A crucible for liquid phase growth of silicon carbide crystals and method of use

Abstract

The application discloses a liquid-phase method growth crucible for silicon carbide crystals and a use method, relates to the technical field of silicon carbide crystal preparation, and comprises a charging crucible, a crucible cover arranged above the charging crucible, a heating cavity arranged on the outer wall of the charging crucible, a center positioning column arranged at the bottom of the charging crucible, a limiting seat with a smaller cross-section diameter fixedly arranged at the top of the center positioning column, a graphite soft felt detachably arranged on the limiting seat through screw threads, a limiting plate sleeved on the graphite soft felt above the limiting seat, a penetrating sealing hole arranged at the center point of the crucible cover, a pulling rod penetratingly arranged on the sealing hole, a seed crystal holder connected with the bottom of the pulling rod through screw threads, and the graphite soft felt and the limiting plate being immersed in a fluxing agent. The application can accelerate the carbon dissolving speed, improve the carbon concentration in the melt, improve the crystal growth speed, reduce the fluxing agent inclusions in the crystal, effectively alleviate the problem of the melting-through of the crucible, and is convenient for opening the crucible cover and taking out the produced silicon carbide crystals, and is suitable for promotion.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of silicon carbide crystal preparation, and particularly relates to a liquid phase method growth crucible for silicon carbide crystals and a use method. BACKGROUND

[0002] The preparation methods of silicon carbide crystals as the third generation semiconductor material include a physical vapor transport method (PVT), a high-temperature chemical vapor deposition method (HTCVD) and a liquid phase method (LPE). At present, the mainstream preparation method is the PVT method, and the maximum crystal size has reached 8 inches. The dislocation density in the crystal is relatively large due to the high crystal growth temperature of the PVT method, thereby reducing the yield. Compared with the PVT method, the LPE method has a lower crystal growth temperature, and the dislocation density of the grown crystal is lower than that of the crystal grown by the PVT method. Therefore, many domestic and foreign silicon carbide substrate manufacturing enterprises have carried out researches on the LPE method for growing silicon carbide crystals.

[0003] The principle of the LPE method is to utilize the certain solubility of carbon in the silicon melt, melt the silicon in a high-purity graphite crucible, and continuously feed the carbon on the surface of the graphite crucible into the melt through convection and diffusion. The seed crystal is lowered to contact the liquid surface through a seed crystal lifting mechanism and then slowly lifted upward, so that the silicon and carbon in the melt are crystallized on the surface of the seed crystal to realize crystal growth. The carbon concentration and distribution in the melt are key factors for the liquid phase growth of the silicon carbide crystal. When the carbon concentration is too small and the concentration distribution is uneven, the crystal growth speed is too slow, and the inclusion is prone to occur in the crystal. In addition, the graphite crucible is gradually consumed during the growth, and the crucible will be melted through after a long time of growth, which will cause damage due to the outflow of the high-temperature melt.

[0004] In view of the problem, some patents have been reported. Patent CN116695256A proposes to use a silicon carbide or graphite block floating on the surface of the melt to supplement the carbon source and protect the crucible. Patent CN116988138A proposes to add a stirring member to promote diffusion and improve the concentration distribution. However, since the carbon in the melt comes from the inner wall of the graphite crucible, the two methods cannot solve the problem of low carbon concentration in the melt at the center of the seed crystal when the seed crystal is large. SUMMARY

[0005] The purpose of the present application is to provide a liquid phase growth crucible for silicon carbide crystals and a use method, which can accelerate the carbon dissolution speed, improve the carbon concentration in the melt, improve the crystal growth speed and reduce the inclusion of the dissolving agent in the crystal, effectively alleviate the problem of crucible melting through, and facilitate the opening of the crucible cover and the taking out of the produced silicon carbide crystals, and is suitable for promotion.

[0006] The application provides a liquid phase method growth crucible for silicon carbide crystals, which comprises a charging crucible, a crucible cover arranged above the charging crucible, a heating cavity arranged in the outer wall of the charging crucible, a center positioning column arranged at the center point of the bottom of the charging crucible and detachable, a limiting seat with a smaller cross-sectional diameter than the center positioning column and fixedly arranged at the top of the center positioning column, a graphite soft felt detachably arranged on the limiting seat through screw threads, a limiting plate sleeved on the limiting seat above the graphite soft felt, a through sealing hole arranged at the center point of the crucible cover, a pulling rod arranged through the sealing hole, a seed crystal holder connected with the bottom of the pulling rod through screw threads, and the graphite soft felt and the limiting plate being immersed in a solubilizing agent.

[0007] Upwardly extending and mutually symmetrical erected frames are fixedly arranged at the two side walls of the upper end of the charging crucible, sliding tracks are arranged through the erected frames, the sliding tracks are tracks from top to bottom, lifting sliding blocks are fixedly arranged at the two sides of the erected frames, the lifting sliding blocks pass through the sliding tracks and are slidably connected with the sliding tracks, rotating seats are arranged at the top of the sliding tracks of the erected frames, the rotating seats are embedded in the erected frames and are provided with clamping grooves, the clamping grooves are connected with the sliding tracks, and the depth of the clamping grooves meets the requirement that the lifting sliding blocks are lifted into the clamping grooves and separated from the sliding tracks.

[0008] An insertion ring is fixedly arranged at the lower surface edge of the crucible cover, an insertion groove is arranged at the corresponding position of the insertion ring of the upper end of the charging crucible, an elastic pad is fixedly arranged at the bottom of the insertion groove, the bottom of the insertion ring is pressed on the elastic pad, the inner wall of the insertion groove is tightly connected with the outer wall of the insertion ring, a plurality of downward pressing bins are fixedly arranged in a circumferential array around the insertion ring of the charging crucible, an extrusion groove is arranged at the corresponding downward pressing bin of the insertion ring, a downward pressing block is slidably arranged in the downward pressing bin through a supporting spring, and the cross section of the downward pressing block is conical, and the upper and lower side surfaces thereof are inclined extrusion sliding surfaces.

[0009] Preferably, the limiting plate is circular, a through hole is arranged at the center point of the limiting plate, the through hole is penetrated by the limiting seat and connected through screw threads, and a fan-shaped radial opening is arranged around the through hole of the limiting plate.

[0010] Preferably, the lifting sliding blocks pass through the sliding tracks and are fixedly provided with power-assisted handles.

[0011] Preferably, built-in sliding rails are arranged at the corresponding positions of the downward pressing blocks on the two sides of the inner wall of the downward pressing bin, the downward pressing blocks are slidably connected with the built-in sliding rails, and chamfers are arranged at the upper and lower side edges of the extrusion groove, and the extrusion sliding surfaces are slidably connected with the chamfers.

[0012] Preferably, the graphite soft felt is a loose porous structure composed of graphite fibers.

[0013] Preferably, the height of the rotating seat meets the requirement that the rotation of the crucible cover is not blocked by the charging crucible when the lifting sliding blocks rotate in the clamping grooves.

[0014] A liquid phase method growth crucible of silicon carbide crystal, also includes the following using method:

[0015] 1)、Center positioning column is installed to the bottom of the charging crucible and the cosolvent is filled to a certain height;

[0016] 2)、The graphite soft felt with the same size as the diameter of the limiting plate is cut, and a hole is opened in the center of the soft felt;

[0017] 3)、The graphite soft felt is sleeved into the center positioning column, and the limiting plate is installed and the remaining cosolvent is filled;

[0018] 4)、The heating cavity is heated, and the seed crystal is formed on the seed crystal support;

[0019] 5)、The charging crucible is cooled, the crucible cover is lifted by the power handle, the lifting slide block moves upwards along the sliding rail and enters the clamping groove, and the power handle is twisted at this time, so that the two rotating seats are rotated on the standing frame;

[0020] 6)、The crucible cover is rotated with the rotating seat, the seed crystal support is driven towards the outside, and the seed crystal on the seed crystal support is taken off;

[0021] 7)、The raw material is added to the charging crucible, the crucible cover is lowered along the sliding rail and covered on the charging crucible, and the production is carried out again.

[0022] Preferably, the thickness of the graphite soft felt 11 is 5-15 mm, and the distance between the limiting plate 12 after installation and the melt liquid surface is 15-30 mm.

[0023] The beneficial effects of the present application are as follows:

[0024] (1)、The present application is provided with graphite soft felt, which is a loose porous structure composed of graphite fibers and has a very large specific surface area, playing the role of additional carbon source. After the cosolvent is melted, it can contact more carbon sources. Compared with the inner surface of the crucible, the graphite soft felt has a faster carbon dissolution speed and a larger dissolution amount, which can slow down the speed of the cosolvent corroding the surface of the crucible, reduce the risk of crucible melting during long-time growth, and also improve the growth speed of the crystal. The limiting plate makes the graphite soft felt suspended below the seed crystal surface, shortens the distance between the seed crystal surface and the carbon source, and keeps the distance between the entire seed crystal surface and the carbon source consistent, improves the carbon concentration distribution in the melt, reduces the cosolvent inclusion defects caused by local component supercooling, and improves the crystal quality.

[0025] (2), the seed crystal production is finished on the seed crystal support, the crucible cover is lifted by the power handle, the lifting slide block connected with the crucible cover is lifted along the sliding rail, the clamping groove opening on the rotating seat is connected with the sliding rail at this time, the lifting slide block is in the clamping groove, the rotating seat is rotated by the power handle, the crucible cover is rotated, the seed crystal support connected with the crucibble cover rotates outward with the seed crystal, and the seed crystal on the seed crystal support is taken off.

[0026] (3), the insertion ring is pressed into the insertion groove when the crucible cover is pressed down, the bottom of the insertion ring extrudes the extrusion sliding surface on the upper side of the pressing block in the process of pressing down, the pressing block is extruded into the pressing chamber for the insertion ring to pass, the pressing block is extruded by the supporting spring when the extrusion groove is located at the pressing block, the extrusion sliding surface below the pressing block is extruded downwards to the extrusion groove, the insertion ring is tightly pressed on the elastic pad, and the heat dissipation is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application, and do not constitute a limitation of the application. In the drawings:

[0028] Figure 1 It is the overall schematic diagram of the application;

[0029] Figure 2 It is the half sectional view of the application;

[0030] Figure 3 It is the schematic diagram of the loading crucible working time of the application;

[0031] Figure 4 It is the enlarged view of A in the application;

[0032] Figure 5 It is the enlarged view of B in the application;

[0033] Figure 6 It is the schematic diagram of the limiting plate in the application.

[0034] In the drawings, 1 is a loading crucible, 2 is a crucible cover, 3 is a standing frame, 4 is a sealing hole, 5 is a power handle, 6 is a pressing chamber, 7 is a pulling rod, 8 is a center positioning column, 9 is a limiting seat, 10 is a heating cavity, 11 is a graphite soft felt, 12 is a limiting plate, 13 is a clamping block, 14 is a seed crystal support, 15 is a seed crystal, 16 is a rotating seat, 17 is a dissolving agent, 18 is a sliding rail, 19 is a clamping groove, 20 is an insertion ring, 21 is a pressing block, 22 is a supporting spring, 23 is an embedded sliding rail, 24 is an extrusion sliding surface, 25 is an insertion groove, 26 is an extrusion groove, 27 is an elastic pad, 28 is a lifting slide block, 29 is a radiation opening, and 30 is a through hole. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application; obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application, and all other embodiments obtained by a person of ordinary skill in the art without creative effort based on the embodiments in the present application shall fall within the protection scope of the present application.

[0036] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom end" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0037] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "provided with", "sleeved / connected", "connected" and the like should be understood broadly, for example, "connected" can be fixedly connected, or detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium; can be internal communication of two elements. For a person of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0038] The structural features of the present application will be described in detail below with reference to the drawings of the specification.

[0039] Referring to Figures 1-2 A liquid phase method growth crucible of silicon carbide crystal, comprising a charging crucible 1, a crucible cover 2 is arranged above the charging crucible 1, a heating cavity 10 is arranged in the outer wall of the charging crucible 1, the charging crucible 1 is heated, a center positioning column 8 is detachably arranged at the bottom center point of the charging crucible 1, a limiting seat 9 with a smaller cross-sectional diameter than the center positioning column 8 is fixedly arranged at the top of the center positioning column 8, a graphite soft felt 11 is detachably arranged on the limiting seat 9 through threads, the graphite soft felt 11 is a loose porous structure composed of graphite fibers, which plays the role of additional carbon source, a limiting plate 12 is sleeved above the graphite soft felt 11, the limiting plate 12 makes the graphite soft felt 11 suspended below the seed crystal surface, shortens the distance between the seed crystal surface and the carbon source, and makes the distance between the entire seed crystal surface and the carbon source consistent, a through sealing hole 4 is arranged at the center point of the crucible cover 2, a pulling rod 7 is arranged through the sealing hole 4, a seed crystal holder 14 is connected to the bottom of the pulling rod 7 through threads, and the graphite soft felt 11 and the limiting plate 12 are immersed in a solubility aid 17.

[0040] Referring to Figure 2 , 4, 5, the upper end of the charging crucible 1 is fixed with upward extending and mutually symmetrical riser 3 on both sides, the riser 3 is provided with through sliding track 18, the sliding track 18 is from top to bottom track, the crucible cover 2 is fixed with lifting slide 28 on both sides at the riser 3, the lifting slide 28 penetrates the sliding track 18, and the two side walls are slidably connected with the sliding track 18, so that the lifting slide 28 cannot rotate on the sliding track 18, but can only move up and down, the lifting slide 28 drives the crucible cover 2 to lift when moving up and down, the riser 3 is provided with rotary seat 16 at the top of the sliding track 18, the rotary seat 16 is embedded in the riser 3 and is provided with clamping groove 19, the clamping groove 19 is communicated with the sliding track 18, and the depth of the clamping groove 19 satisfies that the lifting slide 28 is lifted into the clamping groove 19 away from the sliding track 18, the height of the rotary seat 16 satisfies that the crucible cover 2 is not blocked by the charging crucible 1 when the lifting slide 28 rotates in the clamping groove 19, the lifting slide 28 penetrates out of the sliding track 18 and is fixed with power handle 5, after the lifting slide 28 enters the clamping groove 19, the power handle 5 is twisted to rotate the rotary seat 16, the crucible cover 2 rotates accordingly, the seed crystal holder 14 faces outward, and the seed crystal 15 on it is convenient to take down.

[0041] Referring to Figure 5 , the lower surface edge of the crucible cover 2 is fixed with insertion ring 20, the upper end of the charging crucible 1 is provided with insertion slot 25 corresponding to the insertion ring 20, the bottom of the insertion slot 25 is fixed with elastic pad 27, the insertion ring 20 is pressed into the insertion slot 25, the crucible cover 2 is closed in the opening of the charging crucible 1, the bottom of the insertion ring 20 is pressed on the elastic pad 27, the inner wall of the insertion slot 25 is tightly connected with the outer wall of the insertion ring 20, the charging crucible 1 is fixed with a plurality of downward pressing chambers 6 in circumferential array around the insertion ring 20, the insertion ring 20 is provided with extrusion groove 26 corresponding to the downward pressing chamber 6, the downward pressing chamber 6 is slidably provided with downward pressing block 21 through supporting spring 22, the cross section of the downward pressing block 21 is conical, the upper and lower sides are inclined extrusion sliding surface 24, when the insertion ring 20 is inserted into the extrusion groove 26, the bottom of the insertion ring 20 extrudes the upper side of the extrusion sliding surface 24 of the downward pressing block 21, and the downward pressing block 21 is extruded into the downward pressing chamber 6 for the insertion ring 20 to pass through, when the extrusion groove 26 is located at the downward pressing block 21, the downward pressing block 21 is extruded out by the supporting spring 22, the extrusion sliding surface 24 below extrudes the extrusion groove 26, so that the insertion ring 20 is tightly pressed on the elastic pad 27, the inner wall of the downward pressing chamber 6 is provided with built-in sliding rail 23 corresponding to the downward pressing block 21 on both sides, the downward pressing block 21 is slidably connected with the built-in sliding rail 23, the downward pressing block 21 can be stably translated to the extrusion groove 26 through the built-in sliding rail 23, the upper and lower sides of the extrusion groove 26 are provided with chamfer, the extrusion sliding surface 24 is slidably connected with the chamfer, and the extrusion sliding surface 24 is extruded out of the extrusion groove 26.

[0042] Referring to Figure 6The limiting plate 12 is circular, and a through hole 30 is arranged at the center point of the limiting plate 12, the through hole 30 is penetrated by the limiting seat 9 and is connected through screw thread, and a fan-shaped radial opening 29 is arranged around the through hole 30 on the limiting plate 12, so that the molecules of the carbon dissolved in the graphite soft felt 11 can more fully penetrate the limiting plate 12 and move to the seed crystal holder 14.

[0043] Referring to Figures 1-5 The application further relates to a use method of the silicon carbide crystal liquid-phase growth crucible.

[0044] The center positioning column 8 is installed at the bottom of the charging crucible 1, and the dissolving agent 17 is filled to a certain height;

[0045] Further, the graphite soft felt 11 with the same size as the diameter of the limiting plate 12 is cut and the center of the soft felt is opened;

[0046] Further, the graphite soft felt 11 is sleeved into the center positioning column 8, the remaining dissolving agent 17 is filled after the limiting plate 12 is installed;

[0047] Further, the heating cavity 10 is heated, and the seed crystal 15 on the seed crystal holder 14 is formed;

[0048] Further, the charging crucible 1 is cooled, the crucible cover 2 is lifted through the power-assisted handle 5, the lifting slide block 28 is moved upwards along the sliding rail 18 and is entered into the clamping groove 19, at this time, the power-assisted handle 5 is twisted, so that the two rotating seats 16 are rotated on the vertical frame 3;

[0049] Further, the crucible cover 2 is rotated with the rotating seat 16, the seed crystal holder 14 is driven to face the outside, and the seed crystal 15 on the seed crystal holder 14 is taken off;

[0050] Further, the raw material is added into the charging crucible 1, the crucible cover 2 is lowered on the charging crucible 1 along the sliding rail 18, and the production is carried out again.

[0051] Referring to Figure 3 The thickness of the graphite soft felt 11 is 5-15 mm, and the distance between the limiting plate 12 after installation and the melt liquid surface is 15-30 mm.

[0052] The silicon carbide crystal liquid-phase growth crucible and the use method thereof can accelerate the carbon dissolving speed, improve the carbon concentration in the melt, improve the crystal growth speed and reduce the dissolving agent inclusions in the crystal, the problem of crucible melting can be effectively alleviated, the opening of the crucible cover and the taking out of the produced silicon carbide crystal are convenient, and the application is suitable for promotion.

[0053] Specifically, in use, refer to Figure 3, graphite soft felt 11 is loose porous structure by graphite fiber, has very large specific surface area, plays the role of additional carbon source, after the melting of auxiliary solvent 17 can contact more carbon source, compared with the inner surface of crucible, graphite soft felt 11 carbon dissolving speed is faster, and the dissolution amount is larger, on the one hand, it can slow down the speed of auxiliary solvent corrosion of the surface of the crucible, reduce the risk of crucible melting through in long time growth, in addition, it can also improve the growth rate of crystal, limit plate 12 makes graphite soft felt 11 suspended below the seed crystal surface, shortens the distance between seed crystal surface and carbon source, and makes the distance between the whole seed crystal surface and carbon source consistent, improves the carbon concentration distribution in the melt, reduces auxiliary solvent 17 inclusion defects generated by local component undercooling, then according to the prior art in the field of silicon carbide crystal liquid phase method growth is implemented, and details are not repeated.

[0054] Referring to Figure 1 、 4 , 5, after the production of seed crystal 15 on seed crystal holder 14, the crucible cover 2 is lifted by the power grip 5, the lifting slide block 28 connected with the crucible cover 2 is lifted along the sliding rail 18, at this time, the clamping groove 19 on the rotating seat 16 is opened downward and connected with the sliding rail 18, after the lifting slide block 28 enters the clamping groove 19, the rotating seat 16 is rotated by twisting the power grip 5, the crucible cover 2 is rotated, and the seed crystal holder 14 connected with the crucible cover 2 rotates outward with the seed crystal 15, so that the seed crystal 15 on the seed crystal holder 14 is removed.

[0055] Referring to Figure 5 , when the crucible cover 2 is pressed down, the insertion ring 20 on it is pressed into the insertion groove 25, in the process of pressing down, the bottom of the insertion ring 20 extrudes the extrusion sliding surface 24 on the upper side of the pressing block 21, extrudes the pressing block 21 into the pressing chamber 6 for the insertion ring 20 to pass through, when the extrusion groove 26 is located at the pressing block 21, the pressing block 21 is extruded out by the supporting spring 22, and the extrusion sliding surface 24 below it extrudes the extrusion groove 26 downward, so that the insertion ring 20 is tightly pressed on the elastic pad 27, so that it is tightly closed, reducing heat dissipation.

[0056] The above only describes the preferred embodiments of the present application and is not used to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent replacement for part of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A liquid-phase growth crucible for silicon carbide crystals, comprising a charging crucible (1), characterized in that, The crucible (1) is provided with a crucible cover (2) above it. The outer wall of the crucible (1) is provided with a heating chamber (10). The center positioning post (8) is detachably provided at the center point of the bottom of the crucible (1). A limiting seat (9) with a cross-sectional diameter smaller than the center positioning post (8) is fixedly provided at the top of the center positioning post (8). A graphite soft felt (11) is detachably provided on the limiting seat (9) by means of a thread. A limiting plate (12) is sleeved on the limiting seat (9) above the graphite soft felt (11). A through sealed hole (4) is provided at the center point of the crucible cover (2). A lifting rod (7) is provided through the sealed hole (4). A seed crystal holder (14) is connected to the bottom of the lifting rod (7) by means of a thread. The graphite soft felt (11) and the limiting plate (12) are immersed in a flux (17). The upper side walls of the charging crucible (1) are fixed with upwardly extending and symmetrical upright frames (3). The upright frames (3) are provided with a through sliding track (18). The sliding track (18) is a track from top to bottom. The two sides of the crucible cover (2) are fixed with lifting sliders (28) at the upright frames (3). The lifting sliders (28) pass through the sliding track (18) and the two side walls are slidably connected to the sliding track (18). The upright frames (3) are provided with a rotating seat (16) at the top of the sliding track (18). The rotating seat (16) is embedded in the upright frames (3) and is provided with a slot (19). The slot (19) is connected to the sliding track (18), and the depth of the slot (19) is sufficient for the lifting slider (28) to disengage from the sliding track (18) and rise into the slot (19). An insertion ring (20) is fixedly provided at the lower edge of the crucible cover (2). An insertion groove (25) is provided at the corresponding insertion ring (20) at the upper end of the loading crucible (1). An elastic pad (27) is fixedly provided at the bottom of the insertion groove (25). The bottom of the insertion ring (20) is pressed on the elastic pad (27). The inner wall of the insertion groove (25) is tightly connected to the outer wall of the insertion ring (20). A plurality of pressure chambers (6) in a circular array are fixedly provided around the insertion ring (20) of the loading crucible (1). An extrusion groove (26) is provided at the corresponding pressure chamber (6) of the insertion ring (20). A pressure block (21) is slidably provided in the pressure chamber (6) by a support spring (22). The pressure block (21) has a conical cross section and its upper and lower sides are inclined extrusion sliding surfaces (24).

2. The liquid-phase growth crucible for silicon carbide crystals according to claim 1, characterized in that, The limiting plate (12) is circular, with a through hole (30) at its center. The through hole (30) is penetrated by the limiting seat (9) and connected by threads. The limiting plate (12) has fan-shaped radial openings (29) around the through hole (30).

3. The liquid-phase growth crucible for silicon carbide crystals according to claim 1, characterized in that, The lifting slider (28) extends through the sliding track (18) and is fixedly equipped with a power-assisted grip (5).

4. The liquid-phase growth crucible for silicon carbide crystals according to claim 1, characterized in that, The inner walls of the pressure chamber (6) are provided with built-in slide rails (23) on both sides corresponding to the pressure blocks (21). The pressure blocks (21) are slidably connected to the built-in slide rails (23). The upper and lower edges of the extrusion groove (26) are chamfered, and the extrusion sliding surface (24) is slidably connected to the chamfer.

5. The liquid-phase growth crucible for silicon carbide crystals according to claim 1, characterized in that, The graphite felt (11) is a loose and porous structure composed of graphite fibers.

6. The liquid-phase growth crucible for silicon carbide crystals according to claim 1, characterized in that, The height of the rotating seat (16) is such that when the lifting slider (28) rotates in the slot (19), the rotation of the crucible cover (2) is not blocked by the loading crucible (1).

7. A method of using a liquid-phase growth crucible for silicon carbide crystals, comprising the liquid-phase growth crucible for silicon carbide crystals as described in claims 1-6, characterized in that: 1) Install the central positioning column (8) at the bottom of the loading crucible (1) and fill it with flux (17) to a certain height; 2) Cut graphite soft felt (11) to the same diameter as the limiting plate (12), and make a hole in the center of the soft felt; 3) Insert the graphite soft felt (11) into the central positioning post (8), install the limiting plate (12), and then fill in the remaining flux (17). 4) The heating chamber (10) is heated, and the seed crystal (15) is formed on the seed crystal holder (14); 5) After the crucible (1) is cooled, the crucible lid (2) is lifted by the assist handle (5), and the lifting slider (28) moves upward along the sliding track (18) and enters the slot (19). At this time, the assist handle (5) is twisted to make the two rotating seats (16) rotate on the standing frame (3). 6) The crucible lid (2) rotates with the rotating seat (16), causing the seed crystal holder (14) to face outwards, and the seed crystal (15) on it is removed; 7) Add raw materials into the charging crucible (1), and lower the crucible lid (2) along the sliding track (18) to cover the charging crucible (1) for further production.

8. The method of using a liquid-phase growth crucible for silicon carbide crystals according to claim 7, characterized in that, The graphite soft felt (11) is 5~15mm thick, and the limiting plate (12) after installation is 15~30mm away from the melt surface.

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