Liquid phase method silicon carbide crystal growth apparatus and growth method

Abstract

The application discloses a liquid-phase-method silicon carbide crystal growth device, which comprises a heat preservation assembly with a heat preservation cavity, a crucible fixed in the heat preservation cavity, a temperature measuring instrument matched with the crucible and a heating assembly; the crucible is provided with a growth cavity; a seed crystal rod penetrates through the top of the heat preservation assembly; the seed crystal rod is coaxial with the crucible, and the axis of the seed crystal rod extends in the vertical direction; a seed crystal holder for bearing a silicon carbide crystal is connected to the bottom end of the seed crystal rod; the seed crystal rod can reciprocatingly ascend and descend to drive the seed crystal holder to enter and exit the growth cavity through a material passing opening; the heating assembly comprises an inner heating cylinder, an outer heating cylinder and an induction heating coil; the inner heating cylinder and the outer heating cylinder are coaxially sleeved on the outside of the crucible; the outer peripheral wall of the outer heating cylinder is circumferentially matched with the inner peripheral wall of the heat preservation cavity; the inner heating cylinder is slidably matched with the inner peripheral wall of the outer heating cylinder in a reciprocating ascending and descending manner; and the inner peripheral wall of the inner heating cylinder is in clearance fit with the outer peripheral wall of the crucible. The application further discloses a growth method using the above-mentioned liquid-phase-method silicon carbide crystal growth device.

Description

Technical Field

[0001] This invention relates to the field of crystal growth technology, specifically to a liquid-phase silicon carbide crystal growth apparatus for improving the quality of liquid-phase silicon carbide crystals and a growth method using the apparatus. Background Technology

[0002] Silicon carbide (SiC) is a typical wide-bandgap semiconductor material, representing the third generation of semiconductor materials after silicon and gallium arsenide (GaAs). Compared to silicon and GaAs, SiC plays a crucial role in electronic devices due to its high critical breakdown field strength, high thermal conductivity, and chemical stability. It is suitable for fabricating high-density power microelectronic devices and electronic devices operating under extreme conditions such as high temperature, high frequency, high voltage, and high power. Gallium nitride (GaN) radio frequency devices using high-purity semi-insulating SiC as a substrate are primarily used in 5G communications. In particular, high-voltage, high-current power electronic devices using conductive SiC as a substrate can be applied in large-scale substation systems, electric vehicles, and charging piles.

[0003] Correspondingly, there are currently many different types of processes for the production of silicon carbide crystals. Among them, top seed solution growth (TSSG) silicon carbide crystal growth technology, as a representative of the liquid phase method in silicon carbide crystal growth process, has a relatively lower silicon carbide crystal growth temperature compared to the physical vapor transport (PVT) method, and is closer to thermodynamic equilibrium. It is a method with the potential to grow high-quality silicon carbide single crystals.

[0004] Specifically, in the TSSG method, the basic growth principle of silicon carbide crystals is to use a graphite crucible as a container for raw materials and as a source of carbon. During crystal growth, carbon dissolves at the crucible wall (high temperature zone) and is transported to the seed crystal (low temperature zone) through the solution to combine with silicon and precipitate to form silicon carbide single crystals.

[0005] However, in the early stages of silicon carbide crystal growth using the TSSG method, scratches caused by polishing the surface of the silicon carbide seed crystal and volatiles adhering to the surface of the seed crystal before entering the solution can hinder the discharge of bubbles at the crystal growth interface and even affect the step flow growth of the silicon carbide crystal, thus affecting the subsequent growth quality of the crystal and causing adverse effects on the corresponding silicon carbide crystal products.

[0006] At the present stage, in the industry, the process of remelting treatment can be used to remove the damaged layer on the surface of the silicon carbide seed crystal at the initial growth stage, and discharge the bubbles at the growth interface at the same time, so that the silicon carbide crystal can reach a relatively ideal growth state and optimize the quality of silicon carbide products. Generally, when the relevant process is implemented, it is necessary to arrange the silicon carbide seed crystal near the surface of the solution for remelting and growth. During the remelting process, the silicon carbide seed crystal needs to be arranged at a position with a relatively high temperature in the molten material, so as to maintain the unsaturated state of the seed crystal for a longer time, thereby leaving sufficient time for seed crystal remelting and bubble discharge. In the subsequent growth process of the silicon carbide crystal, the silicon carbide seed crystal needs to be located at a position with a relatively low temperature in the molten material for crystal growth, which causes great difficulties for the matching arrangement of the corresponding process equipment.

[0007] In view of this, how to optimize the structural layout of the liquid-phase silicon carbide crystal growth device matched with the TSSG method, so that it can meet the different requirements of the remelting process of silicon carbide seed crystals and the growth process of silicon carbide crystals on the temperature distribution of the thermal field, so as to ensure the growth quality of the corresponding silicon carbide crystals, is an important technical problem that those skilled in the art need to solve at present. Summary of the Invention

[0008] The object of the present invention is to provide a liquid-phase silicon carbide crystal growth apparatus, which can meet different requirements of thermal field temperature distribution for the remelting process of silicon carbide seeds and the growth process of silicon carbide crystals, so as to ensure the growth quality of corresponding silicon carbide crystals. Another object of the present invention is to provide a silicon carbide crystal growth method using the above-mentioned liquid-phase silicon carbide crystal growth apparatus.

[0009] To solve the above technical problem, the present invention provides a liquid-phase silicon carbide crystal growth apparatus, comprising a thermal insulation component with a thermal insulation cavity inside, a crucible fixed in the thermal insulation cavity, a temperature detector adapted to the crucible, and a heating component capable of heating the crucible;

[0010] The crucible has a growth cavity inside, the top of the crucible is provided with a material passing port communicated with the growth cavity, a seed rod is penetrated through the top of the thermal insulation assembly in the vertical direction, the seed rod is coaxially adapted to the crucible, the axis of the seed rod extends in the vertical direction, the bottom end of the seed rod is linked with a seed holder capable of carrying silicon carbide crystals, and the seed rod can reciprocate up and down to drive the seed holder to enter and exit the growth cavity through the material passing port;

[0011] The heating assembly includes an inner heating cylinder, an outer heating cylinder, and an induction heating coil that can be thermally coupled and adapted to the inner heating cylinder and the outer heating cylinder. The inner heating cylinder and the outer heating cylinder are coaxially sleeved on the outside of the crucible. The outer peripheral wall of the outer heating cylinder is circumferentially fitted to the inner peripheral wall of the heat preservation cavity. The inner heating cylinder can reciprocate and slide to fit on the inner peripheral wall of the outer heating cylinder, and the inner peripheral wall of the inner heating cylinder is clearance-fitted with the outer peripheral wall of the crucible.

[0012] Preferably, the bottom surface of the inner heating cylinder is provided with a protruding lower positioning ring that extends circumferentially and can abut against the bottom inner wall of the heat preservation cavity, and the inner peripheral wall of the lower positioning ring is provided with a recessed lower positioning groove.

[0013] The top surface of the inner heating cylinder is provided with an upper positioning ring that extends circumferentially and is in clearance fit with the inner wall of the top of the heat preservation cavity. The inner circumferential wall of the upper positioning ring is provided with an upper positioning groove.

[0014] A positioning tray is coaxially and linkedly provided in the middle of the seed crystal rod, and the outer periphery of the positioning tray protrudes radially from the outer periphery of the seed crystal rod.

[0015] The liquid phase silicon carbide crystal growth apparatus also includes a lifting drive device that can drive the seed crystal rod to reciprocate up and down along a fixed axis, a rotation drive device that can drive the seed crystal rod to rotate back and forth along a fixed axis, and a linkage bracket connected between the seed crystal rod and the inner heating cylinder.

[0016] The linkage bracket includes a linkage ring coaxially sleeved on the seed crystal rod and a plurality of linkage rods with their inner ends fixed to the outer circumferential surface of the linkage ring. The linkage ring slides with the seed crystal rod and can abut against and adapt to the top surface of the positioning tray. The linkage ring can also be circumferentially linked with the positioning tray and can be disassembled and adapted. The outer ends of the linkage rods are provided with linkage sliders corresponding to each other.

[0017] The inner wall of the inner heating cylinder is recessed with several positioning grooves that connect the upper positioning groove and the lower positioning groove. The linkage slider slides and the positioning grooves correspond to each other to make the linkage slider slide into the upper positioning groove or the lower positioning groove.

[0018] Preferably, each of the positioning grooves extends spirally in the same direction with the axis of the crucible as the central axis, and each of the positioning grooves is evenly distributed at equal intervals along the circumference of the crucible.

[0019] Preferably, the linkage rod includes a transverse section and a longitudinal section connected sequentially from its inner end to its outer end. The transverse section extends radially along the crucible, and the longitudinal section extends axially along the crucible. The top end of the longitudinal section is vertically connected to the outer end of the transverse section, and the linkage slider protrudes radially along the crucible and is disposed at the bottom end of the longitudinal section.

[0020] Preferably, the cross-section of the linkage slider along the tangential direction of the inner peripheral wall of the inner heating cylinder is circular or parallelogram.

[0021] Preferably, the top surface of the positioning tray is recessed and provided with a linkage groove, and the bottom surface of the linkage ring is protruding and provided with a linkage boss that is aligned with and snapped into the linkage groove.

[0022] Preferably, the inner peripheral wall of the external heating cylinder is provided with a plurality of guide grooves extending along its axial direction, and each of the guide grooves is evenly distributed at equal intervals along the circumference of the external heating cylinder.

[0023] The outer peripheral wall of the inner heating cylinder is provided with a plurality of guide protrusions extending along its axial direction. Each guide protrusion is evenly distributed at equal intervals along the circumference of the inner heating cylinder, and the guide protrusions are aligned and slidably fitted into the guide groove.

[0024] Preferably, the insulation component includes a quartz cylinder and an insulation tube coaxially attached to the inner peripheral wall of the quartz cylinder, and further includes an insulation top felt detachably connected to the top of the quartz cylinder and an insulation bottom felt detachably connected to the bottom of the quartz cylinder. The insulation top felt and the insulation bottom felt are respectively aligned, abutted, and pressed tightly against the top and bottom of the insulation tube to form the insulation cavity between the insulation tube, the insulation top felt, and the insulation bottom felt.

[0025] Preferably, a main tray is provided inside the insulation cavity, and a positioning rod extends vertically through the bottom of the insulation component. The top end of the positioning rod extends into the insulation cavity and is linked to the bottom of the main tray. A main support groove is recessed in the middle of the top surface of the main tray, and the bottom of the crucible is aligned, inserted, and disassembled into the main support groove.

[0026] The present invention also provides a method for growing silicon carbide crystals, using the liquid-phase silicon carbide crystal growth apparatus as described in any of the preceding claims, comprising the following steps:

[0027] The silicon carbide seed crystal used for growth is bonded to the seed crystal holder, and the growth raw material is filled into the growth chamber. The linkage bracket and the inner heating cylinder assembly are assembled so that the linkage slider is located in the positioning groove under the inner heating cylinder assembly. Then the insulation chamber is sealed and the inside of the insulation chamber is evacuated to keep the internal space of the insulation chamber clean.

[0028] Start the heating assembly and run the induction heating coil to heat the outer and inner heating cylinders respectively to heat the inside of the insulation cavity until the temperature measuring instrument detects that the ambient temperature at the crucible meets the requirements of the remelting process.

[0029] The seed crystal rod moves the seed crystal holder downward from the initial position to the appropriate position so that the silicon carbide seed crystal on the seed crystal holder comes into contact with the molten growth material. At this time, the internal heating cylinder is located at a higher position inside the heat preservation cavity. The temperature at the growth interface is relatively high, and the temperature at the bottom of the molten material is relatively low, forming a reverse thermal field, so that the seed crystal can be fully melted back.

[0030] After the silicon carbide seed crystal on the seed crystal holder has been melted back, the seed crystal rod is raised and lowered moderately until the seed crystal is pulled out of the molten material. Then, the seed crystal rod is rotated to move the linkage slider into the positioning groove. At this time, the heating cylinder slowly descends under gravity and continues to rotate until the linkage slider reaches the fixed position of the positioning groove on the inner heating cylinder assembly and stops. After the rotation stops, the seed crystal rod is lowered. First, the lower positioning ring of the inner heating cylinder contacts the insulation felt, and at the same time, the positioning tray and the linkage ring separate. The seed crystal rod continues to descend until the seed crystal contacts the solution. At this time, the inner heating cylinder is located at a lower position inside the insulation cavity. The temperature at the growth interface is relatively low, and the temperature at the bottom of the molten material is relatively high, forming a positive thermal field. The seed crystal rod is started to rotate, and crystal growth begins until the silicon carbide seed crystal on the seed crystal holder continues to grow and obtains a silicon carbide crystal that meets the process requirements.

[0031] After the silicon carbide crystal on the seed crystal holder has grown, the seed crystal rod is raised until the seed crystal is removed from the molten material. Then, the seed crystal rod is rotated at a low speed and the cooling program is started until the program ends. After the temperature drops to room temperature, the grown silicon carbide crystal is removed from the seed crystal holder for subsequent processing.

[0032] Compared to the aforementioned background technology, the liquid-phase silicon carbide crystal growth apparatus provided by this invention is suitable for the TSSG method of silicon carbide crystal growth. During operation, a silicon carbide seed crystal is installed on the seed crystal holder. The insulation cavity is then sealed and evacuated to ensure a clean environment for subsequent processes. The heating components are then activated, using induction heating coils to heat the outer and inner heating cylinders to heat the interior of the insulation cavity until the temperature sensor detects that the ambient temperature at the crucible meets the requirements for the remelting process. After the ambient temperature is preheated to the required level, the seed crystal rod moves the seed crystal holder downwards from its initial position to an appropriate position, so that the silicon carbide seed crystal on the seed crystal holder is located at the remelting position in contact with the molten material surface. At this time, the internal heating cylinder is located at a higher position inside the heat preservation cavity, the temperature at the growth interface is relatively high, and the temperature at the bottom of the molten material is relatively low, forming a reverse thermal field. The seed crystal can be fully remelted, thereby performing a remelting treatment on the silicon carbide seed crystal on the seed crystal holder to remove scratches or attachments on the surface of the silicon carbide seed crystal, so that the surface of the silicon carbide seed crystal is restored to a smooth and regular state, in preparation for the subsequent growth of silicon carbide crystals. After the silicon carbide seed crystal on the seed crystal holder has been melted back, the seed crystal rod is raised and lowered moderately until the seed crystal is pulled out of the molten material. Then, the seed crystal rod is rotated to move the linkage slider into the positioning groove. At this time, the heating cylinder slowly descends under gravity and continues to rotate until the linkage slider reaches the fixed position of the positioning groove on the inner heating cylinder assembly and stops. After the rotation stops, the seed crystal rod is lowered. First, the lower positioning ring of the inner heating cylinder contacts the bottom inner wall of the insulation assembly, that is, the inner wall of the insulation felt. At the same time, the positioning tray and the linkage ring separate. The seed crystal rod continues to descend until the seed crystal contacts the solution. At this time, the inner heating cylinder is located at a lower position inside the insulation cavity. The temperature at the growth interface is relatively low, and the temperature at the bottom of the molten material is relatively high, forming a positive thermal field. The rotation of the seed crystal rod is started, and crystal growth begins until the silicon carbide seed crystal on the seed crystal holder continues to grow and obtains a silicon carbide crystal that meets the process requirements. After the silicon carbide crystal growth on the seed crystal holder is complete, the seed crystal rod is raised until the seed crystal detaches from the molten material. Then, the seed crystal rod is rotated at a low speed while a cooling program is initiated until the program ends. Once the temperature drops to room temperature, the grown silicon carbide crystal is removed from the seed crystal holder for subsequent processing. This liquid-phase silicon carbide crystal growth apparatus utilizes the position adjustment of the internal heating cylinder in conjunction with the seed crystal rod to move the silicon carbide seed crystal on the seed crystal holder. This allows for continuous processing of the silicon carbide seed crystal's remelting and growth processes, ensuring the different temperature distribution requirements of the thermal field during the remelting and growth processes. It maintains the unsaturated state of the silicon carbide seed crystal for a longer period, providing sufficient time for remelting and bubble removal, improving the crystallization quality of the silicon carbide crystal, and making the corresponding silicon carbide seed crystal remelting and growth processes smoother and more efficient. The integration of related supporting equipment is also improved accordingly. Attached Figure Description

[0033] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required for describing the embodiments and the prior art are briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative efforts.

[0034] Figure 1 is an exploded view of an assembly structure of a liquid-phase silicon carbide crystal growth apparatus provided by a specific embodiment of the present invention;

[0035] Figure 2 is Figure 1 a partial exploded axial view of a seed rod and a linkage bracket assembly;

[0036] Figure 3 is a bottom perspective axial view of Figure 2 the linkage bracket in ;

[0037] Figure 4 is an exploded view of an inner heating cylinder and an outer heating cylinder assembly in Figure 1 ;

[0038] Figure 5 is a sectional view of a matching structure of related components of a thermal insulation chamber when the silicon carbide seed is at a remelting station in the liquid-phase silicon carbide crystal growth apparatus in Figure 1 ;

[0039] Figure 6 is a sectional view of a matching structure of related components of a thermal insulation chamber when the silicon carbide seed moves from the remelting station to a growth station in the liquid-phase silicon carbide crystal growth apparatus in Figure 1 ;

[0040] Figure 7 is a sectional view of a matching structure of related components of a thermal insulation chamber when the silicon carbide seed is at the growth station in the liquid-phase silicon carbide crystal growth apparatus in Figure 1 .

[0041] wherein:

[0042] 10 - quartz cylinder; 101 - thermal insulation chamber; 102 - induction heating coil; 103 - thermal insulation cylinder; 104 - thermal insulation top felt; 105 - thermal insulation bottom felt;

[0043] 11 - crucible; 111 - growth chamber; 112 - material passing opening;

[0044] 12 - seed rod; 121 - seed holder; 122 - positioning tray; 123 - linkage groove;

[0045] 13-Inner heating element; 131-Lower positioning ring; 132-Lower positioning groove; 133-Upper positioning ring; 134-Upper positioning groove; 135-Positioning slide groove; 136-Guide protrusion;

[0046] 14-External heating element; 141-Guide groove;

[0047] 15-Linkage bracket; 151-Linkage ring; 152-Linkage rod; 153-Linkage slider; 154-Horizontal extension section; 155-Longitudinal extension section; 156-Linkage boss;

[0048] 16-Main tray; 161-Positioning rod; 162-Main tray groove;

[0049] 20-Melted material;

[0050] 30-Silicon carbide seed crystal. Detailed Implementation

[0051] The core of this invention is to provide a liquid-phase silicon carbide crystal growth apparatus that can meet the different requirements of the remelting process of silicon carbide seed crystals and the growth process of silicon carbide crystals for the thermal field temperature distribution, thereby ensuring the corresponding silicon carbide crystal growth quality; and also to provide a silicon carbide crystal growth method using the above-mentioned liquid-phase silicon carbide crystal growth apparatus.

[0052] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] In a specific implementation, combined with Figure 1 , Figure 5 , Figure 6 as well as Figure 7 As shown, the liquid phase silicon carbide crystal growth apparatus provided by the present invention is suitable for silicon carbide crystal growth process of TSSG method. The growth apparatus includes a heat preservation component with a heat preservation cavity 101 inside, a crucible 11 fixed in the heat preservation cavity 101, a temperature measuring instrument adapted to the crucible 11, and a heating component capable of heating the crucible 11.

[0054] The crucible 11 has a growth chamber 111 inside. The top of the crucible 11 has a material inlet 112 that communicates with the growth chamber 111. A seed crystal rod 12 extends vertically through the top of the heat preservation component. The seed crystal rod 12 is coaxially adapted with the crucible 11 and the axis of the seed crystal rod 12 extends vertically. A seed crystal holder 121 capable of supporting silicon carbide crystals is linked to the bottom end of the seed crystal rod 12. The seed crystal rod 12 can reciprocate up and down to drive the seed crystal holder 121 into and out of the growth chamber 111 through the material inlet 112.

[0055] The heating assembly includes an inner heating cylinder 13, an outer heating cylinder 14, and an induction heating coil 102 that can be thermally coupled and adapted to the inner heating cylinder 13 and the outer heating cylinder 14. The inner heating cylinder 13 and the outer heating cylinder 14 are coaxially sleeved on the outside of the crucible 11. The outer peripheral wall of the outer heating cylinder 14 is circumferentially fitted to the inner peripheral wall of the heat preservation cavity 101. The inner heating cylinder 13 can slide back and forth on the inner peripheral wall of the outer heating cylinder 14, and the inner peripheral wall of the inner heating cylinder 13 is clearance fitted to the outer peripheral wall of the crucible 11.

[0056] In the specific operation of this growth apparatus, the silicon carbide seed crystal 30 is installed on the seed crystal holder 121. Then, the insulation cavity 101 is sealed and a vacuum is applied to the inside of the insulation cavity 101 to ensure a clean environment for subsequent processes. Afterward, the heating components can be activated, using the induction heating coil 102 to heat the outer heating cylinder 14 and the inner heating cylinder 13 respectively, thereby heating the inside of the insulation cavity 101 until the temperature measuring instrument detects that the ambient temperature at the crucible 11 meets the requirements of the remelting process.

[0057] After the ambient temperature is preheated to the required level, the seed crystal rod 12 moves the seed crystal holder 121 downwards from its initial position to an appropriate position so that the silicon carbide seed crystal 30 on the seed crystal holder 121 is located at the remelting station in contact with the surface of the molten material 20. At this time, the internal heating cylinder 13 is located at a higher position inside the heat preservation cavity 101, the temperature at the growth interface is relatively high, and the temperature at the bottom of the molten material 20 is relatively low, forming a reverse thermal field. The silicon carbide seed crystal 30 can be fully remelted, thereby performing a remelting treatment on the silicon carbide seed crystal 30 on the seed crystal holder 121 to remove scratches or attachments on the surface of the silicon carbide seed crystal 30, so that the surface of the silicon carbide seed crystal 30 is restored to a smooth and regular state, in preparation for the subsequent growth of silicon carbide crystals.

[0058] After the silicon carbide seed crystal 30 on the seed crystal holder 121 has been melted, the seed crystal rod 12 is raised and lowered moderately until the silicon carbide seed crystal 30 is pulled out of the molten material 20. Then, the seed crystal rod 12 is rotated to move the linkage slider 153 into the positioning groove 135. At this time, the inner heating cylinder 13 slowly descends under gravity and continues to rotate until the linkage slider 153 reaches the fixed position of the upper positioning groove 134 of the inner heating cylinder 13 and stops. After the rotation stops, the seed crystal rod 12 descends, and first the lower positioning ring 131 of the inner heating cylinder 13 contacts the bottom of the heat preservation component. The inner wall of the cavity, that is, the inner wall of the insulation base 105, is separated from the positioning tray 122 and the linkage ring 151. The seed crystal rod 12 continues to descend until the silicon carbide seed crystal 30 contacts the solution. At this time, the inner heating cylinder 13 is located at a lower position inside the insulation cavity 101. The temperature at the growth interface is relatively low, and the temperature at the bottom of the molten material 20 is relatively high, forming a positive thermal field. The seed crystal rod 12 is started to rotate, and the growth of silicon carbide crystal begins until the silicon carbide seed crystal 30 located on the seed crystal holder 121 continues to grow and obtain a silicon carbide crystal that meets the process requirements.

[0059] After the silicon carbide crystal on the seed crystal holder 121 has grown, the seed crystal rod 12 is raised until the silicon carbide crystal is removed from the molten material 20. Then, the seed crystal rod 12 is rotated at a low speed and the cooling program is started until the program ends. After the temperature drops to room temperature, the grown silicon carbide crystal is removed from the seed crystal holder 121 for further processing in subsequent processes.

[0060] The liquid-phase silicon carbide crystal growth apparatus can adjust the position of the internal heating cylinder 13 in conjunction with the seed crystal rod 12 to move the position of the silicon carbide seed crystal 30 on the seed crystal holder 121, thereby achieving continuous processing of the silicon carbide seed crystal remelting process and the growth process. This ensures that the different temperature distribution requirements of the thermal field are met during the remelting and growth processes, maintaining the unsaturated state of the silicon carbide seed crystal for a longer period of time. This allows sufficient time for the silicon carbide seed crystal remelting and bubble removal, improving the crystallization quality of the silicon carbide crystal. It also makes the corresponding silicon carbide seed crystal remelting and silicon carbide crystal growth process smoother and more efficient, and the integration of related supporting equipment is correspondingly improved.

[0061] It is easy to understand that, in practical applications, the upstream and downstream supporting equipment related to the liquid-phase silicon carbide crystal growth apparatus described in this solution can also be installed and arranged based on the existing TSSG process in the industry. Accordingly, considering the current conventional technology choices in the industry, the silicon carbide seed crystal 30 in this solution can be directly bonded and fixed to the bottom of the seed crystal holder 121, or it can be reliably connected to the main structure of the seed crystal holder 121 using other methods combined with existing technologies. This solution does not specify the installation arrangement between the silicon carbide seed crystal 30 and the seed crystal holder 121; personnel can refer to the corresponding conventional technologies in the industry for selection, which will not be elaborated further in this article.

[0062] Reference Figure 2 , Figure 3 as well as Figure 4 As shown. Specifically, the bottom surface of the inner heating cylinder 13 has a protruding lower positioning ring 131 that extends circumferentially and abuts against the inner bottom wall of the growth chamber 111. The inner circumferential wall of the lower positioning ring 131 has a recessed lower positioning groove 132. The top surface of the inner heating cylinder 13 has a protruding upper positioning ring 133 that extends circumferentially and has a clearance fit with the inner top wall of the insulation chamber 101. The inner circumferential wall of the upper positioning ring 133 has a recessed upper positioning groove 134. A positioning tray 122 is coaxially and linkedly provided in the middle of the seed crystal rod 12. The outer periphery of the positioning tray 122 protrudes radially from the outer circumferential surface of the seed crystal rod 12.

[0063] The liquid-phase silicon carbide crystal growth apparatus further includes a lifting drive device capable of driving the seed crystal rod 12 to reciprocate up and down along a fixed axis, a rotary drive device capable of driving the seed crystal rod 12 to rotate back and forth along a fixed axis, and a linkage bracket 15 connecting the seed crystal rod 12 and the inner heating cylinder 13. The linkage bracket 15 includes a linkage ring coaxially sleeved on the seed crystal rod 12 and several linkage rods 152 with their inner ends fixed to the outer circumferential surface of the linkage ring. The linkage ring slides with the seed crystal rod 12 and can abut against and adapt to the top surface of the positioning tray 122. The linkage ring can be circumferentially linked with the positioning tray 122 and can be disassembled and adapted. The outer ends of the linkage rods 152 are respectively provided with linkage sliders 153.

[0064] The inner wall of the inner heating cylinder 13 is recessed with several positioning grooves 135 that connect the upper positioning groove 134 and the lower positioning groove 132. The linkage slider 153 slides and adapts to the positioning grooves 135 in a one-to-one correspondence, so that the linkage slider 153 can be aligned and slide into the upper positioning groove 134 or the lower positioning groove 132.

[0065] Key reference Figure 5 As shown. When it is necessary to perform remelting treatment on the silicon carbide seed crystal 30 located on the seed crystal holder 121, the lifting drive device drives the seed crystal rod 12 to move it appropriately downwards, so as to move the silicon carbide seed crystal 30 on the seed crystal holder 121 to a remelting station at an appropriate height above the molten material 20 in the growth chamber 111. During equipment assembly, the linkage slider 153 is placed in the lower positioning groove 132; during the remelting operation, the silicon carbide seed crystal 30 on the seed crystal holder 121 is moved appropriately until the silicon carbide seed crystal 30 contacts the molten material 20. Thus, the internal heating cylinder 13 forms auxiliary heating for the working space at the remelting station to ensure the remelting process requirements of the silicon carbide seed crystal 30 at the remelting station. After all the components required for the remelting process have been moved into place, the lifting drive device and the rotation drive device should be stopped to ensure that the position of each mating component is constant, thereby ensuring the stability of the working conditions during the corresponding remelting process and optimizing the remelting effect of the silicon carbide seed crystal 30.

[0066] Key reference Figure 6As shown. After the silicon carbide seed crystal 30 on the seed crystal holder 121 has been melted, the seed crystal rod 12 is raised and lowered moderately until the silicon carbide seed crystal 30 is pulled out of the molten material 20. Then, the seed crystal rod 121 is rotated to move the linkage slider 153 into the positioning groove 135. At this time, the inner heating cylinder 13 slowly descends under gravity and continues to rotate until the linkage slider 153 reaches the fixed position of the upper positioning groove 134 of the inner heating cylinder 13 assembly and stops. After the rotation stops, the seed crystal rod 121 descends, and first the lower positioning ring 131 of the inner heating cylinder 13 contacts the heat preservation assembly. The bottom inner wall, that is, the inner wall of the insulation base 105, and the positioning tray 122 and the linkage ring 151 separate. The seed crystal rod 121 continues to descend until the silicon carbide seed crystal 30 contacts the molten material 20. At this time, the inner heating cylinder 13 is located at a lower position inside the insulation cavity 101. The temperature at the growth interface is relatively low, and the temperature at the bottom of the molten material 20 is relatively high, forming a positive thermal field. The seed crystal rod 121 is started to rotate, and crystal growth begins until the silicon carbide seed crystal 30 located on the seed crystal holder 121 continues to grow and obtain a silicon carbide crystal that meets the process requirements.

[0067] Reference Figure 7 As shown. After the silicon carbide crystal on the seed crystal holder 121 has grown, the seed crystal rod 12 is raised until the silicon carbide crystal is removed from the molten material 20. Then, the seed crystal rod 12 is rotated at a low speed and the cooling program is started until the program ends. After the temperature drops to room temperature, the grown silicon carbide crystal is removed from the seed crystal holder 121 for subsequent processing.

[0068] It is easy to understand that although the reciprocating lifting and lowering movement of the inner heating cylinder 13 is used to match the working height of the corresponding remelting or growth station during the operation of the above-mentioned equipment, the overall working temperature inside the insulation cavity 101 is still maintained by the outer heating cylinder 14 as the main heat source component to ensure that the main working environment of the corresponding process is stable and meets the operational requirements. Accordingly, the inner heating cylinder 13 is a supporting component that can work in conjunction with the outer heating cylinder 14 to achieve high-intensity auxiliary heating for specific stations. In actual operation of the equipment, the adjustment and maintenance of the working environment temperature of the remelting and growth stations both require the cooperation of the outer heating cylinder 14 and the inner heating cylinder 13 with the induction heating coil 102, respectively. As for the electrical coupling heating adaptation between the induction heating coil 102 and the inner heating cylinder 13 and the outer heating cylinder 14, it is a conventional technical choice in the industry and will not be elaborated here. It should be clarified that, in order to ensure the electrothermal coupling compatibility with the induction heating coil 102, both the inner heating cylinder 13 and the outer heating cylinder 14 should be made of graphite material. As for the actual operating power and other parameters of the induction heating coil 102, they can be flexibly adjusted according to the actual working conditions.

[0069] It should be noted that the raw materials of the molten material 20 located in the crucible 11 generally include silicon raw materials and metal raw materials. The metal raw materials can typically be one or more of the metal materials corresponding to elements such as Cr, Al, Mo, Ce, Sn, Sc, Fe, Ti, Ni, and Cu. The specific composition and material selection of the molten material 20 are also relatively conventional techniques in the industry. As shown in the figure, the selection and adjustment can be flexibly made according to the actual working conditions and process requirements, and will not be elaborated further in this article.

[0070] Furthermore, both the lifting drive and the rotary drive can be applied in combination with existing conventional technologies. Specifically, a conventional motor can be selected as the rotary drive, with the motor's output shaft coaxially linked to the seed crystal rod 12 to achieve the purpose of driving the seed crystal rod 12 to rotate in a fixed direction or in the opposite direction. The lifting drive can be a hydraulic cylinder or pneumatic cylinder of the motor's main structure, whereby the reciprocating extension and retraction of the piston rod drives the motor and the seed crystal rod 12 to achieve corresponding axial reciprocating lifting and lowering movements. Of course, the lifting drive can also use other drive mechanisms such as worm gear mechanisms that can achieve reciprocating lifting and lowering movements, and the rotary drive can also be selected according to the actual installation conditions and working requirements to drive the seed crystal rod 12 to achieve fixed-axis rotation. The specific application mechanism types and assembly connection relationships of the lifting drive and rotary drive are only illustrative examples. In actual applications, any drive mechanism that can meet the drive requirements of fixed-axis rotation and reciprocating lifting and lowering of the seed crystal rod 12 is acceptable. This plan does not specify the specific application type and assembly method of the lifting drive device and the rotary drive device. Workers can choose and apply them adaptably by combining the conventional technologies in the industry. This article will not elaborate further.

[0071] Correspondingly, each positioning groove 135 extends spirally in the same direction with the axis of the crucible 11 as the central axis, and each positioning groove 135 is evenly distributed equidistantly along the circumference of the crucible 11. This distribution structure of multiple positioning grooves 135 arranged equidistantly and spirally extending coaxially helps optimize the structural fit when each linkage slider 153 is correspondingly inserted and slidably fitted into each positioning groove 135. It also makes the stress distribution of the mating structure between the linkage bracket 15 and the inner heating cylinder 13 more balanced, avoiding local stress concentration that could lead to imbalance or damage to the main structure of the inner heating cylinder 13 or the linkage bracket 15. This improves the operational stability and structural reliability of the linkage bracket 15 and the inner heating cylinder 13, and optimizes the linkage fit of the relevant operational components of the liquid phase silicon carbide crystal growth apparatus.

[0072] It is easy to understand that, as shown in the figure, the spiral extension structure of each positioning groove 135 should match the direction of movement of the seed crystal rod 12 during its lifting and rotating motions, in order to meet the adaptation requirements when the corresponding linkage slider 153 slides relative to the positioning groove 135, and to avoid structural obstruction or jamming between the linkage slider 153 and the positioning groove 135. The directional adaptation arrangement of the spiral extension structure of the positioning groove 135 is a basic component geometry design. Industry technicians can complete the corresponding adaptation design based on basic geometric and physical knowledge, and will not elaborate further in this article.

[0073] More specifically, the linkage 152 includes a transverse section 154 and a longitudinal section 155 connected sequentially from its inner end to its outer end. The transverse section 154 extends radially along the crucible 11, and the longitudinal section 155 extends axially along the crucible 11. The top end of the longitudinal section 155 is vertically connected to the outer end of the transverse section 154, and the linkage slider 153 protrudes radially along the crucible 11 and is disposed on the outer side wall of the bottom end of the longitudinal section 155. The radial extension structure of the transverse section 154 can ensure that there is sufficient radial clearance between the linkage slider 153 and the linkage ring, so as to prevent the linkage slider 153 from interfering with the seed crystal rod 12, the seed crystal holder 121, and the silicon carbide crystal located on the seed crystal holder 121.

[0074] The longitudinal section 155 ensures that there is an appropriate axial drop between the linkage slider 153 and the linkage ring, so that when the linkage slider 153 abuts in the lower positioning groove 132, the inner heating cylinder 13 can be lifted to a sufficient height, ensuring that the inner heating cylinder 13 can be matched with the remelting station of the silicon carbide seed crystal 30 located on the seed crystal holder 121, and meet the corresponding remelting process operation requirements. Meanwhile, when the linkage slider 153 abuts against the upper positioning groove 134, the extension length of the longitudinal section 155 is sufficient to ensure that the difference in height between the linkage slider 153 and the linkage ring is sufficient to ensure that the support structure based on the inner heating cylinder 13 can lift the linkage bracket 15 as a whole and keep it constant, so that the axial downward movement of the seed crystal rod 12 is sufficient to disengage the positioning tray 122 from the linkage ring, thereby fully releasing the circumferential linkage between the seed crystal rod 12 and the linkage bracket 15, avoiding the synchronous movement of the linkage bracket 15 caused by the fixed-axis rotation of the seed crystal rod 12 during the subsequent silicon carbide crystal growth process, thus ensuring that the working position of the inner heating cylinder 13 is constant during the silicon carbide crystal growth process, thereby maintaining continuous and efficient heating of the corresponding melt 20 to meet the requirements of the corresponding silicon carbide crystal growth process.

[0075] Based on this, the cross-section of the linkage slider 153 along the tangential direction of the inner peripheral wall of the inner heating cylinder 13 is circular or parallelogram as shown in the figure. The main body structure of the linkage slider 153 with a circular cross-section is cylindrical, so that the smooth extension structure of its outer peripheral surface allows the linkage slider 153 to slide more smoothly into the positioning grooves 135, upper positioning grooves 134, or lower positioning grooves 132 through the slot opening. The main body structure of the linkage slider 153 with a parallelogram cross-section is a regular multi-faceted prism structure, so that each facet fits snugly against the inner wall of the corresponding positioning groove 135, upper positioning groove 134, or lower positioning groove 132, thereby appropriately increasing the contact area between the linkage slider 153 and each groove, optimizing the sliding fit effect between the linkage slider 153 and the corresponding groove, and making the sliding of the linkage slider 153 in the positioning groove 135, upper positioning groove 134, or lower positioning groove 132 smoother and more stable. Furthermore, the contact between the edge of the parallelogram-shaped linkage slider 153 and the inner wall of the corresponding upper positioning groove 134 or lower positioning groove 132 is more sufficient, which can optimize the support and adaptation effect between the linkage bracket 15 and the inner heating cylinder 13, so that the component adaptation structure of the liquid phase silicon carbide crystal growth device can remain stable and reliable under different working conditions.

[0076] Of course, the two shapes of the linkage slider 153 described above are only structural designs considering the needs of most working conditions. In practical applications, the specific shape of the linkage slider 153 and its adaptation method with the positioning groove 135, the upper positioning groove 134, or the lower positioning groove 132 can be adaptively adjusted according to different actual working conditions and differences in the adaptation structure of equipment components. In principle, any shape that can meet the actual application needs of the liquid phase silicon carbide crystal growth device is acceptable.

[0077] Generally, the top surface of the positioning tray 122 is recessed and has a linkage groove 123, while the bottom surface of the linkage ring is protruding and has a linkage boss 156 that aligns with and engages with the linkage groove 123. Thus, when the linkage ring is attached to the top of the positioning tray 122, the linkage boss 156 can be aligned and inserted into the corresponding linkage groove 123. The contact between the outer side wall of the linkage boss 156 and the inner side wall of the linkage groove 123 creates a circumferential linkage fit between the linkage ring and the positioning tray 122. Therefore, when the seed crystal rod 12 rotates on a fixed axis, the abutment fit between the linkage boss 156 and the linkage groove 123 allows the positioning tray 122 to drive the linkage ring to rotate synchronously on a fixed axis, thereby causing the entire linkage bracket 15 to rotate on a fixed axis. When the linkage slider 153 abuts against the inner wall of the upper positioning groove 134, the linkage bracket 15 is lifted by the inner heating cylinder 13 as a whole, so that the linkage ring is disengaged from the positioning tray 122. At this time, the linkage boss 156 is also pulled out from the corresponding linkage groove 123, thereby releasing the circumferential linkage adaptation between the linkage ring and the positioning tray 122.

[0078] Accordingly, there can be two or more linkage slots 123, and each linkage slot 123 is evenly distributed along the circumference of the positioning tray 122. Correspondingly, the linkage bosses 156 can also be arranged in the same number as the linkage slots 123, and each linkage boss 156 is evenly distributed along the circumference of the linkage ring to ensure that each linkage boss 156 can be inserted and fitted into each linkage slot 123 in a one-to-one correspondence. Thus, by utilizing the circumferentially evenly distributed structure, the stress distribution of the fitting structure between the linkage slots 123 and the linkage bosses 156 is optimized, avoiding structural imbalance caused by stress concentration in the fitting structure between the linkage ring and the positioning tray 122. This ensures a smoother and more stable linkage fitting process between the seed crystal rod 12 and the linkage bracket 15.

[0079] On the other hand, the inner peripheral wall of the external heating cylinder 14 is recessed and provided with a number of guide grooves 141 extending along its axial direction, and each guide groove 141 is evenly distributed at equal intervals along the circumference of the external heating cylinder 14. The outer peripheral wall of the inner heating cylinder 13 is provided with several guide ridges 136 extending along its axial direction. Each guide ridge 136 is evenly distributed along the circumference of the inner heating cylinder 13, and the guide ridges 136 are aligned and slidably fitted into the guide grooves 141. During the reciprocating movement of the inner heating cylinder 13 along the axial direction of the crucible 11, the guide ridges 136 can slide and fit into the corresponding guide grooves 141. The extension structure of the guide grooves 141, in conjunction with the fitting of the guide ridges 136, forms circumferential limiting and axial guidance for the movement of the inner heating cylinder 13. This ensures the tracking performance of the movement of the inner heating cylinder 13 and avoids circumferential loosening or misalignment during the movement of the inner heating cylinder 13. This optimizes the efficiency of the movement of the inner heating cylinder 13 and improves the alignment accuracy between the inner heating cylinder 13 and the corresponding remelting or growth station.

[0080] Furthermore, the insulation assembly includes a quartz cylinder 10 and an insulation cylinder 103 coaxially attached to the inner circumferential wall of the quartz cylinder 10. It also includes an insulation top felt 104 detachably connected to the top of the quartz cylinder 10 and an insulation bottom felt 105 detachably connected to the bottom of the quartz cylinder 10. The insulation top felt 104 and insulation bottom felt 105 are respectively aligned, abutted, and pressed tightly against the top and bottom of the insulation cylinder 103, thereby forming an insulation cavity 101 between the insulation cylinder 103, the insulation top felt 104, and the insulation bottom felt 105. The quartz cylinder 10, as the main load-bearing component of the insulation assembly, provides a reliable installation and support structure foundation for the insulation cylinder 103, the insulation top felt 104, and the insulation bottom felt 105. Accordingly, the coordinated operation of the insulation cylinder 103, the top insulation felt 104, and the bottom insulation felt 105 ensures the overall spatial arrangement of the insulation cavity 101. Furthermore, when it is necessary to remove the silicon carbide crystal from the seed crystal holder 121, or to install the silicon carbide seed crystal 30 onto the seed crystal holder 121, the insulation cavity 101 can be opened and closed by disassembling and assembling the top insulation felt 104, thus meeting the operational requirements under different working conditions. The specific manufacturing materials of the insulation cylinder 103, the top insulation felt 104, and the bottom insulation felt 105 can be selected and adapted using conventional technologies in the field, and will not be elaborated further in this solution.

[0081] In addition, a main tray 16 is provided inside the insulation cavity 101. A positioning rod 161 extends vertically through the bottom of the insulation component. The top of the positioning rod 161 extends into the insulation cavity 101 and is linked to the bottom of the main tray 16. A main support groove 162 is recessed in the center of the top surface of the main tray 16. The bottom of the crucible 11 is aligned, inserted, and disassembled into the main support groove 162. The main support groove 162 provides sufficient installation space and appropriate structural restraint for the crucible 11. Combined with the coordinated operation of the main tray 16 and the positioning rod 161, it provides sufficient and reliable structural support for the crucible 11, ensuring that the position of the crucible 11 remains constant during the process, and thereby ensuring that the structure of each adapter component of the crucible 11 is more stable and reliable.

[0082] Generally, an action mechanism that can drive the positioning rod 161 to reciprocate up and down or rotate on a fixed axis can be arranged at the bottom of the insulation component. Its arrangement is similar to the lifting drive device and rotation drive device adapted to the seed crystal rod 12. Thus, the positioning rod 161 can be driven to rise and fall or rotate on a fixed axis when necessary, so as to make adaptive adjustments to the arrangement height of the main support groove 162 and the crucible 11, or drive the crucible 11 to rotate appropriately, so as to meet the operational requirements of the corresponding silicon carbide crystal growth process and optimize the corresponding silicon carbide crystal growth effect.

[0083] It is easy to understand that the operation, start and stop of each action mechanism and driving device in the present solution can be cooperatively controlled by a controller matched with the liquid-phase silicon carbide crystal growth apparatus. The controller can be a PLC (Programmable Logic Controller) or a computer device. Correspondingly, the temperature measuring instrument is also communicatively connected and adapted to the controller, and the specific arrangement position of the temperature measuring instrument can be flexibly selected according to the actual internal installation space of the apparatus and the adaptation requirements of components. In principle, any arrangement that can ensure accurate temperature detection of the relevant working environment of the crucible 11 is acceptable.

[0084] For the convenience of intuitively understanding the action process and operation principle of the liquid-phase silicon carbide crystal growth apparatus in the present solution, some key processes in the operation process of each core action component of the growth apparatus are explained as follows: 1. When the seed rod 12 supports the lower positioning groove 132 of the inner heating cylinder, the silicon carbide seed crystal 30 descends and contacts the surface of the molten material 20 for the first time, and the seed crystal remelting step is implemented; 2. The seed rod 12 is pulled to a higher position, then starts to rotate, driving the linkage ring 151 and the linkage rod 152 to rotate together. When the linkage sliding block 153 reaches the linkage groove 123, the inner heating cylinder 13 descends by its own gravity until the linkage sliding block 153 reaches the upper positioning groove 134, and at this time the inner heating cylinder 13 does not contact the heat insulating bottom felt 105; 3. When the seed rod 12 descends again, the inner heating cylinder 13 gradually touches the heat insulating bottom felt 105, then continues to descend so that the seed rod 12 is separated from the linkage bracket 15 / linkage ring 151, and then continues to descend to contact the solution and rotate at a high speed, and the rotation of the seed rod 12 will not be interfered by other objects.

[0085] In a specific embodiment, the silicon carbide crystal growth method provided by the present invention is suitable for the TSSG silicon carbide crystal growth process. The growth method adopts the liquid-phase silicon carbide crystal growth apparatus as described above, and comprises the following steps:

[0086] S101: bonding the silicon carbide seed crystal 30 for growth to the seed holder 121, filling the growth raw material into the growth cavity 111, assembling the linkage bracket 15 and the inner heating cylinder 13 assembly so that the linkage sliding block 153 is located in the lower positioning groove 132 of the inner heating cylinder 13 assembly, then sealing the heat insulation cavity 101 and vacuumizing the interior of the heat insulation cavity 101 to keep the internal space of the heat insulation cavity 101 clean.

[0087] S102: starting the heating assembly, and enabling the outer heating cylinder 14 and the inner heating cylinder 13 to generate heat respectively by operation of the induction heating coil 102 to heat the interior of the heat insulation cavity 101 until the temperature measured by the temperature measuring instrument shows that the ambient temperature at the crucible 11 meets the requirement of the remelting process.

[0088] S103, the seed crystal rod 12 moves the seed crystal holder 121 downward from the initial position to an appropriate position so that the silicon carbide seed crystal 30 on the seed crystal holder 121 comes into contact with the molten growth material. At this time, the internal heating cylinder 13 is located at a higher position inside the heat preservation cavity 111, the temperature at the growth interface is relatively high, and the temperature at the bottom of the molten material 20 is relatively low, forming a reverse thermal field, so that the silicon carbide seed crystal 30 can be fully melted back.

[0089] After the silicon carbide seed crystal 30 on the seed crystal holder 121 has been melted back, the seed crystal rod 12 is raised and lowered moderately until the silicon carbide seed crystal 30 is pulled out of the molten material 20. Then, the seed crystal rod 12 is rotated to move the linkage slider 153 into the positioning groove 135. At this time, the inner heating cylinder 13 slowly descends under gravity. It continues to rotate until the linkage slider 153 reaches the fixed position of the upper positioning groove 134 of the inner heating cylinder 13 assembly and then stops. After the rotation stops, the seed crystal rod 12 is lowered. First, the lower part of the inner heating cylinder 13... Positioning ring 131 contacts insulation base 105, while positioning tray 122 and linkage ring 151 separate. Seed crystal rod 12 continues to descend until the seed crystal contacts the solution. At this time, internal heating cylinder 13 is located at a lower position inside insulation cavity 101. The temperature at the growth interface is relatively low, while the temperature at the bottom of molten material 20 is relatively high, forming a positive thermal field. The seed crystal rod 12 is started to rotate, and crystal growth begins until the silicon carbide seed crystal 30 located on seed crystal tray 121 continues to grow to obtain silicon carbide crystal that meets the process requirements.

[0090] S105. After the silicon carbide crystal on the seed crystal holder 121 has grown, the seed crystal rod 12 is raised until the silicon carbide crystal is removed from the molten material 20. Then, the seed crystal rod 12 is rotated at a low speed and the cooling program is started until the program ends. After the temperature drops to room temperature, the grown silicon carbide crystal is removed from the seed crystal holder 121 for subsequent processing.

[0091] This silicon carbide crystal growth method, through sequential implementation of each operation step, simultaneously satisfies the different requirements for thermal field temperature distribution during the remelting process of the silicon carbide seed crystal 30 and the growth process of the silicon carbide crystal, thereby ensuring the corresponding silicon carbide crystal growth quality.

[0092] It should be noted that in practical applications, the silicon carbide crystal growth method provided in this solution is usually adapted to the specific component structures of the liquid phase silicon carbide crystal growth device mentioned above. Specifically, the actual operation and working process of the component adaptation structure, such as the linkage bracket 15, can be directly understood by referring to the corresponding content above for the operation of each specific component, and will not be elaborated here.

[0093] In summary, the liquid-phase silicon carbide crystal growth apparatus provided in this invention is suitable for the TSSG method of silicon carbide crystal growth. During operation, the silicon carbide seed crystal is installed on the seed crystal holder. The insulation cavity is then sealed and evacuated to ensure a clean environment for subsequent processes. The heating components are then activated, using induction heating coils to heat the outer and inner heating cylinders to heat the inside of the insulation cavity until the temperature sensor detects that the ambient temperature at the crucible meets the requirements for the remelting process. After the ambient temperature is preheated to the required level, the seed crystal rod moves the seed crystal holder downwards from its initial position to an appropriate position, so that the silicon carbide seed crystal on the seed crystal holder is located at the remelting position above the molten material surface. At this time, the internal heating cylinder is located at a higher position inside the insulation cavity, the temperature at the growth interface is relatively high, and the temperature at the bottom of the molten material is relatively low, forming a reverse thermal field. The seed crystal can be fully remelted, thereby performing a remelting treatment on the silicon carbide seed crystal on the seed crystal holder to remove scratches or attachments on the surface of the silicon carbide seed crystal, so that the surface of the silicon carbide seed crystal is restored to a smooth and regular state, in preparation for the subsequent growth of silicon carbide crystals. After the silicon carbide seed crystal on the seed crystal holder has been melted back, the seed crystal rod is raised and lowered moderately until the seed crystal is pulled out of the molten material. Then, the seed crystal rod is rotated to move the linkage slider into the positioning groove. At this time, the heating cylinder slowly descends under gravity and continues to rotate until the linkage slider reaches the fixed position of the positioning groove on the inner heating cylinder assembly and stops. After the rotation stops, the seed crystal rod is lowered. First, the lower positioning ring of the inner heating cylinder contacts the bottom inner wall of the insulation assembly, that is, the inner wall of the insulation felt. At the same time, the positioning tray and the linkage ring separate. The seed crystal rod continues to descend until the seed crystal contacts the solution. At this time, the inner heating cylinder is located at a lower position inside the insulation cavity. The temperature at the growth interface is relatively low, and the temperature at the bottom of the molten material is relatively high, forming a positive thermal field. The rotation of the seed crystal rod is started, and crystal growth begins until the silicon carbide seed crystal on the seed crystal holder continues to grow and obtains a silicon carbide crystal that meets the process requirements. After the silicon carbide crystal growth on the seed crystal holder is complete, the seed crystal rod is raised until the seed crystal detaches from the molten material. Then, the seed crystal rod is rotated at a low speed while a cooling program is initiated until the program ends. Once the temperature drops to room temperature, the grown silicon carbide crystal is removed from the seed crystal holder for subsequent processing. This liquid-phase silicon carbide crystal growth device, by adjusting the position of the internal heating cylinder in conjunction with the seed crystal rod, allows for continuous processing of the silicon carbide seed crystal's remelting and growth processes. This ensures that the remelting and growth processes meet different temperature requirements, maintaining the silicon carbide seed crystal in an unsaturated state for a longer period. This provides sufficient time for remelting and bubble removal, improving the crystallization quality of the silicon carbide crystal and making the remelting and growth processes smoother and more efficient. The integration of related supporting equipment is also improved accordingly.

[0094] In addition, the silicon carbide crystal growth method provided in this invention adopts the liquid phase silicon carbide crystal growth device as described above, which simultaneously meets the different requirements for thermal field temperature distribution during the remelting process of silicon carbide seed crystal and the growth process of silicon carbide crystal, thereby ensuring the corresponding silicon carbide crystal growth quality.

[0095] The liquid-phase silicon carbide crystal growth apparatus and the silicon carbide crystal growth method using the liquid-phase silicon carbide crystal growth apparatus provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A liquid-phase silicon carbide crystal growth apparatus, characterized in that, It includes a heat-insulating component with an internal heat-insulating cavity, a crucible fixed inside the heat-insulating cavity, a temperature measuring instrument adapted to the crucible, and a heating component capable of heating the crucible; The crucible has a growth chamber inside, and the top of the crucible has a material inlet communicating with the growth chamber. A seed crystal rod is vertically inserted through the top of the heat preservation component. The seed crystal rod is coaxially adapted with the crucible and the axis of the seed crystal rod extends vertically. A seed crystal holder capable of supporting silicon carbide crystals is linked to the bottom end of the seed crystal rod. The seed crystal rod can reciprocate up and down to drive the seed crystal holder into and out of the growth chamber through the material inlet. The heating assembly includes an inner heating cylinder, an outer heating cylinder, and an induction heating coil that can be thermally coupled and adapted to the inner heating cylinder and the outer heating cylinder. The inner heating cylinder and the outer heating cylinder are coaxially sleeved on the outside of the crucible. The outer peripheral wall of the outer heating cylinder is circumferentially fitted to the inner peripheral wall of the heat preservation cavity. The inner heating cylinder can reciprocate and slide to fit the inner peripheral wall of the outer heating cylinder, and the inner peripheral wall of the inner heating cylinder is clearance fitted to the outer peripheral wall of the crucible. The bottom surface of the inner heating cylinder is provided with a protruding lower positioning ring that extends circumferentially and can abut against the bottom inner wall of the heat preservation cavity. The inner circumferential wall of the lower positioning ring is provided with a lower positioning groove. The top surface of the inner heating cylinder is provided with an upper positioning ring that extends circumferentially and is in clearance fit with the inner wall of the top of the heat preservation cavity. The inner circumferential wall of the upper positioning ring is provided with an upper positioning groove. A positioning tray is coaxially and linkedly provided in the middle of the seed crystal rod, and the outer periphery of the positioning tray protrudes radially from the outer periphery of the seed crystal rod. The liquid phase silicon carbide crystal growth apparatus also includes a lifting drive device that can drive the seed crystal rod to reciprocate up and down along a fixed axis, a rotation drive device that can drive the seed crystal rod to rotate back and forth along a fixed axis, and a linkage bracket connected between the seed crystal rod and the inner heating cylinder. The linkage bracket includes a linkage ring coaxially sleeved on the seed crystal rod and a plurality of linkage rods with their inner ends fixed to the outer circumferential surface of the linkage ring. The linkage ring slides with the seed crystal rod and can abut against and adapt to the top surface of the positioning tray. The linkage ring can also be circumferentially linked with the positioning tray and can be disassembled and adapted. The outer ends of the linkage rods are provided with linkage sliders corresponding to each other. The inner wall of the inner heating cylinder is recessed with several positioning grooves that connect the upper positioning groove and the lower positioning groove. The linkage slider slides and the positioning grooves correspond to each other to make the linkage slider slide into the upper positioning groove or the lower positioning groove.

2. The liquid-phase silicon carbide crystal growth apparatus as described in claim 1, characterized in that, Each of the positioning grooves extends spirally in the same direction with the axis of the crucible as the central axis, and each of the positioning grooves is evenly distributed at equal intervals along the circumference of the crucible.

3. The liquid-phase silicon carbide crystal growth apparatus as described in claim 2, characterized in that, The linkage rod includes a transverse section and a longitudinal section connected sequentially from its inner end to its outer end. The transverse section extends radially along the crucible, and the longitudinal section extends axially along the crucible. The top end of the longitudinal section is vertically connected to the outer end of the transverse section, and the linkage slider protrudes radially along the crucible and is disposed on the outer side wall of the bottom end of the longitudinal section.

4. The liquid-phase silicon carbide crystal growth apparatus as described in claim 3, characterized in that, The cross-section of the linkage slider along the tangential direction of the inner peripheral wall of the inner heating cylinder is circular or parallelogram.

5. The liquid-phase silicon carbide crystal growth apparatus as described in claim 1, characterized in that, The top surface of the positioning tray is recessed and has a linkage groove, and the bottom surface of the linkage ring is protruding and has a linkage boss that is aligned with and snapped into the linkage groove.

6. The liquid-phase silicon carbide crystal growth apparatus as described in claim 1, characterized in that, The inner peripheral wall of the external heating cylinder is recessed and provided with a plurality of guide grooves extending along its axial direction, and each of the guide grooves is evenly distributed at equal intervals along the circumference of the external heating cylinder. The outer peripheral wall of the inner heating cylinder is provided with a plurality of guide protrusions extending along its axial direction. Each guide protrusion is evenly distributed at equal intervals along the circumference of the inner heating cylinder, and the guide protrusions are aligned and slidably fitted into the guide groove.

7. The liquid-phase silicon carbide crystal growth apparatus as described in claim 1, characterized in that, The insulation component includes a quartz cylinder and an insulation tube coaxially attached to the inner circumferential wall of the quartz cylinder. It also includes an insulation top felt detachably connected to the top of the quartz cylinder and an insulation bottom felt detachably connected to the bottom of the quartz cylinder. The insulation top felt and the insulation bottom felt are respectively aligned, abutted, and pressed tightly against the top and bottom of the insulation tube to form the insulation cavity between the insulation tube, the insulation top felt, and the insulation bottom felt.

8. The liquid-phase silicon carbide crystal growth apparatus as described in claim 1, characterized in that, The insulation cavity is provided with a main tray. The bottom of the insulation component is provided with a positioning rod extending vertically. The top of the positioning rod extends into the insulation cavity and is linked to the bottom of the main tray. The top surface of the main tray is recessed in the center and a main support groove is provided. The bottom of the crucible is aligned, inserted, and disassembled into the main support groove.

9. A method for growing silicon carbide crystals, characterized in that, The liquid-phase silicon carbide crystal growth apparatus as described in any one of claims 1 to 8 includes the following steps: The silicon carbide seed crystal used for growth is bonded to the seed crystal holder, and the growth raw material is filled into the growth chamber. The linkage bracket and the inner heating cylinder assembly are assembled so that the linkage slider is located in the positioning groove under the inner heating cylinder assembly. Then the insulation chamber is sealed and the inside of the insulation chamber is evacuated to keep the internal space of the insulation chamber clean. Start the heating assembly and run the induction heating coil to heat the outer and inner heating cylinders respectively to heat the inside of the insulation cavity until the temperature measuring instrument detects that the ambient temperature at the crucible meets the requirements of the remelting process. The seed crystal rod moves the seed crystal holder downward from the initial position to the appropriate position so that the silicon carbide seed crystal on the seed crystal holder comes into contact with the molten growth material. At this time, the internal heating cylinder is located at a higher position inside the heat preservation cavity. The temperature at the growth interface is relatively high, and the temperature at the bottom of the molten material is relatively low, forming a reverse thermal field, so that the seed crystal can be fully melted back. After the silicon carbide seed crystal on the seed crystal holder has been melted back, the seed crystal rod is raised and lowered moderately until the seed crystal is pulled out of the molten material. Then, the seed crystal rod is rotated to move the linkage slider into the positioning groove. At this time, the heating cylinder slowly descends under gravity and continues to rotate until the linkage slider reaches the fixed position of the positioning groove on the inner heating cylinder assembly and stops. After the rotation stops, the seed crystal rod is lowered. First, the lower positioning ring of the inner heating cylinder contacts the insulation base felt, and at the same time, the positioning tray and the linkage ring separate. The seed crystal rod continues to descend until the seed crystal contacts the solution. At this time, the inner heating cylinder is located at a lower position inside the insulation cavity. The temperature at the growth interface is relatively low, and the temperature at the bottom of the molten material is relatively high, forming a positive thermal field. The seed crystal rod is started to rotate, and crystal growth begins until the silicon carbide seed crystal on the seed crystal holder continues to grow and obtains a silicon carbide crystal that meets the process requirements. After the silicon carbide crystal on the seed crystal holder has grown, the seed crystal rod is raised until the seed crystal is removed from the molten material. Then, the seed crystal rod is rotated at a low speed and the cooling program is started until the program ends. After the temperature drops to room temperature, the grown silicon carbide crystal is removed from the seed crystal holder for subsequent processing.

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