CN117457694A - Image sensor pixel with infrared enhancement function and manufacturing method thereof - Google Patents
Image sensor pixel with infrared enhancement function and manufacturing method thereof Download PDFInfo
- Publication number
- CN117457694A CN117457694A CN202311498124.2A CN202311498124A CN117457694A CN 117457694 A CN117457694 A CN 117457694A CN 202311498124 A CN202311498124 A CN 202311498124A CN 117457694 A CN117457694 A CN 117457694A
- Authority
- CN
- China
- Prior art keywords
- photosensitive material
- material layer
- electrode
- infrared
- image sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 8
- 239000000463 material Substances 0.000 claims abstract description 129
- 238000002955 isolation Methods 0.000 claims abstract description 43
- 238000009792 diffusion process Methods 0.000 claims abstract description 17
- 230000004044 response Effects 0.000 claims abstract description 4
- 239000004065 semiconductor Substances 0.000 claims description 9
- 239000000758 substrate Substances 0.000 claims description 9
- 238000000034 method Methods 0.000 abstract description 11
- 230000006870 function Effects 0.000 description 24
- 238000010586 diagram Methods 0.000 description 13
- 238000003384 imaging method Methods 0.000 description 6
- 230000010354 integration Effects 0.000 description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- 239000010703 silicon Substances 0.000 description 4
- XMWRBQBLMFGWIX-UHFFFAOYSA-N C60 fullerene Chemical compound C12=C3C(C4=C56)=C7C8=C5C5=C9C%10=C6C6=C4C1=C1C4=C6C6=C%10C%10=C9C9=C%11C5=C8C5=C8C7=C3C3=C7C2=C1C1=C2C4=C6C4=C%10C6=C9C9=C%11C5=C5C8=C3C3=C7C1=C1C2=C4C6=C2C9=C5C3=C12 XMWRBQBLMFGWIX-UHFFFAOYSA-N 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 229910003472 fullerene Inorganic materials 0.000 description 3
- 239000006096 absorbing agent Substances 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 238000002329 infrared spectrum Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 239000002861 polymer material Substances 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 229910000530 Gallium indium arsenide Inorganic materials 0.000 description 1
- 229910000661 Mercury cadmium telluride Inorganic materials 0.000 description 1
- 206010070834 Sensitisation Diseases 0.000 description 1
- MCEWYIDBDVPMES-UHFFFAOYSA-N [60]pcbm Chemical compound C123C(C4=C5C6=C7C8=C9C%10=C%11C%12=C%13C%14=C%15C%16=C%17C%18=C(C=%19C=%20C%18=C%18C%16=C%13C%13=C%11C9=C9C7=C(C=%20C9=C%13%18)C(C7=%19)=C96)C6=C%11C%17=C%15C%13=C%15C%14=C%12C%12=C%10C%10=C85)=C9C7=C6C2=C%11C%13=C2C%15=C%12C%10=C4C23C1(CCCC(=O)OC)C1=CC=CC=C1 MCEWYIDBDVPMES-UHFFFAOYSA-N 0.000 description 1
- KXNLCSXBJCPWGL-UHFFFAOYSA-N [Ga].[As].[In] Chemical compound [Ga].[As].[In] KXNLCSXBJCPWGL-UHFFFAOYSA-N 0.000 description 1
- XHCLAFWTIXFWPH-UHFFFAOYSA-N [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] XHCLAFWTIXFWPH-UHFFFAOYSA-N 0.000 description 1
- 239000011358 absorbing material Substances 0.000 description 1
- MCMSPRNYOJJPIZ-UHFFFAOYSA-N cadmium;mercury;tellurium Chemical compound [Cd]=[Te]=[Hg] MCMSPRNYOJJPIZ-UHFFFAOYSA-N 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002513 implantation Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 230000031700 light absorption Effects 0.000 description 1
- XZWYZXLIPXDOLR-UHFFFAOYSA-N metformin Chemical compound CN(C)C(=N)NC(N)=N XZWYZXLIPXDOLR-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 230000008313 sensitization Effects 0.000 description 1
- 239000002210 silicon-based material Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 229910001935 vanadium oxide Inorganic materials 0.000 description 1
- 230000005570 vertical transmission Effects 0.000 description 1
- 235000012431 wafers Nutrition 0.000 description 1
Classifications
-
- 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
- H01L27/14609—Pixel-elements with integrated switching, control, storage or amplification elements
- H01L27/1461—Pixel-elements with integrated switching, control, storage or amplification elements characterised by the photosensitive area
-
- 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
-
- 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
- H01L27/14632—Wafer-level processed structures
-
- 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
- H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
- H01L27/14687—Wafer level processing
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K39/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic radiation-sensitive element covered by group H10K30/00
- H10K39/30—Devices controlled by radiation
- H10K39/32—Organic image sensors
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Power Engineering (AREA)
- Electromagnetism (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Manufacturing & Machinery (AREA)
- Solid State Image Pick-Up Elements (AREA)
Abstract
The application relates to an image sensor pixel with infrared enhancement function, including incident face and with the non-incident face that the incident face is opposite, its characterized in that, image sensor pixel includes: an infrared photosensitive material layer disposed proximate to the incident face or the non-incident face, the infrared photosensitive material layer generating a second photo-generated charge in response to incident light; the first electrode and the second electrode are used for collecting the second photo-generated charge generated by the infrared photosensitive material layer and transferring the second photo-generated charge to a floating diffusion point; and the isolation structure is perpendicular to the incident surface and surrounds the infrared photosensitive material layer and is used for isolating adjacent pixels, wherein the adjacent pixels are RGB pixels. The method and the device can improve the electrical performance of the image sensor in the near infrared band.
Description
Technical Field
The embodiment of the application relates to the technical field of image sensors, in particular to an image sensor pixel with an infrared enhancement function and a manufacturing method thereof.
Background
Image sensors have been widely used in consumer electronics, security, industry, etc., and are also gradually beginning to be applied in the fields of natural environment monitoring, agricultural product detection, military seekers, reconnaissance equipment, etc. However, the quantum efficiency of the pixel structure of the conventional image sensor in the Near Infrared (NIR) band is low, for example, the quantum efficiency in the 850nm band is about 10%, and the quantum efficiency in the 940nm band is only about 4%, so that in some application scenarios with high requirement on the sensitivity of the NIR band, the conventional image sensor is often difficult to be qualified, and how to enhance the sensitivity of the image sensor in the NIR band becomes important.
Disclosure of Invention
The technical problem solved by the embodiment of the application is to provide the image sensor pixel with the infrared enhancement function and the manufacturing method thereof, and the electrical performance of the image sensor in the NIR band is improved.
To solve the above-mentioned problem, in a first aspect, an embodiment of the present application provides an image sensor pixel with an infrared enhancement function, including an incident surface and a non-incident surface opposite to the incident surface, where the image sensor pixel includes: an infrared photosensitive material layer disposed proximate to the incident face or the non-incident face, the infrared photosensitive material layer generating a second photo-generated charge in response to incident light; the first electrode and the second electrode are used for collecting the second photo-generated charge generated by the infrared photosensitive material layer and transferring the second photo-generated charge to a floating diffusion point; and the isolation structure is perpendicular to the incident surface and surrounds the infrared photosensitive material layer and is used for isolating adjacent pixels, wherein the adjacent pixels are RGB pixels.
Optionally, the infrared photosensitive material layer is disposed near the incident surface, where the first electrode is disposed on a surface of the infrared photosensitive material layer near the incident surface, and the first electrode is a transparent electrode; the second electrode is arranged on the surface of the infrared photosensitive material layer, which is far away from the incident surface; or the first electrode is arranged on the incidence surface, and the first electrode is a transparent electrode; the second electrode is arranged on the non-incident surface, and is electrically connected with the infrared photosensitive material layer through heavy doping; or the first electrode and the second electrode are respectively arranged on two opposite side surfaces of the infrared photosensitive material layer.
Optionally, the isolation structure starts from the incident surface and vertically extends to the non-incident surface; or the isolation structure starts from the incidence surface and vertically extends to the surface, close to the non-incidence surface, of the infrared photosensitive material layer; or the isolation structure extends vertically from the incident surface until it is at least flush with the lower surface of the photodiode in the adjacent pixel in the horizontal direction.
Optionally, the infrared photosensitive material layer is disposed near the non-incident surface, where the first electrode is disposed on a surface of the infrared photosensitive material layer away from the non-incident surface, and the first electrode is a transparent electrode; the second electrode is arranged on the surface, close to the non-incident surface, of the infrared photosensitive material layer; or the first electrode is arranged on the incident surface, the first electrode and the infrared photosensitive material layer are electrically connected through heavy doping, and the first electrode is a transparent electrode; the second electrode is arranged on the non-incident surface; or the first electrode and the second electrode are respectively arranged on two opposite side surfaces of the infrared photosensitive material layer.
Optionally, a transparent insulating layer is formed between the infrared photosensitive material layer and the photodiode.
Optionally, the isolation structure starts from the incident surface and vertically extends to the non-incident surface; or the isolation structure comprises a first section and a second section, wherein the first section starts from the incident surface and extends vertically until at least the first section is flush with the lower surface of the photodiode in the adjacent pixel; the second segment starts from the non-incident face and extends vertically until at least flush with a surface of the infrared photosensitive material layer remote from the non-incident face.
Optionally, the material of the infrared photosensitive material layer is an organic photosensitive material or an inorganic photosensitive material, the thickness range of the organic photosensitive material is 300 nm-6000 nm, the material of the infrared photosensitive material layer is an inorganic photosensitive material, and the thickness range of the inorganic photosensitive material is 700 nm-6000 nm.
In a second aspect, an embodiment of the present application further provides an image sensor pixel array with an infrared enhancement function, including a plurality of the image sensor pixels and RGB pixels.
In a third aspect, an embodiment of the present application further provides an image sensor with an infrared enhancement function, including the image sensor pixel array.
In a fourth aspect, embodiments of the present application further provide a method for manufacturing an image sensor pixel having an infrared enhancement function, including: providing a semiconductor substrate, forming RGB pixels on the semiconductor substrate, wherein the pixels comprise: a photodiode, a floating diffusion point, a first transfer tube; forming a first opening at a position close to the RGB pixel, wherein the first opening is positioned on the incidence surface or the non-incidence surface; filling infrared photosensitive material into the first opening to form an infrared photosensitive material layer, and a first electrode and a second electrode connected with the infrared photosensitive material layer, so as to form an IR pixel; an isolation structure is formed between the RGB pixels and the IR pixels.
Compared with the prior art, the technical scheme of the embodiment of the application has the following advantages:
the embodiment of the application provides an image sensor pixel with an infrared enhancement function, which can improve the electrical performance of an image sensor in an NIR (near infrared) band; the image sensor pixel provided by the embodiment can realize imaging of a short wave infrared band exceeding 1100nm through the infrared photosensitive material layer; and the pixel integration level of the image sensor provided by the implementation is higher, heterogeneous integration can be realized through a hybrid bonding technology, and a sense and calculation integrated function is realized.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present application, and that other drawings may be obtained according to the provided drawings without inventive effort to a person skilled in the art.
Fig. 1 is a schematic structural diagram of an image sensor pixel with infrared enhancement function according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an electrode arrangement of the pixel of the image sensor shown in FIG. 1;
FIG. 3 is a schematic diagram of another electrode arrangement of the pixel of the image sensor shown in FIG. 1;
FIG. 4 is a schematic diagram of another electrode arrangement of the pixel of the image sensor shown in FIG. 1;
FIG. 5 is a schematic diagram of an image sensor pixel with infrared enhancement according to another embodiment of the present invention;
FIG. 6 is a schematic diagram of an electrode arrangement of the pixel of the image sensor shown in FIG. 5;
FIG. 7 is a schematic diagram of another electrode arrangement of the pixel of the image sensor shown in FIG. 5;
FIG. 8 is a schematic diagram of another electrode arrangement of the pixel of the image sensor shown in FIG. 5;
FIG. 9 is a schematic diagram of another electrode arrangement of the pixel of the image sensor shown in FIG. 5;
FIG. 10 is a schematic diagram of a photodiode and a readout circuit according to an embodiment of the present invention;
FIG. 11 is a schematic diagram of an infrared photosensitive material layer and a readout circuit according to an embodiment of the present invention;
fig. 12 is a flowchart of a method for manufacturing an image sensor pixel with infrared enhancement according to an embodiment of the present invention.
Detailed Description
As known from the background art, the existing image sensor has low quantum efficiency in the near infrared band and poor imaging performance. The specific reason is mainly that the depth of the photodiode of the existing image sensor is shallow, so that the red light quantum efficiency is low.
One of the main solutions in the prior art is to increase the thickness of the absorbing layer, and to enhance the absorption of near infrared light by increasing the silicon thickness. But limited to processes such as high energy implantation, the method of increasing the thickness of the absorber layer is difficult to implement, and even if the thickness of the absorber layer is increased, it is generally only possible to optimize to 940nm band, and the short wave infrared band silicon material exceeding 1100nm is no longer responsive.
Another solution is to enhance the optical path of near infrared light by changing the pixel structure of the image sensor so that the incident light is diffracted at the incident surface of the silicon. Specifically, for example, a back scattering structure is adopted, the incident light can be scattered by the scattering structure in the middle of the pixel, and the incident light is reflected between the pixel isolation structures after being scattered, so that the absorption of near infrared light is increased; or for example, an inverted pyramid structure, which can also increase the optical path length and thus enhance light absorption. The above technical solution can enhance near infrared light to a certain extent, but the improvement effect of quantum efficiency in the near infrared light band still cannot meet the requirements of some scenes, and the thickness of the pixel cannot be increased infinitely.
To solve the above technical problems, an embodiment of the present invention provides an image sensor pixel with an infrared enhancement function, including:
the image sensor pixel with the infrared enhancement function can improve the electrical performance of the image sensor in the NIR band.
In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.
Fig. 1 to 4 are schematic structural diagrams of an image sensor pixel 100 with infrared enhancement function according to an embodiment of the present invention.
The image sensor pixel 100 includes an incident surface 101 and a non-incident surface 102 opposite to the incident surface 101, and incident light enters the image sensor pixel 100 after entering from the incident surface 101.
The image sensor pixel 100 further includes: the semiconductor substrate 110, the infrared photosensitive material layer 170, the isolation structure 160, the first electrode, and the second electrode. The infrared photosensitive material layer 170 is used for photosensitive infrared spectrum and converting received infrared light into second photo-generated charges. The second photo-generated charge generated by the infrared photosensitive material layer 170 is collected by the first electrode and the second electrode and transferred to the floating diffusion point. The infrared photosensitive material layer 170 is disposed near the incident surface 101 in this embodiment.
The infrared photosensitive material layer 170 is used to absorb infrared light, and in some embodiments the infrared photosensitive material layer 170 is formed by filling a near infrared light absorbing material inside the pixels.
In some embodiments, the infrared photosensitive material of the infrared photosensitive material layer 170 is an inorganic photosensitive material, such as vanadium oxide, indium gallium arsenide, mercury cadmium telluride, inAsPSb, inGaAsSb, and the like. The thickness range of the inorganic photosensitive material is 700 nm-6000 nm.
In some embodiments, the infrared photosensitive material of the infrared photosensitive material layer 170 is an organic infrared photosensitive material, and the organic infrared photosensitive material may be a polymer material, a small molecular material, a fullerene material, or a non-fullerene material, and specifically, the organic infrared photosensitive material may be a PTT film, a polymer material PDDTT, a fullerene material PC61BM, PDTTP, DTBTT, or the like. The thickness of the organic photosensitive material ranges from 300nm to 6000nm, preferably from 500nm to 3000nm.
The first electrode and the second electrode are used for collecting the second photo-generated charge generated by the infrared photosensitive material layer 170 and transferring the second photo-generated charge to a floating diffusion point.
In some embodiments, referring to fig. 2, electrodes are formed on upper and lower surfaces of the infrared photosensitive material layer 170, and the first electrode 171 and the second electrode 172 are disposed on upper and lower opposite surfaces of the infrared photosensitive material layer 170, respectively. Specifically, the first electrode 171 is disposed on a surface of the infrared photosensitive material layer 170 near the incident surface 101, the first electrode 171 may be a transparent electrode so that incident light is incident on the infrared photosensitive material layer 170 as much as possible, and the second electrode 172 is disposed on a surface of the infrared photosensitive material layer 170 far from the incident surface 101.
In some embodiments, referring to fig. 3, electrodes are formed on upper and lower surfaces of a pixel layer, and the first electrode 171 and the second electrode 172 are disposed on upper and lower opposite surfaces of the pixel layer, respectively. Specifically, the first electrode 171 is disposed on the incident surface 101, the first electrode 171 may be a transparent electrode so that the incident light is incident on the infrared photosensitive material layer 170 as much as possible, and the second electrode 172 is disposed on the non-incident surface 102. In some embodiments, an electrical connection may be formed between the second electrode 172 and the infrared photosensitive material layer 170 through heavy doping.
In some embodiments, referring to fig. 4, electrodes are formed at two opposite sides of the infrared photosensitive material layer 170, and the first electrode 171 and the second electrode 172 are respectively disposed at two opposite side surfaces of the infrared photosensitive material layer 170. As an example, the first electrode 171 is disposed on the left side of the infrared photosensitive material layer 170, and the second electrode 172 is disposed on the right side of the infrared photosensitive material layer 170.
The isolation structures 160 are disposed perpendicular to the incident surface 101 and around the infrared photosensitive material layer 170, and the isolation structures 160 are used to isolate adjacent pixels. In some embodiments, the isolation structures 160 are deep trench isolation structures (Deep Trench Isolation, DTI).
In some embodiments, the isolation structures 160 extend vertically from the incident face 101 of the pixel to the non-incident face 102 of the pixel, isolating the pixel 100 from adjacent RGB pixels 200; in some embodiments, the isolation structures 160 extend vertically from the incident face 101 of the pixel to the surface of the infrared photosensitive material layer 170 near the non-incident face 102, isolating the infrared photosensitive material layer 170 from the adjacent RGB pixels 200; in some embodiments, the isolation structures 160 extend vertically from the incident surface 101 of the pixel to be substantially flush with the lower surface of the Photodiodes (PD) 220 in the RGB pixel 200 in the horizontal direction, isolating the infrared photosensitive material layer 170 from the adjacent photodiodes 220.
It can be seen that, in the embodiment, the image sensor pixel with the infrared enhancement function is provided, so that the electrical performance of the image sensor in the NIR band can be improved; the image sensor pixel provided by the embodiment can realize imaging of a short wave infrared band exceeding 1100nm through the infrared photosensitive material layer; and the integration level is higher, heterogeneous integration can be realized through a hybrid bonding technology, and a sense calculation integrated function is realized.
Compared with the existing compound infrared focal plane detector based on tellurium-cadmium-mercury and other materials, the pixel of the image sensor provided by the embodiment is lower, and color imaging can be realized.
Fig. 5 to 8 are schematic structural diagrams of an image sensor pixel 300 with infrared enhancement function according to another embodiment of the present invention.
The image sensor pixel 300 includes an incident surface 301 and a non-incident surface 302 opposite to the incident surface 301, and incident light enters the image sensor pixel 300 after entering from the incident surface 301.
The image sensor pixel 300 further includes: a semiconductor substrate 310, an infrared photosensitive material layer 370, an isolation structure 360, a first electrode, and a second electrode. The infrared photosensitive material layer 370 is used for photosensitive of infrared spectrum and converting received infrared light into a second photo-generated charge. The second photo-generated charge generated by the infrared photosensitive material layer 370 is collected by the first electrode and the second electrode and transferred to the floating diffusion point. The difference between this embodiment and the image sensor pixel 100 shown in fig. 1 is that the infrared photosensitive material layer 370 is disposed near the non-incident surface 302.
The first electrode and the second electrode are used for collecting the second photo-generated charge generated by the infrared photosensitive material layer 370 and transferring the second photo-generated charge to a floating diffusion point.
In some embodiments, referring to fig. 6, electrodes are formed on upper and lower surfaces of the infrared photosensitive material layer 370, and the first electrode 371 and the second electrode 372 are disposed on upper and lower opposite surfaces of the infrared photosensitive material layer 370, respectively. Specifically, the first electrode 371 is disposed on a surface of the infrared photosensitive material layer 370 away from the non-incident surface 302, the first electrode 371 may be a transparent electrode so that incident light is incident on the infrared photosensitive material layer 370 as much as possible, and the second electrode 372 is disposed on a surface of the infrared photosensitive material layer 370 close to the non-incident surface 302.
In some embodiments, referring to fig. 7, electrodes are formed on upper and lower surfaces of a pixel layer, and the first electrode 371 and the second electrode 372 are disposed on upper and lower opposite surfaces of the pixel layer, respectively. Specifically, the first electrode 371 is disposed on the incident surface 301, the first electrode 371 may be a transparent electrode so that the incident light is incident on the infrared photosensitive material layer 370 as much as possible, and the second electrode 372 is disposed on the non-incident surface 302. In some embodiments, an electrical connection may be formed between the first electrode 371 and the infrared photosensitive material layer 370 through heavy doping.
In some embodiments, referring to fig. 8, electrodes are formed on two opposite sides of the infrared photosensitive material layer 370, and the first electrode 371 and the second electrode 372 are respectively disposed on two opposite side surfaces of the infrared photosensitive material layer 370. As an example, the first electrode 371 is disposed at the left side of the infrared photosensitive material layer 370, and the second electrode 372 is disposed at the right side of the infrared photosensitive material layer 170.
The isolation structures 360 are arranged perpendicular to the incident surface 301 and around the infrared photosensitive material layer 370, and the isolation structures 360 are used to isolate adjacent pixels. In some embodiments, the isolation structures 360 are deep trench isolation structures (Deep Trench Isolation, DTI).
In some embodiments, referring to fig. 5, the isolation structures 360 are fully depth isolated, the isolation structures 360 extend vertically from the incident plane 301 of the pixel to the non-incident plane 302 of the pixel, thereby isolating the pixel 300 from the adjacent RGB pixels 200, such an isolation scheme enables complete isolation between the G/R/B/IR pixels, preventing cross-talk between pixels.
In some embodiments, referring to fig. 6-9, the isolation structure 360 is a segmented isolation, and a first segment of the isolation structure 360 starts from the incident surface 301 and extends vertically until it is substantially level with the lower surface of the Photodiode (PD) 220 in the RGB pixel 200 in the horizontal direction, i.e., isolates the Photodiode 220; the second segment of the isolation structure 360, starting from the non-incident surface 302, extends vertically to the surface of the infrared photosensitive material layer 370 remote from the non-incident surface 302, i.e., isolates the infrared photosensitive material layer 370. This isolation scheme also enables isolation between adjacent pixels and is easier to implement in the etching process.
In some embodiments, referring to fig. 9, a transparent insulating layer 400 is formed between the visible light pixel layer and the infrared photosensitive material layer 370, the transparent insulating layer 400 being a layer of transparent insulating material including, but not limited to, siO for example 2 Etc. The transparent insulating layer 400 may be made of SOI (Silicon On Insulator) wafers, and the thickness of the transparent insulating layer 400 may range from 0.2um to 3 um. The transparent insulating layer 400 can isolate the visible light pixel layer from the IR photosensitive layer, and can effectively prevent electrical crosstalk between the visible light layer and the infrared layer.
Accordingly, the embodiment of the present invention further provides an image sensor pixel array with an infrared enhancement function, which includes a plurality of image sensor pixels, for example, the image sensor pixel 100 with the infrared enhancement function and the RGB pixel 200.
In some embodiments, referring to fig. 1 to 9, the image sensor pixel array includes 4 pixel structures, and the wavelength bands of pixel sensitization are sequentially green (G), red (R), blue (B), and Infrared (IR) from top left to bottom right. It will be appreciated that the image sensor pixel array provided in this embodiment is not limited to the above-described pixel arrangement and number of pixels.
In some embodiments, the RGB pixel 200 further includes a photodiode 220, a first transfer gate (Transmission Gate, TG), a floating diffusion point (Floating Diffusion, FD). The photodiode 220 is located in a semiconductor substrate, and the photodiode 220 generates a first photo-generated charge in response to incident light, in particular, the incident light is collected by the photodiode 220 and converted by the photodiode 220 to generate the first photo-generated charge. In some embodiments, the photodiode 220 is a silicon-based photodiode, and the thickness of the photodiode 220 may range from 4 microns to 6 microns, for example, may be about 5 microns. The first transfer gate is used for transferring the first photo-generated charge, and specifically, the first photo-generated charge generated by the photodiode 220 is transferred into the floating diffusion point through the first transfer gate. In some embodiments, the first transfer gate is disposed below the photodiode 220, and the first transfer gate may be a planar transfer gate (Transmission Gate, TG) or a vertical transfer gate (Vertical Transmission Gate, VTG). The floating diffusion point (Floating Diffusion, FD) is used to store a first photo-generated charge transferred from the photodiode 220 and is also used to store a second photo-generated charge transferred by the infrared photosensitive material layer 170. The floating diffusion point is connected to the readout circuit, and the voltage of the floating diffusion point is read out by the readout circuit. Referring to fig. 10, in some embodiments, the readout circuit 230 of the RGB pixel 200 includes at least 4 transistors, namely a transfer transistor, a reset transistor, a source follower transistor, and a select transistor. Referring to fig. 11, the readout circuit 380 of the image sensor pixel 100 with infrared enhancement function includes a reset transistor, a source follower transistor, and a select transistor.
Correspondingly, the embodiment of the invention also provides an image sensor with the infrared enhancement function, which comprises the image sensor pixel array with the infrared enhancement function.
Correspondingly, referring to fig. 12, the embodiment of the invention further provides a method for manufacturing an image sensor pixel array with an infrared enhancement function, which comprises the following steps:
s100, providing a semiconductor substrate, forming RGB pixels on the semiconductor substrate, wherein the pixels comprise: a photodiode, a floating diffusion point, a first transfer tube.
In some embodiments, the gate of the first transfer tube adopts a planar transfer gate or a vertical transfer gate structure.
In some embodiments, adjacent pixels are isolated from each other using deep trench isolation structures.
In some embodiments, the pixel layer further comprises readout circuitry.
And S200, forming a first opening at the adjacent position of the RGB pixel, wherein the first opening is positioned on the incidence surface or the non-incidence surface.
In some embodiments, the first opening is formed using an etching process.
And S300, filling the infrared photosensitive material into the first opening to form an infrared photosensitive material layer, and connecting a first electrode and a second electrode with the infrared photosensitive material layer to form an IR pixel.
In some embodiments, the infrared photosensitive material layer may be formed by a spray, deposition, or growth process. The infrared photosensitive material layer can be an organic photosensitive material or an inorganic photosensitive material.
S400, forming an isolation structure between the RGB pixels and the IR pixels.
It can be seen that, in the embodiment, the image sensor pixel with the infrared enhancement function is provided, so that the electrical performance of the image sensor in the NIR band can be improved; the image sensor pixel provided by the embodiment can realize imaging of a short wave infrared band exceeding 1100nm through the infrared photosensitive material layer; and the integration level is higher, heterogeneous integration can be realized through a hybrid bonding technology, and a sense calculation integrated function is realized. Compared with the existing compound infrared focal plane detector based on tellurium-cadmium-mercury and other materials, the pixel of the image sensor provided by the embodiment is lower, and color imaging can be realized.
It should be noted that, in the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described as different from other embodiments, and identical and similar parts between the embodiments are all enough to be referred to each other. For the apparatus class embodiments, the description is relatively simple as it is substantially similar to the method embodiments, and reference is made to the description of the method embodiments for relevant points.
Although the embodiments of the present application are disclosed above, the present application is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention shall be defined by the appended claims.
Claims (10)
1. An image sensor pixel with infrared enhancement comprising an entrance face and a non-entrance face opposite the entrance face, the image sensor pixel comprising:
an infrared photosensitive material layer disposed proximate to the incident face or the non-incident face, the infrared photosensitive material layer generating a second photo-generated charge in response to incident light;
the first electrode and the second electrode are used for collecting the second photo-generated charge generated by the infrared photosensitive material layer and transferring the second photo-generated charge to a floating diffusion point;
and the isolation structure is perpendicular to the incident surface and surrounds the infrared photosensitive material layer and is used for isolating adjacent pixels, wherein the adjacent pixels are RGB pixels.
2. The image sensor pixel of claim 1, wherein the infrared photosensitive material layer is disposed proximate the entrance face, wherein,
the first electrode is arranged on the surface of the infrared photosensitive material layer, which is close to the incident surface, and is a transparent electrode; the second electrode is arranged on the surface of the infrared photosensitive material layer, which is far away from the incident surface; or alternatively
The first electrode is arranged on the incidence surface and is a transparent electrode; the second electrode is arranged on the non-incident surface, and is electrically connected with the infrared photosensitive material layer through heavy doping; or alternatively
The first electrode and the second electrode are respectively arranged on two opposite side surfaces of the infrared photosensitive material layer.
3. The image sensor pixel of claim 2 wherein,
the isolation structure vertically extends from the incidence surface to the non-incidence surface; or alternatively
The isolation structure vertically extends to the surface, close to the non-incident surface, of the infrared photosensitive material layer from the incident surface; or alternatively
The isolation structure extends vertically from the incident surface until at least flush with a lower surface of the photodiode in the adjacent pixel in a horizontal direction.
4. The image sensor pixel of claim 1, wherein the infrared photosensitive material layer is disposed adjacent to the non-incident surface, wherein,
the first electrode is arranged on the surface, far away from the non-incident surface, of the infrared photosensitive material layer, and is a transparent electrode; the second electrode is arranged on the surface, close to the non-incident surface, of the infrared photosensitive material layer; or alternatively
The first electrode is arranged on the incident surface, and is electrically connected with the infrared photosensitive material layer through heavy doping, and is a transparent electrode; the second electrode is arranged on the non-incident surface; or alternatively
The first electrode and the second electrode are respectively arranged on two opposite side surfaces of the infrared photosensitive material layer.
5. The image sensor pixel of claim 4, wherein a transparent insulating layer is formed between the infrared photosensitive material layer and the photodiode.
6. The image sensor pixel of claim 1 wherein,
the isolation structure vertically extends from the incidence surface to the non-incidence surface; or alternatively
The isolation structure comprises a first section and a second section, wherein the first section is started by the incidence surface and vertically extends until at least the first section is flush with the lower surface of the photodiode in the adjacent pixel; the second segment starts from the non-incident face and extends vertically until at least flush with a surface of the infrared photosensitive material layer remote from the non-incident face.
7. The image sensor pixel of claim 1, wherein the material of the infrared photosensitive material layer is an organic photosensitive material or an inorganic photosensitive material, the thickness of the organic photosensitive material ranges from 300nm to 6000nm, and the thickness of the inorganic photosensitive material ranges from 700nm to 6000nm.
8. An image sensor pixel array with infrared enhancement comprising a plurality of image sensor pixels as claimed in any one of claims 1 to 7 and RGB pixels.
9. An image sensor with infrared enhancement function comprising the image sensor pixel array of claim 8.
10. A method of manufacturing an image sensor pixel array with infrared enhancement, comprising the steps of:
providing a semiconductor substrate, forming RGB pixels on the semiconductor substrate, wherein the pixels comprise: a photodiode, a floating diffusion point, a first transfer tube;
forming a first opening at a position close to the RGB pixel, wherein the first opening is positioned on the incidence surface or the non-incidence surface;
filling infrared photosensitive material into the first opening to form an infrared photosensitive material layer, and a first electrode and a second electrode connected with the infrared photosensitive material layer, so as to form an IR pixel;
an isolation structure is formed between the RGB pixels and the IR pixels.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311498124.2A CN117457694A (en) | 2023-11-10 | 2023-11-10 | Image sensor pixel with infrared enhancement function and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311498124.2A CN117457694A (en) | 2023-11-10 | 2023-11-10 | Image sensor pixel with infrared enhancement function and manufacturing method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117457694A true CN117457694A (en) | 2024-01-26 |
Family
ID=89596466
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311498124.2A Pending CN117457694A (en) | 2023-11-10 | 2023-11-10 | Image sensor pixel with infrared enhancement function and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117457694A (en) |
-
2023
- 2023-11-10 CN CN202311498124.2A patent/CN117457694A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10411057B2 (en) | Image sensor | |
| US20050212045A1 (en) | Photo-detecting device | |
| CN104681573A (en) | Solid-state imaging element, manufacturing method, and electronic device | |
| US9379158B2 (en) | Optical detector unit | |
| US10770505B2 (en) | Per-pixel performance improvement for combined visible and ultraviolet image sensor arrays | |
| KR20110053796A (en) | Infrared image sensor | |
| US8212901B2 (en) | Backside illuminated imaging sensor with reduced leakage photodiode | |
| US20180342543A1 (en) | Backside illuminated cmos image sensor and method of fabricating the same | |
| US11670661B2 (en) | Image sensor and method of fabricating same | |
| WO2019085374A1 (en) | Photosensitive detector, imaging chip formed using same, and detection method | |
| KR102507474B1 (en) | Image sensor | |
| CN105428379B (en) | The method for improving back-illuminated type infrared image sensor performance | |
| CN112331684B (en) | Image sensor and method of forming the same | |
| US20190214428A1 (en) | Germanium-modified, back-side illuminated optical sensor | |
| US11749699B2 (en) | Solid-state image sensor with pillar surface microstructure and method of fabricating the same | |
| CN111129053B (en) | Pixel unit structure of CMOS image sensor and forming method | |
| US20100026824A1 (en) | Image sensor with reduced red light crosstalk | |
| US20110198499A1 (en) | Near-infrared photodetectors, image sensors employing the same, and methods of manufacturing the same | |
| CN111146221A (en) | Wide-spectrum image sensor structure and forming method | |
| CN109065564B (en) | Image sensor and forming method thereof | |
| KR20150027449A (en) | Image sensor and method for manufacturing the same | |
| CN117457694A (en) | Image sensor pixel with infrared enhancement function and manufacturing method thereof | |
| US20230036152A1 (en) | Image sensor | |
| KR20150055663A (en) | Image sensor and method for manufacturing the same | |
| CN117476722A (en) | Image sensor pixel with infrared enhancement function and manufacturing method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |