Equipment for growing silicon carbide single crystals by PVT (physical vapor transport) method

Abstract

The invention discloses equipment for growing silicon carbide single crystals by a PVT method. The equipment comprises a rack, a furnace chamber; the furnace chamber is arranged on the rack and has a thermal field structure; the thermal field structure is arranged in the furnace chamber; a heating structure; the heating structure surrounds the outer part of the furnace chamber; an air inlet structure; the air inlet structure comprises an air inlet, an air outlet and an air inlet channel, the air inlet is formed in the top of the furnace chamber, and the air inlet channel extends downwards from the air inlet and penetrates through the thermal field structure to the bottom of the furnace chamber; the thermal field structure has the beneficial effects that the structure is compact, the installation space of equipment can be saved, and meanwhile, after the size of the whole equipment is reduced, an operator can conveniently disassemble and assemble the thermal field structure to fill raw materials; according to the technical scheme, the heating structure is provided with the lifting assembly, and the lifting assembly can control the lifting of the main body coil according to the temperature distribution in the furnace chamber, so that the temperature in the furnace chamber is more stable and more uniform, and the heating structure is suitable for the growth of large-size silicon carbide single crystals.

Description

Technical Field

[0001] The invention relates to the technical field of growing silicon carbide single crystals, and in particular to a device for growing silicon carbide single crystals using a PVT method. Background Art

[0002] Silicon carbide (SiC) is a third-generation wide bandgap semiconductor material with properties such as wide bandgap, high thermal conductivity, high electron saturation mobility, and high breakdown electric field. It has obvious advantages over the first-generation semiconductor materials represented by silicon and the second-generation semiconductor materials represented by GaAs. In addition, it has a lattice structure similar to that of GaN, so it is considered to be an ideal semiconductor material for manufacturing optoelectronic devices, high-frequency and high-power devices, and high-temperature electronic devices. It is widely used in white light illumination, screen display, optical storage, high-voltage power transmission, oil exploration, automation, radar and communication, electric vehicles, high-speed rail vehicles, etc. Therefore, the production of high-quality, large-size silicon carbide crystals is an urgent task.

[0003] At present, the main methods for growing silicon carbide include vapor transport (PVT), liquid phase epitaxy (LPE), chemical vapor deposition (CVD), etc. Among them, the PVT method is the most mature method and the only growth method that can meet the demand for commercial silicon carbide substrates. The growth furnace for growing silicon carbide single crystals by the PVT method generally adopts induction heating, that is, medium and high frequency alternating current is passed through the induction coil, and the raw materials in the growth chamber are heated by induction heating of the crucible, so that the raw materials are decomposed, and crystals grow at the seed crystal with lower temperature, thereby achieving crystal growth.

[0004] The advantages of induction heating devices are fast heating speed and high efficiency, but their disadvantages are also obvious. They are large in size, have uneven thermal fields, and are difficult to achieve coil accuracy. Therefore, it is necessary to develop a device for growing silicon carbide single crystals using the PVT method that is small in size and can accurately control the coil. After searching, no technical solution identical to the present invention was found. Summary of the invention

[0005] The main technical problem solved by the present invention is to provide a device for growing silicon carbide single crystals by the PVT method which is small in size and can precisely control the coil, thereby solving one or more of the above-mentioned prior art problems.

[0006] In order to solve the above technical problems, a technical solution adopted by the present invention is: a device for growing silicon carbide single crystals by a PVT method, the innovation of which is: comprising:

[0007] frame;

[0008] A furnace chamber; the furnace chamber is arranged on a frame, and a vacuum pipe is arranged on the top of the furnace chamber;

[0009] A thermal field structure; the thermal field structure is arranged in the furnace cavity;

[0010] A heating structure; the heating structure surrounds the outside of the furnace cavity;

[0011] An air intake structure; the air intake structure comprises an air intake port, an air outlet port and an air intake channel, wherein the air intake port is arranged at the top of the furnace cavity, the air outlet port is arranged on the outer side wall of the bottom of the furnace cavity, and the air intake channel extends downward from the air intake port and passes through the thermal field structure to the bottom of the furnace cavity;

[0012] The thermal field structure comprises a crucible, wherein a cylindrical partition is arranged in the crucible, wherein the cylindrical partition divides the inner cavity of the crucible into an outer chamber and an inner chamber, wherein a plurality of uniformly distributed gas phase holes are arranged on the barrel-shaped partition, wherein a connecting ring is arranged on the upper edge of the crucible, wherein the top of the outer chamber is covered with a first separating ring, wherein a first gasket ring is arranged on the top of the first separating ring, wherein an annular chamber is formed by the gap between the outer side surface of the first gasket ring and the inner wall of the connecting ring, wherein a second separating ring is arranged on the top of the annular chamber, wherein a growth plate is arranged on the top of the inner chamber, wherein the extension of the growth plate is supported on the top of the second separating ring, wherein a second gasket ring is arranged on the top of the growth plate, wherein an upper thermal insulation felt is arranged on the top of the second gasket ring, and wherein a lower thermal insulation felt is arranged on the top of the crucible;

[0013] The thermal field structure further comprises an outer thermal insulation felt which is in a cylindrical shape and covers the upper thermal insulation felt, the crucible and the lower thermal insulation felt.

[0014] In some embodiments, a first connecting step is provided on the inner edge of the top of the crucible, a second connecting step is provided on the outer extension of the bottom of the connecting ring and is positioned in cooperation with the first connecting step, a third connecting step is provided on the inner edge of the top of the connecting ring, a fourth connecting step that can be positioned in cooperation with the third connecting step is provided on the outer lower edge of the second separating ring, a fifth connecting step is provided on the inner upper edge of the second separating ring, and a sixth connecting step that can be positioned in cooperation with the fifth connecting step is provided on the outer edge of the growth plate.

[0015] In some embodiments, the bottom of the connecting ring is located on the back of the second connecting step and is further provided with an extended circular ring, and the top of the extended circular ring is provided with a seventh connecting step for mounting the outer edge of the first separating ring.

[0016] In some embodiments, the furnace cavity is cylindrical, with the top of the furnace cavity closed and the bottom open, the frame is provided with an annular mounting seat for mounting the furnace cavity, the bottom of the inner side wall of the annular mounting seat is provided with a slope, the bottom of the slope is provided with a support ring for supporting the lower edge of the furnace cavity, a first limiting ring is provided in the gap between the inner side wall of the annular mounting seat and the outer wall of the furnace cavity, the width of the first limiting ring is equal to the width of the bottom surface of the slope, the first limiting ring is located at the upper edge of the slope, a second limiting ring is also provided on the top of the annular mounting seat, the inner diameter of the second limiting ring is consistent with the outer diameter of the furnace cavity, and the second limiting ring The bottom of the positioning ring is provided with an annular pin which can be inserted into the gap between the inner wall of the annular mounting seat and the outer wall of the furnace chamber; the furnace chamber also includes a bottom plate, the top surface of the bottom plate is provided with a support member, the thermal field structure is installed on the top of the support member, the furnace chamber also includes an extension section, the extension section is cylindrical, the upper edge of the extension section is fixed to the bottom of the annular mounting seat, the lower edge of the extension section is connected to the top outer edge of the bottom plate, the top outer edge of the bottom plate is provided with a connecting groove for the lower edge of the extension section to be inserted, and the lower edge of the extension section is fixed to the connecting groove by a hook screw; the air outlet is located on the outer side wall of the extension section.

[0017] In some embodiments, the heating structure includes a lifting assembly and a heating assembly, the lifting assembly includes two first lifting units, a second lifting unit and a lifting motor for synchronously driving the first lifting unit and the second lifting unit to move up and down, which are arranged in a mirror-symmetrical manner on the outside of the furnace cavity, the lifting unit is arranged on a frame, the heating assembly is mounted on the outside of the thermal field structure and the bottom of the heating assembly is installed on the lifting unit.

[0018] In some embodiments, the first lifting unit includes a first screw rod vertically arranged on the frame, a first guide column arranged on the side of the first screw rod and parallel to the first screw rod, and a first guide sleeve simultaneously sleeved on the first screw rod and the first guide column, a first synchronous wheel is provided at the bottom of the first screw rod, a first connecting bridge is provided on the first guide sleeve, the extension direction of the first connecting bridge is perpendicular to the extension direction of the first screw rod, and a first lifting seat is provided at the front end of the first connecting bridge; the second lifting unit includes a second screw rod vertically arranged on the frame, a second guide column arranged on the side of the second screw rod and parallel to the second screw rod, and a second guide sleeve simultaneously sleeved on the second screw rod and the second guide column, a second synchronous wheel is provided at the bottom of the second screw rod, a second connecting bridge is provided on the second guide sleeve, the extension direction of the second connecting bridge is perpendicular to the extension direction of the second screw rod, and a second lifting seat is provided at the front end of the second connecting bridge; the lifting motor is vertically downwardly installed on the frame and forms a triangular formation with the first lifting unit and the second lifting unit, a third synchronous wheel is provided at the output end of the lifting motor, and the lifting assembly also includes a synchronous transmission belt that connects the first synchronous wheel, the second synchronous wheel and the third synchronous wheel for synchronous transmission.

[0019] In some embodiments, the heating assembly comprises

[0020] Support frame; the bottom two sides of the support frame are respectively fixed on the first lifting seat and the second lifting seat;

[0021] Main body coil; the main body coil is mounted on the support frame.

[0022] In some embodiments, the support frame includes a lower ring, an upper ring and a connecting column for connecting the upper ring and the lower ring; the main body coil is composed of a plurality of "C"-shaped coils combined up and down, the tail end of the upper "C"-shaped coil is connected to the head of the adjacent lower "C"-shaped coil, the upper and lower edges of the "C"-shaped coil are provided with "C"-shaped metal plates, and the outer side surface of the "C"-shaped coil is provided with a plurality of connecting ears, the position of the connecting ears corresponds to the position of the connecting body, and a columnar spacer ring is provided between the upper and lower adjacent connecting ears, and the connecting ears and the columnar spacer ring are both sleeved on the middle part of the connecting body, the top of the connecting column is fixedly connected to the upper ring, and the bottom is fixedly connected to the lower ring.

[0023] In some embodiments, a water cooling pipeline extending from the head end of the main body coil to the tail end of the main body coil is provided at the center of the main body coil.

[0024] In some embodiments, the device for growing silicon carbide single crystals by the PVT method also includes a shielding structure, which includes a shielding cover installed on a frame and covering the heating structure, and a water cooling pipe for cooling the shielding cover is provided on the outer surface of the shielding cover.

[0025] The beneficial effects of the present invention are as follows: the technical solution has a compact structure, which can save the installation space of the equipment. At the same time, after the overall equipment volume is reduced, it is convenient for operators to dismantle and install the thermal field structure to fill the raw materials; the heating structure of the technical solution is provided with a lifting assembly, and the lifting assembly can control the lifting and lowering of the main coil according to the temperature distribution in the furnace chamber, so that the temperature in the furnace chamber is more stable and uniform, which is suitable for the growth of large-sized silicon carbide single crystals. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0027] Figure 1 It is an axial view of an apparatus for growing silicon carbide single crystals using a PVT method according to the present invention.

[0028] Figure 2 This is a front view of a device for growing silicon carbide single crystals using a PVT method according to the present invention, with the frame removed.

[0029] Figure 3 yes Figure 2 Cross-sectional view along the A-A direction.

[0030] Figure 4 It is a cross-sectional view of the thermal field structure of a device for growing silicon carbide single crystals using a PVT method according to the present invention.

[0031] Figure 5 The present invention is a schematic diagram of the local structure of the bottom of a furnace chamber of an apparatus for growing silicon carbide single crystals using a PVT method.

[0032] Figure 6 It is a structural diagram of a heating structure of an apparatus for growing silicon carbide single crystals using a PVT method according to the present invention.

[0033] Figure 7 It is a left view of the heating structure of an apparatus for growing silicon carbide single crystals using a PVT method according to the present invention.

[0034] Figure 8 It is a left view of the heating structure of an apparatus for growing silicon carbide single crystals using a PVT method according to the present invention.

[0035] Fig. 9 Is for Figure 1 Schematic diagram of the structure after adding the shielding structure. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] like Figures 1 to 9 As shown, the embodiment of the present invention includes:

[0038] A device for growing silicon carbide single crystals by a PVT method, comprising a frame 100; a furnace chamber 200; the furnace chamber 200 is arranged on the frame 100, and a vacuum duct 201 is arranged on the top of the furnace chamber 200; a thermal field structure; the thermal field structure is arranged in the furnace chamber 200; a heating structure 400; the heating structure 400 surrounds the outside of the furnace chamber 200; an air intake structure; the air intake structure comprises an air inlet 202, an air outlet and an air intake channel, the air inlet 202 is arranged on the top of the furnace chamber 200, and the air outlet is arranged on the bottom of the furnace chamber 200. On the outer wall, the air inlet channel extends downward from the air inlet 202 and passes through the thermal field structure to the bottom of the furnace chamber 200; the thermal field structure includes a crucible 310, and a cylindrical partition 311 is provided in the crucible 310, and the cylindrical partition 311 divides the inner cavity of the crucible 310 into an outer chamber 312 and an inner chamber 313, and a plurality of uniformly distributed gas phase holes 314 are provided on the barrel-shaped partition, and a connecting ring 320 is provided on the upper edge of the crucible 310, and the top of the outer chamber 312 is covered with a first partition ring 321, and the top of the first partition ring 321 is A first gasket ring 322 is provided at the inner part, and the gap between the outer side surface of the first gasket ring 322 and the inner wall of the connecting ring 320 forms an annular chamber 323, and the top of the annular chamber 323 is covered with a second separation ring 324, and the top of the inner chamber 313 is covered with a growth plate 325, and the extension of the growth plate 325 is supported on the top of the second separation ring 324, and the top of the growth plate 325 is a second gasket ring 326, and the top of the second gasket ring 326 is provided with an upper insulation felt 330, and the top of the crucible 310 is provided with a lower insulation felt 331; the thermal field structure The structure also includes an outer insulation felt 332, which is cylindrical and covers the upper insulation felt 330, the crucible 310, and the lower insulation felt 331. In this technical solution, carbon and silicon powders are loaded into the outer chamber 312, and the silicon carbide seed material is attached to the bottom surface of the growth plate 325. The heating structure 400 heats the thermal field structure, heats the carbon and silicon powders into gas, and enters the inner chamber 313 through the gas phase hole 314, where the carbon and silicon ions will rise and react and finally attach to the silicon carbide seed material to complete the growth.

[0039] In this embodiment, if Figure 4As shown, the inner edge of the top of the crucible 310 is provided with a first connecting step, the outer extension of the bottom of the connecting ring 320 is provided with a second connecting step that cooperates with the first connecting step, the inner edge of the top of the connecting ring 320 is provided with a third connecting step, the outer lower edge of the second separating ring 324 is provided with a fourth connecting step that can cooperate with the third connecting step, the inner upper edge of the second separating ring 324 is provided with a fifth connecting step, the outer edge of the growth plate 325 is provided with a sixth connecting step that can cooperate with the fifth connecting step, the bottom of the connecting ring 320 is located on the back of the second connecting step and is also provided with an extension ring, and the top of the extension ring is provided with a seventh connecting step for installing the outer edge of the first separating ring 321; the structure in the present technical solution can make the sealing effect between the various components in the thermal field assembly better.

[0040] In this embodiment, if Figure 5 As shown, the furnace cavity 200 is cylindrical, the top of the furnace cavity 200 is closed, and the bottom is open. The frame 100 is provided with an annular mounting seat 210 for mounting the furnace cavity 200, and the bottom of the inner wall of the annular mounting seat 210 is provided with a slope, and the bottom of the slope is provided with a support ring 211 for supporting the lower edge of the furnace cavity 200, and a first limiting ring 212 is provided in the gap between the inner wall of the annular mounting seat 210 and the outer wall of the furnace cavity 200, and the width of the first limiting ring 212 is equal to the width of the bottom surface of the slope, and the first limiting ring 212 is located at the upper edge of the slope, and the top of the annular mounting seat 210 is also provided with a second limiting ring 213, and the inner diameter of the second limiting ring 213 is consistent with the outer diameter of the furnace cavity 200, and the bottom of the second limiting ring 213 is provided with a support ring 211 that can be inserted between the inner wall of the annular mounting seat 210 and the furnace cavity 200. The furnace cavity 200 further comprises a bottom plate 220, a support member 221 is provided on the top surface of the bottom plate 220, and the thermal field structure is installed on the top of the support member 221. The furnace cavity 200 further comprises an extension section 222, and the extension section 222 is cylindrical. The upper edge of the extension section 222 is welded and fixed to the bottom of the annular mounting seat 210, and the lower edge of the extension section 222 is connected to the top outer edge of the bottom plate 220. The top outer edge of the bottom plate 220 is provided with a connecting groove 223 for inserting the lower edge of the extension section 222, and the lower edge of the extension section 222 is fixed to the connecting groove 223 by a hook screw; the air outlet is located on the outer side wall of the extension section 222. The technical solution can be convenient for technicians to disassemble and assemble, and can improve the efficiency of loading raw materials.

[0041] All components in the thermal field structure are composed of two semicircular structures with the same structure; this technical solution facilitates the disassembly and cleaning of each component

[0042] In this embodiment, if Figures 6 to 8As shown, the heating structure 400 includes a lifting component and a heating component, the lifting component includes two first lifting units and a second lifting unit that are arranged on the outside of the furnace chamber 200 in a mirror-symmetrical manner, and a lifting motor 440 for synchronously driving the first lifting unit and the second lifting unit to move up and down, the lifting unit is arranged on the frame 100, the heating component is sleeved on the outside of the thermal field structure and the bottom of the heating component is installed on the lifting unit; the first lifting unit includes a first screw rod 410 vertically arranged on the frame 100, a first guide column 411 arranged on the side of the first screw rod 410 and parallel to the first screw rod 410, and a first guide sleeve 412 sleeved on the first screw rod 410 and the first guide column 411 at the same time, and the bottom of the first screw rod 410 is provided with A first synchronous wheel 414, a first connecting bridge 413 is provided on the first guide sleeve 412, the extension direction of the first connecting bridge 413 is perpendicular to the extension direction of the first screw rod 410, and a first lifting seat 415 is provided at the front end of the first connecting bridge 413; the second lifting unit includes a second screw rod 420 vertically arranged on the frame 100, a second guide column 421 arranged on the side of the second screw rod 420 and parallel to the second screw rod 420, and a second guide sleeve 422 simultaneously sleeved on the second screw rod 420 and the second guide column 421, a second synchronous wheel 424 is provided at the bottom of the second screw rod 420, and a second connecting bridge 423 is provided on the second guide sleeve 422, the extension direction of the second connecting bridge 423 is perpendicular to the extension direction of the second screw rod 420 The extension direction is vertical, and the front end of the second connecting bridge 423 is provided with a second lifting seat 425; the lifting motor 440 is installed vertically downward on the frame 100 and forms a triangle formation with the first lifting unit and the second lifting unit. The output end of the lifting motor 440 is provided with a third synchronous wheel 441, and the lifting assembly also includes a synchronous transmission belt that connects the first synchronous wheel 414, the second synchronous wheel 424 and the third synchronous wheel 441 for synchronous transmission; the heating assembly includes a supporting frame; the bottom two sides of the supporting frame are respectively fixed on the first lifting seat 415 and the second lifting seat 425; the main body coil; the main body coil is installed on the supporting frame; the supporting frame includes a lower ring 430, an upper ring 431 and a device for connecting the upper ring 431 and the lower ring 430 The connecting column 432; the main body coil is composed of a plurality of "C"-shaped coils 433 combined up and down, the tail end of the "C"-shaped coil 433 of the upper layer is connected to the head of the "C"-shaped coil 433 of the adjacent lower layer, the upper and lower edges of the "C"-shaped coil 433 are both provided with a "C"-shaped metal plate 434, the outer side of the "C"-shaped coil 433 is provided with a plurality of connecting ears 435, the position of the connecting ears 435 corresponds to the position of the connecting body, a columnar spacer ring 436 is provided between the upper and lower adjacent connecting ears 435, the connecting ears 435 and the columnar spacer ring 436 are both sleeved in the middle of the connecting body, the top of the connecting column 432 is fixedly connected to the upper ring 431, and the bottom is fixedly connected to the lower ring 430;The horizontally arranged "C"-shaped coil 433 in this technical solution greatly improves the uniformity and symmetry of the inductance and magnetic field compared to the spiral turns, and can achieve more precise adjustments, making the temperature of the thermal field area more balanced. At the same time, the height of the main coil can be accurately adjusted by the lifting component to ensure a more uniform temperature in the thermal field and accurate control and adjustment of the temperature of its silicon carbide growth area. ;

[0043] In this embodiment, a water cooling pipeline extending from the head end of the main coil to the tail end of the main coil is provided in the center of the main coil. This technical solution can cool the main coil, ensure that the temperature of the thermal field is lower than its own temperature, and make the equipment safer and more reliable.

[0044] In this embodiment, if Fig. 9 As shown, the equipment for growing silicon carbide single crystals by the PVT method also includes a shielding structure, which includes a shielding cover 500 installed on the frame 100 and covering the heating structure 400. The outer surface of the shielding cover 500 is provided with a water cooling pipe 501 for cooling the shielding cover 500. This technical solution can shield the magnetic field generated after the coil is energized to prevent it from affecting the normal operation of external electronic components. The water cooling pipe 501 can be cooled after water is passed through it to ensure maximum safety in production.

[0045] The method for growing silicon carbide single crystal by PVT method is characterized by comprising the following steps:

[0046] 1) Cleaning: The first step is to clean each component of the disassembled thermal field structure, and use a dust-free cloth to wipe each component carefully and comprehensively; the second step is to clean the furnace cavity 200, and use a vacuum cleaner to clean the thermal field furnace cavity 200, and use dust-free paper to wipe the thermal field furnace cavity 200 carefully and comprehensively;

[0047] 2) Loading raw materials; filling the outer chamber 312 with carbon and silicon powder and attaching the silicon carbide seed material to the ground of the growth plate 325;

[0048] 3) Assemble and install all components of the thermal field structure in place according to the installation standards;

[0049] 4) Pretreatment: First, the crucible 310 is vacuumed in the furnace chamber 200 at a pressure of 5.0*10

[0050] 5) Operation of the automated program; Power of the coil 400-16kw; Pressure in the furnace chamber 200 0-600torr; Gas flow, opening of the butterfly valve; Height of the coil; Gas flow: 5L for argon and 200ml for nitrogen; 20ml for nitrogen. Argon is used as a protective gas, and nitrogen participates in the reaction. Nitrogen and argon enter the furnace chamber 200. Both gases have a flow-in and flow-out path to keep the pressure in the furnace chamber 200 stable;

[0051] 6) Grow silicon carbide for the first time, with a cycle of 7 days; repeat the above steps.

[0052] In this embodiment, in step 1, the hot field furnace chamber 200 is carefully and completely wiped with a dust-free cloth and anhydrous ethanol.

[0053] The beneficial effects of the present invention are as follows: the technical solution has a compact structure, which can save the installation space of the equipment. At the same time, after the overall equipment volume is reduced, it is convenient for operators to dismantle and install the thermal field structure to fill the raw materials; the heating structure 400 of the technical solution is provided with a lifting assembly, and the lifting assembly can control the lifting and lowering of the main coil according to the temperature distribution in the furnace chamber 200, so that the temperature in the furnace chamber 200 is more stable and uniform, which is suitable for the growth of large-sized silicon carbide single crystals.

[0054] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A device for growing silicon carbide single crystals by a PVT method, characterized in that: include Rack(100); A furnace chamber (200); the furnace chamber (200) is arranged on the frame (100), and a vacuum extraction pipeline (201) is arranged on the top of the furnace chamber (200); A thermal field structure; the thermal field structure is arranged in the furnace cavity (200); A heating structure (400); the heating structure (400) surrounds the outside of the furnace cavity (200); An air intake structure; the air intake structure comprises an air intake port (202), an air outlet, and an air intake channel, the air intake port (202) being arranged at the top of the furnace cavity (200), the air outlet being arranged on the outer side wall of the bottom of the furnace cavity (200), and the air intake channel extending downward from the air intake port (202) and passing through the thermal field structure to the bottom of the furnace cavity (200); The thermal field structure comprises a crucible (310), wherein a cylindrical partition (311) is arranged in the crucible (310), wherein the cylindrical partition (311) divides the inner cavity of the crucible (310) into an outer chamber (312) and an inner chamber (313), wherein a plurality of uniformly distributed gas phase holes (314) are arranged on the barrel-shaped partition, wherein a connecting ring (320) is arranged on the upper edge of the crucible (310), wherein the top of the outer chamber (312) is covered with a first partition ring (321), wherein a first gasket ring (322) is arranged on the top of the first partition ring (321), wherein the first gasket ring (322) is provided on the top of the first gasket ring (322). The gap between the outer side surface of the connecting ring (322) and the inner wall of the connecting ring (320) forms an annular chamber (323), the top of the annular chamber (323) is covered with a second separation ring (324), the top of the inner chamber (313) is covered with a growth plate (325), the extension of the growth plate (325) is supported on the top of the second separation ring (324), the top of the growth plate (325) is provided with a second gasket (326), the top of the second gasket (326) is provided with an upper insulation felt (330), and the top of the crucible (310) is provided with a lower insulation felt (331); The thermal field structure further comprises an outer thermal insulation felt (332), the outer thermal insulation felt (332) is cylindrical, and the outer thermal insulation felt (332) covers the upper thermal insulation felt (330), the crucible (310), and the lower thermal insulation felt (331).

2. The device for growing silicon carbide single crystal by PVT method according to claim 1, characterized in that: The inner edge of the top of the crucible (310) is provided with a first connecting step, the outer extension of the bottom of the connecting ring (320) is provided with a second connecting step that cooperates with the first connecting step, the inner edge of the top of the connecting ring (320) is provided with a third connecting step, the outer lower edge of the second separating ring (324) is provided with a fourth connecting step that can cooperate with the third connecting step, the inner upper edge of the second separating ring (324) is provided with a fifth connecting step, and the outer edge of the growth plate (325) is provided with a sixth connecting step that can cooperate with the fifth connecting step.

3. The device for growing silicon carbide single crystal by PVT method according to claim 2, characterized in that: The bottom of the connecting ring (320) is located on the back of the second connecting step and is also provided with an extended circular ring, and the top of the extended circular ring is provided with a seventh connecting step for mounting the outer edge of the first separating ring (321).

4. The device for growing silicon carbide single crystal by PVT method according to claim 1, characterized in that: The furnace cavity (200) is cylindrical, the top of the furnace cavity (200) is closed, and the bottom is open; an annular mounting seat (210) for mounting the furnace cavity (200) is provided on the frame (100); a slope is provided at the bottom of the inner wall of the annular mounting seat (210); a support ring (211) for supporting the lower edge of the furnace cavity (200) is provided at the bottom of the slope; a first limiting ring (212) is provided in the gap between the inner wall of the annular mounting seat (210) and the outer wall of the furnace cavity (200); the width of the first limiting ring (212) is equal to the width of the bottom surface of the slope; the first limiting ring (212) is located at the upper edge of the slope; a second limiting ring (213) is also provided at the top of the annular mounting seat (210); the inner diameter of the second limiting ring (213) is equal to the inner diameter of the furnace cavity (200); The outer diameter of the annular mounting seat (210) is consistent with that of the annular mounting seat (210), and the bottom of the second limiting ring (213) is provided with an annular latch (214) which can be inserted into the gap between the inner side wall of the annular mounting seat (210) and the outer wall of the furnace cavity (200); the furnace cavity (200) further comprises a bottom plate (220), the top surface of the bottom plate (220) is provided with a support member (221), the thermal field structure is installed on the top of the support member (221), and the furnace cavity (200) further comprises an extension section (222), the extension section (222) is cylindrical, the upper edge of the extension section (222) is fixed to the bottom of the annular mounting seat (210), the lower edge of the extension section (222) is connected to the top outer edge of the bottom plate (220), and the top outer edge of the bottom plate (220) is provided with a connecting groove (223) for the lower edge of the extension section (222) to be inserted.

5. The device for growing silicon carbide single crystal by PVT method according to claim 1, characterized in that: The heating structure (400) comprises a lifting assembly and a heating assembly, wherein the lifting assembly comprises a first lifting unit and a second lifting unit which are arranged in a mirror-symmetrical manner outside the furnace cavity (200), and a lifting motor (440) for synchronously driving the first lifting unit and the second lifting unit to move up and down, wherein the lifting unit is arranged on a frame (100), and the heating assembly is sleeved outside the thermal field structure, and the bottom of the heating assembly is mounted on the lifting unit.

6. The device for growing silicon carbide single crystal by PVT method according to claim 5, characterized in that: The first lifting unit comprises a first screw rod (410) vertically arranged on the frame (100), a first guide column (411) arranged on the side of the first screw rod (410) and parallel to the first screw rod (410), and a first guide sleeve (412) simultaneously sleeved on the first screw rod (410) and the first guide column (411); a first synchronous wheel (414) is arranged at the bottom of the first screw rod (410); a first connecting bridge (413) is arranged on the first guide sleeve (412); the extension direction of the first connecting bridge (413) is perpendicular to the extension direction of the first screw rod (410); and a first lifting seat (415) is arranged at the front end of the first connecting bridge (413); the second lifting unit comprises a second screw rod (420) vertically arranged on the frame (100), a second guide column (411) arranged on the side of the second screw rod (420) and parallel to the second screw rod (420); A guide column (421) and a second guide sleeve (422) which is simultaneously sleeved on the second screw rod (420) and the second guide column (421); a second synchronous wheel (424) is provided at the bottom of the second screw rod (420); a second connecting bridge (423) is provided on the second guide sleeve (422); the extension direction of the second connecting bridge (423) is perpendicular to the extension direction of the second screw rod (420); a second lifting seat (425) is provided at the front end of the second connecting bridge (423); the lifting motor (440) is vertically installed on the frame (100) downward and forms a triangular formation with the first lifting unit and the second lifting unit; a third synchronous wheel (441) is provided at the output end of the lifting motor (440); and the lifting assembly also includes a synchronous transmission belt which connects the first synchronous wheel (414), the second synchronous wheel (424) and the third synchronous wheel (441) for synchronous transmission.

7. The device for growing silicon carbide single crystal by PVT method according to any one of claims 5 or 6, characterized in that: The heating component comprises A support frame; two sides of the bottom of the support frame are respectively fixed on the first lifting seat (415) and the second lifting seat (425); Main body coil; the main body coil is mounted on the support frame.

8. The device for growing silicon carbide single crystal by PVT method according to claim 7, characterized in that: The support frame comprises a lower ring (430), an upper ring (431) and a connecting column (432) for connecting the upper ring (431) and the lower ring (430); the main body coil is composed of a plurality of "C"-shaped coils (433) assembled from top to bottom, the tail end of the "C"-shaped coil (433) of the upper layer is connected to the head of the "C"-shaped coil (433) of the adjacent lower layer, and the upper and lower edges of the "C"-shaped coil (433) are both provided with "C"-shaped metal plates (434), a plurality of connecting ears (435) are provided on the outer side surface of the "C"-shaped coil (433), the position of the connecting ears (435) corresponds to the position of the connecting body, a columnar spacer ring (436) is provided between the upper and lower adjacent connecting ears (435), the connecting ears (435) and the columnar spacer ring (436) are both sleeved on the middle part of the connecting body, the top of the connecting column (432) is fixedly connected to the upper ring (431), and the bottom is fixedly connected to the lower ring (430).

9. The device for growing silicon carbide single crystal by PVT method according to claim 8, characterized in that: The center of the main body coil is provided with a water cooling pipeline extending from the head end of the main body coil to the tail end of the main body coil.

10. The device for growing silicon carbide single crystal by PVT method according to claim 1, characterized in that: The device for growing silicon carbide single crystals using the PVT method further comprises a shielding structure, wherein the shielding structure comprises a shielding cover (500) installed on a frame (100) and covering the heating structure (400), and a water cooling pipe (501) for cooling the shielding cover (500) is provided on the outer surface of the shielding cover (500).

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