CN112530986A - Image sensor pixel structure for reducing dark current and electric crosstalk - Google Patents
Image sensor pixel structure for reducing dark current and electric crosstalk Download PDFInfo
- Publication number
- CN112530986A CN112530986A CN202011413537.2A CN202011413537A CN112530986A CN 112530986 A CN112530986 A CN 112530986A CN 202011413537 A CN202011413537 A CN 202011413537A CN 112530986 A CN112530986 A CN 112530986A
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- Prior art keywords
- dark current
- image sensor
- energy
- injection layer
- pixel structure
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- 239000002131 composite material Substances 0.000 claims abstract description 23
- 238000002955 isolation Methods 0.000 claims abstract description 22
- 239000000758 substrate Substances 0.000 claims abstract description 20
- 238000002347 injection Methods 0.000 claims abstract description 19
- 239000007924 injection Substances 0.000 claims abstract description 19
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 13
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 13
- 239000010703 silicon Substances 0.000 claims abstract description 13
- 239000004065 semiconductor Substances 0.000 claims abstract description 10
- 230000005684 electric field Effects 0.000 claims abstract description 8
- 239000002184 metal Substances 0.000 claims abstract description 4
- 238000010586 diagram Methods 0.000 description 2
- 238000002513 implantation Methods 0.000 description 2
- 239000007943 implant Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14601—Structural or functional details thereof
- H01L27/1463—Pixel isolation structures
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14601—Structural or functional details thereof
- H01L27/14636—Interconnect structures
Abstract
The invention discloses an image sensor pixel structure for reducing dark current and electric crosstalk, which comprises a photosensitive element arranged in a semiconductor substrate, a shallow groove isolation, a composite injection layer of a shallow groove isolation region, a dielectric layer, a contact hole and a metal interconnection line arranged in a front side insulating medium. A composite injection layer is formed in a shallow groove isolation region between adjacent photosensitive devices, the composite injection layer comprises high-concentration low-energy N-type doping, low-concentration high-energy N-type multi-step doping and low-concentration medium-energy P-type multi-step doping, an effective concentration gradient is formed in the composite injection layer and is connected to an external bias voltage or a power supply through a contact hole, and the composite injection layer is driven by an electric field formed by the external bias voltage, so that electrons from substrate crosstalk are eliminated, and dark current generated at a shallow groove isolation and silicon-based interface is absorbed.
Description
Technical Field
The present invention relates to an image sensor pixel structure, and more particularly, to an image sensor pixel structure that reduces dark current and electrical crosstalk.
Background
The image sensor pixel is a commonly used semiconductor device at present, can convert a light image on a photosensitive surface into an electric signal in a corresponding proportional relation with the light image, and has wide application in various industries.
In the prior art, an image sensor pixel structure is shown in fig. 1, and includes a silicon substrate 101, a shallow trench isolation 102, a shallow trench implantation 103, and a photodiode 104.
The above prior art has at least the following disadvantages:
the single shallow trench implant is difficult to completely eliminate the dark current generated by the shallow trench isolation and the silicon-based interface, and also cannot eliminate electrons from substrate crosstalk.
Disclosure of Invention
It is an object of the present invention to provide an image sensor pixel structure that reduces dark current and electrical crosstalk.
The purpose of the invention is realized by the following technical scheme:
the image sensor pixel structure for reducing dark current and electric crosstalk comprises a plurality of photosensitive elements arranged in a semiconductor substrate, wherein shallow trench isolations 202 are arranged between adjacent photosensitive elements, and composite injection layers are arranged in the regions of the shallow trench isolations 202;
the front surface of the semiconductor substrate is provided with a dielectric layer 206, a metal interconnection line is arranged in the dielectric layer 206, and a contact hole 207 is arranged at a position corresponding to the composite injection layer.
According to the technical scheme provided by the invention, the image sensor pixel structure for reducing dark current and electric crosstalk provided by the embodiment of the invention has the advantages that a composite injection layer is formed in a shallow groove isolation region between adjacent photosensitive devices, the composite injection layer forms an effective concentration gradient and is connected to an external bias voltage or a power supply through a contact hole, and the composite injection layer is driven by an electric field formed by the external bias voltage, so that electrons from substrate crosstalk are eliminated, and dark current generated at a shallow groove isolation and silicon-based interface is absorbed.
Drawings
Fig. 1 is a schematic diagram of a pixel structure of an image sensor in the prior art.
Fig. 2 is a schematic diagram of an image sensor pixel structure for reducing dark current and electrical crosstalk according to an embodiment of the present invention.
In the figure:
101 Silicon substrate Silicon
Shallow Trench Isolation (STI) (shallow trench isolation) 102.
103 shallow trench implantation fld (field imp): b/10 to 30K/5E12 to 1E14.
Photodiode PD (photodiode) 104.
201 Silicon substrate Silicon
202 Shallow Trench Isolation (STI) (shallow trench isolation).
203, high-concentration low-energy N-type doping: as (or P)/10-50 KeV/1E 15-5E 15.
204 is low-concentration high-energy N-type multi-step doping of As (or P)/100-2000 KeV/3E 11-5E 12.
205 low concentration medium energy P-type multi-step doping: b/100 to 1000KeV/3E11 to 5E12.
206 dielectric layer
207 contact hole (to forward bias or power)
208 photodiode PD (photodiode)
Detailed Description
The embodiments of the present invention will be described in further detail below. Details which are not described in detail in the embodiments of the invention belong to the prior art which is known to the person skilled in the art.
The preferred embodiment of the pixel structure of the image sensor for reducing dark current and electrical crosstalk according to the present invention is shown in fig. 2:
the light-sensitive element structure comprises a plurality of light-sensitive elements arranged in a semiconductor substrate, shallow groove isolation 202 is arranged between adjacent light-sensitive elements, and a composite injection layer is arranged in the region of the shallow groove isolation 202;
the front surface of the semiconductor substrate is provided with a dielectric layer 206, a metal interconnection line is arranged in the dielectric layer 206, and a contact hole 207 is arranged at a position corresponding to the composite injection layer.
The composite implanted layer comprises high-concentration low-energy N-type doping 203, low-concentration high-energy N-type multi-step doping 204 and low-concentration medium-energy P-type multi-step doping 205, and the composite implanted layer forms an effective concentration gradient and is connected to an external bias or power supply through the contact hole 207.
The high concentration low energy N-type doping 203 comprises: as or P/10 to 50KeV/1E15 to 5E 15;
the low-concentration high-energy N-type multi-step doping 204 comprises As or P/100-2000 KeV/3E 11-5E 12;
the low concentration medium energy P-type multi-step doping 205 comprises: b/100 to 1000KeV/3E11 to 5E12.
The semiconductor substrate is a silicon substrate 201, and the photosensitive element is a photodiode 208.
The composite injection layer forms an electric field through external bias, and under the driving of the electric field, electrons from substrate crosstalk are eliminated, and dark current generated at a shallow trench isolation and silicon-based interface is absorbed.
According to the image sensor pixel structure for reducing the dark current and the electrical crosstalk, a composite injection layer is formed in a shallow groove isolation region between adjacent photosensitive devices, the composite injection layer comprises high-concentration low-energy N-type doping, low-concentration high-energy N-type multi-step doping and low-concentration medium-energy P-type multi-step doping, an effective concentration gradient is formed in the composite injection layer and is connected to an external bias voltage or a power supply through a contact hole, and electrons from substrate crosstalk are eliminated and the dark current generated at a shallow groove isolation and silicon-based interface is absorbed through an electric field formed by the external bias voltage and under the driving of the electric field.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (5)
1. An image sensor pixel structure for reducing dark current and electric crosstalk comprises a plurality of photosensitive elements arranged in a semiconductor substrate, shallow trench isolations (202) are arranged between adjacent photosensitive elements, and a composite injection layer is arranged in the regions of the shallow trench isolations (202);
the front surface of the semiconductor substrate is provided with a dielectric layer (206), a metal interconnection line is arranged in the dielectric layer (206), and a contact hole (207) is arranged at the position corresponding to the composite injection layer.
2. The image sensor pixel structure for reducing dark current and electrical crosstalk according to claim 1, wherein said composite implanted layer comprises a high concentration low energy N-type doping (203), a low concentration high energy N-type multi-step doping (204), and a low concentration medium energy P-type multi-step doping (205), said composite implanted layer forming an effective concentration gradient and being connected to an external bias or power source through said contact hole (207).
3. The image sensor pixel structure of claim 2, wherein the dark current and electrical crosstalk are reduced by:
the high concentration low energy N-type doping (203) comprises: as or P/10 to 50KeV/1E15 to 5E 15;
the low-concentration high-energy N-type multi-step doping (204) comprises As or P/100-2000 KeV/3E 11-5E 12;
the low concentration medium energy P-type multi-step doping (205) comprises: b/100 to 1000KeV/3E11 to 5E12.
4. The image sensor pixel structure for reducing dark current and electrical crosstalk of claim 3, wherein said semiconductor substrate is a silicon substrate (201) and said photosensitive element is a photodiode (208).
5. The image sensor pixel structure for reducing dark current and electrical crosstalk according to any one of claims 1 to 4, wherein the composite injection layer forms an electric field by external bias, and under the driving of the electric field, not only electrons from substrate crosstalk are eliminated, but also dark current generated at the shallow trench isolation and silicon-based interface is absorbed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011413537.2A CN112530986A (en) | 2020-12-04 | 2020-12-04 | Image sensor pixel structure for reducing dark current and electric crosstalk |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011413537.2A CN112530986A (en) | 2020-12-04 | 2020-12-04 | Image sensor pixel structure for reducing dark current and electric crosstalk |
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| Publication Number | Publication Date |
|---|---|
| CN112530986A true CN112530986A (en) | 2021-03-19 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202011413537.2A Pending CN112530986A (en) | 2020-12-04 | 2020-12-04 | Image sensor pixel structure for reducing dark current and electric crosstalk |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI815124B (en) * | 2021-03-30 | 2023-09-11 | 台灣積體電路製造股份有限公司 | Image sensor and method of forming the same |
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2020
- 2020-12-04 CN CN202011413537.2A patent/CN112530986A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI815124B (en) * | 2021-03-30 | 2023-09-11 | 台灣積體電路製造股份有限公司 | Image sensor and method of forming the same |
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