Arrangement structure of four shared pixels and image sensor

Abstract

The present invention provides an arrangement structure and an image sensor of four shared pixels, wherein the arrangement structure includes first to fourth photosensitive elements, first to fourth transmission tubes, floating diffusion nodes, source follower tubes and first reset tubes; the first photosensitive element and the second photosensitive element and the third photosensitive element and the fourth photosensitive element are all symmetrically arranged along the first direction, and the first photosensitive element and the fourth photosensitive element and the second photosensitive element and the third photosensitive element are all symmetrically arranged along the second direction; each transmission tube is correspondingly arranged at the corners facing each photosensitive element and forms a built-in area; the floating diffusion node includes a first node area, which is arranged between the transmission tubes corresponding to any two symmetrical photosensitive elements in the built-in area; the source follower tube is arranged on the inner side of the first node area in the built-in area; and the first reset tube is arranged on the outer side of the first node area in the built-in area. The present invention solves the problem that the existing four-shared pixel design has a large parasitic capacitance due to the large length of the metal wire connected to the floating diffusion node.

Description

Technical Field

[0001] The present invention relates to the technical field of image sensors, and in particular to an arrangement structure of four shared pixels and an image sensor. Background Art

[0002] In the four-shared pixel design, the four transmission tubes M11'~M14' corresponding to the four photosensitive elements PD1'~PD4' share a floating diffusion node FD' and are arranged around the periphery of the floating diffusion node FD'. The source follower tube M2', the reset tube M3' and the row selection tube M4' are arranged outside the four transmission tubes M11'~M14' and are electrically connected through metal wires. Figure 1 As shown. In the above arrangement, the source follower tube M2' and the reset tube M3' need longer metal wires to be electrically connected to the floating diffusion node FD', especially for products with four shared large pixels (for example, >1.5μm). However, the longer metal wires greatly increase the parasitic capacitance of the floating diffusion node FD'. Since the conversion gain of the image sensor is negatively correlated with the parasitic capacitance of the floating diffusion node FD', the conversion gain of the image sensor is reduced, the signal read noise is deteriorated, and ultimately the imaging quality is affected.

[0003] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present invention and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are described in the background technology section of the present invention. Summary of the invention

[0004] In view of the shortcomings of the prior art described above, an object of the present invention is to provide a four-shared pixel arrangement structure and an image sensor, which are used to solve the problem in the existing four-shared pixel design that the parasitic capacitance of the floating diffusion node is large due to the large length of the metal line connected to the floating diffusion node, and ultimately leads to a small conversion gain of the image sensor.

[0005] To achieve the above objectives and other related objectives, the present invention provides an arrangement structure of four shared pixels, the arrangement structure comprising:

[0006] A first photosensitive element, a second photosensitive element, a third photosensitive element, a fourth photosensitive element, a first transmission tube, a second transmission tube, a third transmission tube, a fourth transmission tube, a floating diffusion node, a source follower tube and a first reset tube;

[0007] The first photosensitive element and the second photosensitive element, the third photosensitive element and the fourth photosensitive element are all symmetrically arranged along the first direction, and the first photosensitive element and the fourth photosensitive element, the second photosensitive element and the third photosensitive element are all symmetrically arranged along the second direction;

[0008] Each transmission tube is arranged at a corner facing each photosensitive element to form a built-in area; the floating diffusion node includes a first node area, which is arranged between the transmission tubes corresponding to any two symmetrical photosensitive elements in the built-in area; the source follower tube is arranged on the inner side of the first node area in the built-in area; and the first reset tube is arranged on the outer side of the first node area in the built-in area.

[0009] Optionally, the arrangement structure further includes a first gain tube, which is arranged between the first reset tube and the first node area, or arranged at the position of the first reset tube, while the first reset tube is arranged outside the built-in area and outside the first gain tube.

[0010] Optionally, when the arrangement structure does not include the first gain tube, the source of the first reset tube is made in the same layer as the first node area and the two are directly connected; when the arrangement structure includes the first gain tube, the source of the first gain tube is made in the same layer as the first node area and the two are directly connected; and / or, the floating diffusion node also includes a second node area and a third node area, which are respectively arranged on the side of the transmission tubes corresponding to the other two symmetrical photosensitive elements facing the source follower tube.

[0011] Optionally, the arrangement includes selecting a matching tube;

[0012] When the arrangement structure does not include the first gain tube, the selection matching tube is arranged in the built-in area and is symmetrically arranged with the first reset tube on both sides of the source follower tube;

[0013] When the arrangement structure includes a first gain tube and the first reset tube is arranged in the built-in area, the selection matching tube is arranged in the built-in area and is symmetrically arranged with the first reset tube or the first gain tube on both sides of the source follower tube;

[0014] When the arrangement structure includes a first gain tube and the first reset tube is arranged outside the built-in area, the selection matching tube is arranged in the built-in area and symmetrically arranged with the first gain tube on both sides of the source follower tube, or the selection matching tube is arranged outside the built-in area and symmetrically arranged with the first reset tube on both sides of the source follower tube;

[0015] Wherein, the selection matching tube includes a row selection tube or a first dummy tube.

[0016] Optionally, when the arrangement structure includes the first gain tube, the arrangement structure further includes a second dummy tube, which is symmetrically arranged on both sides of the source follower tube with respect to the first reset tube and the remaining one of the first gain tube.

[0017] Optionally, when the selection matching tube includes a row selection tube, the row selection tube is arranged adjacent to the source follower tube, wherein the source of the source follower tube and the drain of the row selection tube are made in the same layer and are directly connected.

[0018] Optionally, the floating diffusion node further includes a fourth node region, which is arranged between the transmission tubes corresponding to the other two symmetrical photosensitive elements;

[0019] When the arrangement structure does not include the first gain tube, the arrangement structure further includes a second reset tube, which is arranged outside the fourth node region in the built-in region and symmetrically arranged with the first reset tube on both sides of the source follower tube;

[0020] When the arrangement structure includes a first gain tube, the arrangement structure further includes a second gain tube, which is arranged outside the fourth node region in the built-in region and symmetrically arranged with the first gain tube on both sides of the source follower tube.

[0021] Optionally, when the arrangement structure does not include the first gain tube and the second gain tube, the source electrodes of the first reset tube and the second reset tube are manufactured on the same layer as the floating diffusion node, the source electrode of the first reset tube is directly connected to the first node region, and the source electrode of the second reset tube is directly connected to the fourth node region; when the arrangement structure includes the first gain tube and the second gain tube, the source electrodes of the first gain tube and the second gain tube are manufactured on the same layer as the floating diffusion node, the source electrode of the first gain tube is directly connected to the first node region, and the source electrode of the second gain tube is directly connected to the fourth node region.

[0022] Optionally, the arrangement structure further includes a row selection tube, which is arranged on a side of the source follower tube in the built-in area away from the corresponding node area.

[0023] Optionally, the arrangement structure further includes a third dummy tube, which is arranged in the built-in area and symmetrically arranged with the row selection tube on both sides of the source follower tube.

[0024] Optionally, the source of the source follower tube and the drain of the row select tube are manufactured in the same layer and are directly connected.

[0025] The present invention also provides an image sensor, which includes the arrangement structure of four shared pixels as described above.

[0026] As described above, the arrangement structure and image sensor of the four shared pixels of the present invention arrange at least the reset tube and the source follower tube or the gain tube and the source follower tube connected to the floating diffusion node in the built-in area surrounded by four transmission tubes to shorten the length of the metal wire electrically connecting the corresponding tube to the floating diffusion node, reduce the parasitic capacitance of the floating diffusion node, increase the conversion gain of the image sensor, and thus improve the imaging quality; the present invention avoids the use of metal wires by directly connecting the reset tube or the gain tube to the floating diffusion node, thereby further reducing the parasitic capacitance of the floating diffusion node. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Shown is a schematic diagram of an existing arrangement structure of four shared pixels.

[0028] Figure 2 Shown is a circuit diagram of four shared pixels in the first embodiment.

[0029] Figure 3 Display as Figure 2 A schematic diagram of an arrangement structure of four shared pixels is shown.

[0030] Figure 4 Display as Figure 2 Another schematic diagram of the arrangement structure of four shared pixels is shown.

[0031] Figure 5 Display as Figure 2 A schematic diagram of another arrangement structure of four shared pixels is shown.

[0032] Figure 6 Display as Figure 2 A schematic diagram of another arrangement structure of four shared pixels is shown.

[0033] Figure 7 It is a circuit diagram of four shared pixels in the second embodiment.

[0034] Figure 8 Display as Figure 7 A schematic diagram of an arrangement structure of four shared pixels is shown.

[0035] Fig. 9 Display as Figure 7 Another schematic diagram of the arrangement structure of four shared pixels is shown.

[0036] Fig.10 Shown is a circuit diagram of four shared pixels in the fourth embodiment.

[0037] Fig.11 Display as Fig.10 Schematic diagram of the arrangement structure of four shared pixels.

[0038] Fig.12Shown is another circuit schematic diagram of four shared pixels in the fourth embodiment.

[0039] Fig.13 Display as Fig.12 A schematic diagram of an arrangement structure of four shared pixels is shown.

[0040] Fig.14 Display as Fig.12 Another schematic diagram of the arrangement structure of four shared pixels is shown.

[0041] Fig.15 It is a circuit diagram of four shared pixels in the fifth embodiment.

[0042] Fig.16 Display as Fig.15 Schematic diagram of the arrangement structure of four shared pixels.

[0043] Fig.17 Shown is a circuit diagram of four shared pixels in Embodiment 6.

[0044] Fig.18 Display as Fig.17 A schematic diagram of an arrangement structure of four shared pixels is shown.

[0045] Fig.19 Display as Fig.17 Another schematic diagram of the arrangement structure of four shared pixels is shown.

[0046] Fig. 20 Shown is a circuit diagram of four shared pixels in Embodiment 7.

[0047] Fig.21 Display as Fig. 20 Schematic diagram of the arrangement structure of four shared pixels.

[0048] Fig. 22 Shown is another circuit diagram of four shared pixels in the seventh embodiment.

[0049] Fig.23 Display as Fig. 22 A schematic diagram of an arrangement structure of four shared pixels is shown.

[0050] Fig.24 Display as Fig. 22 Another schematic diagram of the arrangement structure of four shared pixels is shown.

[0051] Component number description: 100 four shared pixels, 110 built-in area. DETAILED DESCRIPTION

[0052] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0053] See also Figures 2 to 24 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the form, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated. Embodiment 1

[0054] like Figure 2 As shown, this embodiment provides a four-shared pixel 100, including a first photosensitive element PD1, a second photosensitive element PD2, a third photosensitive element PD3, a fourth photosensitive element PD4, a first transmission tube M11, a second transmission tube M12, a third transmission tube M13, a fourth transmission tube M14, a floating diffusion node FD, a source follower tube M2 and a first reset tube M31.

[0055] Among them, the gate of each transmission tube is respectively connected to the corresponding transmission control signal TX1~TX4, the drain of each transmission tube is connected to the floating diffusion node FD, the source of each transmission tube is correspondingly connected to the cathode of each photosensitive element, and the anode of each photosensitive element is connected to the reference ground; the gate of the source follower tube M2 is connected to the floating diffusion node FD, the drain of the source follower tube M2 is connected to the power supply voltage VDD, and the source of the source follower tube M2 is connected to the column line BL; the gate of the first reset tube M31 is connected to the reset control signal RST, the drain of the first reset tube M31 is connected to the power supply voltage VDD, and the source of the first reset tube M31 is connected to the floating diffusion node FD.

[0056] The arrangement structure obtained by arranging the above four shared pixels 100 is as follows: Figure 3~Figure 6 As shown, where:

[0057] The first photosensitive element PD1 and the second photosensitive element PD2 are symmetrically arranged along the first direction, the third photosensitive element PD3 and the fourth photosensitive element PD4 are symmetrically arranged along the first direction, the first photosensitive element PD1 and the fourth photosensitive element PD4 are symmetrically arranged along the second direction, and the second photosensitive element PD2 and the third photosensitive element PD3 are symmetrically arranged along the second direction; in one example, the first direction is the longitudinal axis direction, and the second direction is the transverse axis direction.

[0058] Each transmission tube is arranged at a corner facing each photosensitive element and forms a built-in area 110, as shown in the dotted line area in the figure. In fact, each transmission tube is arranged at a corresponding angle at a corner facing each photosensitive element; in one example, the angle of inclination of each transmission tube is the same, for example, the angle of inclination is 45 degrees. In the application, the spacing between adjacent transmission tubes is determined by the specific process node and the arrangement position of the corresponding tubes. Take the 65nm process node as an example:

[0059] If the first reset tube M31 and the like are arranged in the second direction of the built-in area 110, the spacing between the first transmission tube M11 and the second transmission tube M12 is the same as the spacing between the third transmission tube M13 and the fourth transmission tube M14, and the spacing is greater than or equal to 0.3 μm, the spacing between the first transmission tube M11 and the fourth transmission tube M14 is the same as the spacing between the second transmission tube M12 and the third transmission tube M13, and the spacing is greater than or equal to 0.4 μm, as Figure 3 and Figure 4 As shown;

[0060] If the first reset tube M31 and the like are arranged in the first direction of the built-in area 110, the spacing between the first transmission tube M11 and the second transmission tube M12 is the same as the spacing between the third transmission tube M13 and the fourth transmission tube M14, and the spacing is greater than or equal to 0.4 μm, the spacing between the first transmission tube M11 and the fourth transmission tube M14 is the same as the spacing between the second transmission tube M12 and the third transmission tube M13, and the spacing is greater than or equal to 0.3 μm, as Figure 5 and Figure 6 As shown;

[0061] If the first reset tube M31 and the like are partially arranged in the first direction of the built-in area 110 and partially arranged in the second direction of the built-in area 110, the spacing between the first transmission tube M11 and the second transmission tube M12 is the same as the spacing between the third transmission tube M13 and the fourth transmission tube M14 and the spacing is greater than or equal to 0.4 μm, and the spacing between the first transmission tube M11 and the fourth transmission tube M14 is the same as the spacing between the second transmission tube M12 and the third transmission tube M13 and the spacing is greater than or equal to 0.4 μm.

[0062] The floating diffusion node FD includes a first node area FD1, and further includes a second node area FD2 and a third node area FD3; wherein the first node area FD1 is arranged between the transmission tubes corresponding to any two symmetrical photosensitive elements in the built-in area 110, and the second node area FD2 and the third node area FD3 are respectively arranged on the side of the transmission tubes corresponding to the other two symmetrical photosensitive elements toward the source follower tube M2.

[0063] For example, Figure 3It is shown that the first node area FD1 is arranged between the first transmission tube M11 corresponding to the first photosensitive element PD1 and the fourth transmission tube M14 corresponding to the fourth photosensitive element PD4, the second node area FD2 is arranged on the side of the second transmission tube M12 corresponding to the second photosensitive element PD2 facing the source follower tube M2, and the third node area FD3 is arranged on the side of the third transmission tube M13 corresponding to the third photosensitive element PD3 facing the source follower tube M2;

[0064] Figure 4 It is shown that the first node area FD1 is arranged between the second transmission tube M12 corresponding to the second photosensitive element PD1 and the third transmission tube M13 corresponding to the third photosensitive element PD3, the second node area FD2 is arranged on the side of the first transmission tube M11 corresponding to the first photosensitive element PD1 facing the source follower tube M2, and the third node area FD3 is arranged on the side of the fourth transmission tube M14 corresponding to the fourth photosensitive element PD4 facing the source follower tube M2;

[0065] Figure 5 It is shown that the first node area FD1 is arranged between the first transmission tube M11 corresponding to the first photosensitive element PD1 and the second transmission tube M12 corresponding to the second photosensitive element PD2, the second node area FD2 is arranged on the side of the third transmission tube M13 corresponding to the third photosensitive element PD3 facing the source follower tube M2, and the third node area FD3 is arranged on the side of the fourth transmission tube M14 corresponding to the fourth photosensitive element PD4 facing the source follower tube M2;

[0066] Figure 6 It is shown that the first node area FD1 is arranged between the third transmission tube M13 corresponding to the third photosensitive element PD3 and the fourth transmission tube M14 corresponding to the fourth photosensitive element PD4, the second node area FD2 is arranged on the side of the first transmission tube M11 corresponding to the first photosensitive element PD1 toward the source follower tube M2, and the third node area FD3 is arranged on the side of the second transmission tube M12 corresponding to the second photosensitive element PD2 toward the source follower tube M2.

[0067] The source follower tube M2 is arranged inside the first node area FD1 in the built-in area 110; in one example, the source follower tube M2 is arranged at the center of the built-in area 110, that is, the center of the source follower tube M2 coincides with the center of the built-in area 110. In application, the source follower tube M2 should be as close to the first node area FD1 as possible, for example, the spacing between the source follower tube M2 and the first node area FD1 is less than or equal to 0.1 μm.

[0068] The first reset tube M31 is arranged outside the first node area FD1 in the built-in area 110; in one example, the center of the first reset tube M31 and the center of the source follower tube M2 are located on the same line, for example, the center of the first reset tube M31 and the center of the source follower tube M2 are located on the same horizontal line (such as Figure 3 and Figure 4Alternatively, the center of the first reset tube M31 and the center of the source follower tube M2 are located on the same vertical line (as shown in Figure 5 and Figure 6 In the application, the source of the first reset transistor M31 and the first node region FD1 are made in the same layer and the two are directly connected without using a metal wire.

[0069] In this embodiment, the source follower tube M2 is as close as possible to the first node region FD1, so that the metal wire connecting the gate of the source follower tube M2 to the first node region FD1 is as short as possible; the source of the first reset tube M31 is made in the same layer as the first node region FD1 and the two are directly connected without using metal wires; by using the shortest metal wires or even no metal wires to electrically connect the source follower tube M2, the first reset tube M31 and the floating diffusion node FD, the parasitic capacitance of the floating diffusion node FD can be reduced, the conversion gain of the image sensor can be increased, and the imaging quality can be improved. In addition, the electrical connection of other parts is mainly carried out through metal wires in the same layer or between different layers, which is well known to those skilled in the art and will not be described here one by one. Embodiment 2

[0070] like Figure 7 As shown, the present embodiment provides a four-shared pixel 100, which is different from the first embodiment in that the four-shared pixel 100 of the present embodiment further includes a first gain tube M41; wherein the first gain tube M41 is connected between the first reset tube M31 and the floating diffusion node FD, specifically, the gate of the first gain tube M41 is connected to the gain control signal DCG, the drain of the first gain tube M41 is connected to the source of the first reset tube M31, and the source of the first gain tube M41 is connected to the floating diffusion node FD. At this time, the source of the first reset tube M31 is no longer connected to the floating diffusion node FD.

[0071] The arrangement structure obtained by arranging the above four shared pixels 100 is as follows: Figure 8 As shown, where:

[0072] The arrangement of the first photosensitive element PD1, the second photosensitive element PD2, the third photosensitive element PD3, the fourth photosensitive element PD4, the first transmission tube M11, the second transmission tube M12, the third transmission tube M13, the fourth transmission tube M14, the floating diffusion node FD, the source follower tube M2 and the first reset tube M31 is the same as that in Example 1. For details, please refer to Example 1 and will not be repeated here.

[0073] The first gain tube M41 is arranged in the built-in area 110 and between the first reset tube M31 and the first node area FD1; in one example, the center of the first gain tube M41, the center of the first reset tube M31 and the center of the source follower tube M2 are located on the same line, for example, the center of the first gain tube M41, the center of the first reset tube M31 and the center of the source follower tube M2 are located on the same horizontal line or the same vertical line. In application, the source of the first gain tube M41 and the first node area FD1 are made in the same layer and the two are directly connected without using a metal wire to reduce the parasitic capacitance of the floating diffusion node FD. At this time, the source of the first reset tube M31 is no longer directly connected to the first node area FD1.

[0074] In this embodiment, the first reset tube M31 is connected to the floating diffusion node FD through the first gain tube M41, that is, the first reset tube M31 is no longer connected to the floating diffusion node FD, so the length of the metal wire connecting the first reset tube M31 to the first gain tube M41 does not affect the parasitic capacitance of the floating diffusion node FD, and without considering making the arrangement structure more compact, the first reset tube M31 can also be arranged outside the built-in area 110, for example, the first gain tube M41 is arranged at the position of the first reset tube M31, and the first reset tube M31 is arranged outside the built-in area 110 and arranged on the outside of the first gain tube M41, as shown in FIG. Fig. 9 shown. Embodiment 3

[0075] The four shared pixels 100 of this embodiment are the same as those of the first or second embodiment, and the difference lies in the arrangement structure; compared with the arrangement structure of the first or second embodiment, a selection matching tube is added to the arrangement structure of this embodiment, and the selection matching tube at this time is the first dummy tube D1.

[0076] According to the arrangement structure of the first embodiment, the first dummy tube D1 is arranged in the built-in area 110 and is symmetrically arranged with the first reset tube M31 on both sides of the source follower tube M2, so as to achieve symmetry of the optical performance of the four shared pixels 100, thereby improving the imaging quality of the four shared pixels 100. Figure 3~Figure 6 As shown; in one example, the center of the first dummy tube D1, the center of the first reset tube M31 and the center of the source follower tube M2 are located on the same line, for example, the center of the first dummy tube D1, the center of the first reset tube M31 and the center of the source follower tube M2 are located on the same horizontal line or the same vertical line.

[0077] According to the arrangement structure of the second embodiment, the first dummy tube D1 is arranged in the built-in area 110 and is symmetrically arranged with the first gain tube M41 on both sides of the source follower tube M2, as shown in FIG. Figure 8As shown, or, the first dummy tube D1 is arranged in the built-in area 110 and is symmetrically arranged with the first reset tube M31 on both sides of the source follower tube M2. Further, in order to achieve completely symmetrical optical performance, the arrangement structure can also be provided with a second dummy tube D2, wherein the second dummy tube D2 is arranged in the built-in area 110 and is symmetrically arranged with the first reset tube M31 and the remaining one of the first gain tube M41 on both sides of the source follower tube M2; for example, if the first dummy tube D1 is symmetrically arranged with the first gain tube M41, the second dummy tube D2 is symmetrically arranged with the first reset tube M31, and vice versa, if the first dummy tube D1 is symmetrically arranged with the first reset tube M31, the second dummy tube D2 is symmetrically arranged with the first gain tube M41. In one example, the center of the first dummy tube D1, the center of the first reset tube M31, the center of the first gain tube M41 and the center of the source follower tube M2 are located on the same line (for example, on the same horizontal line or the same vertical line). When the second dummy tube D2 is included, its center is also located on the same line with the centers of the above-mentioned tubes.

[0078] Of course, for the case where the first gain tube M41 is arranged at the position of the first reset tube M31 in the built-in area 110 and the first reset tube M31 is arranged outside the built-in area 110: the corresponding arrangement structure can also add a first dummy tube D1, or even add a second dummy tube D2; wherein the first dummy tube D1 can be arranged in the built-in area 110 and symmetrically arranged with the first gain tube M41 on both sides of the source follower tube M2 (such as Fig. 9 As shown), it can also be arranged outside the built-in area 110 and symmetrically arranged with the first reset tube M31 on both sides of the source follower tube M2, while the second dummy tube D2 is symmetrically arranged with the first reset tube M31 and the remaining one of the first gain tube M41 on both sides of the source follower tube M2. Embodiment 4

[0079] like Fig.10 and Fig.12 As shown, this embodiment provides a four-shared pixel 100, which is different from the first or second embodiment in that the four-shared pixel 100 of this embodiment also includes a selection matching tube, and the selection matching tube at this time is a row selection tube M5; wherein the row selection tube M5 is connected between the source of the source follower tube M2 and the column line BL, specifically, the gate of the row selection tube M5 is connected to the selection control signal SEL, the drain of the row selection tube M5 is connected to the source of the source follower tube M2, and the source of the row selection tube M5 is connected to the column line BL. At this time, the source of the source follower tube M2 is no longer connected to the column line BL.

[0080] For the arrangement structure of the first embodiment, Fig.11As shown, the row selection tube M5 is arranged in the built-in area 110 and is symmetrically arranged with the first reset tube M31 on both sides of the source follower tube M2. By designing the row selection tube M5 to be symmetrical with the first reset tube M31, the optical performance can be completely symmetrical while realizing readout control; in one example, the center of the row selection tube M5, the center of the first reset tube M31 and the center of the source follower tube M2 are located on the same line (for example, on the same horizontal line or on the same vertical line). In application, the source of the source follower tube M2 and the drain of the row selection tube M5 are made in the same layer and the two are directly connected without using metal wires, so that the arrangement structure of the shared pixel 100 of the fourth embodiment is more compact.

[0081] According to the arrangement structure of the second embodiment, the row selection tube M5 is arranged in the built-in area 110 and is symmetrically arranged with the first gain tube M41 on both sides of the source follower tube M2, as shown in FIG. Fig.13 As shown, or, the row selection tube M5 is arranged in the built-in area 110 and is symmetrically arranged with the first reset tube M31 on both sides of the source follower tube M2. Further, in order to achieve complete symmetry of optical performance, the arrangement structure can also be provided with a second dummy tube D2, wherein the second dummy tube D2 is arranged in the built-in area 110 and is symmetrically arranged with the remaining one of the first reset tube M31 and the first gain tube M41 on both sides of the source follower tube M2. As an optional solution, the row selection tube M5 is arranged adjacent to the source follower tube M2, that is, the row selection tube M5 is arranged in the built-in area 110 and is symmetrically arranged with the first gain tube M41 on both sides of the source follower tube M2. In one example, the center of the row selection tube M5, the center of the first gain tube M41, the center of the first reset tube M31 and the center of the source follower tube M2 are located on the same line (for example, on the same horizontal line or on the same vertical line), and when the second dummy tube D2 is included, its center is also located on the same line with the center of the above-mentioned tubes. In application, the source of the source follower tube M2 and the drain of the row select tube M5 are made in the same layer and are directly connected without using metal wires, so that the arrangement structure of the shared pixel 100 of the fourth embodiment is more compact.

[0082] Of course, for the case where the first gain tube M41 is arranged at the position of the first reset tube M31 in the built-in area 110 and the first reset tube M31 is arranged outside the built-in area 110: the corresponding arrangement structure can also add a row selection tube M5, or even add a second dummy tube D2; wherein the row selection tube M5 can be arranged in the built-in area 110 and symmetrically arranged with the first gain tube M41 on both sides of the source follower tube M2, such as Fig.14As shown, it can also be arranged outside the built-in area 110 and symmetrically arranged with the first reset tube M31 on both sides of the source follower tube M2, while the second dummy tube D2 is symmetrically arranged with the first reset tube M31 and the remaining one of the first gain tube M41 on both sides of the source follower tube M2. As an optional solution, the row selection tube M5 is arranged adjacent to the source follower tube M2, that is, the row selection tube M5 is arranged in the built-in area 110 and symmetrically arranged with the first gain tube M41 on both sides of the source follower tube M2. In application, it can also be designed that the centers of each tube are located on the same line, and the source of the source follower tube M2 and the drain of the row selection tube M5 are made in the same layer and the two are directly connected. Embodiment 5

[0083] like Fig.15 As shown, this embodiment provides a four-shared pixel 100, which is different from the first embodiment in that the four-shared pixel 100 of this embodiment also includes a second reset tube M32; wherein the second reset tube M32 is connected in parallel with the first reset tube M31, specifically, the gate of the second reset tube M32 is connected to the reset control signal RST, the drain of the second reset tube M32 is connected to the drain of the first reset tube M31, and the source of the second reset tube M32 is connected to the source of the first reset tube M31.

[0084] The arrangement structure obtained by arranging the above four shared pixels 100 is as follows: Fig.16 As shown, where:

[0085] The arrangement of the first photosensitive element PD1, the second photosensitive element PD2, the third photosensitive element PD3, the fourth photosensitive element PD4, the first transmission tube M11, the second transmission tube M12, the third transmission tube M13, the fourth transmission tube M14, the first node area FD1, the source follower tube M2 and the first reset tube M31 is the same as that in the first embodiment, and the details can be referred to in the first embodiment, which will not be repeated here. In addition, in the arrangement structure of the present embodiment, the floating diffusion node FD no longer includes the second node area FD2 and the third node area FD3, but includes the fourth node area FD4, wherein the fourth node area FD4 is arranged between the transmission tubes corresponding to the other two symmetrical photosensitive elements (different from the transmission tubes corresponding to the first node area FD1, for example, the first node area FD1 is arranged between the first transmission tube M11 corresponding to the first photosensitive element PD1 and the fourth transmission tube M14 corresponding to the fourth photosensitive element PD4, and the fourth node area FD4 is arranged between the second transmission tube M12 corresponding to the second photosensitive element PD2 and the third transmission tube M13 corresponding to the third photosensitive element PD3).

[0086] The second reset tube M32 is arranged outside the fourth node region FD4 in the built-in region 110 and is symmetrically arranged with the first reset tube M31 on both sides of the source follower tube M2; in one example, the center of the second reset tube M32, the center of the first reset tube M31 and the center of the source follower tube M2 are located on the same line, for example, the center of the second reset tube M32, the center of the first reset tube M31 and the center of the source follower tube M2 are located on the same horizontal line or on the same vertical line. In the application, the source of the first reset tube M31 and the source of the second reset tube M32 are made on the same layer as the floating diffusion node FD, the source of the first reset tube M31 is directly connected to the first node region FD1 without using a metal wire, and the source of the second reset tube M32 is directly connected to the fourth node region FD4 without using a metal wire, so as to reduce the parasitic capacitance of the floating diffusion node FD. In this embodiment, the reset speed is improved by designing the second reset tube M32 and the first reset tube M31 in parallel; the optical performance symmetry of the four shared pixels 100 is achieved by designing the second reset tube M32 and the first reset tube M31 symmetrically, thereby improving the imaging quality of the four shared pixels 100. Embodiment 6

[0087] like Fig.17 As shown, the present embodiment provides a four-shared pixel 100, which is different from the fifth embodiment in that the four-shared pixel 100 of the present embodiment further includes a first gain tube M41 and a second gain tube M42; wherein the first gain tube M41 is connected between the first reset tube M31 and the floating diffusion node FD, specifically, the gate of the first gain tube M41 is connected to the gain control signal DCG, the drain of the first gain tube M41 is connected to the source of the first reset tube M31, and the source of the first gain tube M41 is connected to the floating diffusion node FD, at which time, the source of the first reset tube M31 is no longer connected to the floating diffusion node FD; the second gain tube M42 is connected in parallel with the first gain tube M41, specifically, the gate of the second gain tube M42 is connected to the gain control signal DCG, the drain of the second gain tube M42 is connected to the drain of the first gain tube M41, and the source of the second gain tube M42 is connected to the source of the first gain tube M41.

[0088] The arrangement structure obtained by arranging the above four shared pixels 100 is as follows: Fig.18 As shown, where:

[0089] The arrangement of the first photosensitive element PD1, the second photosensitive element PD2, the third photosensitive element PD3, the fourth photosensitive element PD4, the first transmission tube M11, the second transmission tube M12, the third transmission tube M13, the fourth transmission tube M14, the floating diffusion node (including the first node area FD1 and the fourth node area FD4), the source follower tube M2, the first reset tube M31 and the second reset tube M32 are the same as those in Example 5. For details, please refer to Example 5 and will not be repeated here.

[0090] The first gain tube M41 is arranged in the built-in area 110 and between the first reset tube M31 and the first node area FD1, and the second gain tube M42 is arranged on the outside of the fourth node area FD4 in the built-in area 110 and is symmetrically arranged with the first gain tube M41 on both sides of the source follower tube M2; in one example, the centers of the first gain tube M41, the second gain tube M42, the first reset tube M31, the second reset tube M32 and the center of the source follower tube M2 are located on the same line (for example, on the same horizontal line or the same vertical line). In application, the source of the first gain tube M41 and the source of the second gain tube M42 are made on the same layer as the floating diffusion node FD, the source of the first gain tube M41 is directly connected to the first node area FD1 without using a metal wire, and the source of the second gain tube M42 is directly connected to the fourth node area FD4 without using a metal wire, thereby reducing the parasitic capacitance of the floating diffusion node FD; at this time, the source of the first reset tube M31 is no longer directly connected to the first node area FD1, and the source of the second reset tube M32 is no longer directly connected to the fourth node area FD4.

[0091] In this embodiment, the first reset tube M31 and the second reset tube M32 are no longer connected to the floating diffusion node FD, so the length of the metal wires corresponding to the first reset tube M31 and the second reset tube M32 does not affect the parasitic capacitance of the floating diffusion node FD. Without considering making the arrangement structure more compact, the first reset tube M31 and the second reset tube M32 can also be arranged outside the built-in area 110. For example, the first gain tube M41 and the second gain tube M42 are arranged at the positions of the first reset tube M31 and the second reset tube M32 respectively, and the first reset tube M31 is arranged outside the built-in area 110 and arranged on the outside of the first gain tube M41, and the second reset tube M32 is arranged outside the built-in area 110 and arranged on the outside of the second gain tube M42. Fig.19 shown. Embodiment 7

[0092] like Fig. 20 and Fig. 22 As shown, this embodiment provides a four-shared pixel 100, which is different from the fifth or sixth embodiment in that the four-shared pixel 100 of this embodiment also includes a row selection tube M5; wherein the row selection tube M5 is connected between the source of the source follower tube M2 and the column line BL, specifically, the gate of the row selection tube M5 is connected to the selection control signal SEL, the drain of the row selection tube M5 is connected to the source of the source follower tube M2, and the source of the row selection tube M5 is connected to the column line BL. At this time, the source of the source follower tube M2 is no longer connected to the column line BL.

[0093] For the arrangement structure of the fifth or sixth embodiment, Fig.21 , Fig.23 and Fig.24As shown, the row selection tube M5 is arranged on the side of the source follower tube M2 in the built-in area 110 away from the corresponding node area. Further, in order to achieve complete symmetry of optical performance, the arrangement structure can also be provided with a third dummy tube D3, wherein the third dummy tube D3 is arranged in the built-in area 110 and is symmetrically arranged with the row selection tube M5 on both sides of the source follower tube M2. In one example, the center of the row selection tube M5 is located on the same line as the center of the source follower tube M2, and the line is perpendicular to another line where the center of the first reset tube M31, the center of the second reset tube M32 and the center of the source follower tube M2 are located. For example, the center of the row selection tube M5 is located on the same vertical line as the center of the source follower tube M2, and the center of the first reset tube M31, the center of the second reset tube M32 and the center of the source follower tube M2 are located on the same horizontal line; when the third dummy tube D3 is included, its center is also located on the same line as the center of the row selection tube M5 and the source follower tube M2. In application, the source of the source follower tube M2 and the drain of the row select tube M5 are made in the same layer and are directly connected without using metal wires, so that the arrangement structure of the shared pixel 100 of the fourth embodiment is more compact. Embodiment 8

[0094] This embodiment provides an image sensor, including the arrangement structure of four shared pixels 100 recorded in any one of Embodiments 1 to 7; of course, the image sensor of this embodiment may also include a readout structure, a ramp voltage providing structure, etc., and no specific limitation is made to this.

[0095] In summary, the arrangement structure and image sensor of four shared pixels of the present invention arrange at least the reset tube and source follower tube or the gain tube and source follower tube connected to the floating diffusion node in the built-in area surrounded by four transmission tubes to shorten the length of the metal wire electrically connecting the corresponding tube to the floating diffusion node, reduce the parasitic capacitance of the floating diffusion node, increase the conversion gain of the image sensor, and thus improve the imaging quality; the present invention further reduces the parasitic capacitance of the floating diffusion node by directly connecting the reset tube or the gain tube to the floating diffusion node and avoiding the use of metal wires. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0096] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A four-shared pixel arrangement structure, It is characterized in that The arrangement structure comprises: A first photosensitive element, a second photosensitive element, a third photosensitive element, a fourth photosensitive element, a first transmission tube, a second transmission tube, a third transmission tube, a fourth transmission tube, a floating diffusion node, a source follower tube and a first reset tube; The first photosensitive element and the second photosensitive element, the third photosensitive element and the fourth photosensitive element are all symmetrically arranged along the first direction, and the first photosensitive element and the fourth photosensitive element, the second photosensitive element and the third photosensitive element are all symmetrically arranged along the second direction; Each transmission tube is arranged at a corner facing each photosensitive element, and a built-in area is formed based on the outer side of each transmission tube and the vertices of the angles at the outer side of each transmission tube in the first direction and the second direction; the floating diffusion node includes a first node area, which is arranged between the transmission tubes corresponding to any two symmetrical photosensitive elements in the built-in area; the source follower tube is arranged on the inner side of the first node area in the built-in area; and the first reset tube is arranged on the outer side of the first node area in the built-in area.

2. The arrangement structure of four shared pixels according to claim 1, It is characterized in that The arrangement structure further includes a first gain tube, which is arranged between the first reset tube and the first node area, or arranged at the position of the first reset tube, while the first reset tube is arranged outside the built-in area and outside the first gain tube.

3. The arrangement structure of four shared pixels according to claim 1 or 2, It is characterized in that When the arrangement structure does not include the first gain tube, the source of the first reset tube is made in the same layer as the first node area and the two are directly connected; when the arrangement structure includes the first gain tube, the source of the first gain tube is made in the same layer as the first node area and the two are directly connected; and / or the floating diffusion node also includes a second node area and a third node area, which are respectively arranged on the side of the transmission tubes corresponding to the other two symmetrical photosensitive elements facing the source follower tube.

4. The arrangement structure of four shared pixels according to claim 1 or 2, It is characterized in that The arrangement structure includes selecting matching tubes; When the arrangement structure does not include the first gain tube, the selection matching tube is arranged in the built-in area and is symmetrically arranged with the first reset tube on both sides of the source follower tube; When the arrangement structure includes a first gain tube and the first reset tube is arranged in the built-in area, the selection matching tube is arranged in the built-in area and is symmetrically arranged with the first reset tube or the first gain tube on both sides of the source follower tube; When the arrangement structure includes a first gain tube and the first reset tube is arranged outside the built-in area, the selection matching tube is arranged in the built-in area and symmetrically arranged with the first gain tube on both sides of the source follower tube, or the selection matching tube is arranged outside the built-in area and symmetrically arranged with the first reset tube on both sides of the source follower tube; Wherein, the selection matching tube includes a row selection tube or a first dummy tube.

5. The arrangement structure of four shared pixels according to claim 4, It is characterized in that When the arrangement structure includes the first gain tube, the arrangement structure further includes a second dummy tube, which is symmetrically arranged on both sides of the source follower tube with respect to the first reset tube and the remaining one of the first gain tube.

6. The arrangement structure of four shared pixels according to claim 4, It is characterized in that When the selection matching tube includes a row selection tube, the row selection tube is arranged adjacent to the source follower tube, wherein the source of the source follower tube and the drain of the row selection tube are made in the same layer and are directly connected.

7. The arrangement structure of four shared pixels according to claim 1 or 2, It is characterized in that The floating diffusion node also includes a fourth node region, which is arranged between the transmission tubes corresponding to the other two symmetrical photosensitive elements; When the arrangement structure does not include the first gain tube, the arrangement structure further includes a second reset tube, which is arranged outside the fourth node region in the built-in region and symmetrically arranged with the first reset tube on both sides of the source follower tube; When the arrangement structure includes a first gain tube, the arrangement structure further includes a second gain tube, which is arranged outside the fourth node region in the built-in region and symmetrically arranged with the first gain tube on both sides of the source follower tube.

8. The arrangement structure of four shared pixels according to claim 7, It is characterized in that When the arrangement structure does not include the first gain tube and the second gain tube, the source electrodes of the first reset tube and the second reset tube are manufactured on the same layer as the floating diffusion node, the source electrode of the first reset tube is directly connected to the first node region, and the source electrode of the second reset tube is directly connected to the fourth node region; when the arrangement structure includes the first gain tube and the second gain tube, the source electrodes of the first gain tube and the second gain tube are manufactured on the same layer as the floating diffusion node, the source electrode of the first gain tube is directly connected to the first node region, and the source electrode of the second gain tube is directly connected to the fourth node region.

9. The arrangement structure of four shared pixels according to claim 7, It is characterized in that The arrangement structure further includes a row selection tube, which is arranged on a side of the source follower tube in the built-in area away from the corresponding node area.

10. The arrangement structure of four shared pixels according to claim 9, It is characterized in that The arrangement structure further includes a third dummy tube, which is arranged in the built-in area and symmetrically arranged with the row selection tube on both sides of the source follower tube.

11. The arrangement structure of four shared pixels according to claim 9, It is characterized in that The source of the source follower tube and the drain of the row select tube are made in the same layer and are directly connected.

12. An image sensor, It is characterized in that The image sensor comprises an arrangement structure of four shared pixels as described in any one of claims 1 to 11.

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