阅读说明：本技术 叠层互补金属氧化物半导体图像传感器及图像处理方法 (stacked CMOS image sensor and image processing method ) 是由 杨鑫 于 2019-09-11 设计创作，主要内容包括：本申请实施例提供了一种叠层互补金属氧化物半导体图像传感器及图像处理方法、存储介质,该叠层互补金属氧化物半导体图像传感器包括：叠层像素单元,叠层像素单元包括多层光电二极管PD柱,多层PD柱包括三种尺寸的PD柱,多层PD柱中的每一层PD柱的尺寸相同,叠层像素单元用于利用多层PD柱依次吸收RGB三色光,并将RGB三色光对应的光信号转换成电信号；与叠层像素单元的输出端连接的CMOS像素读出电路,其中,每一层PD柱与一个CMOS像素读出电路连接,CMOS像素读出电路用于放大电信号,并读出电信号。(the embodiment of the application provides a laminated complementary metal oxide semiconductor image sensor, an image processing method and a storage medium, wherein the laminated complementary metal oxide semiconductor image sensor comprises the following components: the laminated pixel unit comprises a plurality of layers of photodiode PD columns, the plurality of layers of PD columns comprise PD columns with three sizes, the size of each layer of PD column in the plurality of layers of PD columns is the same, and the laminated pixel unit is used for absorbing RGB (red, green and blue) three-color light in sequence by utilizing the plurality of layers of PD columns and converting optical signals corresponding to the RGB three-color light into electric signals; and the CMOS pixel reading circuit is connected with the output end of the laminated pixel unit, wherein each layer of PD column is connected with one CMOS pixel reading circuit, and the CMOS pixel reading circuit is used for amplifying electric signals and reading the electric signals.)

1. A stacked CMOS image sensor, comprising:

The laminated pixel unit comprises a plurality of layers of Photodiode (PD) columns, wherein the plurality of layers of PD columns comprise PD columns with three sizes, the size of each layer of PD column in the plurality of layers of PD columns is the same, and the laminated pixel unit is used for absorbing RGB (red, green and blue) three-color light in sequence by utilizing the plurality of layers of PD columns and converting optical signals corresponding to the RGB three-color light into electric signals;

And the CMOS pixel readout circuit is connected with the output end of the laminated pixel unit, wherein each layer of PD column is connected with one CMOS pixel readout circuit, and the CMOS pixel readout circuit is used for amplifying the electric signals and reading out the electric signals.

2. The stacked CMOS image sensor of claim 1, wherein each PD pillar is electrically connected to the one CMOS pixel readout circuit by a transfer gate connection.

3. The stacked CMOS image sensor of claim 1 or 2,

A first PD column layer closest to the light source in the multilayer PD column comprises a group of PD columns;

A second PD column layer in the multilayer PD column includes a first transfer gate connection circuit and a set of PD columns, the first transfer gate connection circuit being at least one transfer gate connection circuit corresponding to at least one PD column layer between the light source and the second PD column layer, the second PD column layer being a PD column layer in the multilayer PD column other than the first PD column layer.

4. The stacked CMOS image sensor of claim 3, wherein a distance between two adjacent PD pillars in each layer of PD pillars is a preset distance, the number of PD pillars in the first PD pillar layer is determined by a size of the stacked pixel unit and the preset distance, and the number of PD pillars in the second PD pillar layer is determined by a size of the at least one transfer gate connection circuit, the size of the stacked pixel unit, and the preset distance.

5. the stacked cmos image sensor of claim 1, further comprising a color filter, wherein the color filter is connected to the input terminal of the stacked pixel unit, and the color filter is used for filtering an imaging light signal of a light source to obtain visible light;

The laminated pixel unit is specifically used for sequentially absorbing RGB three-color light from the visible light by utilizing a plurality of layers of PD columns.

6. The stacked cmos image sensor of claim 1, wherein each PD pillar comprises an n-region, and wherein the electrical signal is concentrated to the n-region of each PD pillar.

7. The stacked cmos image sensor of claim 1, wherein each PD pillar is configured to absorb RGB monochromatic light, and wherein each PD pillar is sized to absorb RGB monochromatic light.

8. the stacked cmos image sensor of claim 1, wherein the PD pillars have a shape including a cylinder and a regular polygon.

9. The stacked CMOS image sensor of claim 2, wherein the one CMOS pixel readout circuit comprises: a transfer transistor connected to the transfer gate connection circuit, a readout region connected to the transfer transistor, and an amplifier tube connected to the readout region;

The transfer transistor is used for transferring the electric signal from the PD pillar to a readout area so as to read the electric signal from the readout area;

the amplifying tube is used for amplifying the electric signal of the readout region.

10. The stacked CMOS image sensor of claim 9, wherein the CMOS pixel readout circuit further comprises: a reset transistor connected to the readout region and the amplifying transistor;

The readout region is also used for reading out a reset level in the reset transistor;

The amplifying tube is also used for amplifying the reset level.

11. an image processing method applied to a stacked CMOS image sensor including a stacked pixel unit composed of a plurality of PD pillars including three-sized PD pillars and a CMOS pixel readout circuit connected to an output terminal of the stacked pixel unit, the method comprising:

Sequentially absorbing RGB (red, green and blue) three-color light by utilizing a plurality of layers of PD (photo diode) columns, and converting optical signals corresponding to the RGB three-color light into electric signals;

Amplifying the electrical signal with the CMOS pixel readout circuit and reading out the electrical signal.

12. The method of claim 11, wherein the stacked cmos image sensor further comprises a color filter coupled to an input of the stacked pixel cell, and wherein the method further comprises, before absorbing RGB three color light with the multi-layered PD pillars:

Filtering an imaging optical signal of the light source by using a color filter to obtain visible light;

correspondingly, the absorption of RGB three-color light by using the multilayer PD column comprises the following steps:

And sequentially absorbing RGB light from the visible light by using the multilayer PD column.

13. The method of claim 11, wherein a CMOS pixel readout circuit comprises: a transfer transistor connected to each of the plurality of layers of PD pillars, a readout region connected to the transfer transistor, and an amplification tube connected to the readout region; the amplifying the electrical signal with the CMOS pixel readout circuit and reading out the electrical signal includes:

Transferring the electrical signal from the each layer of PD pillars to a readout region using the transfer transistor;

Reading the electrical signal from the readout region;

And amplifying the electric signal of the readout region by using an amplifying tube.

14. a storage medium having stored thereon a computer program for a stacked cmos image sensor, wherein the computer program when executed by a processor implements the method of any one of claims 11-13.

Technical Field

the present disclosure relates to the field of image processing, and in particular, to a stacked cmos image sensor, an image processing method, and a storage medium.

Background

A Complementary Metal-Oxide Semiconductor (CMOS) Image Sensor (CIS) has the characteristics of high integration level, low power consumption, high speed, low cost, and the like, and is widely applied to high-resolution pixel products. Typically, CMOS image sensors can only record one of the three RGB colors on the same pixel, resulting in less detail in the color of the resulting image and unnecessary streak effects. In order to increase color detail and avoid unnecessary stripe effect, three layers of photosensitive elements are adopted to record one color channel of RGB respectively, the main working principle is that signals obtained at different depths are measured by utilizing the difference of absorption lengths of light with different wavelengths in silicon, and finally the detection of R, G, B three colors is realized in one pixel.

However, the conventional three-layered photosensitive element has a large pixel size due to a large thickness of each layer of photosensitive element, and a color filter array is coated on the three-layered photosensitive element, which causes a problem of low CIS resolution.

disclosure of Invention

embodiments of the present application provide a stacked cmos image sensor, an image processing method, and a storage medium, which can reduce a pixel size and improve CIS resolution.

the technical scheme of the application is realized as follows:

an embodiment of the present application provides a stacked cmos image sensor, including:

The laminated pixel unit comprises a plurality of layers of Photodiode (PD) columns, wherein the plurality of layers of PD columns comprise PD columns with three sizes, the size of each layer of PD column in the plurality of layers of PD columns is the same, and the laminated pixel unit is used for absorbing RGB (red, green and blue) three-color light in sequence by utilizing the plurality of layers of PD columns and converting optical signals corresponding to the RGB three-color light into electric signals;

And the CMOS pixel readout circuit is connected with the output end of the laminated pixel unit, wherein each layer of PD column is connected with one CMOS pixel readout circuit, and the CMOS pixel readout circuit is used for amplifying the electric signals and reading out the electric signals.

In the stacked CMOS image sensor, each of the PD pillars is connected to the one CMOS pixel readout circuit through a transfer gate connection circuit.

In the stacked cmos image sensor, a first PD column layer closest to a light source among the plurality of PD columns includes a group of PD columns;

A second PD column layer in the multilayer PD column includes a first transfer gate connection circuit and a set of PD columns, the first transfer gate connection circuit being at least one transfer gate connection circuit corresponding to at least one PD column layer between the light source and the second PD column layer, the second PD column layer being a PD column layer in the multilayer PD column other than the first PD column layer.

in the stacked cmos image sensor, a distance between two adjacent PD pillars in each layer of PD pillars is a preset distance, the number of PD pillars in the first PD pillar layer is determined by the size of the stacked pixel unit and the preset distance, and the number of PD pillars in the second PD pillar layer is determined by the size of the at least one transfer gate connection circuit, the size of the stacked pixel unit, and the preset distance.

In the stacked cmos image sensor, the stacked cmos image sensor further includes a color filter, wherein the color filter is connected to an input terminal of the stacked pixel unit, and the color filter is configured to filter an imaging optical signal of a light source to obtain visible light;

the laminated pixel unit is specifically used for sequentially absorbing RGB three-color light from the visible light by utilizing a plurality of layers of PD columns.

In the stacked cmos image sensor, the each layer of PD pillars includes an n-region, and the electrical signal is concentrated to the n-region of the each layer of PD pillars.

In the stacked cmos image sensor, each of the PD pillars absorbs RGB monochromatic light, and a size of each of the PD pillars is determined by the RGB monochromatic light.

In the above stacked cmos image sensor, the PD pillars have a shape including a cylinder and a regular polygon.

In the above stacked CMOS image sensor, the one CMOS pixel readout circuit includes: a transfer transistor connected to the transfer gate connection circuit, a readout region connected to the transfer transistor, and an amplifier tube connected to the readout region;

The transfer transistor is used for transferring the electric signal from the PD pillar to a readout area so as to read the electric signal from the readout area;

The amplifying tube is used for amplifying the electric signal of the readout region.

In the above stacked CMOS image sensor, the CMOS pixel readout circuit further comprises: a reset transistor connected to the readout region and the amplifying transistor;

The readout region is also used for reading out a reset level in the reset transistor;

the amplifying tube is also used for amplifying the reset level.

the embodiment of the application provides an image processing method, which is applied to a stacked complementary metal oxide semiconductor image sensor, wherein the stacked complementary metal oxide semiconductor image sensor comprises a stacked pixel unit and a CMOS pixel readout circuit connected with the output end of the stacked pixel unit, the stacked pixel unit consists of a plurality of layers of PD pillars, the plurality of layers of PD pillars comprise PD pillars with three sizes, and the method comprises the following steps:

Sequentially absorbing RGB (red, green and blue) three-color light by utilizing a plurality of layers of PD (photo diode) columns, and converting optical signals corresponding to the RGB three-color light into electric signals;

amplifying the electrical signal with the CMOS pixel readout circuit and reading out the electrical signal.

in the above method, the stacked cmos image sensor further includes a color filter connected to an input terminal of the stacked pixel unit, and before absorbing RGB three-color light using the multi-layered PD pillars, the method further includes:

Filtering an imaging optical signal of the light source by using a color filter to obtain visible light;

correspondingly, the absorption of RGB three-color light by using the multilayer PD column comprises the following steps:

And sequentially absorbing RGB light from the visible light by using the multilayer PD column.

In the above method, a CMOS pixel readout circuit includes: a transfer transistor connected to each of the plurality of layers of PD pillars, a readout region connected to the transfer transistor, and an amplification tube connected to the readout region; the amplifying the electrical signal with the CMOS pixel readout circuit and reading out the electrical signal includes:

Transferring the electrical signal from the each layer of PD pillars to a readout region using the transfer transistor;

Reading the electrical signal from the readout region;

and amplifying the electric signal of the readout region by using an amplifying tube.

The embodiment of the application provides a storage medium, wherein a computer program is stored on the storage medium, is applied to a stacked complementary metal oxide semiconductor image sensor, and realizes the method according to any one of the above items when the computer program is executed by a processor.

The embodiment of the application provides a laminated complementary metal oxide semiconductor image sensor, an image processing method and a storage medium, wherein the laminated complementary metal oxide semiconductor image sensor comprises the following components: the laminated pixel unit comprises a plurality of layers of photodiode PD columns, the plurality of layers of PD columns comprise PD columns with three sizes, the size of each layer of PD column in the plurality of layers of PD columns is the same, and the laminated pixel unit is used for absorbing RGB (red, green and blue) three-color light in sequence by utilizing the plurality of layers of PD columns and converting optical signals corresponding to the RGB three-color light into electric signals; and the CMOS pixel reading circuit is connected with the output end of the laminated pixel unit, wherein each layer of PD column is connected with one CMOS pixel reading circuit, and the CMOS pixel reading circuit is used for amplifying electric signals and reading the electric signals. By adopting the implementation scheme of the stacked complementary metal oxide semiconductor image sensor, the stacked pixel unit realizes the absorption of RGB three-color light by utilizing the multiple layers of PD columns, and the sizes of the PD columns are all in nanometer magnitude, so that the pixel size of the stacked pixel unit is reduced, each pixel can obtain R, G, B signals of three channels without demosaicing algorithm, and the resolution of the CIS is further improved.

Drawings

fig. 1 is a schematic structural diagram of a stacked cmos image sensor according to an embodiment of the present disclosure;

Fig. 2 is a schematic cross-sectional circuit diagram of an exemplary stacked cmos image sensor according to an embodiment of the present disclosure;

fig. 3(a) is a schematic cross-sectional view of a pixel of an exemplary first layer PD provided in an embodiment of the present application;

Fig. 3(b) is a schematic cross-sectional view of a pixel of an exemplary second layer PD provided in an embodiment of the present application;

fig. 3(c) is a schematic cross-sectional view of an exemplary third layer PD provided in an embodiment of the present application;

fig. 4 is a schematic diagram of an exemplary W color filter array provided by an embodiment of the present application;

Fig. 5 is a schematic circuit diagram of an exemplary CMOS pixel readout circuit of a stacked CMOS image sensor according to an embodiment of the present disclosure;

fig. 6 is a flowchart of an image processing method according to an embodiment of the present application.

Detailed Description

It should be understood that the specific embodiments described herein are merely illustrative of the present application. And are not intended to limit the present application.