Method and device for adjusting carbon-silicon balance of HTCVD (high temperature chemical vapor deposition) crystal growth

Abstract

The invention provides a method and a device for adjusting carbon-silicon balance of HTCVD (high temperature chemical vapor deposition) crystal growth. The device for adjusting the HTCVD crystal growth carbon-silicon balance comprises a crystal growth furnace body, a seed crystal lifting mechanism, a gas inlet structure and a heat preservation structure, the gas inlet structure comprises a gas inlet channel formed by an inner gas channel and an outer gas channel which are concentrically arranged, and a built-in cooling section can stably keep high byproduct gas below the cracking temperature; delaying the cracking time of the high byproduct gas after entering the furnace; the gas inlet structure can also effectively improve the mixing efficiency, and the mixed growth gas is upwards conveyed to a seed crystal area in a uniform mode. According to the method for adjusting the HTCVD crystal growth carbon-silicon balance, the growth gas is subjected to split-flow cooling and mixing at the initial stage of being introduced into the crystal growth furnace, and the gas exhaust position is dynamically adjusted, so that the growth gas in the crystal growth furnace is fully mixed, meanwhile, the exposure time of the growth gas in a high-temperature area is shortened, and the generation of byproducts is effectively reduced.

Description

Technical Field

[0001] This invention belongs to the field of silicon carbide crystal growth and relates to a method and apparatus for adjusting the silicon carbide balance during HTCVD crystal growth. Background Technology

[0002] Silicon carbide (SiC), as a representative of third-generation wide-bandgap semiconductor materials, has shown great application potential in power electronic devices, radio frequency devices, and other fields due to its excellent wide bandgap, high breakdown field strength, high thermal conductivity, high electron saturation drift velocity, chemical stability, and low defect density. Therefore, high-quality, large-size SiC single-crystal substrates are the core foundation for manufacturing these high-performance devices.

[0003] Currently, the mainstream method for industrial preparation of SiC single crystal substrates is physical vapor transport (PVT). However, PVT has some inherent limitations, such as difficulty in controlling the purity of the growth environment, a relatively slow growth rate, and difficulty in real-time monitoring and precise control of the growth process. To overcome the shortcomings of PVT, some crystal growth processes use high-temperature chemical vapor deposition (HTCVD) as an alternative growth technology. This process is usually carried out at temperatures as high as 2200°C to 2500°C, using high-purity gases such as silane (SiH4), ethylene (C2H4), ethane (C2H6), or propane (C3H8) as precursors for silicon and carbon sources, which are directly transported to the high-temperature deposition region under the transport of inert carrier gases (such as argon or hydrogen). Under high-temperature conditions, the precursor gases undergo thermal decomposition and chemical reactions to generate silicon and carbon active groups, which are then chemically vapor deposited on the seed crystal surface, ultimately achieving homoepitaxial growth of silicon carbide single crystals.

[0004] However, during the HTCVD growth of SiC crystals, silicon source gas needs to be mixed and decomposed with carbon source gas in a high-temperature reaction chamber. Since the temperature in the growth region is usually above 2000℃, which is much higher than the decomposition temperature of the growth gas, some of the growth gas will be converted into byproducts that affect crystal quality before decomposition and synthesis. At the same time, because the decomposition temperatures and decomposition rates of the two growth gases are different, the decomposition efficiency is difficult to control. Under the same carbon-silicon ratio, the remaining single carbon source or silicon source gas will not be deposited on the seed crystal to form SiC, but will instead deposit layered structures on the furnace wall, crucible edge, and thermal field structure, resulting in waste of raw material gas and a reduction in the service life of the internal structure of the furnace.

[0005] Therefore, there is a need to develop a method and apparatus for adjusting the carbon-silicon balance in HTCVD crystal growth, which can avoid the generation of more byproducts by the growth gas due to excessively high ambient temperature, improve the mixing efficiency of the two growth gases, and control the carbon-silicon ratio to maintain it within a balanced range. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a method and apparatus for adjusting the carbon-silicon balance in HTCCVD crystal growth. This method involves splitting, cooling and mixing the growth gas in the early stage of its introduction into the crystal growth furnace, and dynamically adjusting the gas discharge position to ensure that the growth gas in the crystal growth furnace is fully mixed. At the same time, it reduces the exposure time of the growth gas in the high-temperature region, effectively reducing the generation of by-products and lowering the risk of encapsulation.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: This invention provides a method for adjusting the carbon-silicon growth equilibrium in HTCVD, comprising the following steps: Step 1: Determine the growth gas byproducts: Select the appropriate carbon source gas and silicon source gas according to the crystal growth process requirements, and determine the decomposition temperature of the carbon source gas. T 1 Decomposition temperature of silicon source gas T 2 Set the carbon-to-silicon ratio of the growth gas, where C:Si = 0.9~1.1:1. Perform silicon carbide crystal growth according to the preset crystal growth conditions. After the growth is completed, check the by-products at the crystal and estimate the mass ratio of carbon-containing by-products to silicon-containing by-products.

[0008] Step 2: Divide the growth gas path: By comparing the quality of carbon-containing byproducts and silicon-containing byproducts, the two growth gases are divided into high-byproduct growth gas and low-byproduct growth gas. Before the growth gases are introduced into the crystal growth furnace, the two growth gases are transported independently and are not mixed.

[0009] Step 3, Arrangement of the growth gas introduction path, specifically including the following steps: Step 3A, Path 1 Layout: Path 1 is used for the initial transport of high-byproduct growth gas in the crystal growth furnace. The bottom end of Path 1 is inserted at the gas inlet of the crystal growth furnace. Based on the thermal field simulation results inside the crystal growth furnace, it is determined that the growth gas entering one side of the crystal growth furnace reaches maximum ( T 1 , T 2 Let the isotherm position be such that the distance between this position and the bottom of the path is . h 1 Path 1 length is l 1 Water cooling is used from bottom to top, among which, l 1 > h 1 .

[0010] Step 3B, Path Two Arrangement: Path Two is used for the initial transport of low-by-product growth gas in the crystal growth furnace. The bottom end of Path Two is inserted at the gas inlet of the crystal growth furnace. The distance from the starting position of the tapered structure of Path Two to the bottom end is... l 2 ,in, l 2 > l 1 .

[0011] Step 3C, Transition Structure Arrangement: Both Path 1 and Path 2 have openings at the top. The growth gas is then mixed and introduced into the transition structure through the same path. The bottom of the transition structure is connected to the openings of Path 1 and Path 2. The transition structure is a tapered, gradually expanding structure from the bottom to the top. Several through holes are opened at the top of the transition structure facing the seed crystal direction. The transition structure is used to improve the uniformity of growth gas deposition and particle control.

[0012] Step 4, Growth Gas Carbon-Silicon Balance Control: The fully mixed growth gas is introduced to the seed crystal, and then silicon carbide crystal growth is carried out. The crystal growth preset conditions are adjusted according to the defects at the crystal to make the crystal free of obvious defects.

[0013] The specific balance control method in step 4 is as follows: Step 4A: Set the carbon-to-silicon ratio of the growth gas, where the carbon-to-silicon ratio satisfies C:Si = 0.9~1.1:1. After the two growth gases are fully mixed, silicon carbide crystal growth begins. The total time for the silicon carbide crystal growth stage is divided into equal intervals. i There are 1 time unit, denoted as T(i).

[0014] Step 4B: Let the distance between the seed crystal and the bottom of path one be... l 4 The distance between the top of the transition structure and the bottom of path one is l 5 2 / 3 of them are always satisfied l 4 ≥ l 5 .

[0015] Step 4C: After the silicon carbide crystal growth is completed, the silicon carbide crystal is divided into different growth segments, the crystal height H(i) corresponding to each time unit T(i) is recorded, and the defect situation in different growth segments is detected.

[0016] Step 4D: Select two adjacent sets of data based on the crystal defect situation and the crystal height H(i), and record the distance between the top of the corresponding transition structure and the seed crystal. l 3n and l 3（n+1） .

[0017] Step 4E, and repeating steps 4A to 4D, in the second and subsequent balance control methods, the distance between the top of the transition structure and the seed crystal is maintained at the level obtained in the previous step D. l 3n and l 3（n+1） Between; until a silicon carbide crystal growth segment without obvious defects is obtained.

[0018] A device for adjusting the balance of silicon carbide growth in HTCVD crystal growth includes a crystal growth furnace, a seed crystal pulling mechanism, a heat preservation structure, and an air intake structure.

[0019] The seed crystal pulling structure includes a pulling rod and a seed crystal seat. The seed crystal pulling rod is vertically inserted into the top of the crystal growth furnace body. One side of the seed crystal seat is located at the end of the seed crystal pulling rod near the center of the crystal growth furnace body, and the other side is bonded to the seed crystal.

[0020] The air intake structure includes an air intake passage, a main air intake pipe, and a transition structure. The air intake passage is inserted into the bottom of the crystal growth furnace body and consists of concentric inner and outer air channels. The inner air channel is path one, and the outer air channel is path two. Both paths one and two are sealed at their bottom ends and inserted into the bottom of the crystal growth furnace body. The length of path one is... l 1 The entire section is water-cooled from bottom to top, and the starting position of the tapering structure in path two is [distance from the bottom]. l 2 ,in, l 2 > l 1 Both path one and path two are open at the top. One end of the main air intake pipe is sealed to the top of path two, and the other end is sealed to the bottom of the transition structure. The transition structure is a tapered and gradually expanding structure from the bottom to the top. Several through holes are opened at the top of the transition structure facing the seed crystal direction.

[0021] The height of the top opening of Path 2 is higher than that of the top opening of Path 1. The top opening of Path 2 is a tapered and tapered structure. The top openings of Path 1, Path 2, the main intake pipe, and the transition structure are interconnected.

[0022] The insulation structure includes an insulation crucible and an induction heating coil. The insulation crucible is located above the bottom of the crystal growth furnace and is arranged around the outside of the gas inlet structure and the seed crystal. The induction heating coil is arranged around the outside of the outer wall of the crystal growth furnace and is used to heat the insulation crucible inside the crystal growth furnace to maintain the growth temperature of silicon carbide crystals.

[0023] Compared with existing technical solutions, the present invention has at least the following beneficial effects: 1. In the initial stage of introducing the growth gas into the crystal growth furnace, the present invention performs split cooling and appropriately raises the gas discharge position, thereby reducing the exposure time of the high by-product gas in the high temperature region, effectively controlling the two gases to decompose at the same height and efficiently generating SiC gaseous clusters.

[0024] 2. This invention dynamically adjusts the gas exhaust position to achieve silicon carbide single crystal growth with a carbon-to-silicon ratio close to 1:1, thereby improving the utilization rate of growth gas, precisely controlling the silicon-to-carbon ratio, reducing stoichiometric deviation, improving crystal quality, and preventing excess growth gas from depositing in the furnace.

[0025] 3. On the one hand, the present invention enhances the mixing of carbon source gas and silicon source gas at the end of the growth gas splitting section, and on the other hand, sets a tapered gradually expanding structure at the gas discharge position to increase the uniformity of mixed gas discharge, thereby further helping to control the carbon-silicon ratio of the growth process to a ratio close to 1:1.

[0026] 4. The gas inlet passage design of the HTCVD silicon carbide growth balance device provided by the present invention can prevent particles from depositing on the lower channel or cavity surface, reduce maintenance frequency, and has strong compatibility. It can be adjusted according to the properties of the growth gas and can be adapted to various silicon and carbon source gas combinations.

[0027] Figure 1 This is a cross-sectional schematic diagram of a device for adjusting the balance of HTCVD crystal growth in silicon carbide according to the present invention.

[0028] Figure 2 A schematic diagram of the air intake structure is shown.

[0029] Among them are: 10. Crystal growth furnace body; 20. Seed crystal pulling mechanism; 21. Seed crystal lifting rod; 22. Seed crystal holder; 30. Air intake structure; 31. Intake passage; 311. Path 1; 3111. Water cooling section; 312. Path 2; 32. Main intake pipe; 33. Transition structure; 40. Thermal insulation structure; 41. Insulated crucible; 42. Induction heating coil. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and specific preferred embodiments.

[0031] In the description of this invention, it should be understood that the terms "left side," "right side," "upper part," "lower part," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Terms such as "first" and "second" do not indicate the importance of components and therefore should not be construed as limitations on the invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this invention. Those skilled in the art should understand that the embodiments described are merely to help understand the invention and should not be considered as specific limitations on the invention.

[0032] The present invention provides a method for adjusting the equilibrium of HTCVD-grown silicon-carbon material, comprising the following steps: Step 1: Determine the growth gas byproducts: Select the appropriate carbon source gas and silicon source gas according to the crystal growth process requirements, and determine the decomposition temperature of the carbon source gas. T 1 Decomposition temperature of silicon source gas T 2 Set the carbon-to-silicon ratio of the growth gas, where C:Si = 0.9~1.1:1. Perform silicon carbide crystal growth according to the preset crystal growth conditions. After the growth is completed, check the by-products at the crystal and estimate the mass ratio of carbon-containing by-products to silicon-containing by-products.

[0033] In step 1, to control the carbon-to-silicon ratio of the growth gas to approximately 1:1, silicon carbide growth is first performed using the HTCCVD process according to this ratio. Then, by analyzing the byproducts at the crystal after growth, it's determined which element in the process is causing the most significant impact on the crystal. The growth gas corresponding to this byproduct is then carefully controlled to ensure low-defect crystal growth while maintaining a constant carbon-to-silicon ratio. These byproducts mainly include solid-phase byproducts such as silicon droplets, carbon black, and silicon carbide powder. These byproducts directly disrupt the integrity of the crystal structure and form defects, posing the greatest threat to crystal quality.

[0034] Step 2: Divide the growth gas path: By comparing the mass of carbon-containing and silicon-containing byproducts, the two growth gases are divided into high-byproduct growth gas and low-byproduct growth gas. Before the growth gases are introduced into the crystal growth furnace, the two growth gases are transported independently without mixing. Since the pyrolysis temperature of the carbon source gas was measured in Step 1... T 1 Decomposition temperature of silicon source gas T 2Typically, the cracking rates and cracking speeds of the two growth gases are inconsistent, and they need to be controlled separately to avoid uneven mixing caused by the inconsistent cracking rates in the early stages when they are mixed and introduced into the reaction chamber.

[0035] Step 3, Arrangement of the growth gas introduction path, specifically including the following steps: Step 3A, Path 1 Layout: Path 1 is used for the initial transport of high-byproduct growth gas in the crystal growth furnace. The bottom end of Path 1 is inserted at the gas inlet of the crystal growth furnace. Based on the thermal field simulation results inside the crystal growth furnace, it is determined that the growth gas entering one side of the crystal growth furnace reaches maximum ( T 1 , T 2 Let the isotherm position be such that the distance between this position and the bottom of the path is . h 1 Path 1 length is l 1 Water cooling is used from bottom to top, among which, l 1 > h 1 For the initial introduction path design of high by-product gases, a water-cooling section at the bottom of path one can effectively delay the pyrolysis location of the high by-product gases, reduce their total contact time with the high-temperature environment, and to some extent avoid the occurrence of by-products due to excessively high temperatures and prolonged heating time. The height of the water-cooling section is greater than the height of the isotherm of the maximum pyrolysis temperature of the growth gas to ensure the initial cooling effect of the high by-product gases.

[0036] Step 3B, Path Two Arrangement: Path Two is used for the initial transport of low-by-product growth gas in the crystal growth furnace. The bottom end of Path Two is inserted at the gas inlet of the crystal growth furnace. The distance from the starting position of the tapered structure of Path Two to the bottom end is... l 2 ,in, l 2 > l 1 After the high-byproduct gas leaves the water-cooling section, it will begin to mix with some of the low-byproduct gas, and the high-byproduct gas will begin to crack later than the low-byproduct gas.

[0037] Step 3C, Transition Structure Arrangement: Both Path 1 and Path 2 have open tops. The growth gas is then mixed and introduced into the transition structure through the same path. The bottom of the transition structure is connected to the openings of Path 1 and Path 2. The transition structure is a tapered, gradually expanding structure from bottom to top. Several through-holes are opened at the top of the transition structure facing the seed crystal. The transition structure is used to improve the uniformity of growth gas deposition and particle control. The tapered, gradually expanding structure of the transition structure and the several through-holes on the top surface allow the initially mixed growth gas to diffuse upwards uniformly to the seed crystal growth area, enhancing the mixing effect and preventing the phenomenon of growth gas of the same element precipitating prematurely or delayedly and forming clusters.

[0038] Step 4, Silicon Carbide Equilibrium Control of Growth Gas: The thoroughly mixed growth gas is introduced to the seed crystal, followed by silicon carbide crystal growth. The pre-set crystal growth conditions are adjusted according to the defects at the crystal to ensure that there are no obvious defects at the crystal. The specific equilibrium control method in Step 4 is as follows: Step 4A: Set the carbon-to-silicon ratio of the growth gas, where the carbon-to-silicon ratio satisfies C:Si = 0.9~1.1:1. After the two growth gases are fully mixed, silicon carbide crystal growth begins. The total time for the silicon carbide crystal growth stage is divided into equal intervals. i There are 1 time unit, denoted as T(i).

[0039] Step 4B: To control the location of the growth gas exhaust and avoid the direct gas flow point being too close to the seed crystal, the distance between the seed crystal and the bottom of path one is set to... l 4 The distance between the top of the transition structure and the bottom of path one is l 5 2 / 3 of them are always satisfied l 4 ≥ l 5 In different time units T(i), the remaining parameters for silicon carbide crystal growth, such as temperature, pressure, and gas flow rate, remain constant.

[0040] Step 4C: After the silicon carbide crystal growth is completed, record the crystal height H(i) corresponding to each time unit T(i) and detect the defect situation in different growth segments. The crystal height H(i) can represent the growth gas utilization rate to a certain extent. The higher the crystal height H(i) obtained in each time unit T(i), the higher the growth gas utilization rate.

[0041] Step 4D: Select two adjacent sets of data based on the crystal defect situation and the crystal height H(i), ensuring that these two sets of data are the optimal values ​​in this crystal growth, and record the distance between the top of the corresponding transition structure and the seed crystal. l 3n and l 3（n+1） .

[0042] Step 4E, repeating steps 4A to 4D, in the second and subsequent balance control methods, the distance between the top of the transition structure and the seed crystal is maintained at the level obtained in the previous step D. l 3n and l 3（n+1） Through repeated control experiments, a silicon carbide crystal growth segment without obvious defects was obtained.

[0043] like Figure 1 As shown, an HTCVD silicon carbide crystal growth balance adjustment device includes a crystal growth furnace body 10, a seed crystal pulling mechanism 20, an air intake structure 30, and a heat preservation structure 40.

[0044] The seed crystal pulling structure 20 includes a seed crystal pulling rod 21 and a seed crystal seat 22. The seed crystal pulling rod 21 is vertically inserted into the top of the crystal growth furnace body 10. One side of the seed crystal seat 22 is located at the end of the seed crystal pulling rod 21 near the center of the crystal growth furnace body 10, and the other side is bonded to the seed crystal. The seed crystal pulling rod 21 can continuously pull the seed crystal seat 22 during the crystal growth stage, thereby ensuring that the lower end face of the continuously growing seed crystal remains at the same height, keeping its growth temperature constant.

[0045] The air intake structure 30 includes an air intake passage 31, a main air intake pipe 32, and a transition structure 33. The air intake passage 31 is inserted into the bottom of the crystal growth furnace body 10. The air intake passage 31 is composed of concentric inner and outer double air channels. The inner and outer double air channel design not only reduces the space occupied by the air intake passage 31 in the crystal growth furnace body 10, but also facilitates the connection and mixing of the two growth gases. The inner air channel of the air intake passage 31 is path one 311, and the outer air channel of the air intake passage 31 is path two 312. The bottom ends of both path one 311 and path two 312 are sealed and inserted into the bottom of the crystal growth furnace body 10. The pipe wall of path one 311 is a water-cooled section from the bottom end to the top end. The water-cooled section is mainly used to perform pre-heating work on the high by-product gas introduced into path one 311, so that the temperature of the high by-product gas is kept below its decomposition temperature, thus delaying the decomposition time of the high by-product gas after entering the furnace. According to the temperature field simulation, the internal temperature of the cavity at the top of Path 1 311 is 600℃~800℃, the water flow temperature of the water-cooled section is 25℃, the outer surface temperature of the water-cooled section is about 200℃~300℃, and the internal temperature is controlled at 50℃~80℃, which can stably keep the high by-product gas below the pyrolysis temperature.

[0046] The preferred flow rate of the low-byproduct gas is 0.1~3 L / min, while the flow rate of the high-byproduct gas is adjusted according to the carbon-silicon ratio. Both path 1 (311) and path 2 (312) have openings at their tops. The opening at the top of path 2 (312) is higher than that at the top of path 1 (311), and the opening at the top of path 2 (312) has a tapered, tapered structure. The top openings of path 1 (311), path 2 (312), the main inlet pipe 32, and the transition structure 33 are interconnected, forming a growth gas transport pathway.

[0047] One end of the main intake pipe 32 is connected to the top of path two 312, and the other end is connected to the bottom of the transition structure 33. The transition structure 33 is a tapered, gradually expanding structure from bottom to top. Several through holes are opened at the top of the transition structure 33 facing the seed crystal direction. This through hole design can uniformly transport the mixed growth gas in the transition structure 33 upward to the seed crystal region. The diameter of the top surface of the transition structure 33 is preferably set to 8~12cm, and the through holes at the top are preferably centrally symmetrically arranged with a diameter of 2~5mm. The tapered, gradually expanding angle of the transition structure 33 is less than 20° to prevent backflow and secondary flow.

[0048] The heat preservation structure 40 includes a heat preservation crucible 41 and an induction heating coil 42. The heat preservation crucible 41 is disposed above the bottom of the crystal growth furnace body 10 and is arranged around the outside of the gas inlet structure 30 and the seed crystal. The induction heating coil 42 is arranged around the outside of the outer wall of the crystal growth furnace body 10 and is used to heat the heat preservation crucible 41 inside the crystal growth furnace body 10 to maintain the growth temperature of silicon carbide crystal.

[0049] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0050] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0051] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for adjusting the carbon-silicon growth equilibrium in HTCVD, characterized in that: Includes the following steps: Step 1: Determine the growth gas byproducts: Select the appropriate carbon source gas and silicon source gas according to the crystal growth process requirements, and determine the decomposition temperature of the carbon source gas. T 1 Decomposition temperature of silicon source gas T 2 Set the carbon-to-silicon ratio of the growth gas, where C:Si = 0.9~1.1:

1. Perform silicon carbide crystal growth according to the preset crystal growth conditions. After the growth is completed, check the by-products at the crystal and estimate the mass ratio of carbon-containing by-products to silicon-containing by-products. Step 2, dividing the growth gas path: By comparing the quality of carbon-containing byproducts and silicon-containing byproducts, the two growth gases are divided into high-byproduct growth gas and low-byproduct growth gas. Before the growth gas is introduced into the crystal growth furnace, the two growth gases are transported independently and are not mixed. Step 3, Arrangement of the growth gas introduction path, specifically including the following steps: Step 3A, Path 1 Layout: Path 1 is used for the initial transport of high-byproduct growth gas in the crystal growth furnace. The bottom end of Path 1 is inserted at the gas inlet of the crystal growth furnace. Based on the thermal field simulation results inside the crystal growth furnace, it is determined that the growth gas entering one side of the crystal growth furnace reaches maximum ( T 1 , T 2 Let the isotherm position be such that the distance between this position and the bottom of the path is . h 1 Path 1 length is l 1 Water cooling is used from bottom to top, among which, l 1 > h 1 ; Step 3B, Path Two Arrangement: Path Two is used for the initial transport of low-by-product growth gas in the crystal growth furnace. The bottom end of Path Two is inserted at the gas inlet of the crystal growth furnace. The distance from the starting position of the tapered structure of Path Two to the bottom end is... l 2 ,in, l 2 > l 1 ; Step 3C, Transition Structure Arrangement: Both Path 1 and Path 2 have openings at the top. The growth gas is then mixed and introduced into the transition structure through the same path. The bottom of the transition structure is connected to the openings of Path 1 and Path 2. The transition structure is a tapered and gradually expanding structure from the bottom to the top. Several through holes are opened at the top of the transition structure facing the seed crystal direction. The transition structure is used to improve the uniformity of growth gas deposition and particle control. Step 4, Growth Gas Carbon-Silicon Balance Control: The fully mixed growth gas is introduced to the seed crystal, and then silicon carbide crystal growth is carried out. The crystal growth preset conditions are adjusted according to the defects at the crystal to make the crystal free of obvious defects.

2. The method for adjusting the carbon-silicon growth balance in HTCVD according to claim 1, characterized in that: The specific balance control method in step 4 is as follows: Step 4A: Set the carbon-to-silicon ratio of the growth gas, where the carbon-to-silicon ratio satisfies C:Si = 0.9~1.1:

1. After the two growth gases are fully mixed, silicon carbide crystal growth begins. The total time for the silicon carbide crystal growth stage is divided into equal intervals. i There are 1 time unit, and the unit name is denoted as T(i); Step 4B: Let the distance between the seed crystal and the bottom of path one be... l 4 The distance between the top of the transition structure and the bottom of path one is l 5 2 / 3 of them are always satisfied l 4 ≥ l 5 This allows for the regulation of the distance between the top of the transition structure and the seed crystal. l 3i ; Step 4C: After the silicon carbide crystal growth is completed, the silicon carbide crystal is divided into different growth segments, the crystal height H(i) corresponding to each time unit T(i) is recorded, and the defect situation in different growth segments is detected. Step 4D: Select two adjacent sets of data based on the crystal defect situation and the crystal height H(i), and record the distance between the top of the corresponding transition structure and the seed crystal. l 3n and l 3（n+1） ; Step 4E, and repeating steps 4A to 4D, in the second and subsequent balance control methods, the distance between the top of the transition structure and the seed crystal is maintained at the level obtained in the previous step D. l 3n and l 3（n+1） Between; until a silicon carbide crystal growth segment without obvious defects is obtained.

3. The method for adjusting the carbon-silicon growth balance in HTCVD according to claim 2, characterized in that: In step 4B, let the distance between the seed crystal and the bottom of path one be... l 4 The distance between the top of the transition structure and the bottom of path one is l 5 2 / 3 of them are always satisfied l 4 ≥ l 5 .

4. The device for adjusting the balance of HTCCVD crystal growth in silicon carbide according to any one of claims 1 to 3, characterized in that: This includes the crystal growth furnace body, the seed crystal pulling mechanism, and the gas intake structure; The seed crystal pulling structure includes a seed crystal pulling rod and a seed crystal seat. The seed crystal pulling rod is vertically inserted into the top of the crystal growth furnace body. One side of the seed crystal seat is located at the end of the seed crystal pulling rod near the center of the crystal growth furnace body, and the other side is bonded to the seed crystal. The air intake structure includes an air intake passage, a main air intake pipe, and a transition structure. The air intake passage is inserted into the bottom of the crystal growth furnace body and consists of concentric inner and outer air channels. The inner air channel is path one, and the outer air channel is path two. Both paths one and two are sealed at their bottom ends and inserted into the bottom of the crystal growth furnace body. Path one is a water-cooled section from bottom to top. The starting position of the transition structure is [distance from bottom to top]. l 2 ,in, l 2 > l 1 Both Path 1 and Path 2 have openings at the top. One end of the main air intake pipe is connected to the top of Path 2, and the other end is connected to the bottom of the transition structure. The transition structure is a tapered, gradually expanding structure from the bottom to the top. Several through holes are opened at the top of the transition structure facing the seed crystal direction.

5. The device for adjusting the balance of HTCCVD crystal growth in silicon carbide according to claim 4, characterized in that: The height of the top opening of Path 2 is higher than that of the top opening of Path 1. The top opening of Path 2 is a tapered tapered structure. The top openings of Path 1, Path 2, the main intake pipe, and the transition structure are interconnected.

6. The device for adjusting the balance of HTCCVD crystal growth in silicon carbide according to claim 4, characterized in that: It also includes a heat preservation structure, which includes a heat preservation crucible and an induction heating coil. The heat preservation crucible is located above the bottom of the crystal growth furnace body and is arranged around the outside of the gas inlet structure and the seed crystal. The induction heating coil is arranged around the outside of the outer wall of the crystal growth furnace body and is used to heat the heat preservation crucible inside the crystal growth furnace body to maintain the growth temperature of silicon carbide crystal.

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