A high-performance crucible coating for large-diameter single-crystalline silicon and its preparation method

Abstract

The present invention belongs to the technical field of coating materials, and specifically refers to a high-performance crucible coating for large-diameter single-crystalline silicon and a preparation method thereof. Among them, a high-performance crucible coating for large-diameter single-crystalline silicon is prepared from the following raw materials in parts by weight: 10-15 parts of coating composite, 5-8 parts of composite colloid, 1 part of magnesium powder, 2-5 parts of SiC, and 0.5 part of quartz fiber. The present invention takes aluminum nitride obtained by co-heating Al2O3 and boron nitride as the main body, adds carbon powder to form Al-C bonds, enhances high-temperature resistance and stable structure; alcoholizes it and treats it with a silane coupling agent to improve adsorption. Adding magnesium powder removes oxygen and generates MgO at the same time, improving temperature resistance and corrosion resistance, and promoting crystal form transformation; then using silica sol, ethanol, and polyethylene glycol to form a film to enhance adhesion, and adding silicon nitride and aluminum phosphate to improve high-temperature resistance performance.

Description

Technical Field

[0001] The invention belongs to the technical field of coating materials, and specifically refers to a high-performance crucible coating for large-diameter single-crystal silicon and a preparation method thereof. Background Art

[0002] As the core material in the growth process of single crystal silicon, quartz crucible needs to withstand high temperature and highly corrosive environment, while also having excellent thermal stability, thermal shock resistance and structural integrity.

[0003] In the existing technology, quartz crucible coatings are mostly made of single materials such as silicon nitride and silicon carbide. Although they have certain high temperature resistance, they have obvious limitations. First, in high temperature environments, the thermal stress distribution of these traditional coating materials is uneven, which makes the quartz crucible prone to bulging or cracking; second, when preparing single crystal silicon, the quartz crucible is easily corroded by oxygen and impurities, showing insufficient corrosion resistance and shortening the service life; third, the interface bonding strength between the coating and the quartz crucible substrate is low, and it is easy to peel off or fall off; finally, the existing coating preparation process is complicated and costly, and cannot meet the needs of large-scale production.

[0004] Therefore, preparing a high-performance crucible coating for large-diameter single crystal silicon to improve the temperature resistance, corrosion resistance and structural stability of the quartz crucible has become a key technical problem that needs to be urgently solved in the photovoltaic industry. Summary of the invention

[0005] To overcome the defects existing in the prior art, for the high-performance crucible coating for large-diameter single-crystalline silicon prepared by the present invention, aluminum nitride is prepared as the main material by the co-heating method of Al2O3 and boron nitride for the first time, and an excessive amount of carbon powder is introduced. On the one hand, it can enhance the strength of the coating and improve the thermal conductivity of the coating at high temperatures, avoiding the shedding of the coating caused by uneven heat conduction. On the other hand, carbon reacts with aluminum nitride to form Al-C bonds, which not only significantly enhances the high-temperature resistance of the material, but also inhibits crystal slip deformation by hindering the movement of dislocations, improving the high-temperature structural stability. Moreover, the uniform distribution of carbon makes the thermal stress distribution more uniform, preventing the quartz crucible from bulging or cracking due to uneven heat; and C-N bonds are formed between Al-C bonds and Al-N bonds, which can enhance the binding force between atoms, making the coating harder, more wear-resistant and more ductile; to further improve the performance, the aluminum nitride-carbon composite material is alcoholized to make its surface rich in hydroxyl groups, and after being treated with a silane coupling agent, it condenses with the hydroxyl groups to improve the surface adsorption. At the same time, magnesium powder is introduced to remove oxygen to generate MgO, improving the temperature resistance and corrosion resistance of the coating. MgO acts as a nucleating agent to promote the crystal form transformation of the quartz crucible, further improving the overall temperature resistance; in addition, to enhance the adhesion and structural stability, silica sol and absolute ethanol are mixed, and ethanol adjusts the viscosity and surface tension to form a continuous and uniform film layer. Polyethylene glycol is added to reduce the surface tension, improve the wettability and adhesion, and form a network structure to enhance the flexibility and integrity. Aluminum phosphate is introduced, and the characteristics of filling gaps and densifying the structure by aluminum phosphate are utilized. Moreover, the decomposition of aluminum phosphate provides a protective film for the coating, improving the high-temperature corrosion resistance, and forming a more stable high-temperature phase at high temperatures, significantly enhancing the high-temperature resistance of the coating.

[0006] To achieve the above object, the technical solution adopted by the present invention is a high-performance crucible coating for large-diameter single-crystalline silicon, which is prepared from the following raw materials in parts by weight: 10-15 parts of coating composite, 5-8 parts of composite colloid, 1 part of magnesium powder, 2-5 parts of SiC and 0.5 part of quartz fiber.

[0007] Further, the preparation method of the composite A includes the following steps:

[0008] (a) Weigh 1-2 parts of Al2O3, 4-8 parts of boron nitride and 0.3 part of flux, grind and mix them to obtain a reactant precursor;

[0009] (b) Put the reactant precursor obtained in step (a) into a calcining furnace with an argon flow rate of 0.5 L / min, perform heat treatment at a temperature of 1600-1800 °C for 6 h, and then naturally cool to room temperature to obtain aluminum nitride composite A;

[0010] (c) Weigh 0.2 - 0.5 parts of carbon powder and add it to the aluminum nitride composite A obtained in step (b), grind it evenly, put it into a calcination furnace with an argon flow rate of 0.5 L / min, and perform heat treatment at a temperature of 1800 - 2000 °C for 6 h, then naturally cool it to room temperature to obtain composite A.

[0011] Further, the flux is GaO.

[0012] Further, the preparation method of the coating composite includes the following steps:

[0013] (α) Weigh 3 - 5 parts of composite A and add it to 0.5 - 1.5 parts of mixed alcohols, stir for 30 min under the condition of a rotation speed of 500 - 800 r / min to obtain a mixed solution A;

[0014] (β) Add 1 part of silane coupling agent to the mixed solution A obtained in step (α), stir for 30 min under the condition of a rotation speed of 500 - 800 r / min, heat at a temperature of 60 - 90 °C for 2 h, and let it stand at room temperature for 72 h to obtain the coating composite.

[0015] Further, the mixed alcohols are a mixture of silanol and absolute ethanol, and the mass ratio of silanol to absolute ethanol is 1 - 2:3.

[0016] Further, the preparation method of the composite colloid includes the following steps:

[0017] (i) Weigh 6 - 10 parts of absolute ethanol and 4 - 8 parts of silica sol, mix them and stir for 30 min under the condition of a rotation speed of 500 - 800 r / min to obtain a homogeneous solution A;

[0018] (ii) Add 1 - 2 parts of polyethylene glycol to the homogeneous solution A obtained in step (i), stir for 30 min under the condition of a rotation speed of 300 - 500 r / min to obtain a mixed solution I;

[0019] (iii) Weigh 0.3 - 0.6 parts of silicon nitride and 1 part of aluminum phosphate, mix and grind them, sieve them with a 40 - mesh sieve to obtain a mixture I, add the obtained mixture I to the mixed solution I obtained in step (ii), and perform ultrasonic treatment for 30 min under the condition of an ultrasonic power of 0.3 - 0.5 kw to obtain a colloidal suspension;

[0020] (iv) Heat the colloidal suspension obtained in step (iii) to 50 °C and cure it for 12 h, then store it sealed to obtain the composite colloid.

[0021] The present invention also provides a preparation method for a high - performance crucible coating for large - diameter single - crystal silicon, including the following steps:

[0022] Step 1: Weigh 2 - 5 parts of SiC and add it to 5 - 8 parts of composite colloid. Ultrasonic it for 30 min under the condition that the ultrasonic power is 0.8 - 1.2 kw, and stir it for 30 min under the condition that the rotation speed is 500 - 800 r / min to obtain a substrate;

[0023] Step 2: Weigh 10 - 15 parts of coating composite and 0.5 part of quartz fiber and add them to the substrate obtained in Step 1. Heat it for 2 h under the condition that the temperature is 80 - 120 °C, and stir it under the condition that the rotation speed is 300 - 500 r / min to obtain a high-performance crucible coating precursor for large-diameter single-crystalline silicon;

[0024] Step 3: Deoxygenate the high-performance crucible coating precursor for large-diameter single-crystalline silicon obtained in Step 2 for 2 h under the condition that the argon flow rate is 300 ml / min. Weigh 1 part of magnesium powder and add it to the high-performance crucible coating precursor for large-diameter single-crystalline silicon obtained in Step 2. Ultrasonic it for 20 min under the condition that the ultrasonic power is 0.3 - 0.6 kw, and stir it for 30 min under the condition that the rotation speed is 300 - 500 r / min. Fill it with argon protective gas and seal it for storage to obtain a high-performance crucible coating for large-diameter single-crystalline silicon.

[0025] The beneficial effects obtained by the present invention are as follows:

[0026] The high-performance crucible coating for large-diameter single-crystalline silicon prepared by the present invention uses the co-heating method of Al2O3 and boron nitride to prepare aluminum nitride, which is used as the main material of the coating. It has high strength and will not introduce impurities into the preparation of single-crystalline silicon. On this basis, an excessive amount of carbon powder is introduced. In a high-temperature environment, the carbon powder can significantly enhance the mechanical strength of the coating and greatly improve the thermal conductivity of the coating. The uniform heat conduction characteristics effectively avoid the problem of coating peeling caused by uneven heat conduction. Moreover, the carbon powder reacts with aluminum nitride at high temperature to form Al-C bonds. The formation of this chemical bond not only greatly enhances the high-temperature resistance of the material, but also effectively inhibits the slip deformation of the crystal at high temperature by hindering the movement of dislocations, thereby effectively improving the structural stability of the coating in a high-temperature environment; in addition, the introduction of carbon powder enables the thermal stress to be more evenly dispersed, avoiding the phenomenon of bulging or cracking of the quartz crucible due to local heat concentration; on the basis of forming Al-C bonds, further reaction occurs between Al-N bonds and Al-C bonds to form C-N bonds. The presence of C-N bonds significantly enhances the atomic bonding force, enabling the coating to have higher hardness, excellent wear resistance and good toughness, effectively improving the comprehensive mechanical properties of the coating.

[0027] The high-performance crucible coating for large-diameter single-crystalline silicon prepared by the present invention, in order to further explore the performance potential of the coating, the aluminum nitride-carbon composite material is alcoholized to make the material surface rich in a large number of hydroxyl groups; subsequently, it is treated with a silane coupling agent, and the silane coupling agent undergoes a condensation reaction with the hydroxyl groups on the surface, significantly improving the adsorption performance of the coating surface. At the same time, magnesium powder is introduced, and the magnesium powder reacts with the oxygen generated during the single-crystal preparation process to generate MgO; the generation of MgO not only improves the high-temperature resistance and corrosion resistance of the coating, but also, due to its property as a nucleating agent, can promote the crystal form transformation of the quartz crucible, improve the mechanical strength of the quartz crucible, and prevent the crucible from collapsing.

[0028] The high-performance crucible coating for large-diameter single-crystalline silicon prepared by the present invention, in terms of enhancing the coating adhesion and structural stability, mixes silica sol and absolute ethanol. The absolute ethanol can effectively adjust the viscosity and surface tension of the mixed solution, enabling the solution to form a continuous and uniform film layer on the substrate surface. Polyethylene glycol is added to it. The polyethylene glycol can further reduce the surface tension, significantly improve the wettability and adhesion of the coating, and at the same time form a network structure inside the coating, enhancing the flexibility and integrity of the coating; in addition, a key component, aluminum phosphate, is introduced. The aluminum phosphate can fully fill the gaps inside the coating, making the coating structure more dense; under high-temperature conditions, the decomposition of aluminum phosphate will form a dense protective film on the coating surface, effectively improving the high-temperature corrosion resistance of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a diagram of the preparation method of the high-performance crucible coating for large-diameter single-crystalline silicon proposed by the present invention;

[0030] Figure 2 is a diagram of the corrosion rate of the high-performance crucible coating for large-diameter single-crystalline silicon prepared in the examples and comparative examples;

[0031] Figure 3 is a diagram of the deoxidation rate of the high-performance crucible coating for large-diameter single-crystalline silicon prepared in the examples and comparative examples.

[0032] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0034] Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to the described content can be applied to the present invention. The preferred implementation methods and materials described herein are for illustrative purposes only and do not limit the content of this application.

[0035] The preparation methods in the following examples refer to Figure 1 , unless otherwise specified, they are all conventional methods; unless otherwise specified, the purity of the materials used in the following examples is 99.999%, the parts are calculated by mass, and the materials used are all new materials purchased from the market.

[0036] Example 1: A high-performance crucible coating for large-diameter single-crystalline silicon is prepared from the following raw materials in parts by weight: 10 parts of coating composite, 5 parts of composite colloid, 1 part of magnesium powder, 2 parts of SiC, and 0.5 part of quartz fiber.

[0037] The preparation method of composite A includes the following steps:

[0038] (a) Weigh 1 part of Al2O3, 4 parts of boron nitride, and 0.3 part of GaO, grind and mix them to obtain a reactant precursor;

[0039] (b) Put the reactant precursor obtained in step (a) into a calcination furnace with an argon flow rate of 0.5 L / min, perform heat treatment at a temperature of 1600 °C for 6 h, and then naturally cool to room temperature to obtain aluminum nitride composite A;

[0040] (c) Weigh 0.2 part of carbon powder, add it to the aluminum nitride composite A obtained in step (b), grind it evenly, put it into a calcination furnace with an argon flow rate of 0.5 L / min, perform heat treatment at a temperature of 1800 °C for 6 h, and then naturally cool to room temperature to obtain composite A.

[0041] The preparation method of the coating composite includes the following steps:

[0042] (α) Weigh 3 parts of composite A and add 0.5 part of mixed alcohol, where the mixed alcohol is a mixture of silanol and absolute ethanol, and the mass ratio of silanol to absolute ethanol is 1:3. Stir at a rotation speed of 500 r / min for 30 min to obtain mixture A;

[0043] (β) Add 1 part of silane coupling agent to the mixture A obtained in step (α), stir at a rotation speed of 500 r / min for 30 min, heat at a temperature of 60 °C for 2 h, and let it stand at room temperature for 72 h to obtain the coating composite.

[0044] The preparation method of the composite colloid includes the following steps:

[0045] (i) Weigh 6 parts of absolute ethanol and 4 parts of silica sol, mix them and stir for 30 min under the condition of a rotation speed of 500 r / min to obtain a homogeneous liquid A;

[0046] (ii) Add 1 part of polyethylene glycol to the homogeneous liquid A obtained in step (i), and stir for 30 min under the condition of a rotation speed of 300 r / min to obtain a mixed liquid I;

[0047] (iii) Weigh 0.3 part of silicon nitride and 1 part of aluminum phosphate, mix and grind them, sieve them with a 40-mesh screen to obtain a mixture I. Add the obtained mixture I to the mixed liquid I obtained in step (ii), and perform ultrasonic treatment for 30 min under the condition of an ultrasonic power of 0.3 kw to obtain a colloidal suspension;

[0048] (iv) Heat the colloidal suspension obtained in step (iii) to 50 °C and cure it for 12 h, then seal and store it to obtain a composite colloid.

[0049] This example also provides a preparation method for a high-performance crucible coating for large-diameter single-crystalline silicon, which includes the following steps:

[0050] Step 1: Weigh 2 parts of SiC and add it to 5 parts of the composite colloid. Perform ultrasonic treatment for 30 min under the condition of an ultrasonic power of 0.8 kw, and stir for 30 min under the condition of a rotation speed of 500 r / min to obtain a substrate;

[0051] Step 2: Weigh 10 parts of a coating composite and 0.5 part of quartz fiber, add them to the substrate obtained in step 1, heat at 80 °C for 2 h, and stir under the condition of a rotation speed of 300 r / min to obtain a precursor for the high-performance crucible coating for large-diameter single-crystalline silicon;

[0052] Step 3: Deoxygenate the precursor for the high-performance crucible coating for large-diameter single-crystalline silicon obtained in step 2 under the condition of an argon flow rate of 300 ml / min for 2 h. Weigh 1 part of magnesium powder and add it to the precursor for the high-performance crucible coating for large-diameter single-crystalline silicon obtained in step 2. Perform ultrasonic treatment for 20 min under the condition of an ultrasonic power of 0.3 kw, and stir for 30 min under the condition of a rotation speed of 300 r / min. Then, fill it with argon as a protective gas, seal and store it to obtain the high-performance crucible coating for large-diameter single-crystalline silicon.

[0053] Example 2: A high-performance crucible coating for large-diameter single-crystalline silicon is prepared from the following raw materials by weight: 13 parts of a coating composite, 6.5 parts of a composite colloid, 1 part of magnesium powder, 3.5 parts of SiC, and 0.5 part of quartz fiber.

[0054] The preparation method of composite A includes the following steps:

[0055] (a) Weigh 1 part of Al2O3, 4 parts of boron nitride, and 0.3 part of GaO, grind and mix them to obtain a reactant precursor.

[0056] (b) Put the reactant precursor obtained in step (a) into a calcination furnace with an argon flow rate of 0.5 L / min, conduct heat treatment at a temperature of 1700 °C for 6 h, and then naturally cool to room temperature to obtain aluminum nitride composite A.

[0057] (c) Weigh 0.35 part of carbon powder, add it to the aluminum nitride composite A obtained in step (b), grind evenly, put it into a calcination furnace with an argon flow rate of 0.5 L / min, conduct heat treatment at a temperature of 1900 °C for 6 h, and then naturally cool to room temperature to obtain composite A.

[0058] A method for preparing a coating composite, comprising the following steps:

[0059] (α) Weigh 4 parts of composite A and add it to 1 part of a mixed alcohol, where the mixed alcohol is a mixture of silanol and absolute ethanol, and the mass ratio of silanol to absolute ethanol is 1.5:3. Stir at a rotation speed of 650 r / min for 30 min to obtain a mixed solution A.

[0060] (β) Add 1 part of a silane coupling agent to the mixed solution A obtained in step (α), stir at a rotation speed of 650 r / min for 30 min, heat at a temperature of 75 °C for 2 h, and let it stand at room temperature for 72 h to obtain a coating composite.

[0061] A method for preparing a composite colloid, comprising the following steps:

[0062] (i) Weigh 8 parts of absolute ethanol and 6 parts of silica sol, mix and stir at a rotation speed of 650 r / min for 30 min to obtain a homogeneous solution A.

[0063] (ii) Add 1.5 parts of polyethylene glycol to the homogeneous solution A obtained in step (i), stir at a rotation speed of 400 r / min for 30 min to obtain a mixed solution I.

[0064] (iii) Weigh 0.45 part of silicon nitride and 1 part of aluminum phosphate, mix and grind them, sieve them with a 40-mesh screen to obtain a mixture I, add the obtained mixture I to the mixed solution I obtained in step (ii), and conduct ultrasonic treatment at an ultrasonic power of 0.4 kw for 30 min to obtain a colloidal suspension.

[0065] (iv) Heat the colloidal suspension obtained in step (iii) to 50 °C and cure it for 12 h, and store it sealed to obtain a composite colloid.

[0066] This embodiment also provides a method for preparing a high-performance crucible coating for large-diameter single-crystalline silicon, comprising the following steps:

[0067] Step 1: Weigh 3.5 parts of SiC and add it to 6.5 parts of a composite colloid. Ultrasonic for 30 min under the condition of an ultrasonic power of 1.0 kw, and stir for 30 min under the condition of a rotation speed of 650 r / min to obtain a substrate.

[0068] Step 2: Weigh 13 parts of a coating composite and 0.5 part of quartz fiber and add them to the substrate obtained in Step 1. Heat at 100 °C for 2 h and stir under the condition of a rotation speed of 400 r / min to obtain a precursor of the high-performance crucible coating for large-diameter single-crystalline silicon.

[0069] Step 3: Deoxygenate the precursor of the high-performance crucible coating for large-diameter single-crystalline silicon obtained in Step 2 for 2 h under the condition of an argon flow rate of 300 ml / min. Weigh 1 part of magnesium powder and add it to the precursor of the high-performance crucible coating for large-diameter single-crystalline silicon obtained in Step 2. Ultrasonic for 20 min under the condition of an ultrasonic power of 0.45 kw and stir for 30 min under the condition of a rotation speed of 450 r / min, then fill with argon protective gas and seal for storage to obtain the high-performance crucible coating for large-diameter single-crystalline silicon.

[0070] Example 3: A high-performance crucible coating for large-diameter single-crystalline silicon is prepared from the following raw materials in parts by weight: 15 parts of a coating composite, 8 parts of a composite colloid, 1 part of magnesium powder, 5 parts of SiC, and 0.5 part of quartz fiber.

[0071] The preparation method of composite A comprises the following steps:

[0072] (a) Weigh 2 parts of Al2O3, 8 parts of boron nitride, and 0.3 part of GaO, grind and mix them to obtain a reactant precursor.

[0073] (b) Put the reactant precursor obtained in step (a) into a calcination furnace with an argon flow rate of 0.5 L / min, conduct heat treatment at 1800 °C for 6 h, and then naturally cool to room temperature to obtain aluminum nitride composite A.

[0074] (c) Weigh 0.5 part of carbon powder, add it to the aluminum nitride composite A obtained in step (b), grind it evenly, put it into a calcination furnace with an argon flow rate of 0.5 L / min, conduct heat treatment at 2000 °C for 6 h, and then naturally cool to room temperature to obtain composite A.

[0075] The preparation method of the coating composite comprises the following steps:

[0076] (α) Weigh 5 parts of complex A and add it to 1.5 parts of a mixed alcohol substance, where the mixed alcohol substance is a mixture of silanol and absolute ethanol, and the mass ratio of silanol to absolute ethanol is 2:3. Stir for 30 min under the condition of a rotation speed of 800 r / min to obtain mixed liquid A;

[0077] (β) Add 1 part of silane coupling agent to the mixed liquid A obtained in step (α), stir for 30 min under the condition of a rotation speed of 800 r / min, heat at 90 °C for 2 h, and let it stand at room temperature for 72 h to obtain a coated complex.

[0078] A preparation method of a composite colloid substance, comprising the following steps:

[0079] (i) Weigh 10 parts of absolute ethanol and 8 parts of silica sol, mix them and stir for 30 min under the condition of a rotation speed of 800 r / min to obtain homogeneous liquid A;

[0080] (ii) Add 2 parts of polyethylene glycol to the homogeneous liquid A obtained in step (i), stir for 30 min under the condition of a rotation speed of 500 r / min to obtain mixed liquid I;

[0081] (iii) Weigh 0.6 parts of silicon nitride and 1 part of aluminum phosphate, mix and grind them, sieve them using a 40-mesh sieve to obtain mixture I, add the obtained mixture I to the mixed liquid I obtained in step (ii), and perform ultrasonic treatment for 30 min under the condition of an ultrasonic power of 0.5 kw to obtain a colloidal suspension;

[0082] (iv) Heat the colloidal suspension obtained in step (iii) to 50 °C and cure for 12 h, and store it sealed to obtain a composite colloid substance.

[0083] This embodiment also provides a preparation method of a high-performance crucible coating for large-diameter single-crystalline silicon, comprising the following steps:

[0084] Step 1: Weigh 5 parts of SiC and add it to 8 parts of the composite colloid substance, perform ultrasonic treatment for 30 min under the condition of an ultrasonic power of 1.2 kw, and stir for 30 min under the condition of a rotation speed of 800 r / min to obtain a substrate;

[0085] Step 2: Weigh 15 parts of the coated complex and 0.5 part of quartz fiber, add them to the substrate obtained in step 1, heat at 120 °C for 2 h, and stir under the condition of a rotation speed of 500 r / min to obtain a precursor of a high-performance crucible coating for large-diameter single-crystalline silicon;

[0086] Step 3: Deoxygenate the high-performance crucible coating precursor for large-diameter single-crystalline silicon obtained in Step 2 for 2 hours under the condition that the argon gas flow rate is 300 ml / min. Weigh 1 portion of magnesium powder and add it to the high-performance crucible coating precursor for large-diameter single-crystalline silicon obtained in Step 2. Ultrasonic for 20 minutes under the condition that the ultrasonic power is 0.6 kw, and stir for 30 minutes under the condition that the rotation speed is 500 r / min. Fill with argon protective gas and seal for storage to obtain a high-performance crucible coating for large-diameter single-crystalline silicon.

[0087] Comparative example:

[0088] The difference between Comparative Example 1 and Example 2 is that no coating composite is added, and the rest is the same as Example 2;

[0089] The difference between Comparative Example 2 and Example 2 is that no quartz fiber is added, and the rest is the same as Example 2;

[0090] The difference between Comparative Example 3 and Example 2 is that no magnesium powder is added, and the rest is the same as Example 2;

[0091] Comparative Example 4 is an ordinary quartz crucible without further treatment.

[0092] The performance of the prepared high-performance crucible coating for large-diameter single-crystalline silicon is specifically analyzed as follows:

[0093] First, polish and wipe the surface of the quartz crucible. Then, use chemical vapor deposition to uniformly deposit the prepared high-performance crucible coating for large-diameter single-crystalline silicon on the outer surface of the quartz crucible. The thickness of the sprayed coating is 150 - 200 μm. Then, put it into a single crystal furnace, fill with 15 L / min of argon gas and solidify for 72 hours to obtain a quartz crucible coated with a high-performance crucible coating for large-diameter single-crystalline silicon. Then, put the obtained quartz crucible coated with a high-performance crucible coating for large-diameter single-crystalline silicon into the furnace for preparing single crystals. This product is a 12-inch n-type single-crystalline silicon. The average oxygen content of the n-type single-crystalline silicon wafer is 10.5 ppma. In this example, the test range of oxygen involves removing 1000 mm from the head and tail of the complete single-crystalline silicon rod (with a length greater than 3500 mm and above), and slicing and testing the middle silicon rod;

[0094] Table 1 shows the peeling-off situation of the coatings in the examples and comparative examples:

[0095]

[0096] As can be seen from Table 1, for the high-performance crucible coating for large-diameter single-crystalline silicon prepared in Example 1, partial peeling of the surface coating occurred after 550 h of single-crystalline silicon preparation. The coating obtained in Example 2 did not peel off, and the coating obtained in Example 3 showed partial corrosion. For the high-performance crucible coating for large-diameter single-crystalline silicon prepared in the comparative example, the coatings in Comparative Example 1 and Comparative Example 2 peeled off and the bubbles appeared after 450 h of use, and the ordinary quartz crucible showed corrosion and foaming and was withdrawn from use after 350 h of use. From the above results, it can be seen that the high-performance crucible coating for large-diameter single-crystalline silicon prepared in Example 2 has high corrosion resistance and high-temperature resistance, which prolongs the service life and reduces the cost in the process of preparing large-diameter single-crystalline silicon.

[0097] Figure 2 For the corrosion rate test of the high-performance crucible coating for large-diameter single-crystalline silicon prepared in the examples and comparative examples during use, the average corrosion rate of Example 2 in the first 200 hours was 0.082 μm / h, the average corrosion rate in the range of 200 - 450 hours was 0.037 μm / h, and the average corrosion rate in the range of 450 - 550 hours was 0.025 μm / h. It can be seen that the high-performance crucible coating for large-diameter single-crystalline silicon prepared in Example 2 has good corrosion resistance, which is crucial for protecting the quartz crucible, and the corrosion rate is significantly lower than other values compared with other examples and comparative examples; Figure 3 For the deoxidation rate of the single-crystalline silicon wafers drawn by the high-performance crucible coatings for large-diameter single-crystalline silicon prepared in the examples and comparative examples, the deoxidation rate of the first rod in Example 2 was 20.4%, the deoxidation rate of the second rod was 19.7%, and the deoxidation rate of the third rod was 19.1%. It can be seen that the high-performance crucible coating for large-diameter single-crystalline silicon prepared has a certain effect on the control of oxygen in the single crystal, and the deoxidation rate differences are not large, indicating that the introduction of magnesium powder plays a certain role in deoxidation.

[0098] Obviously, the above comparative examples and examples are only part of the comparative examples and examples of the present invention, and the comparative examples and examples referred to based on this category are all within the scope protected by this invention.

[0099] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirits of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

[0100] The above describes the present invention and its implementation manners. Such description is not restrictive. What is shown in the drawings is only one of the implementation manners of the present invention, and the actual application is not limited thereto. All in all, if those of ordinary skill in the art are inspired by it and design, without creative efforts, similar manners and embodiments to the technical solution without departing from the gist of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A high-performance crucible coating for large-diameter single crystal silicon, characterized in that: The invention comprises the following raw materials in parts by weight: 10-15 parts of coating compound, 5-8 parts of composite colloid, 1 part of magnesium powder, 2-5 parts of SiC and 0.5 parts of quartz fiber; The raw materials for preparing the coating composite consist of composite A, mixed alcohol and silane coupling agent, the mass ratio of composite A, mixed alcohol and silane coupling agent is 3-5:0.5-1.5:1, the raw materials for preparing the composite A consist of Al2O3, boron nitride, flux and carbon powder, the mass ratio of Al2O3, boron nitride, flux and carbon powder is 1-2:4-8:0.3:1.5-2.5, the mixed alcohol is a mixture of silanol and anhydrous ethanol, the mass ratio of silanol and anhydrous ethanol is 1-2:3; The raw materials for preparing the composite colloid are composed of anhydrous ethanol, silica sol, polyethylene glycol, silicon nitride and aluminum phosphate, and the mass proportion of the anhydrous ethanol, silica sol, polyethylene glycol, silicon nitride and aluminum phosphate is 6-10:4-8:1-2:0.3-0.6:

1.

2. The high-performance crucible coating for large-diameter single crystal silicon according to claim 1, characterized in that: The method for preparing the coating composite comprises the following steps: (α) Weighing the complex A, adding it to the mixed alcohol, stirring, and obtaining a mixed solution A; (β) Adding a silane coupling agent to the mixed solution A obtained in step (α), stirring and heating, and allowing the mixture to stand to obtain a coating composite.

3. The high-performance crucible coating for large-diameter single crystal silicon according to claim 1, characterized in that: The preparation method of the composite colloid comprises the following steps: (i) weighing anhydrous ethanol and silica sol, mixing and stirring to obtain a homogeneous solution A; (ii) adding polyethylene glycol to the homogenous solution A obtained in step (i), stirring, to obtain a mixed solution I; (iii) weighing silicon nitride and aluminum phosphate, mixing and grinding, and sieving to obtain a mixture I, adding the obtained mixture I to the mixed solution I obtained in step (ii), and ultrasonically treating to obtain a colloidal suspension; (iv) ripening the colloidal suspension obtained in step (iii), and sealing to obtain a composite colloidal material.

4. The high-performance crucible coating for large-diameter single crystal silicon according to claim 1, characterized in that: The preparation method of the complex A comprises the following steps: (a) weighing Al2O3, boron nitride and flux, grinding and mixing them to obtain a reactant precursor; (b) heat-treating the reactant precursor obtained in step (a), and cooling to room temperature to obtain an aluminum nitride composite; (c) Weigh carbon powder and add it to the aluminum nitride composite obtained in step (b), grind it evenly, perform heat treatment, and cool it to room temperature to obtain composite A.

5. The high-performance crucible coating for large-diameter single crystal silicon according to claim 4, characterized in that: The flux described in step (a) is GaO.

6. A method for preparing a high-performance crucible coating for large-diameter single crystal silicon according to any one of claims 1 to 5, characterized in that: The steps include: Step 1, weighing SiC and adding it to the composite colloid, ultrasonicating and stirring to obtain a substrate; Step 2: weighing the coating compound and quartz fiber and adding them to the substrate obtained in step 1, heating and stirring to obtain a high-performance crucible coating precursor for large-diameter single crystal silicon; Step 3: introduce argon gas into the high-performance crucible coating precursor for large-diameter single-crystalline silicon obtained in step 2, weigh magnesium powder and add it thereto, perform ultrasonication and stirring, and obtain a high-performance crucible coating for large-diameter single-crystalline silicon.

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