit.

13. The image sensor according to any one of claims 4-5, characterized in that, It also includes a column driving circuit, wherein the gates of the selection transistors of the pixel units located in the same column are interconnected and connected to the column driving circuit.

14. An electronic device, characterized in that, The image sensor included in any one of claims 1-13.

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