Silicon carbide crystal growth device and method

Abstract

The invention provides a silicon carbide crystal growth device and method, and relates to the technical field of crystal growth, the device comprises a crucible, a seed rod and a heat preservation assembly, the heat preservation assembly comprises a first heat preservation structure, a second heat preservation structure and a third heat preservation structure, the first heat preservation structure is arranged at the top of the crucible, and the second heat preservation structure sleeves the peripheral surface of the crucible; the third heat preservation structure is arranged at the bottom of the crucible, a first through hole allowing a seed rod to penetrate through is formed in the middle of the first heat preservation structure, and the hole diameter of the first through hole in the axial direction can change according to different radial temperature gradients needed by crystal growth; and the outer diameter of the second thermal insulation structure along the axial direction can be changed according to different axial temperature gradients required by crystal growth. Therefore, accurate control of temperature distribution can be realized in different stages of crystal growth, the crystal growth rate is accelerated, and the crystal growth quality is improved.

Description

Technical Field

[0001] This invention relates to the field of crystal growth technology, and in particular to a silicon carbide crystal growth apparatus and method. Background Technology

[0002] Silicon carbide (SiC), as a highly anticipated third-generation semiconductor material, possesses characteristics such as a wide bandgap, high critical electric field strength, high saturation mobility, and high thermal conductivity, making it one of the fastest-growing semiconductor devices currently available.

[0003] Compared to the currently prevalent sublimation method, liquid-phase silicon carbide (SiC) crystal growth is lower in cost and can produce high-quality SiC single crystals with zero microtubes, making it a very promising SiC single crystal growth technology. During liquid-phase SiC crystal growth, a high temperature needs to be maintained within the crucible to meet the melting conditions of the flux material and promote the dissolution of the crucible sidewalls to provide a carbon source. Subsequently, carbon is transported to the seed crystal end through various convection currents within the flux. The top seed crystal is kept at a lower temperature, increasing the carbon supersaturation within the flux, thus facilitating crystal growth. In this process, the temperature gradient is closely related to the crystal growth rate and crystal quality. When the temperature gradient is too large, the crystal growth rate is too fast, and the supply and transport of carbon source are insufficient to meet consumption, leading to defects such as flux encapsulation and trenches within the grown crystal. Furthermore, a large temperature gradient results in excessive carbon supersaturation, causing severe spontaneous nucleation of SiC in the solution, which is detrimental to crystal growth quality. Conversely, when the temperature gradient is too small, the carbon supersaturation decreases, the crystal growth driving force weakens, the growth rate slows down, and the time cost increases. Therefore, a suitable temperature gradient is crucial in the growth of silicon carbide single crystals. Summary of the Invention

[0004] The purpose of this application is to provide a silicon carbide crystal growth apparatus and method to solve the technical problem that existing silicon carbide crystal growth apparatuses cannot adjust the thermal field structure based on the temperature gradient requirements at different stages during silicon carbide crystal growth.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: In a first aspect, this application provides a silicon carbide crystal growth apparatus, including a crucible, a seed crystal rod, and a heat-insulating component. The crucible contains a fluxing agent. A seed crystal holder is provided at the bottom of the seed crystal rod, and a seed crystal is provided on the side of the seed crystal holder facing the fluxing agent. The heat-insulating component includes a first heat-insulating structure, a second heat-insulating structure, and a third heat-insulating structure. The first heat-insulating structure is located at the top of the crucible, the second heat-insulating structure is fitted onto the outer circumferential surface of the crucible, and the third heat-insulating structure is located at the bottom of the crucible. A first through-hole is provided in the middle of the first heat-insulating structure, allowing the seed crystal rod to pass through. The diameter of the first through-hole along its axial direction can vary according to different radial temperature gradients required for crystal growth. The outer diameter of the second heat-insulating structure along its axial direction can vary according to different axial temperature gradients required for crystal growth.

[0006] In one or more embodiments of this application, the first insulation structure includes a first fixed insulation component and at least one first adjustable insulation component. All the first adjustable insulation components are sequentially sleeved on the inner side of the first fixed insulation component along the radial direction of the crucible, and the outer peripheral surface of the outermost first adjustable insulation component is in contact with the inner peripheral surface of the first fixed insulation component. A first through hole is provided through the innermost first adjustable insulation component. Each first adjustable insulation component includes a plurality of first sub-insulation layers stacked sequentially along the axial direction of the crucible. The diameter of the first through hole along its axial direction varies based on the different thicknesses of the first adjustable insulation components.

[0007] In one or more embodiments of this application, the first fixed insulation component and the adjacent first adjustable insulation component are fixedly connected by a first fixing component; and / or, Two adjacent first adjusting insulation components are fixedly connected by a first fixing component; and / or, The multiple first sub-insulation layers of each first adjusting insulation component are connected by a second fastener.

[0008] In one or more embodiments of this application, the second insulation structure includes a second fixed insulation element and at least two second adjustable insulation elements. The second fixed insulation element is sleeved on the outer peripheral surface of the crucible. All the second adjustable insulation elements are stacked sequentially along the axial direction of the crucible and sleeved on the outer peripheral surface of the second fixed insulation element. The inner peripheral surface of all the second adjustable insulation elements is in contact with the outer peripheral surface of the second fixed insulation element. Each second adjustable insulation element includes a plurality of second sub-insulation layers sequentially sleeved along the radial direction of the crucible. The outer diameter of the second insulation structure along its axial direction varies based on the different thicknesses of the second adjustable insulation elements.

[0009] In one or more embodiments of this application, two adjacent second adjusting insulation members are fixedly connected by a third fixing member.

[0010] In one or more embodiments of this application, the height of the second fixing insulation member is consistent with the height of the crucible along its axial direction; and / or, Along the radial direction of the crucible, the outer diameter of the first insulation structure coincides with the maximum outer diameter of the second insulation structure; and / or, The outer diameter of the third insulation structure is the same as that of the first insulation structure.

[0011] In one or more embodiments of this application, the method further includes: a growth furnace and a clamping assembly. The growth furnace includes a reaction chamber and a storage chamber that are connected to each other. A crucible is housed in the reaction chamber. Along the axial direction of the crucible, the storage chamber is located above the reaction chamber and is used to store a first sub-insulation layer and a second sub-insulation layer. The clamping assembly is disposed above the crucible and is used to clamp the first sub-insulation layer to the top of the crucible or to move the first sub-insulation layer above the crucible to the storage chamber. The clamping assembly is also used to clamp the second sub-insulation layer to the outside of the crucible or to move the second sub-insulation layer outside the crucible to the storage chamber. A driving mechanism is drivenly connected to the clamping assembly.

[0012] In one or more embodiments of this application, the clamping assembly includes a first lifting rod and a clamping member. The top end of the first lifting rod is slidably disposed on the top of the growth furnace, and the clamping member is hinged to the end of the first lifting rod. A groove is provided on the top of the growth furnace, the groove extending radially along the crucible, and the top end of the first lifting rod is slidably disposed in the groove.

[0013] Secondly, this application also provides a method for growing silicon carbide crystals, comprising the following steps: In the initial state, the first insulation structure is placed on the top of the crucible, the second insulation structure is placed on the outer circumference of the crucible, and the third insulation structure is placed on the bottom of the crucible. The first through hole of the first insulation structure is kept at the minimum diameter along its axial direction, and the outer diameter of the second insulation structure is kept at the maximum diameter along its axial direction. After the growth furnace is closed and a vacuum is applied, the crucible is heated to completely melt the flux inside the crucible. In the first stage of crystal growth, the control drive mechanism drives the clamping assembly to adjust the first sub-insulation layer in the first adjustment insulation component, so that the diameter of the first through hole along its axial direction gradually decreases or increases from bottom to top; the control drive mechanism drives the clamping assembly to adjust the second sub-insulation layer in the second adjustment insulation component, so that the outer diameter of the second insulation structure along its axial direction gradually decreases or increases from bottom to top. In the second stage of crystal growth, the control drive mechanism drives the clamping assembly to adjust the first sub-insulation layer in the first adjustment insulation component, so that the diameter of the first through hole along its axial direction is configured to be the minimum diameter.

[0014] In one or more embodiments of this application, the first stage is a growth stage and the second stage is a cooling stage.

[0015] Based on the above technical solution, the silicon carbide crystal growth apparatus and method of this application have at least the following beneficial technical effects: In the silicon carbide crystal growth apparatus of this application embodiment, the heat preservation component includes a first heat preservation structure, a second heat preservation structure, and a third heat preservation structure. The first heat preservation structure is disposed at the top of the crucible, the second heat preservation structure is sleeved on the outer peripheral surface of the crucible, and the third heat preservation structure is disposed at the bottom of the crucible. Thus, the first, second, and third heat preservation structures form a heat preservation cavity surrounding the crucible. The first heat preservation structure has a first through-hole in its middle, allowing the seed crystal rod to pass through. The diameter of the first through-hole along its axial direction can be varied according to different radial temperature gradients required for crystal growth. This allows for changing the structure of the first through-hole during crystal growth, thereby flexibly adjusting the heat dissipation mode on the back of the seed crystal holder to meet the radial temperature distribution requirements at different stages of crystal growth. The outer diameter of the second heat preservation structure along its axial direction can be varied according to different axial temperature gradients required for crystal growth. This allows for changing the structural form of the second heat preservation structure on the outer peripheral surface of the crucible, thereby changing the axial temperature gradient inside the crucible during crystal growth to meet the axial temperature distribution requirements at different stages of crystal growth. This allows for precise control of temperature distribution at different stages of crystal growth, accelerating the crystal growth rate and improving crystal growth quality. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the silicon carbide crystal growth apparatus provided in the embodiments of this application.

[0018] Figure 2 This is a three-dimensional structural diagram of the first heat preservation structure in the silicon carbide crystal growth apparatus provided in the embodiments of this application.

[0019] Figure 3 This is a cross-sectional view of one form of the first heat preservation structure in the silicon carbide crystal growth apparatus provided in the embodiments of this application.

[0020] Figure 4 This is a cross-sectional view of another form of the first heat preservation structure in the silicon carbide crystal growth apparatus provided in the embodiments of this application.

[0021] Figure 5 This is a cross-sectional view of another form of the first heat preservation structure in the silicon carbide crystal growth apparatus provided in the embodiments of this application.

[0022] Figure 6This is a schematic diagram of the first heat preservation structure in a silicon carbide crystal growth apparatus provided in another embodiment of this application.

[0023] Figure 7 yes Figure 6 Enlarged view of point A in the image.

[0024] Figure 8 This is a three-dimensional structural diagram of the first fixing member of the first heat preservation structure in the silicon carbide crystal growth apparatus provided in the embodiments of this application.

[0025] Figure 9 This is a schematic diagram of the first heat preservation structure in a silicon carbide crystal growth apparatus provided in another embodiment of this application.

[0026] Figure 10 This is a schematic diagram of the support member in the second fixing member of the first heat preservation structure in the silicon carbide crystal growth apparatus provided in the embodiments of this application.

[0027] Figure 11 This is a three-dimensional structural diagram of the second heat preservation structure in the silicon carbide crystal growth apparatus provided in the embodiments of this application.

[0028] Figure 12 This is a cross-sectional view of one form of the second heat preservation structure in the silicon carbide crystal growth apparatus provided in the embodiments of this application.

[0029] Figure 13 This is a cross-sectional view of another form of the second heat preservation structure in the silicon carbide crystal growth apparatus provided in the embodiments of this application.

[0030] Figure 14 This is a cross-sectional view of another form of the second heat preservation structure in the silicon carbide crystal growth apparatus provided in the embodiments of this application.

[0031] Figure 15 This is a schematic diagram of the second heat preservation structure in a silicon carbide crystal growth apparatus provided in another embodiment of this application.

[0032] Figure 16 yes Figure 15 Enlarged view of point B in the image.

[0033] Figure 17 This is a three-dimensional structural diagram of the third fixing member in the second heat preservation structure of the silicon carbide crystal growth apparatus provided in the embodiments of this application.

[0034] Figure 18 This is a photograph of the silicon carbide crystal grown in Example 1 of this application.

[0035] Figure 19 This is a photograph of the silicon carbide crystals grown in Example 2 of this application.

[0036] Figure 20 This is a photograph of the silicon carbide crystal grown in Comparative Example 1 of this application.

[0037] In the diagram: 1-Growth furnace; 2-Support plate; 3-Drive mechanism; 4-Slide groove; 5-Pulley; 6-First lifting rod; 7-Clamping component; 8-Seed crystal rod; 9-First insulation structure; 10-Seed crystal holder; 11-Seed crystal; 12-Second insulation structure; 13-Crucible; 14-Third insulation structure; 15-First through hole; 20-First fixing component; 21-Second fixing component; 22-Third fixing component; 90-First sub-insulation layer; 9 1-First fixed insulation component; 92-First adjustable insulation component; 101-Reaction chamber; 102-Storage chamber; 120-Second sub-insulation layer; 121-Second fixed insulation component; 122-Second adjustable insulation component; 201-First fixing part; 202-First insertion part; 211-Second lifting rod; 212-Positioning rod; 213-Support component; 214-Fixing column; 221-Second fixing part; 222-Second insertion part. Detailed Implementation

[0038] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0039] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0040] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and 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. Therefore, they should not be construed as limitations on this application.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0042] In related technologies, the thermal field structure used in liquid-phase silicon carbide crystal growth is typically fixed. This structure is determined and installed before crystal growth and cannot be adjusted during the growth process. However, the liquid-phase silicon carbide crystal growth process involves multiple stages, such as heating, growth, and cooling, each requiring different temperature distributions. Furthermore, crystal growth is accompanied by crucible surface dissolution and consumption of growth materials, causing changes in the relative positions of the crystal growth surface and the flux surface (solid / liquid interface) within the crucible, thus altering the temperature gradient and making it difficult to maintain stable crystal growth conditions over extended periods. Therefore, using a single, fixed thermal field structure throughout the liquid-phase silicon carbide crystal growth process is insufficient to address the variability of conditions and cannot meet the requirements for rapid growth of high-quality silicon carbide crystals.

[0043] Based on the above considerations, and to address the technical problem that existing silicon carbide crystal growth apparatuses cannot adjust the thermal field structure according to the temperature gradient requirements at different stages of silicon carbide crystal growth, this application provides a silicon carbide crystal growth apparatus and method.

[0044] The technical solution of this application will now be described in detail with reference to the accompanying drawings.

[0045] Please refer to Figure 1 This application provides a silicon carbide crystal growth apparatus, including: a crucible 13, a seed crystal rod 8, and a heat preservation component. The crucible 13 contains a fluxing agent; the crucible 13 can be made of graphite. The fluxing agent can be a silicon-containing melt. A seed crystal holder 10 is provided at the bottom of the seed crystal rod 8, and both the seed crystal rod 8 and the seed crystal holder 10 can be made of graphite. A seed crystal 11 is provided on the side of the seed crystal holder 10 facing the fluxing agent, so that the seed crystal 11 can be brought into contact with or separated from the fluxing agent by the seed crystal rod 8 and the seed crystal holder 10.

[0046] Reference Figure 1 The insulation assembly includes a first insulation structure 9, a second insulation structure 12, and a third insulation structure 14. The first insulation structure 9 is located at the top of the crucible 13 to insulate the top of the crucible 13. The second insulation structure 12 is fitted onto the outer circumference of the crucible 13 to insulate the outer circumference of the crucible 13. The third insulation structure 14 is located at the bottom of the crucible 13 to insulate the bottom of the crucible 13. Thus, the first insulation structure 9, the second insulation structure 12, and the third insulation structure 14 surround the outside of the crucible to form an insulation cavity around the crucible 13, thereby insulating the crucible 13. Figure 2As shown, the first heat-insulating structure 9 has a first through hole 15 in the middle, allowing the seed crystal rod 8 to pass through. The diameter of the first through hole 15 along its axial direction can vary according to different radial temperature gradients required for crystal growth. It can be understood that the diameter of the first through hole 15 along its axial direction can be equal at the top and bottom or unequal during crystal growth, and can vary according to different radial temperature gradients required during crystal growth. This allows for changes in the structure of the first through hole 15 during crystal growth, thus enabling flexible adjustment of the heat dissipation mode on the back of the seed crystal holder 10 during crystal growth to meet the radial temperature distribution requirements at different stages of crystal growth. Figure 11 As shown, the outer diameter of the second heat-insulating structure 12 along its axial direction can vary according to the different axial temperature gradients required for crystal growth. It can be understood that the outer diameter of the second heat-insulating structure 12 along its axial direction can be equal at the top and bottom or unequal during crystal growth, varying according to the different axial temperature gradients required during crystal growth. This allows for changes in the structural form of the second heat-insulating structure 12 on the outer periphery of the crucible 13, thereby altering the axial temperature gradient within the crucible 13 during crystal growth to meet the axial temperature distribution requirements at different stages of crystal growth. This enables precise control of temperature distribution at different stages of crystal growth, accelerating the crystal growth rate and improving crystal growth quality.

[0047] In some embodiments, such as Figure 1 As shown, along the radial direction of the crucible 13, the outer diameter of the first insulation structure 9 matches the maximum outer diameter of the second insulation structure 12. The outer diameter of the third insulation structure 14 matches the outer diameter of the first insulation structure 9. The height of the second insulation structure 12 matches the height of the crucible 13, so that an insulation cavity is formed around the crucible 13 by the first insulation structure 9, the second insulation structure 12, and the third insulation structure 14.

[0048] In some embodiments, please refer to Figure 2 The first insulation structure 9 includes a first fixed insulation element 91 and at least one first adjustable insulation element 92. The number of first adjustable insulation elements 92 can be one, two, three, or even more. The number of first adjustable insulation elements 92 can be selected and adjusted as needed, such as... Figure 2In the example shown, two first adjusting insulation elements 92 are sequentially fitted inside the first fixed insulation element 91. The first fixed insulation element 91 is fixed, with no change in thickness or outer diameter, so that it serves as the basic insulation structure above the crucible 13. All the first adjusting insulation elements 92 are sequentially fitted inside the first fixed insulation element 91 along the radial direction of the crucible 13, with the outer circumferential surface of the outermost first adjusting insulation element 92 fitting against the inner circumferential surface of the first fixed insulation element 91. Adjacent first adjusting insulation elements 92 fit against each other, and a first through-hole 15 is provided through the innermost first adjusting insulation element 92 to allow the seed crystal rod 8 to pass through the first through-hole 15. Each first adjusting insulation element 92 includes multiple first sub-insulation layers 90 sequentially stacked along the axial direction of the crucible 13, and the diameter of the first through-hole 15 along its axial direction varies based on the different thicknesses of the first adjusting insulation elements 92. The thickness of the first adjusting insulation element 92 is determined based on the number of the first sub-insulation layers 90. This allows the aperture of the first through hole 15 along its axial direction to be adjusted by changing the number of the first sub-insulation layers 90 in each first adjusting insulation element 92, thereby changing the structure of the first through hole 15 during crystal growth. This allows for flexible adjustment of the heat dissipation mode on the back of the seed crystal holder 10 during crystal growth to meet the radial temperature distribution requirements at different stages of crystal growth.

[0049] In some embodiments, such as Figure 2 or Figure 3 As shown, the first fixed insulation element 91 may also include a plurality of first sub-insulation layers 90 stacked sequentially along the axial direction of the crucible 13. The first sub-insulation layers 90 may have a ring-shaped structure. The first sub-insulation layers 90 may be graphite hard felt or graphite soft felt. In some embodiments, the number of first sub-insulation layers 90 may be 5 to 20 pieces, and the thickness of each first sub-insulation layer 90 may be 5 to 20 mm. In some embodiments, to improve the insulation effect, adjacent first fixed insulation elements 91 and first adjusting insulation elements 92, as well as two adjacent first adjusting insulation elements 92, are bonded together. Figure 2As shown, taking two first adjusting insulation components 92 as an example, the minimum inner diameter of the innermost first adjusting insulation component 92 is d1, which in some embodiments is 20~40mm. The inner diameter of the outermost first adjusting insulation component 92 is d2, which is also the outer diameter of the innermost first adjusting insulation component 92, which in some embodiments is 60~120mm. The outer diameter of the outermost first adjusting insulation component 92 is d3, which is also the inner diameter of the first fixed insulation component 91, which in some embodiments is 100~200mm. The outer diameter of the first fixed insulation component 91 is d4, which in some embodiments is 300~600mm. This arrangement ensures that adjacent first fixed insulation components 91 and first adjusting insulation components 92, as well as two adjacent first adjusting insulation components 92, fit tightly together, preventing heat loss.

[0050] In some embodiments, the width of the first adjusting insulation member 92 is 20~40mm, that is, d2-d1 or d3-d2=20~40mm. The width of the first fixing insulation member 91 is 100~200mm, that is, d4-d3=100~200mm.

[0051] Please refer to section 3. Figure 5 As shown, where, Figure 3 The number of first sub-insulation layers 90 in all the first adjusting insulation components 92 is equal to the number of first sub-insulation layers 90 in the first fixed insulation component 91. This ensures that the diameter of the first through-hole 15 is equal vertically along its axial direction, and that the diameter of the first through-hole 15 is a constant-diameter structure with the minimum diameter. This reduces heat loss, allowing the temperature inside the crucible to rise rapidly during the material heating stage to melt the flux solid raw material, while ensuring uniform and slow heat dissipation during the cooling stage, preventing crystal cracking. Figure 4 As shown, when the number of first sub-insulation layers 90 in the first fixed insulation member 91 is greater than the number of first sub-insulation layers 90 in the adjacent first adjusting insulation member 92, and the number of first sub-insulation layers 90 in the outermost first adjusting insulation member 92 is greater than the number of first sub-insulation layers 90 in the innermost first adjusting insulation member 92, and the tops of the first fixed insulation member 91 and all the first adjusting insulation members 92 are aligned, the diameter of the first through hole 15 along its axial direction decreases sequentially from bottom to top. This expands the heat dissipation range on the back of the seed crystal holder 10, making the radial temperature distribution of the crystal growth environment more uniform, optimizing crystal quality, and simultaneously promoting the release of latent heat during crystal growth, reducing internal stress in the crystal, and preventing crystal cracking. Figure 5As shown, when the number of first sub-insulation layers 90 in the first fixed insulation member 91 is greater than the number of first sub-insulation layers 90 in the adjacent first adjusting insulation member 92, and the number of first sub-insulation layers 90 in the outermost first adjusting insulation member 92 is greater than the number of first sub-insulation layers 90 in the innermost first adjusting insulation member 92, and the bottom ends of the first fixed insulation member 91 and all the first adjusting insulation members 92 are aligned, the diameter of the first through hole 15 along its axial direction will gradually increase from bottom to top. This will allow less heat dissipation from the surface of the flux to maintain a relatively high surface temperature, preventing excessive carbon supersaturation in the surface area from causing spontaneous nucleation of SiC inside the flux to form polycrystalline particles that adhere to the crystal growth surface, thus suppressing defects such as flux encapsulation. The increased diameter at the upper end of the seed crystal rod 8 can promote heat conduction from the seed crystal support 10 to the seed crystal rod 8, reducing the temperature at the seed crystal end and accelerating crystal growth. Of course, once the silicon carbide crystal has cooled, depending on the size of the crystal, some or all of the first adjusting insulation components 92 can be removed, so that the first through hole 15 forms a constant diameter structure with the maximum inner diameter, allowing the crystal to pass through and the crystal can be directly removed.

[0052] To further increase the stability of the aperture of the first through hole 15 in the first thermal insulation structure 9, in some embodiments, such as Figure 6 and Figure 7 As shown, the first fixed insulation component 91 is fixedly connected to the adjacent first adjustable insulation component 92 by a first fixing member 20; two adjacent first adjustable insulation components 92 are fixedly connected by a first fixing member 20. In some embodiments, the first fixing member 20 can be fixed between the bottommost first sub-insulation layers 90. Please refer to... Figure 8The first fixing member 20 includes a first insert portion 202 and a first fixing portion 201, which are integrally formed. The first fixing portion 201 may be U-shaped, allowing it to be fixed to the outer peripheral surface of the first adjusting insulation member 92 and sandwiching one or more first sub-insulation layers 90. The first insert portion 202 and the first fixing portion 201 are parallel, and the first insert portion 202 can be inserted between two adjacent first sub-insulation layers 90 to serve as a force-bearing point for fixation. This achieves the fixation of the first fixing insulation member 91 with the adjacent first adjusting insulation member 92 and between two adjacent first adjusting insulation members 92. In some embodiments, the first insert portion 202 and the first fixing portion 201 may be sheet structures, with the thickness of the first insert portion 202 and the first fixing portion 201 being 0.5~1.5mm and the width being 5~10mm, thereby preventing the first fixing member 20 from generating large gaps between the first sub-insulation layers 90 and maintaining a good insulation effect. In some embodiments, the material of the first fixing member 20 can be high-temperature resistant graphite. The number of first fixing members 20 can be 2 to 4. In the preparation stage before loading the furnace, the first fixing part 201 of the first fixing member 20 can be fixed to the outer edge of the bottom first sub-insulation layer 90 of each first adjusting insulation member 92. The first insert part 202 of the first fixing member 20 is inserted into the adjacent first fixing insulation member 91 or the adjacent first adjusting insulation member 92. During the crystal reaction, when the first sub-insulation layer 90 is moved by the clamping assembly, the first fixing part 201 is always fixed on the bottom first sub-insulation layer 90, and the first insert part 202 moves accordingly and is then inserted into the adjacent first fixing insulation member 91 or the adjacent first adjusting insulation member 92.

[0053] In some other embodiments, such as Figure 9 As shown, the multiple first sub-insulation layers 90 of each first adjusting insulation component 92 are connected by a second fixing member 21. The second fixing member 21 includes a second lifting rod 211, a positioning rod 212, and a support member 213. The top of the second lifting rod 211 is fixed to the top of the growth furnace 1, and the bottom of the second lifting rod 211 is fixed to the top of the positioning rod 212. Positioning holes are provided on the first sub-insulation layers 90 forming the first adjusting insulation component 92 and located along the same diameter extension line. The positioning rod 212 passes through the positioning hole, and the outer diameter of the positioning rod 212 is less than or equal to the diameter of the positioning hole. In some embodiments, the diameter of the positioning hole is 5-10 mm. The support member 213 is located at the bottom of the positioning rod 212 and is used to support the bottom first sub-insulation layer 90. Figure 10As shown, the support member 213 has a fixing post 214 on its surface. The outer circumferential surface of the fixing post 214 has an external thread structure, and the interior of the positioning rod 212 has an internal thread structure, so that the positioning rod 212 can be threadedly connected to the fixing post 214 through the external thread. The support member 213 can be circular or rectangular. In some embodiments, each first sub-insulation layer 90 has a slit communicating with the positioning hole in the radial direction. The slit can be located inside or outside the positioning hole to facilitate the clamping assembly to clamp the first sub-insulation layer 90 and fix it to the positioning rod 212 or remove it from the positioning rod 212 during crystal growth. The positioning rod 212 and the support member 213 can be made of high-temperature resistant graphite. The length of the positioning rod 212 is adjusted by the second lifting rod 211 to accommodate the first adjusting insulation member 92 of different thicknesses.

[0054] Please refer to Figure 11 The second insulation structure 12 includes a second fixed insulation element 121 and at least two second adjustable insulation elements 122. The number of second adjustable insulation elements 122 can be two, three, four, or even more. For example, Figure 12 As shown, the second adjusting insulation component 122 includes three components stacked sequentially along the axial direction of the crucible 13. The second fixing insulation component 121 is fitted onto the outer circumferential surface of the crucible 13, and its height is the same as the height of the crucible 13 along its axial direction, thus providing basic insulation for the outer circumference of the crucible 13. All the second adjusting insulation components 122 are stacked sequentially along the axial direction of the crucible 13 and fitted onto the outer circumferential surface of the second fixing insulation component 121, with the inner circumferential surface of all the second adjusting insulation components 122 fitting against the outer circumferential surface of the second fixing insulation component 121. It can be understood that both the second fixing insulation component 121 and the second adjusting insulation component 122 are hollow cylindrical. The second fixing insulation component 121 tightly wraps around the outer circumferential surface of the crucible 13, and the second adjusting insulation component 122 tightly wraps around the outer circumferential surface of the second fixing insulation component 121. Each second adjusting insulation element 122 includes a plurality of second sub-insulation layers 120 sequentially nested radially along the crucible 13. The outer diameter of the second insulation structure 12 along its axial direction varies based on the different thicknesses of the second adjusting insulation element 122. The thickness of the second adjusting insulation element 122 is determined based on the number of second sub-insulation layers 120, so that the outer diameter of the second insulation structure 12 along its axial direction can be adjusted by adjusting the number of second sub-insulation layers 120 in each second adjusting insulation element 122. This allows for changes in the structure of the second insulation structure 12 during crystal growth, thereby altering the axial temperature gradient within the crucible 13 to meet the axial temperature distribution requirements at different stages of crystal growth. The second sub-insulation layer 120 can be a hard graphite felt or a soft graphite felt.

[0055] In some embodiments, the inner diameter of the second fixed insulation member 121 is 150-250 mm, the outer diameter is 300-500 mm, and the height is 200-300 mm. The inner diameter of the second adjustable insulation member 122 is 300-500 mm, the maximum outer diameter is 400-600 mm, and the number of second sub-insulation layers 120 constituting each second adjustable insulation member 122 can be 2-10 layers. The thickness of each second sub-insulation layer 120 is 5-20 mm.

[0056] In some embodiments, the second fixing insulation element 121 is made of a one-piece graphite rigid felt. Of course, in other embodiments, the second fixing insulation element 121 may also be made of multiple second sub-insulation layers 120 sequentially arranged radially along the crucible 13 and tightly wrapped around the outside of the crucible 13. During crystal growth, the size and position of the second fixing insulation element 121 remain fixed, serving as the basic insulation structure for the outer periphery of the crucible 13, thus providing the second insulation structure 12 with the most basic insulation capability.

[0057] Please refer to Figures 12 to 14 ,like Figure 12 As shown, the number of second sub-insulation layers 120 in all the second adjusting insulation components 122 is equal. This ensures that the outer diameter of the second insulation structure 12 along its axial direction is equal both vertically and horizontally, reducing heat loss and allowing the temperature inside the crucible to rise rapidly to melt the solid flux raw material. For example... Figure 13 As shown, the number of second sub-insulation layers 120 constituting each second adjusting insulation element 122 increases sequentially from top to bottom. This results in the second insulation structure 12 having an outer diameter that increases sequentially from top to bottom along its axial direction. This strengthens the insulation effect at the bottom of the crucible 13, while weakening the insulation at the top, thereby increasing the axial temperature gradient and accelerating the growth rate of silicon carbide single crystals. Figure 14 As shown, the number of second sub-insulation layers 120 constituting each second adjusting insulation element 122 decreases sequentially from top to bottom. This makes the outer diameter of the second insulation structure 12 along its axial direction decrease sequentially from top to bottom, so as to enhance the insulation effect of the top of the crucible 13, while the insulation of the bottom of the crucible 13 is weaker, the axial temperature gradient is reduced, the growth rate of silicon carbide single crystal is slowed down, and the carbon supersaturation on the surface of the flux is slightly reduced, which can inhibit the spontaneous nucleation of silicon carbide in the flux and improve the crystal quality.

[0058] To further enhance the stability of the second insulation structure 12, in some embodiments, adjacent second adjusting insulation members 122 are fixedly connected by a third fastener 22. Please refer to... Figures 15 to 17 In some embodiments, when the outer diameter of the second insulation structure 12 gradually increases from bottom to top along the axial direction, the third fastener 22 can be fixed on the outermost second sub-insulation layer 120.

[0059] Please refer to Figure 16 and Figure 17 The third fixing member 22 includes a second insert portion 222 and a second fixing portion 221, which are integrally formed. The extension direction of the second fixing portion 221 is perpendicular to the second insert portion 222, and both ends of the second insert portion 222 protrude from the second fixing portion 221. The second fixing portion 221 can be U-shaped, allowing it to be fixed to the circumferential surface of the second adjusting insulation member 122 and sandwiching a second sub-insulation layer 120. The second insert portion 222 can be supported on the bottom of the upper second adjusting insulation member 122 to maintain structural stability. The second fixing portion 221 can be sandwiched on a second sub-insulation layer 120 of the lower second adjusting insulation member 122, thereby fixing two adjacent second adjusting insulation members 122. In some embodiments, the second insert portion 222 and the second fixing portion 221 can be thin sheet structures, with the thickness of the second insert portion 222 and the thickness of the second fixing portion 221 being 0.5~1.5mm and the width being 5~10mm, thereby preventing the third fixing member 22 from generating large gaps between the second sub-insulation layers 120 and maintaining good insulation performance. In some embodiments, the material of the third fixing member 22 can be high-temperature resistant graphite. The number of third fixing members 22 can be 2~4. The fixing position of the third fixing member 22 can be installed at a selected position so that when the outer diameter of the second insulation structure 12 is wider at the top and narrower at the bottom, that is, gradually increases from bottom to top, it is beneficial for the second adjusting insulation member 122 located below to support the second adjusting insulation member 122 above.

[0060] In some embodiments, the third insulation structure 14 is composed of solid graphite hard felt or graphite soft felt. The third insulation structure 14 is cylindrical in shape. The diameter of the third insulation structure 14 is 400~600mm, and the height is 150~300mm. It is used to maintain a stable temperature at the bottom of the crucible 13 and provide a sufficient carbon source for crystal growth.

[0061] Please refer to Figure 1 The silicon carbide crystal growth apparatus of this application further includes a growth furnace 1, which includes a reaction chamber 101 and a storage chamber 102 connected to each other. A crucible 13 is housed in the reaction chamber 101, and the storage chamber 102 is located above the reaction chamber 101 along the axial direction of the crucible 13. The storage chamber 102 is used to store the first sub-insulation layer 90 and the second sub-insulation layer 120. In some embodiments, a support plate 2 is provided in the reaction chamber 101, and the edge of the support plate 2 forms a baffle. The first sub-insulation layer 90 and the second sub-insulation layer 120 can be stored on the support plate 2, and the baffle can prevent the first sub-insulation layer 90 and the second sub-insulation layer 120 from falling off.

[0062] In some embodiments, please refer to Figure 1The silicon carbide crystal growth apparatus of this application further includes a clamping assembly and a driving mechanism 3. The driving mechanism 3 is drivenly connected to the clamping assembly. The clamping assembly is located above the crucible 13 and is used to clamp the first sub-insulation layer 90 to the top of the crucible 13, or to move the first sub-insulation layer 90 above the crucible 13 to the storage chamber 102; and to clamp the second sub-insulation layer 120 to the outside of the crucible 13, or to move the second sub-insulation layer 120 on the outside of the crucible 13 to the storage chamber 102. The clamping assembly includes a first lifting rod 6 and a clamping member 7. The top end of the first lifting rod 6 is slidably disposed on the top of the growth furnace 1, and the clamping member 7 is fixed to the end of the first lifting rod 6. A groove 4 is provided on the top of the growth furnace 1. The groove 4 extends radially along the crucible 13, and the top end of the first lifting rod 6 is slidably disposed in the groove 4. The top end of the first lifting rod 6 can be slidably disposed in the groove 4 by means of a pulley 5. The clamping member 7 is hinged to the bottom of the first lifting rod 6, so that the clamping member 7 of the clamping assembly can be flexibly clamped by the drive mechanism to clamp the first sub-insulation layer 900 or the second sub-insulation layer 120. The first lifting rod 6 and the pulley 5 together realize the axial and radial movement of the clamping assembly. Both the first lifting rod 6 and the clamping member 7 can be made of high temperature resistant, corrosion resistant and load-bearing materials.

[0063] This application also provides a method for growing silicon carbide crystals, including the following steps: In the initial state, the first insulation structure 9 is placed on top of the crucible 13, the second insulation structure 12 is placed on the outer circumference of the crucible 13, and the third insulation structure 14 is placed on the bottom of the crucible 13. The first through hole 15 of the first insulation structure 9 is kept at its minimum diameter along its axial direction, and the outer diameter of the second insulation structure 12 is kept at its maximum diameter along its axial direction. After the growth furnace 1 is closed and a vacuum is applied, the crucible 13 is heated to completely melt the flux inside the crucible 13. This achieves optimal insulation, reduces heat loss, and allows the temperature inside the reaction chamber to rise rapidly to melt the solid flux raw material.

[0064] In the first stage of crystal growth, the control drive mechanism 3 drives the clamping assembly to adjust the first sub-insulation layer 90 in the first adjusting insulation component 92, so that the diameter of the first through hole 15 gradually decreases or increases from bottom to top along its axial direction. During crystal growth, the diameter structure of the first through hole 15 can be adjusted as needed to be wider at the top and narrower at the bottom, i.e., gradually increasing from bottom to top, to maintain a higher solution surface temperature and reduce polycrystalline formation, or narrower at the top and wider at the bottom, i.e., gradually decreasing from bottom to top, so that the radial temperature distribution of the crystal growth environment is more uniform. The control drive mechanism 3 drives the clamping assembly to adjust the second sub-insulation layer 120 in the second adjusting insulation component 122, so that the outer diameter of the second insulation structure 12 gradually decreases or increases from bottom to top along its axial direction. During crystal growth, the outer diameter of the second insulation structure 12 can be adjusted as needed to be wider at the top and narrower at the bottom, or narrower at the top and wider at the bottom, in order to increase or decrease the axial temperature gradient. This first stage can be the growth stage.

[0065] In the second stage of crystal growth, the control drive mechanism 3 drives the clamping assembly to adjust the first sub-insulation layer 90 in the first adjusting insulation member 92, so that the diameter of the first through hole 15 along its axial direction is configured to be a constant diameter with the smallest diameter. This allows the grown crystal to dissipate heat uniformly and slowly, preventing crystal cracking. This second stage can be a cooling stage.

[0066] The technical solution of this application will be described below with reference to the embodiments.

[0067] Example 1 This embodiment provides a liquid-phase silicon carbide crystal growth apparatus, the schematic diagram of which is shown below. Figure 1 As shown.

[0068] In this embodiment 1, the first insulation structure 9 includes a first fixed insulation component 91 and two first adjustable insulation components 92, all of which are made of graphite soft felt. The number of the three types of annular first sub-insulation layers 90 that make up the first fixed insulation component 91 and the two first adjustable insulation components 92 are 20 pieces, each with a thickness of 10mm. They are horizontally stacked above the crucible 13. The inner diameter d1 of the innermost first adjustable insulation component 92 is 25mm, the outer diameter of the innermost first adjustable insulation component 92 or the inner diameter of the outermost first adjustable insulation component 92 is 65mm, the outer diameter of the outermost first adjustable insulation component 92 or the inner diameter of the first fixed insulation component 91 is 105mm, and the outer diameter of the first fixed insulation component 91 is 400mm. The second fixed insulation component 121 in the second insulation structure 12 is a cut, one-piece graphite hard felt with an inner diameter of 200mm, an outer diameter of 350mm, and a height of 200mm. The second adjusting insulation component 122 is formed by five layers of 10mm thick second sub-insulation layers 120 vertically wrapped in a ring-shaped cylinder, with an inner diameter of 350mm and an outer diameter of 400mm. The second adjusting insulation component 122 includes three components stacked sequentially along the axial direction, with a total height of 200mm. The third insulation structure 14 is a solid graphite hard felt cylinder with a diameter of 400mm and a height of 200mm. The crucible 13 has an inner diameter of 160mm and an outer diameter of 200mm.

[0069] This embodiment describes the steps for growing silicon carbide crystals using the above-described apparatus in a liquid-phase method: (1) Place the growth material into the crucible 13 and assemble the apparatus. As an initial state, the first through-hole 15 of the first insulation structure 9 has a minimum diameter equal-diameter structure, and the outer wall structure of the second insulation structure 12 has a maximum diameter equal-diameter structure. Close the growth furnace and simultaneously evacuate the storage chamber 102 and the reaction chamber 101. When the gas pressure inside the furnace is less than 2 × 10⁻⁶... -4 After Pa, high-purity argon gas is introduced as a protective gas to heat the crucible 13, so that the growth material inside the crucible 13 is completely melted.

[0070] (2) By controlling the clamping assembly to descend through the drive mechanism 3, the aperture structure of the first through hole 15 of the first insulation structure 9 is adjusted to be wider at the top and narrower at the bottom, that is, gradually increasing from bottom to top. The outer diameter structure of the second insulation structure 12 is adjusted to be wider at the top and narrower at the bottom, that is, gradually increasing from bottom to top. The removed first sub-insulation layer 90 or second sub-insulation layer 120 is stored in the storage compartment 102.

[0071] (3) Control the seed crystal rod 8 to descend, and immerse the seed crystal 11 on the seed crystal holder 10 into the flux liquid 4 mm below the surface, and remelt for 60 min.

[0072] (4) Control the seed crystal rod 8 to rise, and the seed crystal 11 is at the liquid surface to start crystal growth. During the growth process, the seed crystal rod 8 is rotated at a speed of 30 rpm and rises at a speed of 40 μm / h.

[0073] (5) After 48 hours of growth, the seed crystal rod 8 is quickly pulled off at a rising speed of 4 mm / h. The drive mechanism 3 is used again to control the clamping assembly to adjust the hole structure of the first through hole 15 of the first heat preservation structure 9 to the smallest diameter equal diameter structure, and the crystal enters the cooling stage.

[0074] (6) After cooling, remove all the first adjustment insulation parts 92 and take out the crystal directly. The silicon carbide crystal growth is complete.

[0075] like Figure 18 As shown, the final results indicate that the grown silicon carbide single crystal has a smooth and flat surface, without cracks or grooves, and without obvious step aggregation. The steps are evenly distributed at the microscale, and there is no flux encapsulation inside the crystal. The crystal quality is excellent, and the crystal growth rate is 140 μm / h.

[0076] Example 2 The difference between Example 2 and Example 1 is that: After the growth raw material is melted, in step (2), the aperture structure of the first through hole 15 of the first insulation structure 9 is adjusted to be narrower at the top and wider at the bottom, that is, gradually decreasing from bottom to top, and the outer diameter structure of the second insulation structure 12 is adjusted to be narrower at the top and wider at the bottom, that is, gradually decreasing from bottom to top.

[0077] like Figure 19 As shown, the final results indicate that the grown silicon carbide single crystal has a smooth surface, no cracks, a small amount of step-like clusters, and a small amount of flux encapsulation inside the crystal. The crystal growth rate is 170 μm / h.

[0078] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is as follows: Crystal growth was performed using a conventional fixed insulation layer. Throughout the crystal growth process, the upper insulation layer maintained a constant diameter structure with an inner diameter of 25 mm and an outer diameter of 400 mm, while the side insulation layers maintained a constant diameter structure with an inner diameter of 200 mm and an outer diameter of 400 mm.

[0079] like Figure 20 As shown, the final results indicate that the surface of the grown silicon carbide single crystal is rough, with a large number of grooves and obvious step clusters. After cutting, there is a lot of flux encapsulation inside the crystal, and the crystal growth rate is 150 μm / h.

[0080] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A silicon carbide crystal growth apparatus, characterized in that, include: A crucible (13) containing a fluxing solvent; Seed crystal rod (8), the bottom of the seed crystal rod (8) is provided with a seed crystal holder (10), and a seed crystal (11) is provided on the side of the seed crystal holder (10) facing the cosolvent. The heat insulation component includes a first heat insulation structure (9), a second heat insulation structure (12), and a third heat insulation structure (14). The first heat insulation structure (9) is located at the top of the crucible (13), the second heat insulation structure (12) is fitted onto the outer circumferential surface of the crucible (13), and the third heat insulation structure (14) is located at the bottom of the crucible (13). The first heat insulation structure (9) has a first through hole (15) in the middle that allows the seed crystal rod (8) to pass through. The diameter of the first through hole (15) along its axial direction can vary according to the different radial temperature gradients required for crystal growth. The outer diameter of the second heat insulation structure (12) along its axial direction can vary according to the different axial temperature gradients required for crystal growth.

2. The silicon carbide crystal growth apparatus of claim 1, wherein, The first heat insulation structure (9) includes a first fixed heat insulation component (91) and at least one first adjustable heat insulation component (92). All the first adjustable heat insulation components (92) are sequentially sleeved on the inner side of the first fixed heat insulation component (91) along the radial direction of the crucible (13), and the outer peripheral surface of the outermost first adjustable heat insulation component (92) is in contact with the inner peripheral surface of the first fixed heat insulation component (91). The first through hole (15) is provided through the innermost first adjustable heat insulation component (92). Each first adjustable heat insulation component (92) includes a plurality of first sub-heat insulation layers (90) stacked sequentially along the axial direction of the crucible (13). The aperture of the first through hole (15) along its axial direction varies based on the different thicknesses of the first adjustable heat insulation component (92).

3. The silicon carbide crystal growth apparatus of claim 2, wherein, The first fixed insulation component (91) is fixedly connected to the adjacent first adjusting insulation component (92) via a first fixing component (20); and / or, The two adjacent first adjusting insulation components (92) are fixedly connected by a first fixing member (20); and / or, The plurality of first sub-insulation layers (90) of each first adjusting insulation element (92) are connected to each other by a second fastener (21).

4. The silicon carbide crystal growth apparatus according to any one of claims 1 to 3, wherein The second insulation structure (12) includes a second fixed insulation element (121) and at least two second adjustable insulation elements (122). The second fixed insulation element (121) is sleeved on the outer peripheral surface of the crucible (13). All the second adjustable insulation elements (122) are stacked sequentially along the axial direction of the crucible (13) and sleeved on the outer peripheral surface of the second fixed insulation element (121). The inner peripheral surface of all the second adjustable insulation elements (122) is in contact with the outer peripheral surface of the second fixed insulation element (121). Each second adjustable insulation element (122) includes a plurality of second sub-insulation layers (120) sequentially sleeved along the radial direction of the crucible (13). The outer diameter of the second insulation structure (12) along its axial direction varies based on the different thicknesses of the second adjustable insulation elements (122).

5. The silicon carbide crystal growth apparatus of claim 4, wherein, Two adjacent second adjusting heat preservation members (122) are fixedly connected through a third fixing member (22).

6. The silicon carbide crystal growth apparatus of claim 4, wherein, Along the axial direction of the crucible (13), the height of the second fixed heat preservation member (121) is consistent with the height of the crucible (13); and / or, Along the radial direction of the crucible (13), the outer diameter of the first heat preservation structure (9) is consistent with the maximum outer diameter of the second heat preservation structure (12); and / or, The outer diameter of the third heat preservation structure (14) is consistent with the outer diameter of the first heat preservation structure (9).

7. The silicon carbide crystal growth apparatus of claim 4, wherein Further comprising: a growth furnace (1) comprising a reaction bin (101) and a storage bin (102) in communication, wherein the crucible (13) is contained in the reaction bin (101), along the axial direction of the crucible (13), the storage bin (102) is located above the reaction bin (101), and the storage bin (102) is used for storing a first sub heat preservation layer (90) and a second sub heat preservation layer (120); a clamping assembly provided above the crucible (13) and used for clamping the first sub heat preservation layer (90) above the crucible (13) or moving the first sub heat preservation layer (90) above the crucible (13) to the storage bin (102), and clamping the second sub heat preservation layer (120) outside the crucible (13) or moving the second sub heat preservation layer (120) outside the crucible (13) to the storage bin (102); a driving mechanism (3) in driving connection with the clamping assembly.

8. The silicon carbide crystal growth apparatus of claim 7, wherein, The clamping assembly comprises a first lifting rod (6) and a clamping piece (7), the top end of the first lifting rod (6) is slidingly provided at the top of the growth furnace (1), and the clamping piece (7) is hingedly connected to the end of the first lifting rod (6); a sliding groove (4) is provided at the top of the growth furnace (1), the sliding groove (4) extends along the radial direction of the crucible (13), and the top end of the first lifting rod (6) is slidingly provided in the sliding groove (4).

9. A method of growing a silicon carbide crystal, characterized by, The method comprises the following steps: In the initial state, the first heat preservation structure (9) is placed on the top of the crucible (13), the second heat preservation structure (12) is placed on the outer circumferential surface of the crucible (13), and the third heat preservation structure (14) is placed on the bottom of the crucible (13), and the first through hole (15) of the first heat preservation structure (9) keeps the same diameter along the axial direction to keep the minimum diameter, and the outer diameter of the second heat preservation structure (12) keeps the same diameter along the axial direction to keep the maximum diameter; the growth furnace (1) is closed, vacuum treatment is performed, and then the crucible (13) is heated to completely melt the cosolvent in the crucible (13); In the first stage of crystal growth, the driving mechanism (3) drives the clamping assembly to adjust the first sub-heat preservation layer (90) in the first adjustment heat preservation piece (92), so that the first through hole (15) gradually decreases or gradually increases in the aperture along the axial direction from bottom to top; the driving mechanism (3) drives the clamping assembly to adjust the second sub-heat preservation layer (120) in the second adjustment heat preservation piece (122), so that the second heat preservation structure (12) gradually decreases or gradually increases in the outer diameter along the axial direction from bottom to top; In the second stage of crystal growth, the driving mechanism (3) drives the clamping assembly to adjust the first sub-heat preservation layer (90) in the first adjustment heat preservation piece (92), so that the first through hole (15) is configured as an equal diameter with the minimum diameter along the axial direction.

10. The silicon carbide crystal growth process of claim 9 wherein, The first stage is a growth stage, and the second stage is a cooling stage.

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