Alumina ceramic crucible, its use structure and method for growing single crystal

Abstract

The invention discloses an alumina ceramic crucible, a structure for use thereof and a method for growing a single crystal. The alumina ceramic crucible comprises an alumina ceramic crucible, an alumina ceramic cap, an aluminum silicate ceramic fiber sealing gasket and an aluminum silicate ceramic fiber paper layer; the alumina ceramic crucible comprises a seed crystal cavity, a cone and a body connected in sequence from bottom to top, the top of the body is an open structure, the alumina ceramic cap is threadedly connected to the top of the body, and the ceramic fiber sealing gasket is arranged between the alumina ceramic cap screw and the top of the body; the aluminum silicate ceramic fiber paper layer is movably laid on the inner side of the alumina ceramic crucible. When the present invention grows a single crystal, the alumina ceramic crucible is used to replace the quartz crucible, and the quartz hydrogen-oxygen flame welding and sealing are not required, and the nitrogen balance pressure is not required in the VGF single crystal furnace, thereby reducing the production cost; through the setting of the aluminum silicate ceramic fiber paper, the stability of the temperature field of the single crystal furnace is greatly improved, the dislocation density of the indium phosphide single crystal is reduced, and the crystallization rate is improved.

Description

Technical Field

[0001] The invention relates to an alumina ceramic crucible, a use structure thereof and a method for growing a single crystal, and belongs to the technical field of InP single crystal growth. Background Art

[0002] Indium phosphide (InP) is one of the important III-V compound semiconductor materials and a new generation of electronic functional materials after Si and GaAs. GaAs, InP and other materials have superior properties that Ge and Si do not have (such as high electron mobility, large bandgap, etc.), and can be widely used in the field of microwave and optoelectronic devices. InP materials are suitable for manufacturing millimeter-wave frequency conversion devices and can be widely used in radar communications and precision guidance. InP-based microwave devices are key components of the new generation of satellite communications and precision guidance, which directly determine the rapid response capability of weapon equipment systems.

[0003] The main method for obtaining InP single crystal material at present is vertical temperature gradient solidification (VGF), firstly, after cleaning the indium phosphide polycrystalline material, it is loaded into the cleaned PBN crucible with dopant, B2O3 liquid sealant, high-purity red phosphorus, seed crystal, etc., and then put into a quartz crucible together, and the inside of the quartz crucible is evacuated to vacuum using a molecular vacuum pump, and the quartz crucible evacuated to vacuum is sealed with a hydrogen-oxygen flame; a heater with a multi-stage heating structure is used to establish a vertical temperature gradient, melt the indium phosphide polycrystalline material, control the cooling rate of each temperature zone, and slowly move the growth interface upward to realize the directional solidification growth of indium phosphide. When growing indium phosphide single crystals, as the temperature rises, the high-purity red phosphorus loaded during batching will sublimate into red phosphorus vapor, generating a pressure of 2.75Mpa inside the quartz crucible, and it is necessary to fill the pressure vessel with nitrogen or argon slightly higher than 2.75Mpa to balance the pressure.

[0004] The nitrogen filled in the single crystal furnace produces violent gas convection under high temperature and high pressure conditions, causing large fluctuations in the temperature of the temperature field. The obtained single crystal has a high dislocation density, and small twins are easy to grow inside the crystal. The crystal formation rate is not high, and the quartz tubes and quartz caps are immediately scrapped after use, making the price of large-size and high-quality substrates on the market always high. In addition, there is stress at the weld position after the quartz tube is sealed with hydrogen-oxygen flame. Under high temperature and high pressure conditions, the quartz tube is prone to cracks, resulting in tube cracking, causing the dissociation of indium phosphide polycrystalline materials, and a large amount of red phosphorus burning to damage the single crystal furnace, delaying production. Summary of the invention

[0005] The present invention provides an alumina ceramic crucible, a use structure thereof and a method for growing a single crystal, which can effectively improve the shortcomings of the current indium phosphide single crystal growth process, such as high dislocation density, low crystallization rate and high cost.

[0006] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0007] An alumina ceramic crucible comprises an alumina ceramic crucible, an alumina ceramic sealing cap, an aluminum silicate ceramic fiber sealing gasket and an aluminum silicate ceramic fiber paper layer; the alumina ceramic crucible comprises a seed crystal cavity, a cone and a body which are sequentially connected from bottom to top, the top of the body is an open structure, the alumina ceramic sealing cap is threadedly connected to the top of the body, and the ceramic fiber sealing gasket is arranged between the alumina ceramic sealing cap screw and the top of the body; the aluminum silicate ceramic fiber paper layer is movably laid on the inner side of the alumina ceramic crucible.

[0008] The above-mentioned alumina ceramic crucible and the alumina ceramic cap are threadedly connected to the aluminum ceramic crucible, and the alumina ceramic cap can be reused, which significantly reduces the preparation cost. At the same time, no weld is required, which avoids the loss of raw materials and equipment caused by the cracking of the quartz tube in the existing process, and extends the service life of the equipment; the sealing between the alumina ceramic crucible and the alumina ceramic cap is ensured by the provision of the aluminum silicate ceramic fiber sealing gasket; the provision of the aluminum silicate ceramic fiber paper layer can effectively improve the fitting state of the PBN crucible and the outer crucible, greatly improve the stability of the temperature field of the single crystal furnace, and there is no need to fill nitrogen or argon to balance the pressure during the single crystal preparation process, which reduces the dislocation density of the indium phosphide single crystal, improves the crystallization rate, and obtains a large-size and high-quality indium phosphide substrate.

[0009] In order to improve the connection stability and sealing of the alumina ceramic cap and the aluminum ceramic crucible, an external thread is provided on the outer periphery of the top of the body, and an internal thread matching the external thread on the body is provided on the bottom of the alumina ceramic cap; the aluminum silicate ceramic fiber sealing gasket includes a first sealing gasket and a second sealing gasket, the first sealing gasket is sleeved on the bottom of the external thread of the body, and the second sealing gasket is placed on the top of the internal thread of the alumina ceramic cap.

[0010] In order to further improve the crystallization rate, the above-mentioned cone angle is 90°, that is, the inclination angle of the cone relative to the axial direction is 45°.

[0011] The use structure of the above-mentioned alumina ceramic crucible also includes a PBN crucible, which is located on the inner side of the aluminum silicate ceramic fiber paper layer, and the PBN crucible and the aluminum silicate ceramic fiber paper layer are tightly fitted, and the aluminum silicate ceramic fiber paper layer and the alumina ceramic crucible are tightly fitted; the bottom of the PBN crucible seed crystal cavity is sealed with a boron nitride ceramic rod.

[0012] PBN is the abbreviation for pyrolytic boron nitride.

[0013] In order to ensure smooth production, the aluminum silicate ceramic fiber paper layer completely covers the outer side wall of the PBN crucible, that is, there is no gap.

[0014] The method for growing a single crystal using the above-mentioned alumina ceramic crucible comprises the following steps:

[0015] 1) Cleaning of raw materials and auxiliary materials:

[0016] 1.1) Soak the indium phosphide polycrystalline material in a mixed solution of ammonium hydroxide and hydrogen peroxide for 2 to 4 hours, then use pure water for ultrasonic cleaning for 2 to 4 hours, replace the pure water every hour during ultrasonic cleaning, and then dry;

[0017] 1.2) Ultrasonic cleaning of alumina ceramic crucible, alumina ceramic cap, aluminum silicate ceramic fiber sealing gasket and boron nitride ceramic rod in pure water for 2-4 hours, changing the pure water every hour during ultrasonic cleaning, and then drying; drying in a vacuum drying oven at 120°C for 2 hours after ultrasonic cleaning;

[0018] 1.3) Soak the indium phosphide seed crystal in a mixed solution of bromine and anhydrous ethanol for 1 to 5 minutes, then use pure water for ultrasonic cleaning for 2 to 4 hours, replace the pure water every hour during ultrasonic cleaning, and then dry;

[0019] 1.4) Soak the PBN crucible in aqua regia for 2-4 hours, and then ultrasonically clean it with pure water for 2-4 hours. During the ultrasonic cleaning, the pure water is replaced every hour. Then, the crucible is dried under natural conditions, and then oxidized at 1000±100℃ in a pure oxygen atmosphere for 3-4 hours;

[0020] 2) Loading:

[0021] 2.1) Place indium phosphide polycrystal, indium phosphide seed crystal, anhydrous boron oxide, dopant, alumina ceramic crucible, alumina ceramic cap, aluminum silicate ceramic fiber sealing gasket, aluminum silicate ceramic fiber paper and boron nitride ceramic rod into a vacuum glove box and evacuate to below 1.0E-2Pa;

[0022] 2.2) Loading the indium phosphide seed crystal into the seed crystal cavity of the PBN crucible, sealing the lower end with a boron nitride ceramic rod, and then loading the indium phosphide polycrystal, anhydrous boron oxide, 6N red phosphorus and dopants into the PBN crucible;

[0023] 2.3) Lay a layer of aluminum silicate ceramic fiber paper on the inner wall of the alumina ceramic crucible, and put the PBN crucible filled with raw materials into the alumina ceramic crucible. The aluminum silicate ceramic fiber paper has a certain plasticity. The PBN crucible filled with raw materials presses the aluminum silicate ceramic fiber paper so that the alumina ceramic crucible, the aluminum silicate ceramic fiber paper and the PBN crucible are tightly fitted;

[0024] 2.4) Place an aluminum silicate ceramic fiber sealing gasket on the sealing surface of the alumina ceramic crucible, and tighten the alumina ceramic sealing cap and the alumina ceramic crucible;

[0025] 3) Single crystal growth:

[0026] 3.1) Take the loaded alumina ceramic crucible out of the vacuum glove box, place it in a VGF single crystal furnace, heat it to 350±10°C for 30-45 minutes, and evacuate the furnace to -0.1±0.01MPa;

[0027] 3.2) Controlling the heating rate to 3-5°C / min, heating to the melting point of indium phosphide polycrystalline material at 1070-1090°C for 3-5h, melting the indium phosphide polycrystalline material in the furnace, and melting the indium phosphide seed crystal to 5-15mm;

[0028] 3.3) After maintaining the temperature at a constant temperature for 22 to 24 hours, the temperature is controlled to drop slowly so that the temperature gradient of the growth interface is 5 to 6°C / cm and the cooling rate is 0 to 5°C / h. Stepwise cooling growth is performed. When the temperature drops below 150°C, the single crystal furnace is opened to obtain an indium phosphide single crystal.

[0029] The sealing surface of the alumina ceramic crucible is the surface where the alumina ceramic sealing cap contacts the alumina ceramic crucible.

[0030] In the above step 3.3), when the growth interface drops below the crystallization point temperature (1062±7°C), the growth begins. After the growth is completed, the temperature is still around 900°C, and then it is cooled down to below 150°C before being taken out of the furnace.

[0031] In order to improve the cleaning effect and thus improve the product quality, in step 1.1), in the mixed solution of ammonium hydroxide and hydrogen peroxide, the volume ratio of ammonium hydroxide (EL grade), hydrogen peroxide (EL grade) and pure water is (1.5-2.5):1:1; the drying is carried out in a vacuum drying oven at 115-125°C for 1.5-2h. In step 1.2), the drying is carried out in a vacuum drying oven at 115-125°C for 1.5-2h.

[0032] In order to further improve the cleaning effect and thus enhance the product quality, in step 1.3), the mass ratio of bromine to anhydrous ethanol is 1:(2.5-3.5); and the drying is performed in a vacuum drying oven at 115-125°C for 1.5-2h.

[0033] To avoid contamination, in step 1.4), after ultrasonic cleaning, place it on a class 100 clean bench to dry.

[0034] In order to further improve product quality, in step 2.2), the mass ratio of indium phosphide polycrystal, anhydrous boron oxide, 6N red phosphorus and dopant is: (3500-4000): (36-48): (30-60): (0-1).

[0035] The technologies not mentioned in the present invention are all referred to the prior art.

[0036] When growing a single crystal, the present invention uses an alumina ceramic crucible to replace a quartz crucible, does not require quartz oxyhydrogen flame welding and sealing, and does not require nitrogen to be filled into a VGF single crystal furnace to balance the pressure, so that the single crystal furnace is kept in a vacuum state. At the same time, a layer of plastic aluminum silicate ceramic fiber paper is added between the PBN crucible and the outer crucible to improve the fitting state of the PBN crucible and the outer crucible, greatly improve the stability of the temperature field of the single crystal furnace, can reduce the dislocation density of the indium phosphide single crystal, improve the crystallization rate, and obtain a large-size and high-quality indium phosphide substrate; at the same time, it avoids the loss of raw materials and equipment caused by the cracking of the quartz tube in the existing process, and prolongs the service life of the equipment. At the same time, unlike the one-time use of the quartz tube, the alumina ceramic crucible and the alumina ceramic sealing cap of the present invention can be reused, which significantly reduces the production cost of the indium phosphide substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram of the use structure of the alumina ceramic crucible of the present invention;

[0038] In the figure, 1 is a boron nitride ceramic rod; 2 is a seed crystal; 3 is an alumina ceramic crucible; 31 is an alumina ceramic crucible seed crystal cavity; 32 is an alumina ceramic crucible cone (angle 90°); 4 is an aluminum silicate ceramic fiber paper layer; 5 is an indium phosphide polycrystalline material; 6 is a PBN crucible; 61 is a PBN crucible seed crystal cavity; 62 is a PBN crucible cone (angle 90°); 7 is an aluminum silicate ceramic fiber sealing gasket; and 8 is an alumina ceramic cap. DETAILED DESCRIPTION

[0039] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0040] In this application, directional words such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings or in use, and are only for the convenience of describing this application, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0041] Example 1

[0042] like Figure 1As shown, an alumina ceramic crucible comprises an alumina ceramic crucible, an alumina ceramic sealing cap, an aluminum silicate ceramic fiber sealing gasket and an aluminum silicate ceramic fiber paper layer; the alumina ceramic crucible comprises a seed crystal cavity, a cone and a body which are connected in sequence from bottom to top, the angle of the cone is 90°, the top of the body is an open structure, the outer periphery of the top of the body is provided with an external thread, and the bottom of the alumina ceramic sealing cap is provided with an internal thread which matches the external thread on the body; the aluminum silicate ceramic fiber sealing gasket comprises a first sealing gasket and a second sealing gasket, the first sealing gasket is sleeved on the bottom of the external thread of the body, the second sealing gasket is placed on the top of the internal thread of the alumina ceramic sealing cap, the alumina ceramic sealing cap is threadedly connected to the top of the body, and the ceramic fiber sealing gasket is sealed between the alumina ceramic sealing cap screw and the top of the body; the aluminum silicate ceramic fiber paper layer is movably laid on the inner side of the alumina ceramic crucible.

[0043] Example 2

[0044] The use structure of the alumina ceramic crucible in the above example also includes a PBN crucible. The PBN crucible is located on the inner side of the aluminum silicate ceramic fiber paper layer. The cone of the PBN crucible has the same angle as the cone of the alumina ceramic crucible. The PBN crucible and the aluminum silicate ceramic fiber paper layer are tightly fitted, and the aluminum silicate ceramic fiber paper layer and the alumina ceramic crucible are tightly fitted. The aluminum silicate ceramic fiber paper layer completely covers the outer side wall of the PBN crucible. The bottom of the seed crystal cavity of the PBN crucible is sealed with a boron nitride ceramic rod.

[0045] The method for growing a single crystal using the alumina ceramic crucible in the above example comprises the following steps:

[0046] 1. Cleaning of raw and auxiliary materials:

[0047] 1. Use ammonium hydroxide (containing 25wt% ammonia), hydrogen peroxide (mass concentration of 35%), and pure water in a volume ratio of 2:1:1 to prepare a solution. Soak 4000g of indium phosphide polycrystalline material in the solution for 4 hours, then use pure water ultrasonic cleaning for 4 hours. During ultrasonic cleaning, replace the pure water every hour. After ultrasonic cleaning, use a vacuum drying oven at 120°C to dry for 2 hours.

[0048] 2. Ultrasonicate the alumina ceramic crucible, alumina ceramic cap, aluminum silicate ceramic fiber sealing gasket and boron nitride ceramic rod with pure water for 4 hours, replace the pure water every hour, and dry them in a vacuum drying oven at 120°C for 2 hours after the ultrasonication;

[0049] 3. Prepare a solution with bromine and anhydrous ethanol in a ratio of 1:3. Soak the indium phosphide seed crystal in the solution for about 3 minutes, then ultrasonicate it in pure water for 4 hours. Replace the pure water every hour during the ultrasonication. After the ultrasonication, dry it in a vacuum drying oven at 120°C for 2 hours.

[0050] 4. Soak the PBN crucible in aqua regia for 4 hours, then clean it with pure water ultrasonic for 4 hours. Change the pure water every hour during ultrasonic cleaning. After ultrasonic cleaning, dry it on a Class 100 clean bench, and then oxidize it at 1000℃ in a pure oxygen atmosphere for 4 hours.

[0051] 2. Loading:

[0052] 1. Place indium phosphide polycrystals, seed crystals, anhydrous boron oxide, dopants, alumina ceramic crucibles, alumina ceramic caps, aluminum silicate ceramic fiber sealing gaskets, aluminum silicate ceramic fiber paper, boron nitride ceramic rods and other raw and auxiliary materials into a vacuum glove box and evacuate to below 1.0E-2Pa;

[0053] 2. Place the seed crystal into the seed crystal cavity of the PBN crucible, seal the lower end with a boron nitride ceramic rod, and then place 4000 g of indium phosphide polycrystal, 48 g of anhydrous boron oxide, 60 g of 6N red phosphorus and 0.5 g of dopant In2S3 into the PBN crucible;

[0054] 3. Lay a layer of aluminum silicate ceramic fiber paper on the inner wall of the alumina ceramic crucible, and put the PBN crucible filled with raw materials into the alumina ceramic crucible. The aluminum silicate ceramic fiber paper has a certain plasticity. The PBN crucible filled with raw materials presses the aluminum silicate ceramic fiber paper to make the alumina ceramic crucible, the aluminum silicate ceramic fiber paper and the PBN crucible fit tightly together;

[0055] 4. Place the aluminum silicate ceramic fiber sealing gasket on the sealing surface of the alumina ceramic crucible, and tighten the alumina ceramic sealing cap and the alumina ceramic crucible;

[0056] 3. Single Crystal Growth

[0057] 1. Take out the loaded material and place it in the VGF single crystal furnace, raise the temperature to 350℃ in 30-45min, and evacuate the furnace to -0.1MPa;

[0058] 2. Control the heating rate to 4°C / min, heat to the melting point of indium phosphide polycrystalline material 1070-1090°C, melt the indium phosphide polycrystalline material in the furnace, and melt the seed crystal 5-15mm;

[0059] 3. After keeping the temperature constant for 24 hours, the temperature is controlled to drop slowly so that the temperature gradient of the growth interface is 5°C / cm and the cooling rate is 2°C / h. Step-by-step cooling growth is performed. When the temperature drops below 150°C, the single crystal furnace is opened to take out the obtained indium phosphide single crystal.

[0060] 4. The obtained indium phosphide single crystal was cut and sampled for Hall test and dislocation corrosion, and the performance of indium phosphide single crystal obtained by the existing VGF process (using quartz crucible, nitrogen or argon gas to balance pressure during preparation) was compared as follows:

[0061] Table 1

[0062]

[0063] Table 2

[0064]

[0065] It can be seen from the above table that the single crystal yield of the output described in this application is significantly improved, and the dislocation density of the product is significantly reduced, and the uniformity of product performance is improved. After many tests and pilot tests, the product quality is stable and meets the requirements for expanding production.

Claims

1. A method for growing a single crystal, characterized in that: A single crystal is grown using an alumina ceramic crucible, the alumina ceramic crucible comprising: an alumina ceramic crucible, an alumina ceramic cap, an aluminum silicate ceramic fiber sealing gasket and an aluminum silicate ceramic fiber paper layer; the alumina ceramic crucible comprises a seed crystal cavity, a cone and a body connected in sequence from bottom to top, the top of the body is an open structure, the alumina ceramic cap is threadedly connected to the top of the body, the ceramic fiber sealing gasket is arranged between the alumina ceramic cap screw and the top of the body; the aluminum silicate ceramic fiber paper layer is movably laid on the inner side of the alumina ceramic crucible; The preparation comprises the following steps: 1) Cleaning of raw materials and auxiliary materials: 1.1) Soak the indium phosphide polycrystalline material in a mixed solution of ammonium hydroxide and hydrogen peroxide for 2 to 4 hours, then use pure water for ultrasonic cleaning for 2 to 4 hours. During ultrasonic cleaning, replace the pure water every hour, and then dry it; 1.2) Ultrasonicate the alumina ceramic crucible, alumina ceramic cap, aluminum silicate ceramic fiber sealing gasket and boron nitride ceramic rod with pure water for 2-4 hours, replace the pure water every hour during ultrasonic cleaning, and then dry; after the ultrasonic cleaning, use a vacuum drying oven at 120℃ to dry for 2 hours; 1.3) Soak the indium phosphide seed crystal in a mixed solution of bromine and anhydrous ethanol for 1 to 5 minutes, then use pure water for ultrasonic cleaning for 2 to 4 hours. During ultrasonic cleaning, replace the pure water every hour, and then dry it; 1.4) Soak the PBN crucible in aqua regia for 2~4 hours, and then use pure water for ultrasonic cleaning for 2~4 hours. During ultrasonic cleaning, change the pure water every hour, then dry it under natural conditions, and then oxidize it at 1000±100℃ in a pure oxygen atmosphere for 3~4 hours; 2) Loading: 2.1) Place indium phosphide polycrystal, indium phosphide seed crystal, anhydrous boron oxide, dopant, alumina ceramic crucible, alumina ceramic cap, aluminum silicate ceramic fiber sealing gasket, aluminum silicate ceramic fiber paper and boron nitride ceramic rod into a vacuum glove box and evacuate to below 1.0E-2Pa; 2.2) Load the indium phosphide seed crystal into the seed crystal cavity of the PBN crucible, seal the lower end with a boron nitride ceramic rod, and then load the indium phosphide polycrystal, anhydrous boron oxide, 6N red phosphorus and dopant into the PBN crucible; 2.3) Lay a layer of aluminum silicate ceramic fiber paper on the inner wall of the alumina ceramic crucible, and put the PBN crucible filled with raw materials into the alumina ceramic crucible. The aluminum silicate ceramic fiber paper has a certain plasticity. The PBN crucible filled with raw materials presses the aluminum silicate ceramic fiber paper to make the alumina ceramic crucible, the aluminum silicate ceramic fiber paper and the PBN crucible fit tightly together; 2.4) Place the aluminum silicate ceramic fiber sealing gasket on the sealing surface of the alumina ceramic crucible, and tighten the alumina ceramic sealing cap and the alumina ceramic crucible; 3) Single crystal growth: 3.1) Take the loaded alumina ceramic crucible out of the vacuum glove box and place it in a VGF single crystal furnace. Heat it to 350±10℃ for 30-45min and evacuate the furnace to -0.1±0.01MPa. 3.2) Control the heating rate to 3-5°C / min, and use 3-5h to heat up to the melting point of indium phosphide polycrystalline material 1070-1090°C, melt the indium phosphide polycrystalline material in the furnace, and melt the indium phosphide seed crystal 5-15mm; 3.3) After maintaining the constant temperature for 22 to 24 hours, the temperature is controlled to drop slowly so that the temperature gradient of the growth interface is 5 to 6°C / cm and the cooling rate is 0 to 5°C / h. Step-by-step cooling growth is performed. When the temperature drops below 150°C, the single crystal furnace is opened to obtain an indium phosphide single crystal.

2. The method according to claim 1, characterized in that: In step 1.1), in the mixed solution of ammonium hydroxide and hydrogen peroxide, the volume ratio of ammonium hydroxide, hydrogen peroxide and pure water is (1.5-2.5):1:1; the drying is carried out in a vacuum drying oven at 115-125°C for 1.5-2h.

3. The method according to claim 1 or 2, characterized in that: In step 1.2), the drying is performed in a vacuum drying oven at 115-125°C for 1.5-2 hours.

4. The method according to claim 1 or 2, characterized in that: In step 1.3), the mass ratio of bromine to anhydrous ethanol is 1:(2.5-3.5); the drying is performed in a vacuum drying oven at 115-125°C for 1.5-2h.

5. The method according to claim 1 or 2, characterized in that: In step 1.4), after ultrasonic cleaning, place it on a Class 100 clean bench to dry.

6. The method according to claim 1 or 2, characterized in that: In step 2.2), the mass ratio of indium phosphide polycrystal, anhydrous boron oxide, 6N red phosphorus and dopant is: (3500-4000): (36-48): (30-60): (0-1).

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