A semi-insulating SiC single crystal growth apparatus and growth method

Abstract

The application belongs to the technical field of SiC single crystal growth, and discloses a semi-insulating SiC single crystal growth device and a growth method, which comprise a heat preservation shell and a growth crucible, the growth crucible is placed in the heat preservation shell, and a first gap is left between the sidewall of the growth crucible and the heat preservation shell; a plurality of first air channels are uniformly arranged in the region close to the crucible cover on the upper part of the crucible body; a flow guide member is arranged in the interior of the crucible body, a plurality of second air channels are arranged on the flow guide member, and the second air channels are partially or wholly coincident with the first air channels; a second gap is left between the flow guide member and the seed crystal; a graphite gas pipe is arranged through the top of the heat preservation shell, the gas outlet end of the graphite gas pipe faces the crucible cover of the growth crucible, and a third gap is left between the gas outlet end and the crucible cover. The problems of high impurity content and unqualified resistivity of semi-insulating silicon carbide single crystal are solved.

Description

Technical Field

[0001] This invention belongs to the field of SiC single crystal growth technology, and in particular relates to a semi-insulating SiC single crystal growth apparatus and growth method. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Silicon carbide single crystal is one of the most important third-generation semiconductor materials. Due to its excellent properties such as large bandgap, high saturated electron mobility, strong breakdown field, and high thermal conductivity, it is widely used in power electronics, radio frequency devices, optoelectronic devices and other fields.

[0004] The main impurities in semi-insulating silicon carbide single crystals are nitrogen, along with boron, aluminum, and other impurities. Some nitrogen impurities originate from nitrogen adsorbed in the insulation material. This adsorbed nitrogen cannot be completely removed before growth, and it desorbs again when the growth temperature is reached, becoming the primary source of nitrogen pollution. Another source is nitrogen, boron, and aluminum impurities in the silicon carbide powder, which are released during high-temperature sublimation and enter the crystal during growth, affecting the purity and resistivity of the silicon carbide single crystal. Using semi-insulating silicon carbide containing these impurities to fabricate microwave power devices will negatively impact the device's performance. Therefore, preparing high-purity semi-insulating silicon carbide materials is crucial for ensuring device quality.

[0005] Currently, impurities such as nitrogen, boron, and aluminum in silicon carbide powder are difficult to remove, making it challenging to prepare high-purity silicon carbide. Furthermore, while improving the purity of silicon carbide powder, it is difficult to specifically control its particle size, crystal form, and other parameters. When using this type of silicon carbide powder to prepare silicon carbide single crystals, it easily leads to uneven and unstable crystallization quality and purity along the silicon carbide crystal axis, resulting in poor uniformity and consistency of the prepared silicon carbide substrate. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a semi-insulating SiC single crystal growth apparatus and method to solve problems such as high impurity content and unqualified resistivity in semi-insulating silicon carbide single crystals.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] In a first aspect, the present invention provides a semi-insulating SiC single crystal growth apparatus, comprising an insulating shell and a growth crucible, wherein the growth crucible is placed inside the insulating shell and a first gap is left between the side wall of the growth crucible and the insulating shell.

[0009] Several first gas channels are evenly distributed in the upper part of the crucible body near the crucible lid;

[0010] The flow guiding component is located inside the crucible body, and several second gas channels are opened on it. The second gas channels partially or completely overlap with the first gas channels; a second gap is left between the flow guiding component and the seed crystal.

[0011] A graphite gas pipe is installed through the top of the insulation shell, with the gas outlet of the graphite gas pipe facing the crucible lid of the growth crucible, and a third gap is left between the graphite gas pipe and the crucible lid.

[0012] Secondly, the present invention provides a method for growing semi-insulating SiC single crystals, comprising the following steps:

[0013] Silicon carbide powder is placed in a growth crucible, and the seed crystal is fixed on the top of the growth crucible.

[0014] After sealing the single crystal growth furnace, a vacuum is drawn.

[0015] After vacuuming, heating is performed, and carrier gas is introduced into the mixture to a preset growth pressure to grow the crystal.

[0016] When the crystal growth reaches the later stage, the carrier gas flow rate is increased, or an inert gas with a higher thermal conductivity than the carrier gas is added to the carrier gas. The carrier gas then acts directly on the crucible lid to cool it down.

[0017] After the crystal growth is complete, the carrier gas flow rate is increased again, or an inert gas with a thermal conductivity greater than that of the carrier gas is added to the carrier gas, and the growth crucible is cooled down rapidly to obtain the crystal.

[0018] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows:

[0019] In this invention, by setting a gas gap between the insulation material and the side wall of the growth crucible, the carrier gas enters the gas gap through the graphite gas tube. During the entire growth process, the carrier gas continuously flushes the insulation material, which can promptly remove impurities desorbed in the insulation material at high temperature and prevent them from flowing into the growth chamber, thereby improving the purity of the single crystal.

[0020] Meanwhile, the gas channels of the crucible sidewall and the flow guide component serve as impurity discharge channels. By adjusting the overlap rate of the gas channels between the crucible sidewall and the flow guide component, the volatile impurities in the graphite components and SiC powder in the crucible during the growth process are cleverly discharged through the gas channels. This reduces the stringent requirements for the purity of SiC powder and graphite components for the growth of high-purity semi-insulating crystals, and to a certain extent reduces the growth cost.

[0021] In this invention, the carrier gas is introduced from the top of the growth furnace, allowing impurities volatilized from the insulation material and crucible to be discharged from the bottom of the growth chamber via forced convection. This effectively prevents impurities in the crucible and insulation from being transported to the upper part of the furnace under the influence of the temperature gradient, effectively solving the problem of impurity deposition on the temperature measuring window and avoiding the phenomenon of impurities contaminating the temperature measuring window and affecting temperature measurement. This ensures accurate temperature measurement throughout the crystal growth process and facilitates the adjustment of process parameters during growth.

[0022] In this invention, a gas channel is provided in the flow guide, which allows some gas components in the growth chamber to overflow the growth crucible through the flow guide. By creating a tiny gap between the crystal edge and the flow guide, close contact between the surface-grown crystal and the flow guide is effectively avoided. This solves the problem of compression on the crystal during heating and cooling due to the difference in thermal expansion coefficients between the crystal and the flow guide, reducing stress in the grown crystal and improving crystal quality.

[0023] In this invention, the carrier gas acts directly on the top cover of the crucible. During crystal growth, by continuously adjusting the carrier gas flow rate or increasing the proportion of carrier gas with high thermal conductivity, the temperature at the top of the growth crucible can be effectively reduced by increasing the carrier gas flow rate in the later stage of growth, thereby reducing the temperature at the growth front. This solves the problem of the growth front temperature continuously increasing during the growth process. It can maintain the growth front temperature unchanged without changing the powder temperature, thereby maintaining the growth rate unchanged during the growth process. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0025] Figure 1 This is a schematic diagram of the silicon carbide single crystal growth apparatus of the present invention.

[0026] Figure 2 This is a schematic diagram of the silicon carbide single crystal growth apparatus of Comparative Example 1 of the present invention.

[0027] Among them, 1-induction heating coil, 2-insulation shell, 3-growth crucible, 4-graphite gas pipe, 5-first void, 6-seed crystal, 7-SiC powder, 8-flow guiding component, 9-second gas channel, 10-first gas channel, 11-second void, 12-third void. Detailed Implementation

[0028] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0029] In a first aspect, the present invention provides a semi-insulating SiC single crystal growth apparatus, comprising an insulating shell and a growth crucible, wherein the growth crucible is placed inside the insulating shell and a first gap is left between the side wall of the growth crucible and the insulating shell.

[0030] Several first gas channels are evenly distributed in the upper part of the crucible body near the crucible lid;

[0031] The flow guiding component is located inside the crucible body, and several second gas channels are opened on it. The second gas channels partially or completely overlap with the first gas channels; a second gap is left between the flow guiding component and the seed crystal.

[0032] A graphite gas pipe is installed through the top of the insulation shell, with the gas outlet of the graphite gas pipe facing the crucible lid of the growth crucible, and a third gap is left between the graphite gas pipe and the crucible lid.

[0033] Because the insulation shell has a porous structure, there is no need to set up a gas outlet.

[0034] In some embodiments, the height of the gas channels on the growth crucible is 1 / 4 to 1 / 2 of the height of the growth crucible, preferably 1 / 4 to 1 / 3.

[0035] Preferably, the diameter of the first airway is 1-20 mm, and the center-to-center distance between two adjacent airways is 5-100 mm.

[0036] More preferably, the diameter of the first airway is 2-10 mm, and the center-to-center distance between two adjacent airways is 20-50 mm.

[0037] Preferably, the arrangement of the second airway is the same as that of the first airway.

[0038] In some embodiments, the flow guiding member is a cylindrical structure with uniformly distributed radial air channels. The flow guiding member is fixed around the seed crystal and guides the airflow of sublimated components towards the seed crystal for single crystal growth. The flow guiding member is mechanically fixed to the inner wall of the crucible body by a support.

[0039] Preferably, the overlap rate of the gas passage between the flow guiding component and the side wall of the crucible is 20%-100%, more preferably 50%-80%. When the overlap rate is too low, the volatile impurities cannot be completely discharged.

[0040] Preferably, the flow guiding component is made of hydrostatic graphite, and the surface of the flow guiding component is coated with a carbide layer.

[0041] The carbide layer is used to protect the graphite components from corrosion by the silicon-rich components of the powder sublimation.

[0042] More preferably, the carbide layer is tantalum carbide or tungsten carbide.

[0043] In some embodiments, the inner diameter of the graphite gas tube is 10-100 mm.

[0044] Preferably, the inner diameter of the graphite gas tube is 20-50 mm.

[0045] In some embodiments, the width of the third gap is 10-200 mm, preferably 50-150 mm.

[0046] In some embodiments, the width of the first gap is 10-300 mm, preferably 30-150 mm.

[0047] In some embodiments, the semi-insulating SiC single crystal growth apparatus further includes an induction heating coil, which is arranged around an insulation shell. The induction heating coil is used to heat the silicon carbide crystal growth process to ensure the growth of the silicon carbide crystal.

[0048] In some embodiments, the insulating shell is made of graphite insulating felt.

[0049] Secondly, the present invention provides a method for growing semi-insulating SiC single crystals, comprising the following steps:

[0050] Silicon carbide powder is placed in a growth crucible, and the seed crystal is fixed on the top of the growth crucible.

[0051] After sealing the single crystal growth furnace, a vacuum is drawn.

[0052] After vacuuming, heating is performed, and carrier gas is introduced into the mixture to a preset growth pressure to grow the crystal.

[0053] When the crystal growth reaches the later stage, the carrier gas flow rate is increased, or an inert gas with a higher thermal conductivity than the carrier gas is added to the carrier gas. The carrier gas then acts directly on the crucible lid to cool it down.

[0054] After the crystal growth is complete, the carrier gas flow rate is increased again, or an inert gas with a thermal conductivity greater than that of the carrier gas is added to the carrier gas, and the growth crucible is cooled down rapidly to obtain the crystal.

[0055] The later stage of crystal growth refers to the last third of the entire growth cycle of silicon carbide crystals.

[0056] The early to middle stage of growth refers to the first two-thirds of the entire growth cycle.

[0057] In some embodiments, the preset growth pressure is 10-100 mbar, preferably 10-50 mbar.

[0058] In some embodiments, during the early and middle stages of silicon carbide crystal growth, the carrier gas flow rate is 100-1000 sccm, preferably 200-500 sccm.

[0059] Preferably, when the crystal growth reaches the later stage, the carrier gas flow rate increases to 2-10 times that of the early and middle stage, more preferably 4-6 times. As the growth time increases, the thickness of the grown crystal increases, the distance between the growth interface and the high-temperature zone shortens, the axial temperature gradient decreases, and the growth rate decreases.

[0060] Preferably, when the crystal grows to the later stage, the volume fraction of the inert gas doped into the carrier gas with a thermal conductivity greater than that of the carrier gas is 1-60%, preferably 10-40%.

[0061] When silicon carbide crystals grow to the later stage, the cooling effect on the crucible lid can be increased by increasing the carrier gas flow rate or by adding an inert gas with high thermal conductivity to the carrier gas, thereby increasing the axial temperature gradient of the growth crucible and thus increasing the growth rate of silicon carbide crystals.

[0062] In some embodiments, after crystal growth is completed, the carrier gas flow rate is increased to 10-50 times the carrier gas flow rate in the early and middle stages of growth, preferably 15-20 times.

[0063] Preferably, after crystal growth is completed, an inert gas with a thermal conductivity greater than that of the carrier gas is incorporated into the carrier gas, such that the volume percentage of the inert gas is 50-100%, preferably 70-80%.

[0064] In some embodiments, the inert gas with a thermal conductivity greater than that of the carrier gas is hydrogen or helium.

[0065] The present invention will be further described below with reference to the embodiments.

[0066] Example 1

[0067] A semi-insulating SiC single crystal growth apparatus, participating in Figure 1 It includes an induction heating coil 1, a heat preservation shell 2, a growth crucible 3, and a graphite gas pipe 4;

[0068] The growth crucible 3 includes: a SiC seed crystal 6 adhered to the inner side of the crucible lid; SiC powder 7 placed at the bottom of the growth crucible 3, opposite to the SiC seed crystal 6; a flow guiding component 8 provided at the top of the growth crucible 3, which is covered with uniformly distributed second air channels 9, corresponding to the positions of the first air channels 10 on the side wall of the growth crucible; the diameter of the first air channel 10 is 2 mm, and the center-to-center distance between two adjacent first air channels 10 is 5 mm; the area on the crucible where the first air channels 10 are distributed occupies 1 / 4 of the crucible height.

[0069] The diameter of the second air passage 9 of the flow guide component 8 is 2 mm, and the center-to-center distance between two adjacent second air passages 9 is 5 mm.

[0070] The flow guiding component 8 is made of isostatic graphite and its surface is coated with carbides such as tantalum carbide and tungsten carbide. There is a second gap 11 between the flow guiding component and the seed crystal.

[0071] There is a first gap 5 between the growth crucible 3 and the insulation shell 2. The width of the first gap 5 is 10mm. The graphite gas pipe 4 is placed in the middle of the upper insulation shell 2 and extends towards the growth crucible 3. The graphite gas pipe 4 is provided with a third gap 12 from the top of the growth crucible 3. The width of the third gap 12 is 10mm.

[0072] A gas outlet is provided at the bottom of the insulation shell 2.

[0073] Example 2

[0074] A method for growing high-purity semi-insulating silicon carbide crystals, using the same growth apparatus as in Example 1, includes the following steps:

[0075] (1) Assemble the crucible: Place silicon carbide powder at the bottom of the growth crucible and silicon carbide single crystal at the top of the growth crucible. The diameter of the gas channel above the side wall of the crucible is 2 mm, the center-to-center distance of the gas channel is 5 mm, the height of the gas channel distribution is 1 / 4 of the crucible height, the diameter of the gas channel of the flow guide is 2 mm, the center-to-center distance of the gas channel is 8 mm, the height of the flow guide is the same as the height of the cylinder of the gas channel distribution, the overlap rate of the gas channel of the crucible side wall and the flow guide is 50%, and the gap between the gas hole flow guide and the seed crystal is 2 mm.

[0076] (2) Vacuuming: Place the growth crucible in the insulation material, with a gap of 10 mm between the insulation shell and the side wall of the growth crucible; place the graphite gas pipe in the center of the upper insulation material, with a diameter of 10 mm and a distance of 10 mm from the top of the growth crucible, and place it in the single crystal growth furnace. Use a mechanical pump to evacuate to 0.01 Pa and maintain for 30 min.

[0077] (3) Heating growth: Argon gas is introduced into the furnace to a pressure of 10 mbar, and the graphite crucible is heated to 2100 ℃ at a rate of 300℃ / h. The temperature is held for 90 h, 60 h in the early and middle stages of growth, and the flow rate is 100 sccm. In the later stage of growth, the flow rate is adjusted to 1000 sccm for 30 h.

[0078] (4) Increase pressure and turn off intermediate frequency: Increase pressure, turn off intermediate frequency, increase carrier gas flow rate to 5000 sccm again, cool down rapidly to room temperature, and remove silicon carbide crystal.

[0079] (5) Furnace opening: Remove the graphite crucible from the growth furnace to obtain silicon carbide single crystals.

[0080] (6) Testing and characterization: The grown crystal was cut, ground, and polished to obtain polished wafers. The entire wafer was tested using a non-contact resistance meter, and all results showed values ​​greater than 1E+12 Ω·cm; the SIMS test results for nitrogen were less than 1E+15 cm. -3This indicates that high-purity semi-insulating silicon carbide crystals were successfully prepared.

[0081] Example 3

[0082] Unlike Example 2, this method provides a method for growing high-purity semi-insulating silicon carbide crystals, specifically including the following steps:

[0083] (1) Assemble the crucible: Place silicon carbide powder at the bottom of the growth crucible and silicon carbide single crystal at the top of the growth crucible. The diameter of the gas channel above the side wall of the crucible is 5 mm, the gas channel spacing is 10 mm, the height of the gas channel is 1 / 3 of the height of the cylinder, the diameter of the gas channel of the flow guide is 5 mm, the gas channel spacing is 8 mm, the height of the flow guide is the same as the height of the cylinder of the gas channel, the gas channel repetition rate of the side wall of the crucible and the flow guide is 80%, and the gap between the gas hole flow guide and the seed crystal is 5 mm.

[0084] (2) Vacuuming: Place the growth crucible in the insulation material, with a gap of 100 mm between the insulation material and the side wall of the growth crucible; place the graphite gas pipe in the center of the upper insulation material, with a diameter of 50 mm and a distance of 150 mm from the top cover of the growth crucible, and place it in the single crystal growth furnace. Use a mechanical pump to evacuate to 0.01 Pa and maintain for 30 min.

[0085] (3) Heating growth: Argon gas is introduced into the furnace to a pressure of 10 mbar, and the graphite crucible is heated to 2100 ℃ at a rate of 300℃ / h and held for 90 h. The flow rate is 500 sccm for the first 60 h of growth and 1500 sccm for the second 30 h of growth.

[0086] (4) Increase pressure and turn off intermediate frequency: Increase pressure, turn off intermediate frequency, increase carrier gas flow rate to 6000 sccm again, cool down rapidly to room temperature, and remove silicon carbide crystal.

[0087] (5) Furnace opening: Remove the graphite crucible from the growth furnace to obtain silicon carbide single crystals.

[0088] (6) Testing and characterization: The grown crystal was cut, ground, and polished to obtain polished wafers. The entire wafer was tested using a non-contact resistance meter, and all results showed values ​​greater than 1E+12 Ω·cm; the SIMS test results for nitrogen were less than 1E+15 cm. -3 This indicates that high-purity semi-insulating silicon carbide crystals were successfully prepared.

[0089] Example 4

[0090] Unlike Example 2, this invention provides an apparatus and method for growing high-purity semi-insulating silicon carbide crystals, which specifically includes the following steps:

[0091] (1) Assemble the crucible: Place silicon carbide powder at the bottom of the growth crucible and silicon carbide single crystal at the top of the growth crucible. The diameter of the gas channel above the side wall of the crucible is 10 mm, the gas channel spacing is 20 mm, the height of the gas channel is 1 / 2 of the height of the cylinder, the diameter of the gas channel of the flow guide is 10 mm, the gas channel spacing is 20 mm, the height of the flow guide is the same as the height of the cylinder of the gas channel, the gas channel repetition rate of the side wall of the crucible and the flow guide is 100%, and the gap between the gas hole flow guide and the seed crystal is 15 mm.

[0092] (2) Vacuuming: Place the growth crucible in the insulation material, with a gap of 300 mm between the insulation material and the side wall of the growth crucible; place the graphite gas pipe in the center of the upper insulation material, with a diameter of 100 mm and a distance of 200 mm from the top cover of the growth crucible. Place it in the single crystal growth furnace and use a mechanical pump to evacuate to 0.01 Pa and maintain it for 30 min.

[0093] (3) Heating growth: Argon gas is introduced into the furnace to a pressure of 10 mbar, and the graphite crucible is heated to 2100℃ at a rate of 300℃ / h and held for 100 h. During the early stage of growth, the flow rate is 1000 sccm for 70 h and 4000 sccm for 30 h.

[0094] (4) Increase pressure and turn off intermediate frequency: Increase pressure, turn off intermediate frequency, increase carrier gas flow rate to 10000 sccm again, cool down rapidly to room temperature, and remove silicon carbide crystal.

[0095] (5) Furnace opening: Remove the graphite crucible from the growth furnace to obtain silicon carbide single crystals.

[0096] (6) Testing and characterization: The grown crystal was cut, ground, and polished to obtain polished wafers. The entire wafer was tested using a non-contact resistance meter, and all results showed values ​​greater than 1E+12 Ω·cm; the SIMS test results for nitrogen were less than 1E+15 cm. -3 This indicates that high-purity semi-insulating silicon carbide crystals were successfully prepared.

[0097] Comparative Example 1

[0098] The growth apparatus in this comparative example follows the structure of a traditional PVT, such as... Figure 2 As shown, the growth method is exactly the same as in Example 1. After growth, the growth crucible in the growth furnace is removed to obtain silicon carbide crystals. The crystals are then cut, ground, and polished to obtain polished wafers. A non-contact resistance meter is used to test the entire wafer. The resistance of the entire wafer is unqualified, with the highest resistance being 1E+5 Ω·cm. The SIMS test result for nitrogen is 5E+17 cm⁻¹. -3 .

[0099] Comparative Example 2

[0100] In this comparative example, the growth apparatus lacked a graphite gas pipe; the rest of the apparatus and growth method were identical to those in Example 1. After growth, the growth crucible was removed from the growth furnace to obtain silicon carbide crystals. The crystals were then cut, ground, and polished to obtain polished wafers. A non-contact resistance meter was used to test the entire wafer. The highest resistance of the entire wafer was 1E+7 Ω·cm, and the SIMS test result for nitrogen was 9E+16 cm⁻¹. -3 .

[0101] Comparative Example 3

[0102] In this comparative example, the growth apparatus lacks gas channels on the upper part of the crucible sidewall and the flow guide; the rest of the apparatus and growth method are completely identical to those in Example 1. After growth, the growth crucible is removed from the growth furnace to obtain silicon carbide crystals. The crystals are then cut, ground, and polished to obtain polished wafers. A non-contact resistance meter is used to test the entire wafer. The highest resistance of the entire wafer is 1E+6 Ω·cm, and the SIMS test result for nitrogen is 2E+17 cm⁻¹. -3 .

[0103] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A semi-insulating SiC single crystal growth apparatus, characterized in that: It includes an insulation shell and a growth crucible, wherein the growth crucible is placed inside the insulation shell and a first gap is left between the side wall of the growth crucible and the insulation shell; Several first gas channels are evenly distributed in the upper part of the crucible body near the crucible lid; The flow guiding component is disposed inside the crucible body, and several second air channels are formed on it. The second air channels partially or completely overlap with the first air channels. A second gap is left between the flow guiding component and the seed crystal. The overlap rate of the air channels between the flow guiding component and the side wall of the crucible is 20%-100%. The graphite gas pipe is installed through the top of the insulation shell, with the gas outlet of the graphite gas pipe facing the crucible lid of the growth crucible, and a third gap is left between the graphite gas pipe and the crucible lid. The carrier gas is introduced from the top of the growth furnace through a graphite gas pipe and discharged from the bottom of the growth chamber.

2. The semi-insulating SiC single crystal growth apparatus according to claim 1, characterized in that: The height of the gas channels on the growth crucible is 1 / 4 to 1 / 2 of the height of the growth crucible.

3. The semi-insulating SiC single crystal growth apparatus according to claim 2, characterized in that: The height of the gas channels on the growth crucible is 1 / 4 to 1 / 3 of the height of the growth crucible.

4. The semi-insulating SiC single crystal growth apparatus according to claim 1, characterized in that: The diameter of the first airway is 1-20 mm, and the center-to-center distance between two adjacent airways is 5-100 mm.

5. The semi-insulating SiC single crystal growth apparatus according to claim 4, characterized in that: The diameter of the first airway is 2-10 mm, and the center-to-center distance between two adjacent airways is 20-50 mm.

6. The semi-insulating SiC single crystal growth apparatus according to claim 1, characterized in that: The flow guiding component is a cylindrical structure with evenly distributed radial air passages, and the arrangement of the second air passage is the same as that of the first air passage.

7. The semi-insulating SiC single crystal growth apparatus according to claim 1, characterized in that: The overlap rate of the gas passage between the flow guiding component and the side wall of the crucible is 50%-80%.

8. The semi-insulating SiC single crystal growth apparatus according to claim 1, characterized in that: The flow guiding component is made of hydrostatic graphite, and its surface is coated with a carbide layer.

9. The semi-insulating SiC single crystal growth apparatus according to claim 8, characterized in that: The carbide layer is tantalum carbide or tungsten carbide.

10. The semi-insulating SiC single crystal growth apparatus according to claim 1, characterized in that: The inner diameter of the graphite gas tube is 10-100mm.

11. The semi-insulating SiC single crystal growth apparatus according to claim 1, characterized in that: The inner diameter of the graphite gas tube is 20-50 mm.

12. The semi-insulating SiC single crystal growth apparatus according to claim 1, characterized in that: The width of the third gap is 10-200mm.

13. The semi-insulating SiC single crystal growth apparatus according to claim 12, characterized in that: The width of the third gap is 50-150mm.

14. The semi-insulating SiC single crystal growth apparatus according to claim 1, characterized in that: The width of the first gap is 10-300mm.

15. The semi-insulating SiC single crystal growth apparatus according to claim 14, characterized in that: The width of the first gap is 30-150mm.

16. The semi-insulating SiC single crystal growth apparatus according to claim 1, characterized in that: The semi-insulating SiC single crystal growth apparatus also includes an induction heating coil, which is arranged around the insulation shell.

17. A method for growing semi-insulating SiC single crystals, characterized in that: The growth is performed using any of the semi-insulating SiC single crystal growth apparatuses described in claims 1-16, specifically including the following steps: Silicon carbide powder is placed in a growth crucible, and the seed crystal is fixed on the top of the growth crucible. After sealing the single crystal growth furnace, a vacuum is drawn. After vacuuming, heating is performed, and carrier gas is introduced into the mixture to a preset growth pressure to grow the crystal. When the crystal grows to the later stage, the carrier gas flow rate is increased, or an inert gas with a thermal conductivity greater than that of the carrier gas is added to the carrier gas. The carrier gas then acts directly on the crucible lid to cool it down. After the crystal growth is complete, increase the carrier gas flow rate again, or add an inert gas with a thermal conductivity greater than that of the carrier gas to the carrier gas, and rapidly cool the growth crucible to obtain the crystal. The carrier gas is argon.

18. The method for growing semi-insulating SiC single crystals according to claim 17, characterized in that: The preset growth pressure is 10-100 mbar.

19. The method for growing semi-insulating SiC single crystals according to claim 18, characterized in that: The preset growth pressure is 10-50 mbar.

20. The method for growing semi-insulating SiC single crystals according to claim 17, characterized in that: During the early and middle stages of silicon carbide crystal growth, the carrier gas flow rate is 100-1000 sccm.

21. The method for growing semi-insulating SiC single crystals according to claim 20, characterized in that: It is 200-500 sccm.

22. The method for growing semi-insulating SiC single crystals according to claim 17, characterized in that: As crystal growth progresses to the later stages, the carrier gas flow rate increases to 2-10 times that of the early and middle stages.

23. The method for growing semi-insulating SiC single crystals according to claim 22, characterized in that: As crystal growth progresses to the later stages, the carrier gas flow rate increases to 4-6 times that of the early and middle stages.

24. The method for growing semi-insulating SiC single crystals according to claim 17, characterized in that: When the crystal grows to the later stage, the volume fraction of the inert gas doped into the carrier gas with a thermal conductivity greater than that of the carrier gas is 1-60%.

25. The method for growing semi-insulating SiC single crystals according to claim 24, characterized in that: When the crystal grows to the later stage, the volume fraction of the inert gas doped into the carrier gas with a thermal conductivity greater than that of the carrier gas is 10-40%.

26. The method for growing semi-insulating SiC single crystals according to claim 17, characterized in that: After the crystal growth is complete, increase the carrier gas flow rate to 10-50 times that of the initial and middle stages of growth.

27. The method for growing semi-insulating SiC single crystals according to claim 26, characterized in that: After the crystal growth is complete, increase the carrier gas flow rate to 15-20 times that of the initial and middle stages of growth.

28. The method for growing semi-insulating SiC single crystals according to claim 17, characterized in that: After the crystal growth is complete, an inert gas with a higher thermal conductivity than the carrier gas is added to the carrier gas, so that the volume ratio of the inert gas is 50-100%.

29. The method for growing semi-insulating SiC single crystals according to claim 28, characterized in that: After the crystal growth is complete, an inert gas with a higher thermal conductivity than the carrier gas is added to the carrier gas, so that the volume ratio of the inert gas is 70-80%.

30. The method for growing semi-insulating SiC single crystals according to claim 17, characterized in that: The inert gas with a thermal conductivity greater than that of the carrier gas is hydrogen or helium.

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