Silicon carbide growth device

Abstract

The invention relates to the technical field of silicon carbide single crystals, in particular to a silicon carbide growth device. The silicon carbide growth device comprises a base, a lifting device and a tray, the lifting device comprises a fixed part and a lifting part, and the lifting part is arranged on the fixed part and can move in the vertical direction relative to the fixed part; the tray is arranged at one end, away from the fixed part, of the lifting part and is suitable for placing a graphite crucible; wherein in the first direction, the fixing part is movably arranged on the base and has a first position and a second position, when the tray descends to the preset position and the fixing part is located at the first position, the old graphite crucible on the tray is suitable for being taken away, and when the tray descends to the preset position and the fixing part is located at the second position, the old graphite crucible on the tray is suitable for being taken away. The tray is suitable for placing a new graphite crucible, and the first direction is perpendicular to the vertical direction. The thickness and quality of the silicon carbide crystal can be improved, and the production cost can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of silicon carbide single crystals, and in particular to a silicon carbide growth device. Background Art

[0002] As one of the third-generation semiconductor materials that has received close attention, silicon carbide has excellent characteristics such as large bandgap, high breakdown field strength, high thermal conductivity, high temperature resistance, and large electron saturation drift rate. It is considered to be the preferred substrate material for the preparation of high-voltage, high-frequency, and high-power semiconductor devices, and has been widely used in important fields such as smart grids, new energy vehicles, and aerospace. At present, the main growth method of silicon carbide is physical vapor transport. Although this method is relatively mature and can supply a large number of silicon carbide single crystal substrates to the market, due to the instability of the growth environment, there are still defects such as micropipes and wrapping in its crystals, and there are still various problems in diameter expansion and P-type silicon carbide crystal growth.

[0003] In contrast, the liquid phase growth method requires a low growth temperature, a relatively stable growth environment, and has good prospects in P-type crystal growth and crystal expansion. Liquid phase SiC single crystals are grown in a silicon-based solvent in which carbon is dissolved. This process is carried out under conditions close to thermodynamic equilibrium, and can produce high-quality SiC single crystals with zero microtubes and extremely low dislocation density. At the same time, liquid phase growth can also obtain P-type SiC single crystals with high doping concentrations by introducing metal elements such as aluminum. Currently, liquid phase SiC single crystal growth technology has become a research hotspot.

[0004] However, during the growth of liquid phase SiC single crystals, since the graphite crucible acts as a carbon source, the carbon in the crucible itself will be dissolved by the high-temperature solution, but it cannot be replenished. If the liquid phase growth is carried out for too long, the crucible will be severely corroded or even eroded through. In order to avoid the crucible being eroded through, the only way is to shorten the crystal growth time, which leads to insufficient thickness of SiC ingots and increased production costs. Summary of the invention

[0005] The present application provides a silicon carbide growth device, which can replace a graphite crucible during the crystal growth process, thereby improving the thickness and quality of the silicon carbide crystal and reducing the production cost.

[0006] In order to achieve the above objectives, the main technical solutions adopted in this application include:

[0007] An embodiment of the present application provides a silicon carbide growth device, comprising a base, a lifting device and a tray, the lifting device comprising a fixing part and a lifting part, the lifting part being arranged on the fixing part and movable in a vertical direction relative to the fixing part; a tray being arranged at an end of the lifting part away from the fixing part, the tray being suitable for placing a graphite crucible; wherein, along a first direction, the fixing part is movably arranged on the base and has a first position and a second position, when the tray descends to a preset position and the fixing part is in the first position, the old graphite crucible on the tray is suitable for being removed, and when the tray descends to the preset position and the fixing part is in the second position, the tray is suitable for placing a new graphite crucible, and the first direction is perpendicular to the vertical direction.

[0008] The silicon carbide growth device proposed in the embodiment of the present application can change the position of the graphite crucible by moving the position of the fixing part along the first direction and the position of the lifting part along the vertical direction, thereby removing the old graphite crucible and placing the new graphite crucible, and replacing the graphite crucible during the crystal growth process, thereby extending the growth time of a single silicon carbide crystal, thereby increasing the thickness of the silicon carbide crystal and improving the production effect. At the same time, since the entire silicon carbide crystal growth process is continuous and uninterrupted, the energy utilization rate is improved and the production efficiency is improved.

[0009] Optionally, the base includes at least one guide rail, the guide rail extends along the first direction, and the fixing portion is slidably disposed on the guide rail.

[0010] In the above scheme, at least one guide rail is provided on the base, and the fixed part is slidably arranged on the first guide rail. The fixed part can drive the lifting part to move between the first position and the second position and the position corresponding to the growth of silicon carbide crystals, thereby realizing the replacement of the graphite crucible, thereby improving the growth time of silicon carbide crystals.

[0011] Optionally, the base also includes a bottom plate, which is provided with a fitting gap extending along the first direction, and the maximum outer diameter of the lifting part and the outer diameter of the tray are both smaller than the size of the fitting gap in the second direction, so that when the fixing part moves between the first position and the second position, the lifting part and the tray can both pass through the fitting gap and the graphite crucible is supported on the bottom plate, and the first direction, the second direction and the vertical direction are perpendicular to each other.

[0012] In the above scheme, the size of the fitting gap in the second direction is larger than the maximum outer diameter of the lifting part and the outer diameter of the tray, and smaller than the outer diameter of the graphite crucible in the second direction, so that the lifting part and the tray can pass through the fitting gap, and the lifting part and the tray can rise above the bottom plate or fall below the bottom plate. For example, when the fixing part is in the first position, the lifting part and the tray fall below the bottom plate, and the bottom plate can support the graphite crucible. A new graphite crucible can also be supported on the bottom plate in the second position, the fixing part moves to the second position, the lifting part and the tray rise above the bottom plate, and the graphite crucible is taken away, thereby realizing the replacement of the graphite crucible.

[0013] Optionally, the bottom plate includes a first bottom plate and a second bottom plate, the first bottom plate and the second bottom plate both extend along the first direction, and the first bottom plate and the second bottom plate are spaced apart along the second direction to form the fitting gap.

[0014] In the above scheme, a first bottom plate and a second bottom plate are provided on the base, and the first bottom plate and the second bottom plate are spaced apart along the second direction, and a matching gap is formed between the first bottom plate and the second bottom plate for the lifting part and the tray to pass through. The lifting part and the tray are lowered below the first bottom plate and the second bottom plate to replace the old graphite crucible with the new one.

[0015] Optionally, the silicon carbide growth device also includes a shell, the shell includes a first side plate and a second side plate, the first side plate and the second side plate are opposite to each other and spaced apart along the first direction, the first side plate and the second side plate are both arranged on the bottom plate and extend upward; the first side plate is closer to the first position than the second side plate, the first side plate is provided with a first opening for taking the old graphite crucible from the first position, and the second side plate is provided with a second opening for placing a new graphite crucible toward the second position.

[0016] In the above solution, the first opening is provided on the first side plate, through which the old graphite crucible can be taken away. The second opening is provided on the second side plate, through which the new graphite crucible can be placed on the first bottom plate and the second bottom plate in the housing.

[0017] Optionally, the shell further includes a first plate, which is rotatable relative to the first side plate to open or close the first opening; the shell further includes a second plate, which is rotatable relative to the second side plate to open or close the second opening.

[0018] In the above scheme, the first plate is rotated relative to the first side plate to open the first opening, the old graphite crucible can be taken out, and then the first plate is closed. The second plate is rotated relative to the second side plate to open the second opening, the new graphite crucible can be placed on the first bottom plate and the second bottom plate in the housing, and then the second plate is closed.

[0019] Optionally, the shell also includes a top plate, which is arranged above the first side plate and the second side plate and is respectively connected to the first side plate and the second side plate; a first mounting hole is provided on the top plate, and the first mounting hole is suitable for the lifting part, the tray and the graphite crucible on the tray to pass through.

[0020] In the above scheme, the top plate is connected to the top of the first side plate and the second side plate. After a new graphite crucible is placed on the tray, the lifting part drives the new graphite crucible to rise, pass through the first mounting hole on the top plate, enter the growth zone, and be heated to grow silicon carbide.

[0021] Optionally, an electric heating element is disposed on the top plate, and the electric heating element is disposed on the top plate and around the first mounting hole.

[0022] In the above scheme, an electric heating element is provided above the top plate, and the electric heating element is arranged around the first mounting hole. When the graphite crucible passes through the first mounting hole for silicon carbide crystal growth, medium-frequency alternating current is passed through the electric heating element. After the electric heating element is energized, an alternating magnetic field is generated to heat the graphite crucible.

[0023] Optionally, a heat-insulating component is further provided on the top plate, and the heat-insulating component is provided on the inner side of the electric heating component and around the first mounting hole.

[0024] In the above scheme, when the graphite crucible passes through the first mounting hole for silicon carbide growth, the heat-insulating element is located between the graphite crucible and the electric heating element to insulate the graphite crucible.

[0025] Optionally, the silicon carbide growth device further includes a heat-insulating shell, which covers the electric heating element and the heat-insulating element; the silicon carbide growth device further includes a seed rod, which passes through the heat-insulating shell and is movable in a vertical direction relative to the heat-insulating shell to extend into or out of the graphite crucible.

[0026] In the above scheme, the heat-insulating shell is used for heat insulation and heat preservation. The heat-insulating shell is arranged above the top plate and covers the electric heating element and the heat-insulating element. The seed crystal rod passes through the heat-insulating shell and extends into the graphite crucible for silicon carbide crystal growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is a schematic diagram of the structure of the silicon carbide growth device of the present application;

[0029] Figure 2 This is a schematic diagram of the structure of the silicon carbide growth device of the present application;

[0030] Figure 3 This is a schematic diagram of the structure of the silicon carbide growth device of the present application.

[0031] [Description of Reference Numerals]

[0032] 1: base; 11: first position; 12: second position; 13: guide rail; 14: first bottom plate; 15: second bottom plate; 16: fitting clearance;

[0033] 2: lifting device; 21: fixing part; 22: lifting part;

[0034] 3: tray; 31: bottom insulation layer;

[0035] 4: Graphite crucible;

[0036] 5: housing; 51: first side plate; 510: first opening; 511: first plate; 52: second side plate; 520: second opening; 521: second plate; 53: top plate; 530: first mounting hole;

[0037] 6: Electric heating element;

[0038] 7: Insulation parts;

[0039] 8: Insulation shell;

[0040] 9: seed crystal rod; 91: seed crystal;

[0041] A: first direction; B: second direction; C: vertical direction. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0043] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0044] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0045] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0046] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0047] The term "multiple" as used in this application refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple sheets" refers to more than two sheets (including two sheets).

[0048] The main structure of the liquid phase growth device of silicon carbide single crystal consists of an external induction heating coil, a graphite insulation felt, a high-purity graphite crucible that serves as a high-temperature solution container and a carbon source, a high-temperature melt, a silicon carbide seed crystal, and a suspension rod. When growing a silicon carbide single crystal, first use an induction coil to heat the crucible until the raw material is completely melted. When a stable temperature field is formed and the concentration of carbon in the high-temperature solution reaches equilibrium, the suspension rod with the seed crystal is slowly immersed in the high-temperature solution from the top. Since the temperature at the top of the crucible is low and the temperature at the bottom is high, a temperature gradient will be generated in the crucible. The axial temperature gradient in the crucible leads to a difference in the solubility of carbon, which makes the saturated carbon-containing solution at the bottom flow to the vicinity of the seed crystal with a lower temperature, and a silicon carbide single crystal grows on the surface of the seed crystal. As the crystal grows, the carbon in the solution gradually precipitates and returns to the high-temperature area of ​​the crucible wall through convection, dissolving the carbon again to form a saturated solution, and this process is circulated to continuously grow silicon carbide single crystals. During the growth of the crystal, since the graphite crucible acts as a carbon source, the carbon in the crucible itself will be dissolved by the high-temperature solution but cannot be replenished. If the liquid phase growth is carried out for too long, the crucible will be severely corroded or even etched through. Therefore, in order to avoid the crucible being etched through, the crystal growth time can only be shortened, resulting in insufficient thickness of the silicon carbide ingot and increased production costs.

[0049] To solve the above problems, the present application designs a crystal growth device that can sustainably grow silicon carbide crystals and replace the corroded crucible during the crystal growth process without having to reheat or cool it, thereby achieving the growth of thicker silicon carbide ingots.

[0050] The present application provides a silicon carbide growth device, referring to Figures 1 to 3 The silicon carbide growth device includes a base 1, a lifting device 2 and a tray 3. The lifting device 2 includes a fixing portion 21 and a lifting portion 22. The lifting portion 22 is arranged on the fixing portion 21 and is movable in a vertical direction C relative to the fixing portion 21; the tray 3 is arranged at one end of the lifting portion 22 away from the fixing portion 21, and the tray 3 is suitable for placing a graphite crucible 4; wherein, along a first direction A, the fixing portion 21 is movably arranged on the base 1 and has a first position 11 and a second position 12. When the tray 3 descends to a preset position and the fixing portion 21 is in the first position 11, the old graphite crucible 4 on the tray 3 is suitable for being taken away, and when the tray 3 descends to the preset position and the fixing portion 21 is in the second position 12, the tray 3 is suitable for placing a new graphite crucible 4. The first direction A is perpendicular to the vertical direction C.

[0051] The lifting device 2 is arranged on the base 1, the fixing part 21 is movably arranged on the base 1 along the first direction A, and has a first position 11 and a second position 12 on the base 1, the lifting part 22 is arranged on the fixing part 21, and the lifting part 22 can move in the vertical direction C relative to the fixing part 21. A tray 3 is provided at one end of the lifting part 22 away from the fixing part 21, and the tray 3 is used to place the graphite crucible 4, that is, the tray 3 is used to support the graphite crucible 4 for the growth of silicon carbide crystals.

[0052] Specifically, in the silicon carbide crystal growth experiment, the raw materials required for the growth of silicon carbide crystals are first placed in the graphite crucible 4, and the crucible is placed in the second position 12. When the lifting part 22 descends to the preset position and is in the second position 12, the tray 3 lifts the graphite crucible 4. Then, the fixed part 21 moves on the base 1 to the position directly below the silicon carbide crystal growth reaction, and the lifting part 22 rises to the position of the silicon carbide crystal growth reaction to grow the silicon carbide crystal. After the silicon carbide crystal grows for a certain period of time, the lifting part 22 descends, the fixed part 21 moves to the first position 11, and the lifting part 22 descends to the preset position, so that the old graphite crucible 4 can be taken away. Then, the fixed part 21 moves to the second position 12, and a new graphite crucible 4 is placed on the tray 3. Then, the fixed part 21 moves on the base 1 to the position directly below the silicon carbide crystal growth position, and the lifting part 22 rises to the position of the silicon carbide crystal growth reaction to grow the silicon carbide crystal.

[0053] The silicon carbide growth device proposed in the embodiment of the present application can change the position of the graphite crucible 4 by moving the position of the fixing part 21 along the first direction A and the position of the lifting part 22 along the vertical direction C, thereby removing the old graphite crucible 4 and placing the new graphite crucible 4, and replacing the graphite crucible 4 during the crystal growth process, thereby extending the growth time of a single silicon carbide crystal, thereby increasing the thickness of the silicon carbide crystal and improving the production effect. At the same time, since the entire silicon carbide crystal growth process is continuous and uninterrupted, the energy utilization rate is improved and the production efficiency is improved.

[0054] In the present application, the crucible is moved between the first position 11 and the second position 12 by a movable lifting device 2, without manual operation, and the process is convenient and quick.

[0055] The lifting part 22 in the present application may be composed of a telescopic mechanism composed of a plurality of telescopic rods, and the telescopic mechanism may be mechanically driven or hydraulically driven.

[0056] It should be understood that the lifting device 2 in the present application can also be a screw nut, a hydraulic cylinder telescopic mechanism or a cylinder telescopic mechanism, etc.

[0057] The graphite crucible 4 is made of high-purity graphite and serves as a solution container and a carbon source when the silicon carbide crystal grows.

[0058] In a specific embodiment, a bottom insulation layer 31 is provided on the tray 3. The bottom insulation layer 31 is made of insulation graphite felt and is used for heat preservation and heat resistance.

[0059] Optionally, the base 1 includes at least one guide rail 13 , the guide rail 13 extends along the first direction A, and the fixing portion 21 is slidably disposed on the guide rail 13 .

[0060] At least one guide rail 13 is provided on the base 1, and the fixing part 21 is slidably arranged on the first guide rail 13. The fixing part 21 can drive the lifting part 22 to move between the first position 11 and the second position 12 and the position corresponding to the growth of silicon carbide crystals, thereby realizing the replacement of the graphite crucible 4, thereby improving the growth time of silicon carbide crystals.

[0061] In one embodiment, two guide rails 13 are provided on the base 1, and both guide rails 13 extend along the first direction A. A movable roller is provided at the bottom of the fixed part 21, and the movable roller on the fixed part 21 slides on the corresponding guide rail 13 to achieve the change of the position of the fixed part 21 and the lifting part 22, thereby achieving the purpose of changing the position of the crucible to replace the crucible.

[0062] In another embodiment, a guide rail 13 is provided on the base 1 , and a slide groove is provided at the bottom of the fixing portion 21 . The slide groove cooperates with the guide rail 13 , so as to realize the movement of the fixing portion 21 on the base 1 .

[0063] Optionally, refer to Figure 1 and Figure 2 The base 1 also includes a bottom plate, which is provided with a fitting gap 16 extending along the first direction A. The maximum outer diameter of the lifting portion 22 and the outer diameter of the tray 3 are both smaller than the size of the fitting gap 16 in the second direction B, so that when the fixing portion 21 moves between the first position 11 and the second position 12, the lifting portion 22 and the tray 3 can both pass through the fitting gap 16 and the graphite crucible 4 is supported on the bottom plate, and the first direction A, the second direction B and the vertical direction C are perpendicular to each other.

[0064] The substrate is provided with a fitting gap 16 extending along the first direction A, and the bottom plate is used to support the graphite crucible 4. The size of the fitting gap 16 is smaller than the outer diameter of the graphite crucible 4, so that the graphite crucible 4 can be supported on the bottom plate. The size of the fitting gap 16 in the second direction B is larger than the maximum outer diameter of the lifting part 22 and the outer diameter of the tray 3, so that the lifting part 22 and the tray 3 can pass through the fitting gap 16, and the lifting part 22 and the tray 3 can rise to the top of the bottom plate or descend to the bottom of the bottom plate. For example, when the fixing part 21 is located at the first position 11, the lifting part 22 and the tray 3 descend to the bottom of the bottom plate, and the bottom plate can support the graphite crucible 4. A new graphite crucible 4 can also be supported on the bottom plate at the second position 12. When the fixing part 21 moves to the second position 12, the lifting part 22 and the tray 3 rise to the top of the bottom plate, and the graphite crucible 4 is taken away, thereby realizing the replacement of the graphite crucible 4.

[0065] Optionally, refer to Figure 1 and Figure 2 The bottom plate includes a first bottom plate 14 and a second bottom plate 15 . The first bottom plate 14 and the second bottom plate 15 both extend along a first direction A, and the first bottom plate 14 and the second bottom plate 15 are spaced apart along a second direction B to form a fitting gap 16 .

[0066] Specifically, the base 1 is provided with a first bottom plate 14 and a second bottom plate 15, which are arranged at intervals along the second direction B, and a matching gap 16 is formed between the first bottom plate 14 and the second bottom plate 15 for the lifting part 22 and the tray 3 to pass through. When the lifting part 22 and the tray 3 descend with the old graphite crucible 4 and the fixing part 21 moves to the first position 11, the lifting part 22 and the tray 3 continue to descend with the old graphite crucible 4 to the bottom of the first bottom plate 14 and the second bottom plate 15, and the old graphite crucible 4 is supported on the first bottom plate 14 and the second bottom plate 15. The fixing part 21 drives the lifting part 22 and the tray 3 to move to the second position 12, at which time the lifting part 22 and the tray 3 are located below the first bottom plate 14 and the second bottom plate 15, and the graphite crucible 4 is supported on the first bottom plate 14 and the second bottom plate 15, and the lifting part 22 drives the tray 3 to rise, and the tray 3 supports the graphite crucible 4, so that the new graphite crucible 4 can be taken, and the graphite crucible 4 can be replaced.

[0067] Optionally, refer to Figures 1 to 3 The silicon carbide growth device also includes a shell 5, which includes a first side plate 51 and a second side plate 52. The first side plate 51 and the second side plate 52 are arranged opposite to each other and spaced apart along a first direction A. The first side plate 51 and the second side plate 52 are both arranged on the bottom plate and extend upward; the first side plate 51 is closer to the first position 11 than the second side plate 52, and the first side plate 51 is provided with a first opening 510 for taking the old graphite crucible 4 from the first position 11, and the second side plate 52 is provided with a second opening 520 for placing a new graphite crucible 4 toward the second position 12.

[0068] Specifically, a receiving cavity is formed inside the housing 5, the lifting device 2 is disposed in the receiving cavity in the housing 5, the first side plate 51 is disposed on a side close to the first position 11, and the second side plate 52 is disposed on a side close to the second position 12. A first opening 510 is disposed on the first side plate 51, and the old graphite crucible 4 can be taken out through the first opening 510. A second opening 520 is disposed on the second side plate 52, and a new graphite crucible 4 can be placed on the first bottom plate 14 and the second bottom plate 15 in the housing 5 through the second opening 520.

[0069] Optionally, refer to Figure 1 and Figure 2 The shell 5 also includes a first plate 511, which can be rotated compared to the first side plate 51 to open or close the first opening 510; the shell 5 also includes a second plate 521, which can be rotated compared to the second side plate 52 to open or close the second opening 520.

[0070] The first plate 511 is rotated relative to the first side plate 51 to open the first opening 510, and the old graphite crucible 4 can be taken away, and then the first plate 511 is closed. The second plate 521 is rotated relative to the second side plate 52 to open the second opening 520, and a new graphite crucible 4 can be placed on the first bottom plate 14 and the second bottom plate 15 in the housing 5, and then the second plate 521 is closed.

[0071] It should be understood that the housing 5 is designed as a closed structure, which can reduce the heat loss during the growth of silicon carbide.

[0072] Optionally, refer to Figure 1 and Figure 2 The shell 5 also includes a top plate 53, which is arranged above the first side plate 51 and the second side plate 52 and is connected to the first side plate 51 and the second side plate 52 respectively; a first mounting hole 530 is provided on the top plate 53, and the first mounting hole 530 is suitable for the lifting part 22, the tray 3 and the graphite crucible 4 on the tray 3 to pass through.

[0073] The top plate 53 is connected to the top of the first side plate 51 and the second side plate 52. After a new graphite crucible 4 is placed on the tray 3, the lifting part 22 drives the new graphite crucible 4 to rise, pass through the first mounting hole 530 on the top plate 53, enter the growth area, and grow silicon carbide.

[0074] Optionally, refer to Figures 1 to 3 An electric heating element 6 is disposed on the top plate 53 , and the electric heating element 6 is disposed on the top plate 53 and around the first mounting hole 530 .

[0075] An electric heating element 6 is provided above the top plate 53 and is arranged around the first mounting hole 530. When the graphite crucible 4 passes through the first mounting hole 530 and enters the growth zone to perform silicon carbide crystal growth, medium frequency alternating current is applied to the electric heating element 6. When the electric heating element 6 is energized, an alternating magnetic field is generated to heat the graphite crucible 4.

[0076] In a specific embodiment, the electric heating element 6 is a copper tube.

[0077] Optionally, refer to Figures 1 to 3 A heat-insulating member 7 is also provided on the top plate 53, and the heat-insulating member 7 is provided inside the electric heating member 6 and around the first mounting hole 530. When the graphite crucible 4 passes through the first mounting hole 530 and is located in the growth zone to perform silicon carbide crystal growth, the heat-insulating member 7 is located between the graphite crucible 4 and the electric heating member 6 to insulate the graphite crucible 4.

[0078] Specifically, the heat-insulating member 7 is used to insulate the graphite crucible 4 and control the temperature field. The heat-insulating member 7 can be made of soft graphite felt and evenly wrapped around the outside of the graphite crucible 4.

[0079] Optionally, refer to Figures 1 to 3 The silicon carbide growth device also includes a heat-insulating shell 8, which covers an electric heating element 6 and a heat-insulating element 7; the silicon carbide growth device also includes a seed crystal rod 9, which passes through the heat-insulating shell 8 and is movable in a vertical direction C relative to the heat-insulating shell 8 to extend into or out of the graphite crucible 4.

[0080] The heat-insulating shell 8 is used for heat insulation and heat preservation. The heat-insulating shell 8 is arranged above the top plate 53 and covers the electric heating element 6 and the heat-insulating element 7. The seed crystal rod 9 passes through the heat-insulating shell 8 and extends into the graphite crucible 4 to grow silicon carbide crystals. The heat-insulating shell 8 can be made of multiple layers of heat-resistant and heat-insulating materials, such as graphite felt, ceramics, etc.

[0081] The seed crystal rod 9 is connected to a seed crystal 91 below. The seed crystal 91 can be lifted and rotated together with the seed crystal rod 9. The seed crystal 91 extends into the graphite crucible 4 to perform crystal growth.

[0082] The heat-insulating housing 8 is arranged above the top plate 53, the top plate 53 is arranged as a growth zone, and the bottom of the top plate 53 is arranged as a graphite crucible 4 replacement zone. That is, in the present application, the silicon carbide growth device is divided into two areas, the growth zone and the graphite crucible 4 replacement zone are separated by the top plate 53, and the growth zone and the graphite crucible 4 replacement zone are connected through the first mounting hole 530 to replace the crucible, thereby improving the safety of the silicon carbide growth process and the safety of replacing the crucible.

[0083] When the graphite crucible 4 is located above the top plate for growth, the bottom insulation layer 31 on the tray 3 can play a role in heat insulation, reducing the heat transfer from the insulation shell to the outside, thereby improving energy utilization.

[0084] The silicon carbide growth device in the present application is used in a crystal growth experiment. When the graphite crucible is corroded, the old graphite crucible 4 that has been used for crystal growth and corroded is replaced with a new graphite crucible 4 without re-disassembling the furnace, so as to extend the crystal growth time in a single crystal growth experiment and increase the growth thickness of the silicon carbide crystal; and there is no need to reheat or cool down, which can save electricity and time costs; since the continuity of the production process is guaranteed during the silicon carbide crystal growth process, the time for stopping the furnace and re-loading the furnace due to changing the crucible is reduced, the production efficiency is improved, and the silicon carbide crystal defects caused by production interruptions and uncertain changes introduced by re-disassembling the furnace are reduced.

[0085] The silicon carbide growth experiment includes the following steps:

[0086] Step 1: Loading. First, put the raw materials required for growth into the crucible, open the second plate 521 and place the graphite crucible 4 on the first bottom plate 14 and the second bottom plate 15. The fixing part 21 moves to the second position 12, and the graphite crucible 4 is placed on the tray 3. The fixing part 21 moves to the bottom of the first mounting hole 530, and the lifting part 22 drives the graphite crucible 4 to rise. The graphite crucible 4 passes through the first mounting hole 530 and enters the upper crystal growth area.

[0087] Step 2: Crystal growth. The electric heating element 6 is powered on to start heating the graphite crucible 4. After the temperature in the graphite crucible 4 is stabilized, the seed crystal rod 9 is lowered to immerse the seed crystal 91 in the graphite crucible 4 for crystal growth.

[0088] Step 3: Replace the crucible. Before replacing the crucible, first put the raw materials required for growth into the new graphite crucible 4, then open the second plate 521 and place the graphite crucible 4 on the first bottom plate 14 and the second bottom plate 15. The fixing part 21 moves to the second position 12, and the graphite crucible 4 is placed on the tray 3. The fixing part 21 moves to the bottom of the first mounting hole 530, and the lifting part 22 drives the graphite crucible 4 to rise. The graphite crucible 4 passes through the first mounting hole 530 and enters the upper crystal growth area.

[0089] After a certain period of crystal growth, the current crucible has been corroded and is not suitable for growth operations. At this time, the crucible needs to be replaced. The operation steps are to first drive the seed crystal 91 to rise through the seed crystal rod 9, pull out the seed crystal 91 immersed in the solution in the graphite crucible 4, and then the lifting part 22 descends, driving the current graphite crucible 4 to slowly descend, and the graphite crucible 4 passes through the first mounting hole 530 and enters the crucible replacement area below.

[0090] When the graphite crucible 4 is completely out of the first mounting hole 530, the control unit controls the fixing part 21 to move the graphite crucible 4 to the first position 11. Then the lifting part 22 shrinks below the first bottom plate 14 and the second bottom plate 15, and the graphite crucible 4 is placed on the first bottom plate 14 and the second bottom plate 15. After the graphite crucible 4 is cooled, the staff can open the first plate 511 to take out the old graphite crucible 4. After the old graphite crucible 4 is placed in the first position 11, the control unit controls the fixing part 21 to drive the lifting part 22 to move to the second position 12. After finding the correct position, the lifting part 22 is used to lift the new graphite crucible 4 to separate it from the first bottom plate 14 and the second bottom plate 15. Then, the control unit controls the fixing part 21 to move to the bottom of the first mounting hole 530 again, and the lifting part 22 rises to send the new graphite crucible 4 through the first mounting hole 530 and into the growth area, thereby completing the replacement of the graphite crucible 4.

[0091] Step 4: Continue to grow. When the new graphite crucible 4 is located above the first mounting hole 530 and is ready for crystal growth, before the temperature in the graphite crucible 4 reaches a predetermined temperature, the seed crystal 91 needs to maintain a certain distance from the graphite crucible 4 and the solution in the graphite crucible 4 to reduce the impact of temperature on the crystal growth of the seed crystal, thereby improving the quality of silicon carbide crystal growth. After the material in the new graphite crucible 4 is heated to melt and the temperature reaches the predetermined temperature, the seed crystal rod 9 is lowered to immerse the seed crystal 91 in the solution in the graphite crucible 4 to continue crystal growth. After this graphite crucible 4 has grown for a certain period of time, step three can be repeated to replace the graphite crucible 4 until the crystal growth time reaches the expected time, thereby achieving ultra-long growth of silicon carbide crystals grown by a single furnace liquid phase method to meet the growth thickness requirements of silicon carbide crystals.

[0092] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity or device including the element.

[0093] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0094] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

[0095] Although the embodiments of the present application have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A silicon carbide growth device, characterized in that: include: Pedestal; A lifting device, comprising a fixing portion and a lifting portion, wherein the lifting portion is disposed on the fixing portion and is movable in a vertical direction relative to the fixing portion; A tray, arranged at one end of the lifting part away from the fixing part, the tray being suitable for placing a graphite crucible; Wherein, along the first direction, the fixing portion is movably arranged on the base and has a first position and a second position. When the tray descends to the preset position and the fixing portion is in the first position, the old graphite crucible on the tray is suitable for being taken away. When the tray descends to the preset position and the fixing portion is in the second position, the tray is suitable for being placed with a new graphite crucible. The first direction is perpendicular to the vertical direction.

2. The silicon carbide growth device according to claim 1, characterized in that: The base includes at least one guide rail extending along the first direction, and the fixing portion is slidably disposed on the guide rail.

3. The silicon carbide growth device according to claim 2, characterized in that: The base further comprises a bottom plate, and the bottom plate is provided with a fitting gap extending along the first direction; The maximum outer diameter of the lifting part and the outer diameter of the tray are both smaller than the size of the fitting gap in the second direction, so that when the fixing part moves between the first position and the second position, the lifting part and the tray can both pass through the fitting gap and the graphite crucible is supported on the bottom plate, and the first direction, the second direction and the vertical direction are perpendicular to each other.

4. The silicon carbide growth device according to claim 3, characterized in that: The bottom plate includes a first bottom plate and a second bottom plate, the first bottom plate and the second bottom plate both extend along the first direction, and the first bottom plate and the second bottom plate are spaced apart along the second direction to form the fitting gap.

5. The silicon carbide growth device according to claim 3, characterized in that: The silicon carbide growth device further includes a shell, the shell including a first side plate and a second side plate, the first side plate and the second side plate are arranged opposite to each other and spaced apart along the first direction, and the first side plate and the second side plate are both arranged on the bottom plate and extend upward; The first side plate is closer to the first position than the second side plate. The first side plate is provided with a first opening for taking out the old graphite crucible from the first position, and the second side plate is provided with a second opening for placing a new graphite crucible to the second position.

6. The silicon carbide growth device according to claim 5, characterized in that: The housing further includes a first plate, the first plate being rotatable relative to the first side plate to open or close the first opening; The housing further includes a second plate that is rotatable relative to the second side plate to open or close the second opening.

7. The silicon carbide growth device according to claim 5, characterized in that: The housing further includes a top plate, which is disposed above the first side plate and the second side plate and is connected to the first side plate and the second side plate respectively; The top plate is provided with a first mounting hole, and the first mounting hole is suitable for the lifting part, the tray and the graphite crucible on the tray to pass through.

8. The silicon carbide growth device according to claim 7, characterized in that: An electric heating element is disposed on the top plate, and the electric heating element is disposed on the top plate and around the first mounting hole.

9. The silicon carbide growth device according to claim 8, characterized in that: The top plate is also provided with a heat-insulating component, which is arranged on the inner side of the electric heating component and around the first mounting hole.

10. The silicon carbide growth device according to claim 9, characterized in that: The silicon carbide growth device further comprises a heat-insulating shell, wherein the heat-insulating shell covers the electric heating element and the heat-insulating element; The silicon carbide growing device further comprises a seed crystal rod, which passes through the heat-insulating shell and is movable in a vertical direction relative to the heat-insulating shell so as to extend into or out of the graphite crucible.

Images