CN115377243A - Preparation method of photosensitive diode and semiconductor device - Google Patents

Preparation method of photosensitive diode and semiconductor device Download PDF

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Publication number
CN115377243A
CN115377243A CN202111671859.1A CN202111671859A CN115377243A CN 115377243 A CN115377243 A CN 115377243A CN 202111671859 A CN202111671859 A CN 202111671859A CN 115377243 A CN115377243 A CN 115377243A
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substrate
front surface
oxide layer
doped region
layer
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郭幸辰
鲁艳春
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Beihai Huike Semiconductor Technology Co Ltd
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Beihai Huike Semiconductor Technology Co Ltd
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Abstract

The application relates to a preparation method of a photosensitive diode and a semiconductor device. The preparation method of the photosensitive diode comprises the following steps: providing a substrate, and growing first oxide layers on the front surface and the back surface of the substrate respectively; etching the first oxide layer on the back of the substrate and the first oxide layer on the periphery of the front of the substrate in a wet etching mode; performing diffusion treatment on the front surface and the back surface of the substrate and the front surface and the side surface of the first oxide layer to generate a first doped region; performing high-temperature junction pushing on the front surface and the back surface of the substrate, and growing second oxide layers on the front surface of the first oxide layer, the front surface of the first doped region and the back surface of the first doped region respectively; etching the first oxide layer and the second oxide layer on the front surface of the substrate in a dry etching mode; and carrying out diffusion treatment on the front surface of the substrate to generate a second doped region. The diffusion mode equipment of the application has the advantages of low cost, better etching uniformity and process saving.

Description

Preparation method of photosensitive diode and semiconductor device
Technical Field
The present disclosure relates to the field of semiconductor devices, and more particularly, to a method for manufacturing a photodiode and a semiconductor device.
Background
The die of the photosensitive diode is a PN junction with photosensitive characteristics, has unidirectional conductivity and therefore needs to be applied with reverse voltage during operation. In the absence of illumination, there is very little saturated reverse leakage current, i.e., dark current, at which time the photodiode is turned off. When illuminated, the saturation reverse leakage current increases substantially, creating a photocurrent that varies with the intensity of the incident light. When light irradiates the PN junction, electron-hole pairs can be generated in the PN junction, so that the density of minority carriers is increased. These carriers drift under reverse voltage, causing an increase in reverse current.
For the preparation of the doped region of the photosensitive diode, the ion implantation is mostly adopted for doping, but the ion implanter in the market is expensive and limited in purchase and long in purchase period, and during processing, the double-sided doping of the substrate needs to be carried out by two steps of ion implantation, so that the problem of complicated processing steps of the semiconductor device is caused. In addition, when ions are implanted, the oxide layer is etched in a multi-combination wet etching mode, so that the problem of side etching is caused, and the final yield quality of the photodiode is influenced.
Disclosure of Invention
The application aims to provide a preparation method of a photosensitive diode and a semiconductor device, and aims to solve the problems that ion implantation equipment is expensive, steps are multiple, wet etching is difficult to perform, directional etching is difficult to perform and the like.
In a first aspect, an embodiment of the present application provides a method for manufacturing a photodiode, including:
providing a substrate, and growing first oxide layers on the front surface and the back surface of the substrate respectively;
etching the first oxide layer on the back of the substrate and the first oxide layer on the periphery of the front of the substrate in a wet etching mode;
performing diffusion treatment on the front surface and the back surface of the substrate and the front surface and the side surface of the first oxide layer to generate a first doped region;
performing high-temperature junction pushing on the front surface and the back surface of the substrate, and growing second oxide layers on the front surface of the first oxide layer, the front surface of the first doped region and the back surface of the first doped region respectively;
etching off part of the first oxide layer and part of the second oxide layer on the front surface of the substrate in a dry etching mode;
and carrying out diffusion treatment on the front surface of the substrate to generate a second doped region.
In the step of performing diffusion processing on the front surface and the back surface of the substrate and the front surface and the side surface of the first oxide layer to generate the first doped region, the method includes: and placing the substrate in a high-temperature furnace, introducing boron into the high-temperature furnace, and performing boron source diffusion treatment on the front surface and the back surface of the substrate and the front surface and the side surface of the first oxide layer.
Wherein the boron source is a chemical comprising boron 30.
In the step of etching away the first oxide layer and the second oxide layer at the center of the front surface of the substrate by dry etching, the method further includes: and carrying out anisotropic etching on the first oxide layer and the second oxide layer on the front surface of the substrate.
The step of performing diffusion treatment on the front surface of the substrate to generate the second doped region includes: and (3) placing the substrate in a high-temperature furnace, introducing phosphorus oxychloride into the high-temperature furnace, and performing phosphorus oxychloride diffusion treatment on the center of the front surface of the substrate.
In the step of placing the substrate in a high temperature furnace, introducing phosphorus oxychloride into the high temperature furnace, and performing phosphorus oxychloride diffusion treatment on the center position of the front surface of the substrate, 0.5L +/-0.1L of phosphorus oxychloride is introduced into the high temperature furnace at 950 +/-50 ℃, 10L +/-2L of nitrogen and 0.2L +/-0.05L of oxygen are introduced, and the process time is 16min +/-2 min.
After the step of performing diffusion processing on the front surface of the substrate to generate the second doped region, the method further includes: and (3) respectively growing sacrificial layers on the front surface of the second doping region, the front surface of the second oxidation layer and the back surface of the second oxidation layer by performing high-temperature junction pushing in the furnace, and removing the sacrificial layers, part of the second oxidation layer and organic matters remained on the surfaces of the second oxidation layer in an acid bleaching mode.
After the steps of growing sacrificial layers on the front surface of the second doped region, the front surface of the second oxide layer and the back surface of the second oxide layer respectively by performing high-temperature junction pushing in the furnace, and removing the sacrificial layers, a part of the second oxide layer and residual organic matters on the surface of the second oxide layer in an acid rinsing manner, the method further comprises the following steps: and forming an anti-reflection layer on the front surface of the second doped region and the front surface of the second oxide layer by means of chemical vapor deposition.
After the step of depositing the anti-reflection layer on the front surface of the second doped region and the front surface of the second oxide layer, the method further comprises the following steps: and etching a lead hole on the antireflection layer by a wet etching method, growing a first electrode on the lead hole, and growing a second electrode on the back of the first doped region.
In a second aspect, an embodiment of the present application further provides a semiconductor device, which is manufactured by the method for manufacturing a photodiode, and the semiconductor device includes: a substrate; the first doping area is doped on the back surface of the substrate and the periphery side of the front surface of the substrate; the second doping area is doped in the central position of the front surface of the substrate; the first oxidation layer is formed on the front surface of the substrate; and the second oxidation layer is formed on one side, away from the substrate, of the first oxidation layer.
According to the preparation method of the photosensitive diode and the semiconductor device, firstly, the first doping area and the second doping area replace ion implantation in a diffusion mode, equipment cost is greatly reduced, two diffusion steps can be respectively completed in one step, compared with the step completion of ion implantation, the preparation method of the photosensitive diode saves process steps and improves working efficiency; secondly, the substrate is not scratched in a diffusion mode, so that the thickness of the substrate does not need to be reduced, the process steps are saved, and the working efficiency is further improved; finally, the front and the back of the substrate are etched by a wet method during the first photoetching, so that large-area rapid etching can be realized, the center position of the front of the substrate is etched by a dry method during the second photoetching, so that anisotropy during profile etching can be realized, lateral etching is prevented, photoresist falling or adhesion is reduced, better etching uniformity is realized, the use of chemicals is reduced during etching, and the high-speed photoetching device is good in safety and low in cost.
Drawings
Features, advantages and technical effects of exemplary embodiments of the present application will be described below with reference to the accompanying drawings. In the drawings, like parts are provided with like reference numerals. The drawings are not necessarily to scale, and are merely intended to illustrate the relative positions of the layers, the thicknesses of the layers in some portions being exaggerated for clarity, and the thicknesses in the drawings are not intended to represent the proportional relationships of the actual thicknesses.
Fig. 1 shows a flow chart of a method for manufacturing a photodiode provided in the present application;
fig. 2 (a) is a schematic diagram showing a state after a first oxide layer is grown on the front and back surfaces of a substrate in the method for manufacturing a photodiode provided by the present application;
fig. 2 (b) is a schematic diagram showing a state of the first oxide layer after being subjected to one photolithography in the method for manufacturing a photodiode provided by the present application;
fig. 2 (c) is a schematic diagram showing a state of a photodiode according to the method of manufacturing the photodiode according to the present application when a substrate is diffused;
fig. 2 (d) is a schematic diagram illustrating a state that a first doped region is generated in the substrate of the method for manufacturing a photodiode provided by the present application;
fig. 2 (e) is a schematic state diagram illustrating a growth of a second oxide layer by a high Wen Tuijie after a first doped region is formed on a substrate in the method for manufacturing a photodiode provided by the present application;
fig. 2 (f) is a schematic diagram illustrating a state that a substrate of the method for manufacturing a photodiode provided by the present application is subjected to a second photolithography and then diffusion to generate a second doped region;
fig. 2 (g) is a schematic diagram illustrating a state of a sacrificial layer generated by high-temperature junction-pushing after a second doped region is generated on a substrate in the method for manufacturing a photodiode provided by the present application;
fig. 2 (h) is a schematic diagram illustrating a state that a substrate of a method for manufacturing a photodiode provided by the present application is subjected to third photolithography to remove a sacrificial layer and grow an antireflective layer;
FIG. 2 (i) is a schematic diagram showing a state where a wiring hole is formed in an anti-reflection layer of a substrate by a fourth photolithography in a method for manufacturing a photodiode according to the present application;
fig. 3 shows a cross-sectional view of a semiconductor device provided by the present application.
Description of reference numerals:
1. a substrate; 21. a first doped region; 22. a second doped region; 31. a first electrode; 32. a second electrode; 4. a first oxide layer; 5. a second oxide layer; 6. a sacrificial layer; 7. an anti-reflection layer; 71. and a lead hole.
Detailed Description
Features and exemplary embodiments of various aspects of the present application will be described in detail below. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present application by illustrating examples thereof. In the drawings and the following description, at least some well-known structures and techniques have not been shown in detail in order to avoid unnecessarily obscuring the present application; also, the size of the region structures may be exaggerated for clarity. Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
The directional terms used in the following description are intended to refer to directions shown in the drawings, and are not intended to limit the specific structure of the present application. In the description of the present application, it is also to be noted that, unless otherwise explicitly specified or limited, the terms "mounted" and "connected" are to be interpreted broadly, e.g., as being either fixedly connected, detachably connected, or integrally connected; can be directly connected or indirectly connected. The specific meaning of the above terms in the present application can be understood as appropriate by one of ordinary skill in the art.
A semiconductor device is an electronic device in which conductivity is interposed between a good conductor and an insulator, and a specific function is performed by utilizing special electrical characteristics of a semiconductor material.
Specifically, the semiconductor device mainly includes a P-type diode and an N-type diode. The P-type diode comprises a substrate, a P-type epitaxial layer, a P + doping region and an N + doping region, wherein the substrate and the P-type epitaxial layer are arranged in a main body region of the P-type diode; the substrate and the N-type epitaxial layer are arranged in the main body region of the N-type diode, and a P + doped region and an N + doped region are formed in the N-type epitaxial layer.
The fabrication method and the layered structure of the doped region of the P-type diode will be described below by taking the P-type diode as an example.
First embodiment
Fig. 1 shows a flowchart of a method for manufacturing a photodiode provided in the present application.
Referring to fig. 1, an embodiment of the present application provides a method for manufacturing a photodiode, including the following steps:
s001, providing a substrate 1, and growing a first oxide layer 4 on the front surface and the back surface of the substrate 1 respectively;
s002, etching away the first oxide layer 4 on the back surface of the substrate 1 and the first oxide layer 4 on the periphery of the front surface of the substrate 1 in a wet etching mode;
s003, performing diffusion treatment on the front surface and the back surface of the substrate 1 and the front surface and the side surface of the first oxide layer 4 to generate a first doped region 21;
s004, performing high-temperature junction pushing on the front surface and the back surface of the substrate 1, and growing second oxide layers 5 on the front surface of the first oxide layer 4, the front surface of the first doped region 21 and the back surface of the first doped region 21 respectively;
s005, etching off part of the first oxide layer 4 and part of the second oxide layer 5 on the front surface of the substrate 1 in a dry etching mode;
s006, performing diffusion processing on the front surface of the substrate 1 to generate a second doped region 22.
Wherein, the material of this substrate 1 is polycrystalline silicon, specifically is a P type district fuse-link, the thickness of substrate 1 is 300 μm, compare 600 μm in prior art, the thickness of substrate 1 in this application is thinner, in the course of preparing, because the diffusion does not have damage such as mar to substrate 1, so substrate 1 need not attenuate thickness in the course of preparing, consequently choose substrate 1 that thickness is 300 μm for use, compare with prior art's ion implantation, reduced the technology step, improved work efficiency.
Fig. 2 (a) shows a schematic state diagram after the first oxide layer 4 is grown on the front and back surfaces of the substrate 1 in the method for manufacturing a photodiode provided by the present application.
Referring to fig. 2 (a), in the step S001, the thicknesses of the first oxide layers 4 on the front and back surfaces of the substrate 1 are 6300A ± 500A, and the first oxide layers 4 can be grown on the front and back surfaces of the substrate 1 by a diffusion method of introducing nitrogen and oxygen into a high temperature furnace. Silicon oxide is often used for the first oxide layer 4.
Fig. 2 (b) shows a schematic state diagram of the first oxide layer 4 after one photolithography in the method for manufacturing a photodiode provided by the present application.
Referring to fig. 2 (b), the position of the first oxide layer 4 corresponding to the first doped region 21 is etched by the stop ring lithography, that is, the first oxide layer 4 on the back surface of the substrate 1 and the first oxide layer 4 on the periphery of the front surface of the substrate 1 are etched, and the photoresist is removed by wet etching.
Fig. 2 (c) shows a schematic state diagram of the substrate 1 in diffusion according to the method for manufacturing a photodiode provided by the present application.
Referring to fig. 2 (c), in step S003, the substrate 1 is placed in a high temperature furnace, boron is introduced into the high temperature furnace, and boron source diffusion treatment is performed on the front and back surfaces of the substrate 1 and the front and side surfaces of the first oxide layer 4. Specifically, the boron source is a chemical substance containing boron 30 (B30), i.e., a chemical substance containing more than 30% of boron, so that the diffusion is uniform and the doping concentration of the generated doping region is the same.
Fig. 2 (d) shows a schematic state diagram of the substrate 1 for producing the first doped region 21 according to the method for producing a photodiode provided in the present application.
Referring to fig. 2 (d), in the step S003, after the boron source diffusion, the dopant is doped into a shallow position of the substrate 1, thereby forming the first doped region 21. Then sending the mixture into a diffusion furnace for deposition, wherein the temperature is 1000 ℃, and the junction depth of the first doping area 21 is 1.7 mu m.
Fig. 2 (e) shows a schematic state diagram of the growth of the second oxide layer 5 by the rows Wen Tuijie after the first doping region 21 is formed on the substrate 1 in the method for manufacturing a photodiode provided by the present application.
Referring to fig. 2 (e), in step S004, the substrate 1 is subjected to high temperature junction-pushing to form a second oxide layer 5 with a thickness of 3000A-5000A. The second oxide layer 5 is made of silicon oxide. Specifically, the high-temperature knot pushing is 125 minutes, the knot pushing temperature is 900 +/-200 ℃, 2L of wet oxygen and 10L of dry oxygen are introduced during knot pushing, and the knot pushing time is 10 minutes.
Fig. 2 (f) is a schematic diagram illustrating a state that the substrate 1 is subjected to a second photolithography and then diffusion to form the second doped region 22 according to the method for manufacturing a photodiode provided in the present application.
Referring to fig. 2 (f), in steps S005 and S006, the first oxide layer 4 and the second oxide layer 5 on the front surface of the substrate 1 are removed by dry etching, and then the substrate is sent into a diffusion furnace, and phosphorus oxychloride is introduced for high temperature diffusion to form the second doped region 22, wherein the junction depth of the second doped region 22 is 3 μm. Wherein, the parts of the first oxide layer 4 and the second oxide layer 5 refer to the first oxide layer 4 and the second oxide layer 5 which are positioned at the center of the front surface of the substrate 1.
Wherein, when the phosphorus oxychloride is diffused, 0.5L +/-0.1L of phosphorus oxychloride is introduced into a high-temperature furnace at 950 +/-50 ℃, 10L +/-2L of nitrogen and 0.2L +/-0.05L of oxygen are introduced, and the process time is 16min +/-2 min. The introduction of nitrogen and oxygen gas while ensuring appropriate diffusion temperature and process time for preventing impurities from entering into the substrate 1 helps the diffusion to proceed rapidly.
And at the same time of dry etching, performing anisotropic etching on the first oxide layer 4 and the second oxide layer 5 on the front surface of the substrate 1 to accurately meet the requirement of etching depth. Specifically, the dry etching has good etching uniformity, prevents side etching, does not cause the problem of easy photoresist falling or adhesion, uses less chemicals, is safer and has lower cost compared with the wet etching.
Fig. 2 (g) shows a schematic state diagram of the sacrificial layer 6 generated by high-temperature junction-push after the second doping region 22 is generated on the substrate 1 in the method for manufacturing a photodiode provided by the present application.
Referring to fig. 2 (g), after the second doped region 22 is formed, a sacrificial layer 6 is grown on the front surface of the second doped region 22, the front surface of the second oxide layer 5 and the back surface of the second oxide layer 5 by using nitrogen as a raw material through a high temperature junction push method. Specifically, the thickness of the sacrificial layer 6 is 300A-600A.
Fig. 2 (h) shows a schematic state diagram of the substrate 1 of the method for manufacturing a photodiode provided by the present application after a third photolithography process to remove the sacrificial layer 6 and grow the antireflective layer 7.
As shown in fig. 2 (h), after the step of growing the sacrificial layer 6, the method further includes: and removing the sacrificial layer 6, part of the second oxide layer 5 and the organic matters remained on the surface of the second oxide layer 5 by a bleaching acid mode. An antireflective layer 7 is deposited on the front side of the second doped region 22 and on the front side of the second oxide layer 5. The thickness of the antireflection layer 7 is 1000A-1600A, and the antireflection layer 7 is used for reducing light reflection and increasing the light absorption rate of the P-type photosensitive device.
Specifically, the antireflective layer 7 is formed by Chemical Vapor Deposition (CVD), which is a method of Vapor-phase reaction at high temperature, for example, thermal decomposition of metal halide, organic metal, hydrocarbon, or the like, hydrogen reduction, or Chemical reaction of a mixed gas thereof at high temperature to precipitate inorganic materials such as metal, oxide, carbide, or the like. The anti-reflection layer 7 is generated without a photoetching step, so that the manufacturing cost is reduced, the manufacturing period is shortened, and the time cost is saved.
Fig. 2 (i) is a schematic diagram illustrating a state that the antireflective layer 7 of the substrate 1 is subjected to fourth photolithography to form a lead hole in the method for manufacturing a photodiode provided by the present application.
Referring to fig. 2 (i), after the step of depositing the anti-reflection layer 7, the method further includes: and etching a lead hole on the antireflection layer 7 by a wet etching mode.
Fig. 3 shows a cross-sectional view of a semiconductor device provided by the present application.
Referring to fig. 3, after the step of etching the wiring hole 71 in the anti-reflection layer 7 by wet etching, the method further includes: the first electrode 31 is grown on the lead hole 71, and the second electrode 32 is grown on the back surface of the first doped region 21. The first electrode 31 is a positive electrode formed by depositing aluminum metal, and the thickness of the first electrode 31 is 2 μm to 2.4 μm. The second electrode 32 is a negative electrode formed by depositing metal silver, and the negative electrode is formed by depositing metal titanium, metal nickel and metal silver in sequence from bottom to top.
In summary, in the present application, the first doping region 21 and the second doping region 22 are manufactured by using a diffusion process, and the area occupied by the first doping region 21 is large, so that before the first doping region 21 is manufactured, a portion of the first oxide layer 4 on the front surface and the back surface of the substrate 1 needs to be rapidly etched by wet etching, and when the second doping region 22 is manufactured, since the area occupied by the second doping region 22 is small, the substrate is directionally etched by using a dry etching method, lateral etching does not occur, and other structures are not affected.
In the above-described photolithography step: the method comprises the steps of selecting a material layer, coating photoresist, exposing, removing the photoresist during developing, and finally removing the residual photoresist by dry etching or wet etching, which is a complete photoetching process.
In addition, the high-temperature furnaces are all normal-pressure diffusion furnace tubes, and the normal-pressure diffusion furnace tubes are one of important process equipment of a front procedure of a semiconductor production line and are used for diffusion, oxidation, annealing, alloying, sintering and other processes in industries such as large-scale integrated circuits, discrete devices, power electronics, photoelectric devices, optical fibers and the like.
Process steps not described in detail in the flow are conventional process steps such as via lithography, via etching, rinsing, diffusion, lithography, dry etching, etc., and are not described in detail in this application.
Second embodiment
With reference to fig. 3, the present embodiment provides a semiconductor device manufactured by the method for manufacturing a photodiode, the semiconductor device including: a substrate 1; a first doped region 21 doped on the back surface of the substrate 1 and the periphery of the front surface of the substrate 1; a second doped region 22 doped at the central position of the front surface of the substrate 1; a first oxide layer 4 formed on the front surface of the substrate 1; and a second oxide layer 5 formed on a side of the first oxide layer 4 away from the substrate 1.
The first doped region 21 is a P + doped region, and the second doped region 22 is an N + doped region. The back surface of the substrate 1 is doped to form a P + doped region, an N + doped region is generated at the center position of the front surface of the substrate 1, and the periphery of the N + doped region is the P + doped region, so that a good partial pressure effect can be achieved when the semiconductor device works.
Further, the semiconductor device further includes: the anti-reflection layer 7 is formed on the front surface of the substrate 1, a lead hole is formed in the anti-reflection layer 7, the first electrode 31 is located in the lead hole, the second electrode 32 is located on the back surface of the first doping region 21, and the oxidation layer is located on the front surface of the substrate 1 and comprises a first oxidation layer 4 located on the front surface of the substrate 1 and a second oxidation layer 5 formed on one side, away from the substrate 1, of the first oxidation layer 4.
The first electrode 31 is a positive electrode formed by depositing metal aluminum, and the thickness of the first electrode 31 is 2 μm to 2.4 μm. The second electrode 32 is a negative electrode formed by depositing metal silver, and the negative electrode is formed by depositing metal titanium, metal nickel and metal silver in sequence from bottom to top.
In addition, the material of the substrate 1 is polysilicon, and the material of the oxide layer is silicon oxide. The thickness of the substrate 1 is 300 microns, compared with the 600 microns in the prior art, the thickness of the substrate 1 in the application is smaller, and in the preparation process, the substrate 1 is not damaged by scratches and the like due to double-sided coating, so that the thickness of the substrate 1 does not need to be thinned in the preparation process, and the substrate 1 with the thickness of 300 microns is selected, so that compared with the ion implantation in the prior art, the process steps are reduced, and the working efficiency is improved.
It should be noted that the semiconductor device in this embodiment may further include other layer structures, such as a barrier layer, an epitaxial layer, and the like, which are not described herein again.
The technical scheme of the application can be widely applied to the preparation of various semiconductor devices, such as discrete device gates of a schottky Diode (SBD), a Fast Recovery Diode (FRD), a Transient Voltage Super (TVS), a switch Diode (switch Diode), a Rectifier Diode (Rectifier Diode), a light source triode, a silicon controlled Rectifier element, a small signal triode and the like, and can be applied to the scheme.
It should be readily understood that "on … …", "above … …" and "above … …" in this application should be interpreted in the broadest manner such that "on … …" means not only "directly on something", but also "on something" with intermediate features or layers therebetween, and "above … …" or "above … …" includes not only the meaning of "above" or "on" something, but also the meaning of "above" or "on" without intermediate features or layers therebetween (i.e., directly on something).
The term "layer" as used herein may refer to a portion of material that includes a region having a thickness. A layer may extend over the entire underlying or overlying structure or may have a smaller extent than the underlying or overlying structure. Further, a layer may be a region of a continuous structure, homogeneous or heterogeneous, having a thickness less than the thickness of the continuous structure. For example, a layer may be located between the top and bottom surfaces of the continuous structure or between any pair of lateral planes at the top and bottom surfaces. The layers may extend laterally, vertically, and/or along a tapered surface. The semiconductor device may be a layer, may include one or more layers therein, and/or may have one or more layers located above, and/or below it. The layer may comprise a plurality of layers. For example, the interconnect layer may include one or more conductors and contact layers (within which contacts, interconnect lines, and/or vias are formed) and one or more dielectric layers.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims (10)

1. A method for manufacturing a photodiode, comprising:
providing a substrate, and growing first oxide layers on the front surface and the back surface of the substrate respectively;
etching the first oxide layer on the back of the substrate and the first oxide layer on the periphery of the front of the substrate in a wet etching mode;
performing diffusion treatment on the front surface and the back surface of the substrate and the front surface and the side surfaces of the first oxide layer to generate a first doped region;
performing high-temperature junction pushing on the front surface and the back surface of the substrate, and growing second oxide layers on the front surface of the first oxide layer, the front surface of the first doped region and the back surface of the first doped region respectively;
etching off part of the first oxide layer and part of the second oxide layer on the front surface of the substrate in a dry etching mode;
and carrying out diffusion treatment on the front surface of the substrate to generate a second doped region.
2. The method for preparing the photodiode according to claim 1, wherein the step of performing diffusion treatment on the front and back surfaces of the substrate and the front and side surfaces of the first oxide layer to generate the first doped region comprises: and placing the substrate in a high-temperature furnace, introducing boron into the high-temperature furnace, and performing boron source diffusion treatment on the front surface and the back surface of the substrate and the front surface and the side surface of the first oxide layer.
3. The method of claim 2, wherein the boron source is a chemical comprising boron 30.
4. The method for manufacturing a photodiode according to claim 1, wherein in the step of etching away a portion of the first oxide layer and a portion of the second oxide layer on the front surface of the substrate by dry etching, the method further comprises: and carrying out anisotropic etching on the first oxide layer and the second oxide layer on the front surface of the substrate.
5. The method for preparing a photodiode according to claim 1, wherein the step of performing diffusion treatment on the front surface of the substrate to form the second doped region comprises: and (3) placing the substrate in a high-temperature furnace, introducing phosphorus oxychloride into the high-temperature furnace, and performing phosphorus oxychloride diffusion treatment on the center of the front surface of the substrate.
6. The method for preparing a photodiode according to claim 5, wherein in the step of placing the substrate in a high temperature furnace, introducing phosphorus oxychloride into the high temperature furnace, and performing phosphorus oxychloride diffusion treatment on the central position of the front surface of the substrate, 0.5L ± 0.1L of phosphorus oxychloride is introduced into the high temperature furnace at 950 ℃ ± 50 ℃, and 10L ± 2L of nitrogen and 0.2L ± 0.05L of oxygen are introduced, and the process time is 16min ± 2min.
7. The method for manufacturing a photodiode according to claim 1, further comprising, after the step of performing diffusion processing on the front surface of the substrate to form the second doped region: and (3) respectively growing sacrificial layers on the front surface of the second doping region, the front surface of the second oxidation layer and the back surface of the second oxidation layer by performing high-temperature junction pushing in the furnace, and removing the sacrificial layers, part of the second oxidation layer and organic matters remained on the surfaces of the second oxidation layer in an acid bleaching mode.
8. The method for preparing the photodiode according to claim 7, wherein after the steps of growing the sacrificial layer on the front surface of the second doped region, the front surface of the second oxide layer and the back surface of the second oxide layer respectively by performing the high temperature junction pushing in the furnace, and removing the sacrificial layer, a portion of the second oxide layer and the residual organic matters on the surface of the second oxide layer by rinsing with acid, the method further comprises: and forming an anti-reflection layer on the front surface of the second doped region and the front surface of the second oxide layer by means of chemical vapor deposition.
9. The method as claimed in claim 8, further comprising, after the step of depositing an anti-reflection layer on the front surface of the second doped region and the front surface of the second oxide layer: and etching a lead hole on the anti-reflection layer by a wet etching method, growing a first electrode on the lead hole, and growing a second electrode on the back of the first doped region.
10. A semiconductor device manufactured by the method for manufacturing a photodiode according to any one of claims 1 to 9, comprising:
a substrate;
the first doping area is doped on the back surface of the substrate and the periphery side of the front surface of the substrate;
the second doping area is doped in the central position of the front surface of the substrate;
the first oxidation layer is formed on the front surface of the substrate; and the number of the first and second groups,
and the second oxidation layer is formed on one side of the first oxidation layer, which is far away from the substrate.
CN202111671859.1A 2021-12-31 2021-12-31 Preparation method of photosensitive diode and semiconductor device Pending CN115377243A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117012860A (en) * 2023-10-07 2023-11-07 青岛旭芯互联科技研发有限公司 Preparation method of photodiode and photodiode

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117012860A (en) * 2023-10-07 2023-11-07 青岛旭芯互联科技研发有限公司 Preparation method of photodiode and photodiode

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