Phosphorus-doped silicon target material, preparation method thereof, and photovoltaic cell

Abstract

The present application relates to the technical field of target material preparation, and provides a phosphorus-doped silicon target material and a preparation method thereof and a photovoltaic cell, including: smelting a silicon dioxide block and a phosphorus-containing compound, and then cooling and crushing to obtain silicon-phosphorus oxide powder; reducing the silicon-phosphorus oxide powder to obtain silicon-phosphorus alloy powder; coating the silicon-phosphorus alloy powder with silicon powder to obtain composite powder; thermally spraying the composite powder onto a back tube, and then machining to obtain a phosphorus-doped silicon target material. The present application melts silicon dioxide and a phosphorus-containing compound to allow the two to react fully, thereby forming a uniform, chemically stable silicon-phosphorus oxide powder after cooling and solidification, and forming a more uniform and stable silicon-phosphorus alloy powder after reduction, so that the obtained silicon target material has better structural uniformity and is conducive to controlling the phosphorus content of the silicon target material. Silicon-phosphorus alloy powder is coated with silicon powder to reduce the volatilization of phosphorus during the spraying process, so that the phosphorus content of the silicon target material can be better controlled.

Description

Technical Field

[0001] The present application belongs to the technical field of target material preparation, and in particular relates to a phosphorus-doped silicon target material, a preparation method thereof, and a photovoltaic cell. Background Art

[0002] Crystalline silicon heterojunction solar cells (HJT) use silicon as the main material. The core part is a PN junction formed by the junction area of ​​P-type silicon and N-type silicon, which makes it have the advantages of high conversion efficiency, good stability, low attenuation rate and double-sided power generation, and has broad market prospects. Among them, N-type silicon is mainly a phosphorus-doped silicon layer, which is prepared by in-situ doping or non-in-situ doping. In-situ doping is to add a phosphorus source (such as PH3) during the deposition of polycrystalline silicon. However, the addition of a phosphorus source will greatly reduce the deposition rate of the silicon layer, affect the uniformity of the film, and there will be a serious "around plating" phenomenon during the coating process, affecting the performance of the battery. Non-in-situ doping is to first deposit and grow an intrinsic amorphous silicon layer, then dope it by phosphorus diffusion or phosphorus ion implantation, and then achieve crystal growth by high-temperature annealing. However, the preparation process is cumbersome. In addition, both methods are chemical vapor deposition (CVD), which requires the use of silicon source, doping gas source, etc., and have defects such as high toxicity, environmental pollution caused by reaction tail gas, and high deposition temperature. Therefore, it is of great significance to develop a phosphorus-doped silicon target suitable for physical vapor deposition (PVD) coating (no precursor required, green and environmentally friendly).

[0003] At present, the method for preparing a phosphorus-doped silicon target comprises: sealing red phosphorus and silicon powder in a quartz tube and placing them in a sintering furnace, then subjecting them to high-temperature heat treatment to form phosphorus-doped silicon powder, grinding them into powder and placing them in a graphite mold for vacuum hot pressing to obtain a phosphorus-doped silicon target. However, since red phosphorus sublimates into gas at high temperatures, although sealing red phosphorus and silicon powder in a quartz tube can prevent red phosphorus from volatilizing, the amount of phosphorus diffused into the silicon matrix is ​​affected by multiple factors such as temperature, saturated vapor pressure, and time, making it difficult to control the phosphorus doping amount in the silicon powder, and there is also the problem of uneven phosphorus distribution, which ultimately affects the phosphorus content and structural uniformity of the silicon target. Summary of the invention

[0004] The purpose of the present application is to provide a phosphorus-doped silicon target material, a preparation method thereof and a photovoltaic cell, aiming to solve the problems that the existing preparation method of phosphorus-doped silicon target material has difficulty in controlling the phosphorus content of the silicon target material and poor structural uniformity.

[0005] In order to achieve the above application purpose, the technical solution adopted in this application is as follows:

[0006] In a first aspect, the present application provides a method for preparing a phosphorus-doped silicon target, comprising the following steps:

[0007] The silicon dioxide block and the phosphorus-containing compound powder are smelted, and then cooled and crushed to obtain silicon-phosphorus oxide powder; the phosphorus-containing compound powder is phosphate or phosphorus pentoxide powder;

[0008] The silicon-phosphorus oxide powder is subjected to a reduction treatment to obtain a silicon-phosphorus alloy powder;

[0009] The silicon-phosphorus alloy powder is coated with silicon powder to obtain composite powder;

[0010] The composite powder is thermally sprayed onto a backing tube, and then machined to obtain a phosphorus-doped silicon target.

[0011] In a second aspect, the present application provides a phosphorus-doped silicon target, including a phosphorus-doped silicon target prepared by the method for preparing a phosphorus-doped silicon target provided by the present application;

[0012] The phosphorus content of the phosphorus-doped silicon target is 1-5wt%.

[0013] In a third aspect, the present application provides a photovoltaic cell, comprising an N-type silicon layer, wherein the N-type silicon layer is obtained by sputtering and coating the phosphorus-doped silicon target provided by the present application.

[0014] Compared with the prior art, this application has the following beneficial effects:

[0015] (1) The silicon dioxide block and the phosphorus-containing compound powder are melted to allow the silicon dioxide and the phosphorus-containing compound to react fully, so that after cooling and solidification, a uniform silicon-phosphorus oxide powder with stable chemical properties can be formed. Therefore, after reduction, it can form a more uniform and stable silicon-phosphorus alloy powder. Compared with the method of thermal diffusion doping of silicon powder with phosphorus powder in the prior art, the silicon target material prepared in the present application has better structural uniformity and can also reduce the volatilization of phosphorus, which is beneficial to control the phosphorus content of the silicon target material.

[0016] (2) Using low-cost silicon dioxide and phosphorus-containing compound powder as raw materials, the manufacturing cost is lower.

[0017] (3) Using silicon powder to coat silicon-phosphorus alloy powder can reduce the volatilization of phosphorus during thermal spraying, thereby better controlling the phosphorus content of the silicon target. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 paying any creative work.

[0019] Figure 1It is a process flow chart of the method for preparing a phosphorus-doped silicon target provided in an embodiment of the present application. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0021] In a first aspect, an embodiment of the present application provides a method for preparing a phosphorus-doped silicon target material, such as Figure 1 As shown, the following steps are included:

[0022] S01: smelting silicon dioxide block and phosphorus-containing compound powder, cooling and crushing to obtain silicon-phosphorus oxide powder; the phosphorus-containing compound powder is phosphate or phosphorus pentoxide powder;

[0023] S02: reducing the silicon phosphorus oxide powder to obtain silicon phosphorus alloy powder;

[0024] S03: coating the silicon-phosphorus alloy powder with silicon powder to obtain composite powder;

[0025] S04: thermally spraying the composite powder onto a backing tube, and then machining to obtain a phosphorus-doped silicon target.

[0026] The preparation method of the phosphorus-doped silicon target provided in the embodiment of the present application, the silicon dioxide block and the phosphorus-containing compound powder are melted, and the silicon dioxide and the phosphorus-containing compound are fully reacted, so that a uniform and chemically stable silicon-phosphorus oxide powder can be formed after cooling and solidification, so it can form a more uniform and stable silicon-phosphorus alloy powder after reduction, and compared with the method of thermal diffusion doping of silicon powder by phosphorus powder in the prior art, the organization uniformity of the silicon target prepared by the present application is better, and the volatilization of phosphorus can also be reduced, so as to facilitate the control of the phosphorus content of the silicon target. In addition, the silicon-phosphorus alloy powder is coated with silicon powder, which can reduce the volatilization of phosphorus during thermal spraying, so as to better control the phosphorus content of the silicon target. In addition, with low-cost silicon dioxide and phosphorus-containing compound powder as raw materials, the manufacturing cost is lower.

[0027] In the above step S01, the temperature of the smelting treatment is 1650-1750° C. This temperature range allows the silicon dioxide block and the phosphorus-containing compound powder to melt and react fully to form a uniform glass liquid, so that uniform silicon-phosphorus oxide powder with stable chemical properties can be obtained after subsequent cooling, solidification and crushing.

[0028] In the embodiment, the mass ratio of the silicon dioxide bulk to the phosphorus-containing compound powder is (3.3-32.7) / 1.

[0029] In an embodiment, the phosphate is selected from ammonium phosphate or diammonium phosphate.

[0030] In the embodiment, the particle size of the silicon phosphorus oxide powder is 5-25 μm.

[0031] In the above step S02, the step of reducing the silicon-phosphorus oxide powder includes: mixing the silicon-phosphorus oxide powder, metal magnesium powder and sodium chloride powder to obtain a mixed powder; subjecting the mixed powder to a thermal reduction reaction under an inert atmosphere, and then cooling to obtain a solid product; and purifying the solid product to obtain a silicon-phosphorus alloy powder. Among them, the metal magnesium powder is used as a reducing agent to reduce the silicon-phosphorus oxide powder to silicon-phosphorus alloy powder, and the sodium chloride powder can absorb the heat released during the reduction reaction, thereby preventing side reactions from occurring and ensuring the purity of the silicon-phosphorus alloy powder. The inert atmosphere can be nitrogen, argon, etc.

[0032] In an embodiment, the step of purifying the solid product comprises: soaking the solid product in pure water for 5 to 10 minutes, washing with water (to remove sodium chloride), then soaking the solid product in an ammonium salt solution for 10 to 60 minutes (to remove magnesium oxide), then washing with water, filtering and drying to obtain silicon-phosphorus alloy powder. The ammonium salt solution may be an ammonium chloride solution, an ammonium phosphate solution, an ammonium nitrate solution, etc.

[0033] In the embodiment, the step of subjecting the mixed powder to a thermal reduction reaction treatment in an inert atmosphere comprises: placing the mixed powder in an atmosphere furnace, evacuating the mixture to a vacuum of 10 -2 After the temperature drops below Pa, an inert gas is introduced, and then the temperature is raised to 650-950°C and kept warm for 2-10 hours. After cooling, a solid product is obtained.

[0034] In an embodiment, the mass ratio of silicon-phosphorus oxide powder, metal magnesium powder and sodium chloride powder is 1 / (0.8-2) / (2-20), preferably 1 / (0.8-1.2) / (5-15). This mass ratio range can ensure that the silicon-phosphorus oxide powder is completely reduced to silicon-phosphorus alloy powder, and the sodium chloride can better absorb the heat released during the reduction reaction to prevent the occurrence of side reactions.

[0035] In the above step S03, the step of coating the silicon-phosphorus alloy powder with silicon powder includes: placing the silicon-phosphorus alloy powder in a three-dimensional mixing and granulating device, spraying a binder solution on the silicon-phosphorus alloy powder, and mixing and granulating at the same time to obtain a silicon-phosphorus alloy core; adding silicon powder to the silicon-phosphorus alloy core, and then spraying a binder solution, and mixing and granulating at the same time, and continuing to mix and granulate for 1 to 4 hours after the binder solution is sprayed, to obtain a composite powder. The binder solution can be a mixed solution of polyvinyl alcohol and ethanol. The mass ratio of polyvinyl alcohol to ethanol is (1 to 3) / (7 to 9), and the amount of polyvinyl alcohol added is 0.1 to 1% of the total mass of the silicon powder and the silicon-phosphorus alloy powder.

[0036] In the embodiment, the mass ratio of silicon powder to silicon-phosphorus alloy powder is (1-2) / 1.

[0037] In the embodiment, the particle size of the silicon powder is 5-20 μm.

[0038] In the embodiment, the particle size of the silicon-phosphorus alloy powder is 5-25 μm; the particle size of the silicon-phosphorus alloy core is 45-75 μm.

[0039] In the embodiment, the particle size of the composite powder is 80-150 μm.

[0040] In the above step S04, the step of thermally spraying the composite powder onto the back tube includes: using a vacuum plasma spraying device containing a spray gun to spray the composite powder onto the back tube; wherein, the distance from the spray gun to the central axis of the back tube is 90-110 mm. If the distance between the spray gun and the central axis of the back tube is too long, the particle speed is reduced, the kinetic energy is reduced, and it is easy to cause the bonding strength between the silicon coating and the silicon coating and the back tube to decrease, which ultimately affects the density and strength of the silicon target obtained by spraying; if the distance between the spray gun and the central axis of the back tube is too short, the particle speed is too high, which is easy to cause powder splashing and reduce the deposition rate of the sprayed powder. Therefore, within the scope of this embodiment, the composite powder has a higher deposition rate, and the obtained phosphorus-doped silicon target has a higher density and a stronger mechanical strength; the moving speed of the spray gun is 35-7 5mm / s, this moving speed range makes the composite powder sprayed on the back tube more evenly, and the coating in some areas will not be too thick, which will affect the bonding strength between the coatings and between the coatings and the back tube; the rotation speed of the back tube is 200~300r / mim, and this rotation speed range makes the composite powder sprayed on the back tube more evenly, and the coating in some areas will not be too thick, which will affect the bonding strength between the silicon coatings and between the silicon coatings and the back tube; the powder feeding amount is 100~200g / min, and this powder feeding amount range can ensure a high spraying efficiency, and is also conducive to the uniform spraying of the composite powder on the back tube to form a uniform and dense target material; the atmosphere is an argon-hydrogen mixed gas, and spraying under the conditions of an argon-hydrogen mixed atmosphere can prevent silicon oxidation and ensure the high silicon purity and low oxygen content of the phosphorus-doped silicon target.

[0041] In the embodiment, the volume ratio of argon to hydrogen in the argon-hydrogen mixed gas is (90-95) / (5-10). Spraying under the conditions of argon-hydrogen mixed gas can better prevent silicon oxidation and ensure high silicon purity and low oxygen content of the phosphorus-doped silicon target.

[0042] In an embodiment, machining includes: sandblasting and arc priming of the back tube surface respectively, and spraying can make the surface clean and have a certain roughness; wherein, the sand can be selected from white corundum or brown corundum, and the self-fluxing alloy can be selected from copper-aluminum alloy or nickel-aluminum alloy.

[0043] A second aspect of an embodiment of the present application provides a phosphorus-doped silicon target material, including a phosphorus-doped silicon target material prepared by the method for preparing a phosphorus-doped silicon target material provided in the present application;

[0044] The phosphorus content of the phosphorus-doped silicon target is 1~5wt%.

[0045] The phosphorus-doped silicon target material provided in the embodiment of the present application is prepared by the method for preparing the phosphorus-doped silicon target material provided in the embodiment of the present application. Therefore, the embodiment of the present application can better control the phosphorus content of the silicon target material, and the target material has good structural uniformity, thereby the silicon target material has better electrical conductivity.

[0046] A third aspect of an embodiment of the present application provides a photovoltaic cell, comprising an N-type silicon layer, wherein the N-type silicon layer is obtained by sputtering and coating the phosphorus-doped silicon target material provided by the present application.

[0047] The photovoltaic cell provided in the embodiment of the present application has good electrical conductivity, which helps to improve the conversion efficiency of the solar cell because the N-type silicon layer contained in it is obtained by sputtering and coating the phosphorus-doped silicon target material provided in the present application.

[0048] The following describes the invention in conjunction with specific embodiments.

[0049] Example 1

[0050] The present invention provides a method for preparing a phosphorus-doped silicon target material, comprising the following steps:

[0051] S11: Weigh appropriate amounts of silicon dioxide blocks and ammonium phosphate powder in a mass ratio of 7 / 1 and place them in a crucible, smelt them at 1700°C for 0.5h, then pour them into deionized water for rapid cooling, and then dry, crush and sieve to obtain silicon phosphorus oxide powder (D50=21μm);

[0052] S12: Weigh appropriate amounts of silicon phosphorus oxide powder, metal magnesium powder and sodium chloride powder in a mass ratio of 1 / 1 / 10 and mix them to obtain a mixed powder;

[0053] Place the mixed powder in an atmosphere furnace and evacuate to 10 -2 After the temperature was below Pa, argon was introduced, and then the temperature was raised to 800°C and kept for 4 hours, and a solid product was obtained after cooling;

[0054] The solid product was soaked in pure water for 7 minutes, washed with water to remove sodium chloride, then soaked in ammonium chloride solution for 30 minutes to remove magnesium oxide, then washed with water, filtered and dried to obtain silicon-phosphorus alloy powder (D50=22μm);

[0055] The phosphorus content of the silicon-phosphorus alloy powder was detected to be 5.10wt% by ICP spectrometer;

[0056] S13: placing the silicon-phosphorus alloy powder in a three-dimensional mixing granulation device, spraying a mixed solution of polyvinyl alcohol and ethanol on the silicon-phosphorus alloy powder, and performing mixing and granulation at the same time to obtain a silicon-phosphorus alloy core body (D50=60 μm);

[0057] Add silicon powder (D50=13μm) to the silicon-phosphorus alloy core, then spray the binder solution and mix and granulate at the same time. After the binder solution is sprayed, continue mixing and granulating for 2h to obtain composite powder (D50=108μm);

[0058] The mass ratio of silicon powder to silicon-phosphorus alloy core is 1.5 / 1 (the phosphorus content of the composite powder is 2.04wt%), the binder solution is a mixed solution of polyvinyl alcohol and ethanol in a mass ratio of 2 / 8, and the amount of polyvinyl alcohol added is 0.4% of the total mass of silicon powder and silicon-phosphorus alloy powder;

[0059] S14: The processed back tube is installed on the frame, and the frame drives the back tube to rotate and move axially. The spray gun is installed 100mm above the central axis of the back tube. The movement speed of the spray gun is set to 50mm / s, the rotation speed of the back tube is 260r / min, the powder feeding amount is 160g / min, and the powder feeding gas and the working gas are both argon-hydrogen mixture (the volume ratio of argon and hydrogen is 95 / 5). During the spraying process, water is passed into the back tube to make the temperature of the back tube surface 80°C, and the composite powder is sprayed onto the back tube for 2h to obtain a phosphorus-doped silicon target.

[0060] Example 2

[0061] The present embodiment provides a method for preparing a phosphorus-doped silicon target material, which differs from the embodiment 1 in that:

[0062] In step S13, the mass ratio of silicon powder to silicon-phosphorus alloy core is 1 / 1 (the phosphorus content of the composite powder is 2.55 wt %).

[0063] Example 3

[0064] The present embodiment provides a method for preparing a phosphorus-doped silicon target material, which differs from the embodiment 1 in that:

[0065] In step S13, the mass ratio of silicon powder to silicon-phosphorus alloy core is 2 / 1 (the phosphorus content of the composite powder is 1.70 wt %).

[0066] Example 4

[0067] The present embodiment provides a method for preparing a phosphorus-doped silicon target material, which differs from the embodiment 1 in that:

[0068] In step S11, phosphorus pentoxide powder is used to replace ammonium phosphate powder, and the mass ratio of silicon dioxide block to phosphorus pentoxide powder is 12.7 / 1;

[0069] In step S12, the phosphorus content of the silicon-phosphorus alloy powder is detected to be 5.24wt% by ICP spectrometer;

[0070] In step S13, the phosphorus content of the composite powder is 2.10 wt %.

[0071] Comparative Example 1

[0072] The present invention provides a method for preparing a phosphorus-doped silicon target material, comprising the following steps:

[0073] S1: Weigh an appropriate amount of phosphorus powder (purity of 99.999%) and silicon powder (purity of 99.999%) in a mass ratio of 90 / 10 and put them into a clean quartz tube, evacuate to below 0.1Pa and seal the quartz tube; place the quartz tube in a sintering furnace, start heating to 1000℃, and keep it warm for 12h to obtain silicon-phosphorus alloy powder; use ICP spectrometer to detect that the phosphorus content of the silicon-phosphorus alloy powder is 4.62%;

[0074] S2: Silicon-phosphorus alloy powder, polyethylene glycol and ethanol are ball-milled and mixed, and then polyvinyl alcohol is added and mixed evenly to obtain a slurry, and the slurry is spray-granulated to obtain a composite powder with a phosphorus content of 4.62% (D50=111μm);

[0075] Among them, the addition amount of polyethylene glycol is 0.4% of the mass of silicon-phosphorus alloy powder, and the addition amount of polyvinyl alcohol is 0.4% of the mass of silicon-phosphorus alloy powder;

[0076] S3: The processed back tube is installed on the frame, and the frame drives the back tube to rotate and move axially. The spray gun is installed 100mm above the central axis of the back tube. The movement speed of the spray gun is set to 50mm / s, the rotation speed of the back tube is 260r / min, the powder feeding amount is 160g / min, and the powder feeding gas and the working gas are both argon-hydrogen mixture (the volume ratio of argon and hydrogen is 95 / 5). During the spraying process, water is passed into the back tube to make the temperature of the back tube surface 80℃, and the composite powder is sprayed onto the back tube for 2h to obtain a phosphorus-doped silicon target.

[0077] Comparative Example 2

[0078] The present embodiment provides a method for preparing a phosphorus-doped silicon target material, which differs from the embodiment 1 in that:

[0079] S13: mixing silicon powder, silicon-phosphorus alloy powder, polyethylene glycol and ethanol by ball milling, then adding polyvinyl alcohol and mixing evenly to obtain slurry, spraying and granulating the slurry to obtain composite powder (D50=110 μm);

[0080] The mass ratio of silicon powder to silicon-phosphorus alloy core is 1.5 / 1 (the phosphorus content of the composite powder is 2.04wt%), the added amount of polyethylene glycol is 0.4% of the mass of the silicon-phosphorus alloy powder, and the added amount of polyvinyl alcohol is 0.4% of the mass of the silicon-phosphorus alloy powder.

[0081] Comparative Example 3

[0082] The present embodiment provides a method for preparing a phosphorus-doped silicon target material, which differs from the embodiment 1 in that:

[0083] In step S13, the mass ratio of silicon powder to silicon-phosphorus alloy core is 0.5 / 1 (the phosphorus content of the composite powder is 3.40 wt %).

[0084] Related performance test analysis:

[0085] 1. The resistivity of the phosphorus-doped silicon targets prepared in Examples 1 to 4 and Comparative Examples 1 to 3 was tested using a four-probe tester;

[0086] 2. Using an ICP spectrometer, the phosphorus content of the phosphorus-doped silicon targets prepared in Examples 1 to 4 and Comparative Examples 1 to 3 was measured respectively;

[0087] The test results are shown in Table 1 below:

[0088] Table 1

[0089]

[0090] It can be seen from Table 1 that the phosphorus content of the silicon target materials prepared in Examples 1 to 4 is slightly lower than that of the composite powder, while the phosphorus content of the silicon target materials prepared in Comparative Examples 1 to 3 is significantly lower than that of the composite powder, indicating that the embodiments of the present application use silicon powder to coat the silicon-phosphorus alloy powder, which can reduce the volatilization of phosphorus during thermal spraying, thereby better controlling the phosphorus content of the silicon target material.

[0091] The phosphorus content of the silicon target material prepared in Example 3 is slightly lower than that of the silicon target material prepared in Comparative Example 1. However, the resistivity of the silicon target material prepared in Example 3 is significantly lower than that of the silicon target material prepared in Comparative Example 1. This is mainly because the silicon dioxide block and ammonium chloride salt powder are smelted in the embodiment of the present application to allow the silicon dioxide and the phosphorus-containing compound to fully react. The silicon-phosphorus oxide powder obtained after cooling and solidification is more uniform and stable, and can be reduced to obtain a more uniform and stable silicon-phosphorus alloy powder, so that the structure uniformity of the prepared silicon target material is better. Therefore, the silicon target material prepared in the embodiment of the present application has better conductivity.

[0092] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a phosphorus-doped silicon target, characterized in that: The following steps are involved: The silicon dioxide block and the phosphorus-containing compound powder are smelted, and then cooled and crushed to obtain silicon-phosphorus oxide powder; the phosphorus-containing compound powder is phosphate or phosphorus pentoxide powder; The silicon phosphorus oxide powder, metal magnesium powder and sodium chloride powder are mixed to obtain a mixed powder; The mixed powder is subjected to a thermal reduction reaction treatment under an inert atmosphere, and then cooled to obtain a solid product; Purifying the solid product to obtain silicon-phosphorus alloy powder; Placing the silicon-phosphorus alloy powder in a three-dimensional mixing and granulating device, spraying a binder solution on the silicon-phosphorus alloy powder, and simultaneously performing mixing and granulating to obtain a silicon-phosphorus alloy core body; Adding silicon powder to the silicon-phosphorus alloy core, then spraying the binder solution, and simultaneously performing mixing and granulation, and continuing mixing and granulation for 1 to 4 hours after the binder solution is sprayed, to obtain composite powder; the mass ratio of the silicon powder to the silicon-phosphorus alloy powder is (1 to 2) / 1; thermally spraying the composite powder onto a backing tube, and then machining to obtain a phosphorus-doped silicon target; Wherein, the mass ratio of the silicon phosphorus oxide powder, the metal magnesium powder and the sodium chloride powder is 1 / (0.8-2) / (2-20); The step of subjecting the mixed powder to a thermal reduction reaction treatment in an inert atmosphere comprises: placing the mixed powder in an atmosphere furnace, evacuating the mixture to 10 -2 After the temperature drops below Pa, an inert gas is introduced, and then the temperature is raised to 650-950°C and kept warm for 2-10 hours. After cooling, a solid product is obtained.

2. The preparation method according to claim 1, characterized in that Include at least one of the following conditions: The phosphate is selected from ammonium phosphate or diammonium hydrogen phosphate; The mass ratio of the silicon dioxide block to the phosphorus-containing compound powder is (3.3-32.7) / 1; The temperature of the smelting treatment is 1650~1750℃.

3. The preparation method according to claim 1, characterized in that: Include at least one of the following conditions: The particle size of the silicon powder is 5-20 μm; The particle size of the silicon-phosphorus alloy powder is 5-25 μm; The particle size of the silicon-phosphorus alloy core is 45-75 μm; The particle size of the composite powder is 80-150 μm.

4. The preparation method according to any one of claims 1 to 3, characterized in that The step of thermally spraying the composite powder onto the back tube includes: spraying the composite powder onto the back tube using a vacuum plasma spraying device including a spray gun; wherein the distance between the spray gun and the central axis of the back tube is 90-110 mm, the moving speed of the spray gun is 35-75 mm / s, the rotation speed of the back tube is 200-300 r / mim, the powder feeding amount is 100-200 g / min, and the atmosphere is an argon-hydrogen mixture.

5. The preparation method according to claim 4, characterized in that: In the argon-hydrogen mixed gas, the volume ratio of argon to hydrogen is (90-95) / (5-10).

6. The preparation method according to any one of claims 1 to 3, characterized in that: The phosphorus content of the phosphorus-doped silicon target is 1-5wt%.

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