Image sensor, manufacturing method thereof and imaging system
By injecting hydrocarbon phosphorus ion clusters into the image sensor substrate to form a diffusion barrier layer and activate the ion clusters, the white point and transient noise problems are solved, and the imaging quality of the image sensor is improved.
Patent Information
- Application Number
- CN202510607289.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-12
- Publication Date
- 2025-08-19
AI Technical Summary
The large number of white points in the image sensor and the poor transient noise affect the imaging quality, which is mainly caused by oxygen impurities, metal impurities and interface defects in the substrate.
The hydrocarbon phosphorus ion cluster is injected into the image sensor substrate to form an absorbing and diffusion barrier layer, and ion clusters are activated in the epitaxial structure, including carbon ions and gap silicon clusters, as well as phosphorus ions and gap silicon clusters, blocking the diffusion of oxygen impurities and adsorbing metal impurities. At the same time, hydrogen ions and interface hanging bond pairing reduce the interface state density.
Reduce the number of white dots, improve the imaging quality of the image sensor, reduce transient noise, and improve the overall performance of the image sensor.
Smart Images
Figure CN120512937A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductors, and in particular to an image sensor, a manufacturing method thereof, and an imaging system. Background Art
[0002] In the absence of light, an image sensor's pixel output differs by more than a certain value from the average output of surrounding pixels, resulting in a white pixel (WP). White pixel is a key performance indicator for image sensors, directly reflecting their imaging quality. It is closely related to factors such as metal contamination, interface state density, and design.
[0003] Currently, several factors contribute to white spots. First, oxygen in the image sensor substrate: The substrate is typically silicon, and due to the growth process (typically using the CZ method (Czochralski, a single crystal growth method)), the silicon substrate contains a high concentration of oxygen impurities. During the subsequent image sensor manufacturing process, oxygen in the silicon substrate diffuses from the silicon substrate into the device active area, forming oxygen-related deep energy level defects and recombination centers, which in turn affect white spots. Second, metallic impurities in the substrate and those introduced during the process: Metallic impurities can enter the device active area, forming deep energy level defects in the silicon band gap, which in turn form recombination centers, causing metal contamination and increasing white spots. Third, the defect density at the silicon-silicon dioxide interface: Silicon atoms are periodically arranged within the crystal, but the outermost layer of silicon atoms is missing a layer of silicon atoms, disrupting this periodicity and creating dangling bonds on the surface. Unpaired dangling bonds are unstable, leading to an increase in white spots and deteriorating transient noise, ultimately reducing the image quality of the image sensor.
[0004] Therefore, how to solve the above technical problems should be the focus of those skilled in the art. Summary of the Invention
[0005] The purpose of this application is to provide an image sensor and its manufacturing method, and an imaging system to reduce the number of white spots and improve imaging quality.
[0006] To solve the above technical problems, the present application provides a method for manufacturing an image sensor, comprising:
[0007] preparing the substrate;
[0008] implanting carbon-hydrogen-phosphorus ion clusters into the substrate to form a first gettering diffusion barrier layer in the substrate;
[0009] An epitaxial structure is grown on the upper surface of the substrate, and ions in the first gettering diffusion barrier layer are activated to form clusters, wherein the clusters include clusters formed by carbon ions and interstitial silicon clusters and clusters formed by phosphorus ions and interstitial silicon clusters; the epitaxial structure includes at least one epitaxial layer.
[0010] Optionally, the number of the epitaxial layers is at least two, and growing an epitaxial structure on the upper surface of the substrate includes:
[0011] Step S11: growing a first epitaxial layer on the upper surface of the substrate;
[0012] Step S12: implanting carbon, hydrogen, and phosphorus ion clusters into the first epitaxial layer to form a second gettering diffusion barrier layer in the first epitaxial layer;
[0013] Step S13: growing a second epitaxial layer on the upper surface of the first epitaxial layer, and activating ions in the second gettering diffusion barrier layer to form clusters, wherein the clusters include clusters formed by carbon ions and interstitial silicon clusters and clusters formed by phosphorus ions and interstitial silicon clusters;
[0014] Step S14: determining whether the number of epitaxial layers reaches a preset threshold;
[0015] Step S15: If the number of epitaxial layers does not reach the preset threshold, the second epitaxial layer is used as a new first epitaxial layer, and the process proceeds to step S12 until the number of epitaxial layers reaches the preset threshold.
[0016] Optionally, before growing the first epitaxial layer on the upper surface of the substrate, the method further comprises:
[0017] The upper surface of the substrate is baked in a reducing atmosphere to remove oxides on the surface of the substrate.
[0018] Optionally, before growing the second epitaxial layer on the upper surface of the first epitaxial layer, the method further includes:
[0019] The upper surface of the second epitaxial layer is baked in a reducing atmosphere to remove oxide on the surface of the second epitaxial layer.
[0020] Optionally, the baking temperature ranges from 800°C to 900°C.
[0021] Optionally, the ratio of carbon ions, hydrogen ions and phosphorus ions in the carbon-hydrogen-phosphorus ion cluster is in the range of 1:1:1 to 1:3:1.
[0022] Optionally, when the carbon hydrogen phosphorus ion cluster is injected into the substrate, the injection energy is 80KeV~120KeV and the injection dose is 5E14 atoms / cm 2 ~ 5E15 atoms / cm 2 .
[0023] Optionally, the thickness of the second epitaxial layer is greater than the thickness of the first epitaxial layer.
[0024] The present application also provides an image sensor, which is manufactured using any of the above-mentioned methods for manufacturing an image sensor.
[0025] The present application also provides an imaging system, comprising the image sensor described above.
[0026] The present application provides a method for manufacturing an image sensor, comprising preparing a substrate; implanting carbon-hydrogen-phosphorus ion clusters into the substrate to form a first gettering diffusion barrier layer in the substrate; growing an epitaxial structure on the upper surface of the substrate and activating ions in the first gettering diffusion barrier layer to form clusters, wherein the clusters include clusters formed by carbon ions and interstitial silicon clusters and clusters formed by phosphorus ions and interstitial silicon clusters; the epitaxial structure includes at least one epitaxial layer.
[0027] It can be seen that in the present application, when manufacturing the image sensor, the substrate is implanted with carbon-hydrogen-phosphorus ion clusters to form a first gettering diffusion barrier layer, and then the ions in the first gettering diffusion barrier layer are activated when growing the epitaxial structure to form clusters. These clusters in the first gettering diffusion barrier layer can not only play a blocking effect, preventing oxygen impurities in the substrate silicon from diffusing into the device active area during the manufacturing process, but can also serve as metal gettering centers to adsorb metal impurities in the substrate and metal impurities introduced in the process, thereby reducing white spots. In addition, the hydrogen ions injected into the substrate diffuse outward after heat treatment, thereby pairing with the dangling bonds at the interface of silicon and silicon dioxide generated in the subsequent manufacturing process, reducing the interface state density, and reducing white spots and transient noise. Therefore, the manufacturing method of the present application can reduce the number of white spots and transient noise in the image sensor, and improve the imaging quality of the image sensor.
[0028] In addition, the present application also provides an image sensor and an imaging system having the above advantages. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions of the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0030] Figure 1 A flowchart of a method for manufacturing an image sensor provided in an embodiment of the present application;
[0031] Figures 2 to 5A flowchart of a manufacturing process of an image sensor provided in an embodiment of the present application;
[0032] In the figure, 1 is a substrate, 2 is a first epitaxial layer, 3 is a first gettering diffusion barrier layer, 4 is a second epitaxial layer, and 5 is a second gettering diffusion barrier layer. DETAILED DESCRIPTION
[0033] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. Obviously, the embodiments described are only a part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making any creative efforts are within the scope of protection of the present application.
[0034] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.
[0035] As described in the background technology section, current image sensors have a large number of white spots and relatively poor transient noise, resulting in poor imaging quality.
[0036] In view of this, this application provides a method for manufacturing an image sensor, please refer to Figure 1 , the method may include:
[0037] Step S101: prepare a substrate.
[0038] The substrate in this embodiment is a silicon substrate.
[0039] Step S102: injecting carbon, hydrogen and phosphorus ion clusters into the substrate to form a first gettering diffusion barrier layer in the substrate.
[0040] Carbon hydrogen phosphide ion clusters are clusters formed by carbon ions, hydrogen ions, and phosphorus ions.
[0041] Step S103: growing an epitaxial structure on the upper surface of the substrate, and activating ions in the first gettering diffusion barrier layer to form clusters, wherein the clusters include clusters formed by carbon ions and interstitial silicon clusters and clusters formed by phosphorus ions and interstitial silicon clusters; the epitaxial structure includes at least one epitaxial layer.
[0042] In this embodiment, these clusters in the first gettering diffusion barrier layer can become strong metal gettering centers, absorbing metal impurities in the substrate and metal impurities introduced during the process. In addition, they can also have a blocking effect, preventing oxygen impurities in the substrate silicon from diffusing into the device active area during the manufacturing process, thereby reducing white spots.
[0043] It should be noted that, in this embodiment, there is no limitation on the injection conditions, as long as the injection can be achieved.
[0044] As an implementation method, when injecting carbon hydrogen phosphorus ion clusters into the substrate, the injection energy can be 80KeV~120KeV, and the injection dose can be 5E14 atoms / cm 2 ~ 5E15 atoms / cm 2 .
[0045] For example, the implantation energy may be 80KeV, 90KeV, 100KeV, 110KeV, 120KeV, etc.; the implantation dose may be 5E14 atoms / cm 2 、7E14 atoms / cm 2 、9E14 atoms / cm 2 、5E15 atoms / cm 2 wait.
[0046] It should also be noted that, in this embodiment, there is no limitation on the ratio of injected carbon, hydrogen and phosphorus, which can be set at will.
[0047] As an implementation, the ratio of carbon ions, hydrogen ions, and phosphorus ions in the carbon-hydrogen-phosphorus ion clusters ranges from 1:1:1 to 1:3:1. Compared to carbon and phosphorus ions, hydrogen ions are injected in higher amounts. After subsequent heat treatment, hydrogen ions diffuse to the silicon-silicon dioxide interface, providing a passivation effect, reducing the number of white spots and thereby improving image sensor performance.
[0048] For example, the ratio of carbon ions, hydrogen ions, and phosphorus ions can be 1:1:1, 1:2:1, 1:3:1, etc.
[0049] In this embodiment, the epitaxial layer is a doped silicon layer. The number of epitaxial layers can be one, or two or more. In this embodiment, the number of epitaxial layers is not limited and depends on the circumstances.
[0050] When growing the epitaxial structure, the high temperature of the epitaxial layer growth can activate the first gettering diffusion barrier layer.
[0051] As an implementation method, the first gettering diffusion barrier layer can be activated by heat treatment, which not only activates the first gettering diffusion barrier layer but also repairs implantation damage. The heat treatment temperature can range from 1000°C to 1200°C.
[0052] For example, the temperature of the heat treatment may be 1000° C., 1100° C., 1200° C., etc.
[0053] When the number of epitaxial layers is one, the heat treatment performed during the growth of the epitaxial layer can activate the first impurity diffusion barrier layer in the substrate; when the number of epitaxial layers is two or more, the heat treatment performed during the growth of the second epitaxial layer can activate the second impurity diffusion barrier layer in the first epitaxial layer, and then other epitaxial layers are grown.
[0054] It should be noted that after activating the first gettering diffusion barrier layer in the substrate, the image sensor fabrication method further includes fabricating a device in the epitaxial layer farthest from the silicon substrate. This process is well known to those skilled in the art and will not be described in detail here. The device may be a photodiode, which may be a PN junction photodiode or a PIN photodiode with surface P-type pinning.
[0055] In this embodiment, when manufacturing the image sensor, the substrate is implanted to form a first gettering diffusion barrier layer, which is activated to form clusters, including clusters formed by carbon ions and interstitial silicon clusters and clusters formed by phosphorus ions and interstitial silicon clusters. These clusters in the first gettering diffusion barrier layer can not only play a blocking effect, preventing oxygen impurities in the substrate silicon from diffusing into the device active area during the manufacturing process, but also serve as metal gettering centers to adsorb metal impurities in the substrate and metal impurities introduced in the process, thereby reducing white spots. In addition, the hydrogen ions injected into the substrate diffuse outward after heat treatment, thereby pairing with the dangling bonds at the interface of silicon and silicon dioxide generated in the subsequent manufacturing process, reducing the interface state density, and reducing white spots and transient noise. Therefore, the manufacturing method of the present application can reduce the number of white spots and transient noise in the image sensor, and improve the imaging quality of the image sensor.
[0056] Based on the above embodiment, in one embodiment of the present application, the number of the epitaxial layers is at least two, and growing the epitaxial structure on the upper surface of the substrate includes:
[0057] Step S11: growing a first epitaxial layer on the upper surface of the substrate.
[0058] The first epitaxial layer may be grown by vapor phase epitaxy.
[0059] Step S12: implanting carbon, hydrogen, and phosphorus ion clusters into the first epitaxial layer to form a second gettering diffusion barrier layer in the first epitaxial layer.
[0060] It should be noted that, in this embodiment, there is no limitation on the injection conditions, as long as the injection can be achieved.
[0061] As an implementation method, when the first epitaxial layer is implanted, the implant energy can be 80KeV~120KeV, and the implant dose can be 5E14 atoms / cm 2 ~ 5E15 atoms / cm 2 .
[0062] For example, the implantation energy may be 80KeV, 90KeV, 100KeV, 110KeV, 120KeV, etc.; the implantation dose may be 5E14 atoms / cm 2 、7E14 atoms / cm 2 、9E14 atoms / cm 2 、5E15 atoms / cm 2 wait.
[0063] The implantation conditions in the first epitaxial layer may be the same as those in the substrate.
[0064] It should also be noted that, in this embodiment, there is no limitation on the ratio of injected carbon, hydrogen and phosphorus, which can be set at will.
[0065] As an implementation method, the ratio of carbon ions, hydrogen ions, and phosphorus ions in the carbon-hydrogen-phosphorus ion cluster can range from 1:1:1 to 1:3:1. Compared to carbon and phosphorus ions, more hydrogen ions are injected. After subsequent heat treatment, hydrogen ions can diffuse and migrate to the silicon-silicon dioxide interface, providing a passivation effect, reducing the number of white spots and thereby improving image sensor performance.
[0066] For example, the ratio of carbon ions, hydrogen ions, and phosphorus ions can be 1:1:1, 1:2:1, 1:3:1, etc.
[0067] Step S13: growing a second epitaxial layer on the upper surface of the first epitaxial layer, and activating ions in the second gettering diffusion barrier layer to form clusters, including clusters formed by carbon ions and interstitial silicon clusters and clusters formed by phosphorus ions and interstitial silicon clusters.
[0068] The first epitaxial layer may be grown by vapor phase epitaxy.
[0069] When growing the second epitaxial layer, the high growth temperature of the second epitaxial layer can activate ions in the second gettering diffusion barrier layer to form clusters, including clusters formed by carbon ions and interstitial silicon clusters and clusters formed by phosphorus ions and interstitial silicon clusters.
[0070] These clusters in the second gettering diffusion barrier layer formed in this embodiment can play a blocking role, preventing oxygen impurities in the substrate silicon from diffusing into the active region of the device during the manufacturing process to form white spots.
[0071] These clusters in the second gettering diffusion barrier layer act as metal gettering centers, absorbing metal impurities from the substrate and those introduced during the process, thereby reducing white spots. Furthermore, hydrogen ions implanted in the first epitaxial layer diffuse outward after thermal treatment, pairing with dangling bonds at the silicon-silicon dioxide interface generated during subsequent fabrication. This reduces the interface state density, white spots, and transient noise, ultimately improving image sensor quality.
[0072] As an implementation method, the ions implanted in the first epitaxial layer may be activated by heat treatment, which not only activates the implanted ions but also repairs implantation damage. The heat treatment temperature may range from 1000°C to 1200°C.
[0073] For example, the temperature of the heat treatment may be 1000° C., 1100° C., 1200° C., etc.
[0074] Step S14: determining whether the number of epitaxial layers reaches a preset threshold.
[0075] The number of epitaxial layers in this step refers to the sum of the numbers of all first epitaxial layers and second epitaxial layers.
[0076] In this embodiment, there is no limitation on the size of the preset threshold, which can be set arbitrarily.
[0077] For example, when the preset threshold is 2, the number of first epitaxial layers is one layer, and the number of second epitaxial layers is one layer; when the preset threshold is 3, the number of first epitaxial layers is two layers, and the number of second epitaxial layers is one layer; when the preset threshold is 4, the number of first epitaxial layers is three layers, and the number of second epitaxial layers is one layer.
[0078] Step S15: If the number of epitaxial layers does not reach the preset threshold, the second epitaxial layer is used as a new first epitaxial layer, and the process proceeds to step S12 until the number of epitaxial layers reaches the preset threshold.
[0079] Based on the above embodiment, in one embodiment of the present application, before growing the first epitaxial layer on the upper surface of the substrate, the method further includes:
[0080] The upper surface of the substrate is baked in a reducing atmosphere to remove oxides on the surface of the substrate.
[0081] The oxide on the surface of the substrate is formed by oxidation of the substrate in an air environment.
[0082] The reducing atmosphere may be a hydrogen atmosphere.
[0083] The baking temperature may range from 800° C. to 900° C. For example, the baking temperature may be 800° C., 850° C., 900° C., etc.
[0084] In this embodiment, the performance of the image sensor can be improved by removing oxides on the surface of the substrate.
[0085] Based on the above embodiment, in one embodiment of the present application, before growing the second epitaxial layer on the upper surface of the first epitaxial layer, the method further includes:
[0086] The upper surface of the second epitaxial layer is baked in a reducing atmosphere to remove oxide on the surface of the second epitaxial layer.
[0087] The reducing atmosphere may be a hydrogen atmosphere.
[0088] The baking temperature may range from 800° C. to 900° C. For example, the baking temperature may be 800° C., 850° C., 900° C., etc.
[0089] In this embodiment, the performance of the image sensor can be improved by removing the oxide on the surface of the first epitaxial layer.
[0090] Based on any of the above embodiments, in one embodiment of the present application, the thickness of the second epitaxial layer is greater than the thickness of the first epitaxial layer.
[0091] The thickness of the first epitaxial layer is smaller than that of the second epitaxial layer, which can make the first impurity diffusion barrier layer closer to the active area, thereby making the first impurity diffusion barrier layer more effective and further improving the performance of the image sensor.
[0092] In this embodiment, the thickness of the second epitaxial layer and the first epitaxial layer is not limited and can be set at will. As an implementation method, the thickness of the first epitaxial layer can be 1 micron to 3 microns, and the thickness of the second epitaxial layer can be 2 microns to 10 microns. Since the device is made in the second epitaxial layer, for high-performance image sensors with small pixel sizes, the performance can be improved by increasing the thickness of the epitaxial layer in the active area of the device. The thickness of the second epitaxial layer can be 4 microns to 10 microns. Among them, when the image sensor is a back-illuminated image sensor, after thinning the back of the wafer, the thickness of the second epitaxial layer can range from 2 microns to 8 microns.
[0093] The following describes the method for manufacturing the image sensor in this application using a specific example.
[0094] Step 1: Figure 2As shown, the silicon substrate is implanted with carbon hydrogen phosphorus ion clusters to form a first gettering diffusion barrier layer 3; the implantation energy can be 80KeV~120KeV, and the implantation dose can be 5E14 atoms / cm 2 ~ 5E15 atoms / cm 2 .
[0095] Step 2: Figure 3 As shown, a first epitaxial layer 2 is formed on the top surface of substrate 1 using a vapor phase epitaxial process. The thickness of first epitaxial layer 2 is 1 to 3 microns. The epitaxial growth process includes baking the substrate at 800°C to 900°C in a hydrogen atmosphere to remove surface oxides, and heat treatment at 1000°C to 1200°C to activate ions in the first gettering diffusion barrier layer 3 in the substrate, forming clusters. These clusters include clusters formed by carbon ions and interstitial silicon clusters, and clusters formed by phosphorus ions and interstitial silicon clusters, and repairing implantation damage. These clusters in the first gettering diffusion barrier layer not only act as a barrier, preventing oxygen impurities in the substrate silicon from diffusing into the device active area during fabrication, but also serve as metal gettering centers, attracting metal impurities in the substrate and those introduced during the process, thereby reducing white spots. Furthermore, after heat treatment, the hydrogen ions implanted into the substrate diffuse outward, pairing with dangling bonds at the silicon-silicon dioxide interface generated during subsequent fabrication, reducing interface state density, white spots, and transient noise. Among them, the interface between the silicon substrate and silicon dioxide includes the shallow trench isolation (STI) interface, the silicon substrate and gate oxide interface, the backside deep trench isolation (BDTI) interface, and the backside bonding (BSI bonding) interface.
[0096] Step 3: Figure 4 As shown, the first epitaxial layer 2 is implanted with carbon-hydrogen-phosphorus ion clusters to form a second gettering diffusion barrier layer 5; the implantation energy can be 80KeV~120KeV, and the implantation dose can be 5E14 atoms / cm 2 ~ 5E15 atoms / cm 2 .
[0097] Step 4: Figure 5As shown, a second epitaxial layer 4 is formed on the upper surface of the first epitaxial layer 3 by a vapor phase epitaxial process, and the thickness of the second epitaxial layer 4 is 4 microns to 10 microns; the epitaxial growth process includes baking the surface of the first epitaxial layer in a hydrogen atmosphere at a temperature of 800°C to 900°C to remove the oxide on the surface of the first epitaxial layer, and performing heat treatment at a temperature of 1000°C to 1200°C to activate ions in the second impurity diffusion barrier layer 5 in the first epitaxial layer 2 to form clusters, which include clusters formed by carbon ions and interstitial silicon clusters and clusters formed by phosphorus ions and interstitial silicon clusters, and repairing implantation damage.
[0098] Step 5: forming a device in the second epitaxial layer 4. The device is a photodiode. The photodiode can be a PN junction photodiode or a PIN photodiode with surface P-type pinning.
[0099] The present application also provides an image sensor, which is manufactured using the method for manufacturing an image sensor described in any of the above embodiments.
[0100] The present application also provides an imaging system, comprising the image sensor described in the above embodiment.
[0101] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.
[0102] The above is a detailed introduction to the image sensor, its manufacturing method, and imaging system provided by this application. Specific examples are used herein to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the solution and core ideas of this application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of this application, several improvements and modifications can be made to this application, and these improvements and modifications also fall within the scope of protection of this application.
Claims
1. A method for manufacturing an image sensor, characterized in that: include: preparing the substrate; implanting carbon-hydrogen-phosphorus ion clusters into the substrate to form a first gettering diffusion barrier layer in the substrate; An epitaxial structure is grown on the upper surface of the substrate, and ions in the first gettering diffusion barrier layer are activated to form clusters, wherein the clusters include clusters formed by carbon ions and interstitial silicon clusters and clusters formed by phosphorus ions and interstitial silicon clusters; the epitaxial structure includes at least one epitaxial layer.
2. The method for manufacturing an image sensor according to claim 1, wherein: The number of the epitaxial layers is at least two, and growing an epitaxial structure on the upper surface of the substrate includes: Step S11: growing a first epitaxial layer on the upper surface of the substrate; Step S12: implanting carbon, hydrogen, and phosphorus ion clusters into the first epitaxial layer to form a second gettering diffusion barrier layer in the first epitaxial layer; Step S13: growing a second epitaxial layer on the upper surface of the first epitaxial layer, and activating ions in the second gettering diffusion barrier layer to form clusters, wherein the clusters include clusters formed by carbon ions and interstitial silicon clusters and clusters formed by phosphorus ions and interstitial silicon clusters; Step S14: determining whether the number of epitaxial layers reaches a preset threshold; Step S15: If the number of epitaxial layers does not reach the preset threshold, the second epitaxial layer is used as a new first epitaxial layer, and the process proceeds to step S12 until the number of epitaxial layers reaches the preset threshold.
3. The method for manufacturing an image sensor according to claim 2, wherein: Before growing the first epitaxial layer on the upper surface of the substrate, the method further comprises: The upper surface of the substrate is baked in a reducing atmosphere to remove oxides on the surface of the substrate.
4. The method for manufacturing an image sensor according to claim 2, wherein: Before growing the second epitaxial layer on the upper surface of the first epitaxial layer, the method further includes: The upper surface of the second epitaxial layer is baked in a reducing atmosphere to remove oxide on the surface of the second epitaxial layer.
5. The method for manufacturing an image sensor according to claim 4, wherein: The baking temperature range is 800℃~900℃.
6. The method for manufacturing an image sensor according to claim 1, wherein: The ratio of carbon ions, hydrogen ions and phosphorus ions in the carbon-hydrogen-phosphorus ion clusters ranges from 1:1:1 to 1:3:
1.
7. The method for manufacturing an image sensor according to claim 1, wherein: When the carbon hydrogen phosphorus ion cluster is injected into the substrate, the injection energy is 80KeV~120KeV and the injection dose is 5E14 atoms / cm 2 ~ 5E15 atoms / cm 2 .
8. The method for manufacturing an image sensor according to any one of claims 2 to 7, wherein: The thickness of the second epitaxial layer is greater than the thickness of the first epitaxial layer.
9. An image sensor, characterized in that: The image sensor is manufactured using the method for manufacturing an image sensor according to any one of claims 1 to 8.
10. An imaging system, characterized in that: Comprising the image sensor as claimed in claim 9.