CN110572594B

CN110572594B - Stacked CMOS image sensor and image processing method

Info

Publication number: CN110572594B
Application number: CN201910859504.1A
Authority: CN
Inventors: 杨鑫
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2019-09-11
Filing date: 2019-09-11
Publication date: 2022-04-15
Anticipated expiration: 2039-09-11
Also published as: CN110572594A

Abstract

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.

Description

Stacked CMOS image sensor and image processing method

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.

Example one

The embodiment of the present application provides a stacked cmos image sensor 1, as shown in fig. 1, where the stacked cmos image sensor 1 includes:

the stacked pixel unit 10 includes a multilayer photodiode PD column 100, the multilayer PD column includes three kinds of PD columns, each of the PD columns has the same size, and the stacked pixel unit 10 is configured to sequentially absorb three colors of RGB light by using the PD columns and convert optical signals corresponding to the three colors of RGB light into electrical signals;

and a CMOS pixel readout circuit 11 connected to an output terminal of the stacked pixel unit 10, wherein each layer of PD pillars is connected to one CMOS pixel readout circuit, and the CMOS pixel readout circuit 11 is configured to amplify the electrical signal and read out the electrical signal.

The laminated CIS is suitable for image processing of collected optical signals, and an image corresponding to the optical signals is obtained in a scene.

In the embodiment of the application, the stacked CIS comprises a stacked pixel unit and a CMOS pixel readout circuit, wherein the stacked pixel unit is structured as a multi-layer Photodiode (PD) pillar, the PD pillars with different sizes are used for absorbing different RGB monochromatic lights, and each layer of PD pillar in the multi-layer PD pillar corresponds to one CMOS pixel readout circuit.

In the embodiment of the application, each layer of PD pillars in the multi-layer PD pillars has the same size, visible light sequentially penetrates through the multi-layer PD pillars, each layer of PD pillars in the multi-layer PD pillars sequentially absorbs RGB monochromatic light by using the respective size, and performs photoelectric conversion on the RGB monochromatic light to obtain an electric signal corresponding to the RGB monochromatic light, so that the stacked pixel unit absorbs the RGB monochromatic light through the multi-layer PD pillars and converts the RGB monochromatic light into a corresponding electric signal, thereafter, each layer of PD pillars transmits the electric signal corresponding to the RGB monochromatic light to a corresponding CMOS pixel readout circuit, and the CMOS pixel readout circuit amplifies and reads the electric signal corresponding to the RGB monochromatic light.

In the embodiment of the present application, the size of each layer of PD pillars is determined by the RGB monochromatic light that needs to be absorbed, and the PD pillars are specifically set according to actual conditions, which is not specifically limited in the embodiment of the present application.

In practical application, the stacked pixel unit includes three layers of PD pillars, one layer of PD pillars in the three layers of PD pillars is used for absorbing red light, the next layer of PD pillars is used for absorbing green light, and the last layer of PD pillars is used for absorbing blue light, and the stacking order of the three layers of PD pillars is not limited to RGB, and may also be selected according to practical situations, and the embodiment of the present application is not specifically limited.

For example, for a cylindrical PD column, the diameter of the cylindrical PD column is 90nm when absorbing green light; the diameter of the cylindrical PD column was 60nm when absorbing blue light; the diameter of the cylindrical PD column was 120nm when absorbing red light.

Further, each layer of PD pillars has a thickness of 80nm-500nm, and the higher the absorption rate and the lower the absorption purity, the larger the thickness is, such as in a scenario of absorbing blue light with a PD pillar, the absorption rate of the PD pillar absorbing blue light reaches 98% when the thickness of the PD pillar is 1 μm, however, a part of red light and green light is absorbed, which results in a decrease in the absorption purity of blue light.

In the embodiment of the application, after the CMOS pixel reading circuit reads the electrical signals corresponding to the RGB three-color light, the CMOS pixel reading circuit transmits the electrical signals corresponding to the RGB three-color light to the image processing unit, and the image processing unit processes the electrical signals corresponding to the RGB three-color light to obtain a color image corresponding to the imaging optical signal.

Alternatively, each of the PD pillars 100 of the one layer is connected to the one CMOS pixel readout circuit 11 through a transfer gate connection circuit 12.

In an embodiment of the application, the stacked CIS further includes a transfer gate connection circuit, the transfer gate connection circuit is located between each layer of PD pillars and one CMOS pixel readout circuit corresponding to each layer of PD pillars, and is configured to connect each layer of PD pillars and one CMOS pixel readout circuit corresponding to each layer of PD pillars, and after each layer of PD pillars converts absorbed RGB monochromatic light into an electrical signal corresponding to RGB monochromatic light, the electrical signal corresponding to RGB monochromatic light is transmitted to the CMOS pixel readout circuit through the transfer gate connection circuit, so that the CMOS pixel readout circuit amplifies and reads the electrical signal corresponding to RGB monochromatic light.

Optionally, a first PD column layer closest to the light source in the multilayer PD columns includes a group of PD columns;

In the embodiment of the application, the multilayer PD column comprises two hierarchical structures, wherein the first hierarchical structure is a first PD column layer closest to a light source, and a group of PD columns are arranged in the first hierarchical structure; the second one is a second PD column layer except the first PD column layer in the multilayer PD column, in which a first transfer gate connection circuit and a group of PD columns are arranged, the first transfer gate circuit is 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, and therefore, the transfer gate connection circuit corresponding to any PD column layer in the multilayer PD column passes through each layer of PD column between the PD column layer and the CMOS pixel readout circuit.

Exemplarily, taking a three-layer stacked CIS as an example, a schematic cross-sectional view of a pixel thereof is shown in fig. 2, the three-layer stacked CIS includes a three-layer stacked pixel unit and a CMOS pixel readout circuit, and a signal flow direction thereof is that the signal passes through the three-layer stacked pixel unit and then passes through the CMOS pixel readout circuit, the three-layer stacked pixel unit is composed of a first layer PD closest to a light source, a second layer PD adjacent to the first layer PD, and a third layer PD adjacent to the second layer PD, the first layer PD is used for absorbing blue light, the second layer PD is used for absorbing green light, and the third layer PD is used for absorbing red light; wherein the first layer PD includes 16 PD pillars, as shown in fig. 3(a), there is provided one n region below the 16 PD pillars, the one n region is connected to the transfer gate connection circuit of the first layer PD, the transfer gate connection circuit of the first layer PD is connected to the CMOS pixel readout circuit; the second layer PD includes 12 PD pillars and transfer gate connection circuits of the first layer PD, and as shown in fig. 3(b), an n region is provided below the 12 PD pillars, the n region being connected to the transfer gate connection circuits of the second layer PD, the transfer gate connection circuits of the second layer PD being connected to the CMOS pixel readout circuit; the third layer PD includes 8 PD pillars and transfer gate connection circuits of the first layer PD and the second layer PD, as shown in fig. 3(c), an n region is disposed below the 8 PD pillars, the n region is connected to the transfer gate connection circuit of the third layer PD, and the transfer gate connection circuit of the third layer PD is connected to the CMOS pixel readout circuit; when light passes through the first PD layer, blue light in the light is absorbed and converted into electric signals based on resonance absorption of the first PD layer, the electric signals corresponding to the blue light are transmitted to the CMOS pixel reading circuit through the transfer gate connecting circuit of the first PD layer, the rest light passes through the second PD layer, green light in the light is absorbed and converted into electric signals based on resonance absorption of the second PD layer, the electric signals corresponding to the green light are transmitted to the CMOS pixel reading circuit through the transfer gate connecting circuit of the second PD layer, the rest light passes through the third PD layer, red light in the light is absorbed and converted into electric signals based on resonance absorption of the third PD layer, and the electric signals corresponding to the red light are transmitted to the CMOS pixel reading circuit through the transfer gate connecting circuit of the third PD layer.

Optionally, 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 embodiment of the application, the preset distance between two adjacent PD pillars in each layer of PD pillars is greater than or equal to 50nm, so that mutual interference between the adjacent PD pillars can be avoided.

In the embodiment of the application, the first PD column layer does not have a transfer gate connection circuit corresponding to another PD column layer, so the number of PD columns in the first PD column layer is obtained by dividing the size of the stacked pixel unit by the preset distance; the second PD column layer further includes at least one transfer gate connection circuit, so that the number of PD columns in the second PD column layer is obtained by subtracting the size of the at least one transfer gate circuit from the size of the stacked pixel unit and dividing by the preset distance, and the specific calculation method is set and adjusted according to the actual situation, which is not specifically limited in the embodiment of the present application.

Optionally, the stacked cmos image sensor 1 further includes a color filter 13, where the color filter 13 is connected to an input end of the stacked pixel unit 10, and the color filter 13 is configured to filter an imaging optical signal of a light source to obtain visible light;

the stacked pixel unit 10 is specifically configured to sequentially absorb three colors of RGB light from the visible light by using a plurality of PD pillars.

In the embodiment of the application, the input end of the laminated pixel unit is also provided with a color filter, and the color filter is used for transmitting visible light and filtering other stray light such as ultraviolet light, infrared light and the like.

Optionally, the color filter is a W (white) filter.

In the embodiment of the application, after an imaging light signal sent by a light source passes through a W color filter, ultraviolet light and infrared light in the imaging light signal are filtered, visible light is transmitted, then the visible light sequentially passes through a plurality of layers of PD pillars, each layer of PD pillar in the plurality of layers of PD pillars utilizes the size of the PD pillar to perform corresponding resonance absorption, and each layer of PD pillar sequentially absorbs corresponding RGB monochromatic light from the visible light.

Illustratively, 4W filters are disposed over 4 multi-layer stacked PD pillars, and fig. 4 is a color filter array of 4W filters.

Optionally, each layer of PD pillars includes an n-region, and the electrical signal is concentrated to the n-region of each layer of PD pillars.

In the embodiment of the application, an n area is arranged below each layer of PD pillars, the n area is connected with a transfer gate connecting circuit, and each layer of PD pillars concentrates electric signals after photoelectric conversion to the n area and transmits the electric signals to a CMOS pixel reading circuit through the transfer gate connecting circuit.

Optionally, each layer of PD pillars is configured to absorb RGB monochromatic light, and a size of each layer of PD pillars is determined by the RGB monochromatic light.

In the embodiment of the present application, the diameter of the PD column is determined based on the resonance wavelength of the RGB monochromatic light and the refractive index of the optical signal, or is obtained through optical simulation, and is specifically selected according to the actual situation, which is not specifically limited in the embodiment of the present application.

In the embodiment of the application, the size of the PD column is determined by using the formula (1)

PD column size (resonance wavelength-predetermined constant)/refractive index (1)

In the embodiment of the application, each layer of PD pillars absorbs RGB monochromatic light, and when the PD pillars absorb green light, the diameter of the layer of PD pillars is 90 nm; when absorbing blue light, the diameter of the PD pillar of the layer is 60 nm; the diameter of the PD column of this layer is 120nm when absorbing red light.

Optionally, the shape of the PD column includes a cylinder and a regular polygon, which is specifically selected according to actual situations, and the embodiment of the present application is not specifically limited.

Optionally, the one CMOS pixel readout circuit 11 includes: a transfer transistor 110 connected to the transfer gate connection circuit 12, a readout region 111 connected to the transfer transistor 110, and an amplifier tube 112 connected to the readout region 111;

the transfer transistor 110 for transferring the electrical signal from the PD column to a readout region to read the electrical signal from the readout region;

the amplifying tube 112 is used for amplifying the electric signal of the readout region.

In the embodiment of the application, the source electrode of the transfer transistor is connected with the transfer gate connecting circuit; the drain of the transfer transistor is connected to an FD (readout region); the PD column focuses the electrical signal to the n + region of the transfer transistor and transfers it to the FD via the transfer transistor.

In the embodiment of the application, light rays are subjected to photoelectric conversion in the depletion region of the PD column, optical signals are converted into electric signals, and then the electric signals are gathered to the n + region channel of the transfer transistor by the transfer transistor; and transfers the electrical signal in the n + region channel to the FD.

Optionally, the CMOS pixel readout circuit 11 further includes: a reset transistor 113 connected to the readout region 111 and the amplification tube 112;

the readout region 111 for reading out a reset level in the reset transistor 113;

the amplifying tube 112 is further configured to amplify the reset level.

In the embodiment of the application, the source electrode of the reset tube is connected with the power supply; the drain of the reset tube is connected to the FD, wherein the reset tube stores a reset level, and the reset level is read out through the FD.

In the embodiment of the present application, the reset level is read out from the reset transistor, the electrical signal is read out from the transfer transistor, and then, after the reset level and the electrical signal are amplified, correlated double sampling is performed on the amplified electrical signal and the amplified reset level, thereby reducing noise of the read electrical signal.

As shown in fig. 5, which is a simplified schematic diagram of a single pixel unit circuit, taking the PD pillar layer absorbing blue light of a stacked pixel unit as an example, a transfer gate connection circuit corresponding to the PD pillar absorbing blue light is connected to a source of a transfer transistor, and a drain of the transfer transistor is connected to an FD; the FD is also connected with the drain electrode of the reset tube, and the source electrode of the reset tube is connected with a power supply; the FD is also connected with the grid electrode of the BSF, the source electrode of the BSF is connected with the power supply, the drain electrode of the BSF is connected with the source electrode of the gate tube, and the drain electrode of the gate tube is connected with the output end.

It can be understood that the stacked pixel unit utilizes the multilayer PD columns to realize the absorption of RGB three-color light, and the sizes of the PD columns are all in nanometer order, thereby reducing the pixel size of the stacked pixel unit, each pixel can obtain R, G, B three-channel signals without demosaicing algorithm, and further improving the resolution of the CIS.

Example two

An embodiment of the present application provides an image processing method applied to a stacked CMOS image sensor, where the stacked CMOS image sensor includes a stacked pixel unit and a CMOS pixel readout circuit connected to an output end of the stacked pixel unit, the stacked pixel unit is composed of a plurality of PD pillars, and the PD pillars include PD pillars of three sizes, as shown in fig. 6, the method may include:

s101, sequentially absorbing RGB (red, green, blue) three-color light by using a plurality of layers of PD (photo diode) columns, and converting optical signals corresponding to the RGB three-color light into electric signals.

The image processing method provided by the embodiment of the application is suitable for a scene in which the acquired optical signals are subjected to image processing to obtain the images corresponding to the optical signals.

In the embodiment of the application, each layer of PD pillars in the multilayer PD pillars has the same size, visible light sequentially penetrates through the multilayer PD pillars, each layer of PD pillars in the multilayer PD pillars sequentially absorbs RGB monochromatic light by using the respective size, and performs photoelectric conversion on the RGB monochromatic light to obtain an electric signal corresponding to the RGB monochromatic light, and thus, the stacked pixel unit absorbs the RGB monochromatic light through the multilayer PD pillars and converts the RGB monochromatic light into a corresponding electric signal.

Further, the stacked CIS further comprises a color filter connected with an input end of the stacked pixel unit, and before the stacked DIS absorbs RGB three-color light by using the multi-layer PD column, an imaging light signal of a light source is filtered by using the color filter to obtain visible light; accordingly, the stacked CIS absorbs RGB three-color light using the multi-layered PD columns, including: the stacked CIS absorbs three color lights of RGB in order from visible light using a plurality of PD pillars.

Optionally, the color filter is a W (white) filter.

S102, the CMOS pixel readout circuit amplifies the electrical signal and reads out the electrical signal.

After the stacked CIS converts optical signals corresponding to three color lights of RGB into electrical signals, the stacked CIS amplifies the electrical signals using a CMOS pixel readout circuit and reads out the electrical signals.

In an embodiment of the present application, 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 amplifier tube connected to the readout region; the laminated CIS amplifies an electrical signal by using a CMOS pixel readout circuit, and the process of reading the electrical signal is specifically as follows: transferring the electric signal from each layer of PD pillars to a readout region by using a transfer transistor; reading an electrical signal from a readout region; and amplifying the electric signal of the reading area by using an amplifying tube.

EXAMPLE III

The present embodiment provides a storage medium, on which a computer program is stored, and the computer readable storage medium stores one or more programs, which are executable by one or more processors and applied to a stacked complementary metal oxide semiconductor image sensor 1, and the computer program implements the image processing method according to embodiment two.

Specifically, the program instructions corresponding to an image processing method in the present embodiment, when read or executed by an electronic device, include the steps of:

In an embodiment of the present invention, further, the stacked cmos image sensor further includes a color filter connected to an input terminal of the stacked pixel unit, and the one or more programs are executed by the one or more processors before the RGB three-color light is absorbed by the multi-layered PD pillars, and further implement the following steps:

correspondingly, the absorbing of RGB three-color light by the multilayer PD pillars, the one or more programs being executed by the one or more processors, specifically implement the following steps:

In an embodiment of the present invention, further, 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, wherein the one or more programs are executed by the one or more processors, and specifically implement the steps of:

reading the electrical signal from the readout region;

The above description is only a preferred embodiment of the present application, and is not intended to limit the scope of the present application.

Claims

1. A stacked CMOS image sensor, comprising:

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;

wherein the stacked pixel unit includes three layers of PD pillars.

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;

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;

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;

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 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:

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

wherein the stacked pixel unit includes three layers of PD pillars.

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:

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:

reading the electrical signal from the readout region;

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.