Growth process and application of silicon carbide crystal

Abstract

The invention provides a silicon carbide crystal growth process which comprises the following steps: A) dividing the interior of a crucible into seven loading areas, namely an F area, a D area, a B area, an A area, a C area, an E area and a G area which are adjacent in sequence by adopting graphite partition plates, filling silicon carbide powder in each loading area, and placing the graphite partition plates perpendicular to the bottom surface of the crucible; the particle size of the silicon carbide powder is 10-80 meshes; and B) fixing a seed crystal on the top of the crucible filled with the silicon carbide powder, and growing the silicon carbide crystal by adopting a PVT method. By optimizing the charging process, the uniformity and the utilization rate of sublimation gas of the powder in the growth process can be improved, the stability of a temperature field in a furnace is facilitated, the probability of crystal phase change is reduced, crystal defects (phase change, polycrystal, dislocation and the like) are reduced, and thus the crystal quality is improved.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor technology, and in particular relates to a growth process and application of silicon carbide crystals. Background Art

[0002] Silicon carbide powder refers to the starting material used to manufacture silicon carbide materials. It is usually a mixture of high-purity silicon dioxide and carbon, which can be obtained from natural minerals or synthetic materials. The main components of silicon carbide raw materials are silicon dioxide and carbon. Silicon carbide crystals are grown by the PVT method. During the crystal growth process, it is necessary to suppress the production of crystal forms other than 4H-SiC or the production of microtubes, phase changes, dislocations and heterogeneous inclusions as much as possible to obtain high-quality silicon carbide crystals.

[0003] At present, domestic silicon carbide crystal growth generally has problems such as insufficient crystal thickness and low raw material utilization rate (generally less than 50%). The silicon carbide crystal growth process is unstable and the probability of crystal defects is high, so it is very necessary to improve the silicon carbide raw material utilization rate and crystal growth stability. Summary of the invention

[0004] The purpose of the present invention is to provide a growth process and application of silicon carbide crystals. The growth process in the present invention can improve the utilization rate of raw materials and reduce the generation of crystal defects during the growth process of silicon carbide crystals.

[0005] The present invention provides a growth process of silicon carbide crystal, comprising the following steps:

[0006] A) using a graphite partition to divide the interior of the crucible into seven adjacent charging areas, namely, area F, area D, area B, area A, area C, area E and area G, and loading silicon carbide powder in each charging area, while ensuring that the silicon carbide powder in different charging areas is at the same growth height, and the graphite partition is placed vertically to the bottom surface of the crucible;

[0007] The particle size of the silicon carbide powder is 10 to 80 meshes;

[0008] B) A seed crystal is fixed on the top of a crucible filled with silicon carbide powder, and the silicon carbide crystal is grown using the PVT method.

[0009] Preferably, the particle size of the silicon carbide powder in the A zone is 70-80 mesh, the particle size of the silicon carbide powder in the B zone is 60-70 mesh, the particle size of the silicon carbide powder in the C zone is 50-60 mesh, the particle size of the silicon carbide powder in the D zone is 40-50 mesh, the particle size of the silicon carbide powder in the E zone is 30-40 mesh, the particle size of the silicon carbide in the F zone is 20-30 mesh, and the particle size of the silicon carbide in the G zone is 10-20 mesh.

[0010] Preferably, the mass of the silicon carbide powder in the A zone is 35% to 45% of the mass of the total silicon carbide powder.

[0011] The mass of the silicon carbide powder in the B zone is 15% to 25% of the mass of the total silicon carbide powder.

[0012] The mass of the silicon carbide powder in the C zone is 5% to 15% of the mass of the total silicon carbide powder.

[0013] The mass of the silicon carbide powder in the D zone is 1% to 10% of the mass of the total silicon carbide powder.

[0014] The mass of the silicon carbide powder in the E zone is 5% to 15% of the mass of the total silicon carbide powder.

[0015] The mass of the silicon carbide powder in the F zone is 5% to 15% of the mass of the total silicon carbide powder.

[0016] The mass of the silicon carbide powder in the G zone is 1% to 10% of the mass of the entire silicon carbide powder.

[0017] Preferably, the mass of the silicon carbide powder in the A zone is 40% of the mass of the total silicon carbide powder.

[0018] The mass of the silicon carbide powder in the B zone is 20% of the mass of the total silicon carbide powder.

[0019] The mass of the silicon carbide powder in the C zone is 10% of the mass of the total silicon carbide powder.

[0020] The mass of the silicon carbide powder in the D zone is 5% of the mass of the total silicon carbide powder.

[0021] The mass of the silicon carbide powder in the E zone is 10% of the mass of the total silicon carbide powder.

[0022] The mass of the silicon carbide powder in the F zone is 10% of the mass of the total silicon carbide powder.

[0023] The mass of the silicon carbide powder in the G zone is 5% of the mass of the total silicon carbide powder.

[0024] Preferably, the step B) is specifically:

[0025] A seed crystal is fixed on the top of a crucible filled with silicon carbide powder, and the crucible is placed in a growth furnace. After preheating and evacuation, a protective atmosphere is introduced and the temperature is increased to grow silicon carbide crystals.

[0026] Preferably, the protective atmosphere comprises argon and / or helium;

[0027] When the protective atmosphere is a mixture of argon and nitrogen, the volume ratio of argon to nitrogen in the mixture is (45-50): (4.5-5).

[0028] Preferably, the growth temperature of the silicon carbide crystal is 2000-2400° C.; the growth time of the silicon carbide crystal is 30-150 hours;

[0029] The growth temperature of the silicon carbide crystal is achieved by heating, and the heating rate is 0.1-4°C / hour.

[0030] Preferably, the thickness of the silicon carbide crystal is 14 to 30 mm; and the silicon carbide crystal is a 4H crystal type silicon carbide crystal.

[0031] Preferably, during the growth of the silicon carbide crystal, the thickness of the silicon carbide crystal is controlled by a pulling process and the stability of the temperature field at the growth interface is maintained.

[0032] The present invention provides an application of a silicon carbide assembly process in improving silicon carbide raw material utilization and reducing silicon carbide crystal defects. The silicon carbide assembly process is carried out according to the growth process described above.

[0033] The present invention provides a growth process of silicon carbide crystals, comprising the following steps: A) using a graphite partition to divide the interior of a crucible into seven adjacent charging areas, namely, F area, D area, B area, A area, C area, E area and G area, and filling silicon carbide powder in each charging area, wherein the graphite partition is placed vertically to the bottom surface of the crucible; the particle size of the silicon carbide powder is 10 to 80 meshes; B) fixing a seed crystal on the top of the crucible filled with silicon carbide powder, and growing silicon carbide crystals by a PVT method. The present invention uses a graphite accessory of a certain size in a graphite crucible to divide the charge of the crucible into different areas, and charges silicon carbide raw materials of different meshes, so that the silicon-carbon ratio can be orderly released in the process of subsequent crystal growth. The present invention can improve the uniformity and utilization rate of the sublimation gas of the powder during the growth process by optimizing the charging process, which is helpful to the stability of the temperature field in the furnace, reduce the probability of crystal phase change, and reduce crystal defects (phase change, polycrystalline and dislocation, etc.), thereby improving the quality of the crystal.

[0034] Compared with the silicon carbide crystals grown from the raw materials used before process optimization, the silicon carbide crystals grown according to the growth process of the present invention have a 2% lower probability of phase change, a probability of edge polycrystallinity and dislocation occurrence of <0.05%, and the growth stability of the silicon carbide crystals is effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, 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 embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0036] Figure 1 This is a schematic diagram of the stacking of silicon carbide powder in the present invention;

[0037] Figure 1 In the figure, 1 is a crucible, 2 is a heating coil, 3 is a seed crystal, 4 is silicon carbide powder, and A, B, C, D, E, F and G represent area A, area B, area C, area D, area E, area F and area G respectively. DETAILED DESCRIPTION

[0038] The present invention provides a growth process of silicon carbide crystal, comprising the following steps:

[0039] A) using a graphite partition to divide the interior of the crucible into seven adjacent charging areas, namely, area F, area D, area B, area A, area C, area E and area G, and loading silicon carbide powder in each charging area, while ensuring that the silicon carbide powder in different charging areas is at the same growth height, and the graphite partition is placed vertically to the bottom surface of the crucible;

[0040] The particle size of the silicon carbide powder in the A zone is 70-80 meshes, the particle size of the silicon carbide powder in the B zone is 60-70 meshes, the particle size of the silicon carbide powder in the C zone is 50-60 meshes, the particle size of the silicon carbide powder in the D zone is 40-50 meshes, the particle size of the silicon carbide powder in the E zone is 30-40 meshes, the particle size of the silicon carbide in the F zone is 20-30 meshes, and the particle size of the silicon carbide in the G zone is 10-20 meshes;

[0041] B) A seed crystal is fixed on the top of a crucible filled with silicon carbide powder, and the silicon carbide crystal is grown using the PVT method.

[0042] The growth process of the present invention can improve the utilization rate of silicon carbide powder, reduce the generation of defects such as phase change and inclusions in the crystal, and improve the process stability of silicon carbide crystal growth.

[0043] The present invention places silicon carbide powder in different areas of a crucible according to different mesh sizes and different mass ratios, thereby ensuring smooth gas paths during crystal growth, reducing the generation of crystal defects, improving the utilization rate of raw materials, and reducing the probability of defects such as high dislocation density, phase change and inclusions occurring in silicon carbide crystals during growth, and controlling the crystallization of the material surface within a reasonable range, with the V degree and convexity controlled within a range of 0 to 3.

[0044] In the present invention, it is preferred to use multiple graphite partitions to divide the interior of the crucible into multiple charging areas. Specifically, Figure 1 As shown, a graphite partition perpendicular to the bottom of the crucible is used to divide the interior of the crucible into seven adjacent loading areas, namely, area F, area D, area B, area A, area C, area E and area G, and silicon carbide powder is loaded in each loading area. The volumes of the multiple loading areas are not particularly limited, as long as the silicon carbide powder in different loading areas is at the same growth height.

[0045] In the present invention, the particle size of the silicon carbide powder in the A zone is 70 to 80 mesh, such as 70 mesh, 71 mesh, 72 mesh, 73 mesh, 74 mesh, 75 mesh, 76 mesh, 77 mesh, 78 mesh, 79 mesh, 80 mesh, preferably with any of the above values ​​as the upper or lower limit of the range value; the particle size of the silicon carbide powder in the B zone is 60 to 70 mesh, such as 60 mesh, 61 mesh, 62 mesh, 63 mesh, 64 mesh, 65 mesh, 66 mesh, 67 mesh, 68 mesh, 69 mesh, 70 mesh, 71 mesh, 72 mesh, 73 mesh, 74 mesh, 75 mesh, 76 mesh, 77 mesh, 78 mesh, 79 mesh, 80 mesh. 9 mesh, 70 mesh, preferably with any of the above values ​​as the upper or lower limit of the range value; the particle size of the silicon carbide powder in the C zone is 50-60 mesh, such as 50 mesh, 51 mesh, 52 mesh, 53 mesh, 54 mesh, 55 mesh, 56 mesh, 57 mesh, 58 mesh, 59 mesh, 60 mesh, preferably with any of the above values ​​as the upper or lower limit of the range value; the particle size of the silicon carbide powder in the D zone is 40-50 mesh, such as 40 mesh, 41 mesh, 42 mesh, 43 mesh, 44 mesh, 45 mesh, 46 mesh, 47 mesh, 48 mesh, 49 mesh, 50 mesh, preferably with any of the above values ​​as the upper or lower limit of the range value; the particle size of the silicon carbide powder in the E zone is 30 to 40 mesh, such as 30 mesh, 31 mesh, 32 mesh, 33 mesh, 34 mesh, 35 mesh, 36 mesh, 37 mesh, 38 mesh, 39 mesh, 40 mesh, preferably with any of the above values ​​as the upper or lower limit of the range value; the particle size of the silicon carbide in the F zone is 20 to 30 The particle size of silicon carbide in the G zone is 10 to 20 mesh, such as 10 mesh, 11 mesh, 12 mesh, 13 mesh, 14 mesh, 15 mesh, 16 mesh, 17 mesh, 18 mesh, 19 mesh, 20 mesh, preferably a range value with any of the above values ​​as the upper or lower limit.

[0046] In the present invention, the mass of the silicon carbide powder in the A zone is preferably 35% to 45% of the mass of the total silicon carbide powder, such as 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, preferably a range value with the above arbitrary numerical value as the upper or lower limit; the mass of the silicon carbide powder in the B zone is 15% to 25% of the mass of the total silicon carbide powder, such as 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, preferably a range value with the above arbitrary numerical value as the upper or lower limit; the mass of the silicon carbide powder in the C zone is 5% to 15% of the mass of the total silicon carbide powder, such as 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, preferably a range value with the above arbitrary numerical value as the upper or lower limit. The mass of the silicon carbide powder in the D zone is 1% to 10% of the mass of the total silicon carbide powder, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, preferably a range value with any of the above values ​​as the upper or lower limit; the mass of the silicon carbide powder in the E zone is 5% to 15% of the mass of the total silicon carbide powder, and the mass of the silicon carbide powder in the F zone is 5% to 15% of the mass of the total silicon carbide powder, such as 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, preferably a range value with any of the above values ​​as the upper or lower limit; the mass of the silicon carbide powder in the G zone is 1% to 10% of the mass of the total silicon carbide powder, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, preferably a range value with any of the above values ​​as the upper or lower limit.

[0047] After the silicon carbide powder is loaded into the crucible according to the above-mentioned loading process, a seed crystal is fixed in the top crystal growth area of ​​the crucible, and then the crucible is placed in a growth furnace, and preheating, furnace cleaning and vacuuming are performed in sequence, and then a protective atmosphere is introduced and the temperature is increased to grow silicon carbide crystals.

[0048] During the growth of silicon carbide crystals, after the crucible is heated to a certain temperature, the raw materials gradually begin to sublimate, and the generated atmosphere grows on the growth surface. Under the action of the first certain temperature and pressure, the powder at the bottom of the crucible gradually carbonizes. During the sublimation process of the raw materials in the crucible, due to the optimization of the assembly process, the sublimated gas of raw materials of different mesh sizes rises through the center of the raw materials and drives the sublimation of nearby raw materials. The silicon-carbon-rich atmosphere with an appropriate silicon-carbon ratio and orderly release can improve the overall utilization rate of the raw materials, so that the grown silicon carbide crystals can be carried out efficiently and stably.

[0049] In the present invention, the preheating temperature is preferably 400-550°C, more preferably 450-500°C, and the preheating time is preferably 1-5 hours, more preferably 3-4 hours. The furnace cleaning is to quickly fill the protective gas argon gas 50000Pa for 1-2 hours to ensure that there is no interference from other components in the air in the furnace, and then vacuumize to ensure the stability of the gas components in the growth environment.

[0050] In the present invention, the protective atmosphere includes argon and / or nitrogen; when the protective atmosphere is a mixture of argon and nitrogen, the volume ratio of argon to nitrogen in the mixture is (45-50):(4.5-5), more preferably 48:4.9.

[0051] In the present invention, the temperature of the silicon carbide crystal growth is preferably 2000-2300°C, more preferably 2100-2200°C, such as 2000°C, 2050°C, 2100°C, 2150°C, 2200°C, 2250°C, 2300°C, preferably a range value with any of the above numerical values ​​as the upper or lower limit; the growth time of the silicon carbide crystal is preferably 30-150 hours. The present invention achieves the growth temperature of the above silicon carbide crystal by heating, and the heating rate is preferably 0.1-4°C / hour, more preferably 0.5-3°C / hour, such as 0.1°C / hour, 0.5°C / hour, 1°C / hour, 1.5°C / hour, 2°C / hour, 2.5°C / hour, 3°C / hour, 3.5°C / hour, 4°C / hour, preferably a range value with any of the above numerical values ​​as the upper or lower limit.

[0052] During the growth process of the silicon carbide crystal, the present invention preferably adopts a pulling process, such as controlling the movement rate of the crucible relative to the heating coil to control the stability of the silicon carbide crystal growth interface and the temperature field. The pulling process is a commonly used process in this field and the present invention will not be repeated here.

[0053] The silicon carbide crystal grown according to the process described above has an ideal 4H crystal form, and can grow a silicon carbide crystal with a thickness of 14 to 30 mm and a weight gain of 1500 to 2500 g.

[0054] The present invention provides a growth process of silicon carbide crystals, comprising the following steps: A) using a graphite partition to divide the interior of a crucible into seven adjacent loading areas, namely, an F area, a D area, a B area, an A area, a C area, an E area and a G area, and filling silicon carbide powder in each loading area, wherein the graphite partition is placed vertically to the bottom surface of the crucible; the particle size of the silicon carbide powder in the A area is 70 to 80 meshes, and the particle size of the silicon carbide powder in the B area is 60 to 80 meshes. ~70 mesh, the particle size of the silicon carbide powder in the C zone is 50~60 mesh, the particle size of the silicon carbide powder in the D zone is 40~50 mesh, the particle size of the silicon carbide powder in the E zone is 30~40 mesh, the particle size of the silicon carbide in the F zone is 20~30 mesh, and the particle size of the silicon carbide in the G zone is 10~20 mesh; B) fixing the seed crystal on the top of the crucible filled with silicon carbide powder, and using the PVT method to grow silicon carbide crystals. The present invention uses a graphite accessory of a certain size in the graphite crucible to divide the charge of the crucible into different areas, and charges silicon carbide raw materials of different mesh sizes, so that the silicon-carbon ratio can be orderly released in the subsequent crystal growth process. Silicon-carbon rich atmosphere. The present invention can improve the uniformity and utilization rate of sublimation gas during the growth process of powder by optimizing the charging process, which is helpful to stabilize the temperature field in the furnace, reduce the probability of crystal phase change, reduce crystal defects (phase change, color unevenness, etc.), and thus improve crystal quality.

[0055] Compared with the silicon carbide crystals grown from the raw materials used before process optimization, the silicon carbide crystals grown according to the growth process of the present invention have a 2% lower probability of phase change, a probability of edge polycrystallinity and dislocation occurrence of <0.05%, and the growth stability of the silicon carbide crystals is effectively improved.

[0056] In order to further illustrate the present invention, the growth process and application of a silicon carbide crystal provided by the present invention are described in detail below in combination with embodiments, but it should not be understood as limiting the scope of protection of the present invention.

[0057] Example 1

[0058] like Figure 1 As shown, cut the graphite paper into appropriate size and flatten it, first spread 70-80 mesh fine material in area A, weighing 1600g; then add area B: 60-70 mesh, area C: 50-60 mesh, area D: 40-50 mesh, area E: 30-40 mesh, area F: 20-30 mesh and area G: 10-20 mesh.

[0059] The weight of the raw material 60-70 mesh is 800g, the weight of 50-60 mesh is 400g, the weight of 40-50 mesh is 200g, the weight of 30-40 mesh is 400g, the weight of 20-30 mesh is 350-400g, and the weight of 10-20 mesh is 200g.

[0060] After being placed in the crystal growth furnace, it is preheated, cleaned and evacuated, and then the protective gas argon is flushed in, the temperature is raised to 2100°C, and the pressure control process is 48:4.9 (the volume ratio of argon to helium) is performed. The crystal growth time is 135 hours.

[0061] The utilization rate of silicon carbide raw materials reaches 55% (net weight of raw materials used in the product / weight of raw materials consumed per unit product × 100%), the thickness of the silicon carbide crystal is 23mm, the convexity of the crystal is 1.7 and 1.9 respectively, the V degree is 1.3, and the crystal is defect-free.

[0062] Embodiment 2:

[0063] The difference between this embodiment and embodiment 1 is that in the material assembly stage, embodiment 2 does not optimize the mesh ratio of the powder, but only mixes the coarse and fine materials in a mass ratio of 1:1. Figure 1 The device shown is directly charged, wherein the weight of the fine material 70-80 mesh is 1950-2000g, the weight of the coarse material 10-20 mesh is 1950-2000g, and the other growth processes are the same as those in Example 1.

[0064] The utilization rate of silicon carbide raw materials reaches 44%, the thickness of silicon carbide crystal is 18mm, the crystal is defect-free, the convexity of the crystal is 2.2 and 2.4, and the V degree is 1.7.

[0065] Example 3

[0066] The difference between this embodiment and embodiment 1 is only the difference in crystal growth time. The crystal growth time of this embodiment is 125 hours.

[0067] The utilization rate of silicon carbide raw materials reaches 46%, the thickness of silicon carbide is 16.5mm, the crystal is defect-free, the convexity of the crystal is 1.5 and 1.7, and the V degree is 1.8.

[0068] Example 4

[0069] The difference between this embodiment and embodiment 1 is the difference in crystal growth time. The crystal growth time of this embodiment is 115 hours.

[0070] The utilization rate of silicon carbide raw materials reaches 41%, the thickness of silicon carbide is 13.5mm, the convexity of the crystal is 2.4 and 2.1, the V degree is 2.1, and the crystal is defect-free.

[0071] Comparative Example 1

[0072] The crucible used in Comparative Example 1 was not partitioned inside, and all 80-mesh silicon carbide fine material was used for the growth of silicon carbide crystals, and the growth process was the same as that of Example 1.

[0073] The final silicon carbide raw material utilization rate was 37%, the thickness of the silicon carbide crystal was 13 mm, and polycrystalline defects appeared on the crystal surface.

[0074] Comparative Example 2

[0075] The crucible used in Comparative Example 1 was not partitioned inside, and all 8-mesh coarse materials were used for the growth of silicon carbide crystals. The growth process was the same as that of Example 1.

[0076] The utilization rate of silicon carbide raw materials is 39%, the thickness of the silicon carbide crystal is 11 mm, the convexity of the crystal is 1.2 and 1.7, the V degree is 1.9, and the crystal has defects of initial phase change.

[0077] Comparative Example 3

[0078] The crucible used in Comparative Example 3 is divided into five loading areas, namely, area A, area B, area C, area D and area E, by a graphite partition. The five loading areas are distributed in the order of area D, area B, area A, area C and area E, and the mesh distribution range is: area A: 60-70 mesh (mass proportion: 30%), area B: 50-60 mesh (mass proportion: 20%), area C: 40-50 mesh (mass proportion: 10%), area D: 30-40 mesh (mass proportion: 10%), and area E: 20-30 mesh (mass proportion: 30%). The growth process is the same as that of Example 1.

[0079] The utilization rate of silicon carbide raw materials is 42%, the thickness of silicon carbide crystal is 15mm, the convexity of the crystal is 1.3 and 1.9, the V degree is 2.2, and the crystal has defects of mid-term phase change.

[0080] Comparative Example 4

[0081] Silicon carbide crystal growth was carried out according to the method in Example 1, except that, in Comparative Example 4, when assembling the materials, the mesh distribution range was: A: 70-80 mesh (30% by mass), B: 60-70 mesh (20% by mass), C: 50-60 mesh (10% by mass), D: 40-50 mesh (10% by mass), E: 30-40 mesh (10% by mass), F: 20-30 mesh (10% by mass), and G: 10-20 mesh (10% by mass).

[0082] The utilization rate of silicon carbide raw materials is 40%, the thickness of the silicon carbide crystal is 16 mm, the convexity of the crystal is 1.9 and 1.7, the V degree is 1.5, and the crystal has defects of late phase change.

[0083] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A process for growing silicon carbide crystals, comprising the following steps: A) using a graphite partition to divide the interior of the crucible into seven adjacent charging areas, namely, area F, area D, area B, area A, area C, area E and area G, and loading silicon carbide powder in each charging area, while ensuring that the silicon carbide powder in different charging areas is at the same growth height, and the graphite partition is placed vertically to the bottom surface of the crucible; The particle size of the silicon carbide powder is 10 to 80 meshes; B) A seed crystal is fixed on the top of a crucible filled with silicon carbide powder, and the silicon carbide crystal is grown using the PVT method.

2. The growth process according to claim 1, characterized in that: The particle size of the silicon carbide powder in the A zone is 70-80 mesh, the particle size of the silicon carbide powder in the B zone is 60-70 mesh, the particle size of the silicon carbide powder in the C zone is 50-60 mesh, the particle size of the silicon carbide powder in the D zone is 40-50 mesh, the particle size of the silicon carbide powder in the E zone is 30-40 mesh, the particle size of the silicon carbide in the F zone is 20-30 mesh, and the particle size of the silicon carbide in the G zone is 10-20 mesh.

3. The growth process according to claim 1, characterized in that: The mass of the silicon carbide powder in the A zone is 35% to 45% of the mass of the total silicon carbide powder. The mass of the silicon carbide powder in the B zone is 15% to 25% of the mass of the total silicon carbide powder. The mass of the silicon carbide powder in the C zone is 5% to 15% of the mass of the total silicon carbide powder. The mass of the silicon carbide powder in the D zone is 1% to 10% of the mass of the total silicon carbide powder. The mass of the silicon carbide powder in the E zone is 5% to 15% of the mass of the total silicon carbide powder. The mass of the silicon carbide powder in the F zone is 5% to 15% of the mass of the total silicon carbide powder. The mass of the silicon carbide powder in the G zone is 1% to 10% of the mass of the entire silicon carbide powder.

4. The growth process according to claim 1, characterized in that: The mass of the silicon carbide powder in the A zone is 40% of the mass of the total silicon carbide powder. The mass of the silicon carbide powder in the B zone is 20% of the mass of the total silicon carbide powder. The mass of the silicon carbide powder in the C zone is 10% of the mass of the total silicon carbide powder. The mass of the silicon carbide powder in the D zone is 5% of the mass of the total silicon carbide powder. The mass of the silicon carbide powder in the E zone is 10% of the mass of the total silicon carbide powder. The mass of the silicon carbide powder in the F zone is 10% of the mass of the total silicon carbide powder. The mass of the silicon carbide powder in the G zone is 5% of the mass of the total silicon carbide powder.

5. The growth process according to claim 1, characterized in that: The step B) is specifically as follows: A seed crystal is fixed on the top of a crucible filled with silicon carbide powder, and the crucible is placed in a growth furnace. After preheating and evacuation, a protective atmosphere is introduced and the temperature is increased to grow silicon carbide crystals.

6. The growth process according to claim 5, characterized in that: The protective atmosphere comprises argon and / or helium; When the protective atmosphere is a mixture of argon and nitrogen, the volume ratio of argon to nitrogen in the mixture is (45-50): (4.5-5).

7. The growth process according to claim 5, characterized in that: The growth temperature of the silicon carbide crystal is 2000-2400° C.; the growth time of the silicon carbide crystal is 30-150 hours; The growth temperature of the silicon carbide crystal is achieved by heating, and the heating rate is 0.1-4°C / hour.

8. The growth process according to claim 5, characterized in that: The thickness of the silicon carbide crystal is 14-30 mm; the silicon carbide crystal is a 4H crystal type silicon carbide crystal.

9. The growth process according to claim 1, characterized in that: During the growth of silicon carbide crystals, the thickness of the silicon carbide crystals is controlled through a pulling process and the stability of the temperature field at the growth interface is maintained.

10. Application of a silicon carbide assembly process in improving silicon carbide raw material utilization and reducing silicon carbide crystal defects, characterized in that: The silicon carbide assembly process is carried out according to the growth process in claim 1.

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