Crystal growth equipment and crystal growth method

Abstract

The invention relates to a crystal growth apparatus and a crystal growth method. In one aspect, there is provided a crystal growth apparatus comprising: a crucible for accommodating a raw material and a seed crystal therein; a first thermal field structure for providing a first thermal field is arranged in the annealing chamber; a second thermal field structure used for providing a second thermal field is arranged in the growth chamber, the radial temperature gradient and the axial temperature gradient of the first thermal field are smaller than the radial temperature gradient and the axial temperature gradient of the second thermal field respectively, and the annealing chamber and the growth chamber can communicate with each other; and the driving device is used for driving the crucible to move between the growth chamber and the annealing chamber which are in a communicated state, so as to respectively grow crystals on the seed crystals in the growth chamber and anneal the grown crystals in the annealing chamber. Therefore, the risk of crystal cracking during crystal annealing can be reduced, and the processing yield and quality of the substrate made of the crystal can be improved.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor manufacturing technology, and in particular, to a crystal growth device and a crystal growth method. Background Art

[0002] As a third-generation semiconductor material, silicon carbide (SiC) has shown broad application potential in many fields such as automobiles and communications due to its large bandgap, high electron saturation rate, and high thermal conductivity.

[0003] Physical Vapor Transport (PVT) is a technology used to grow high-melting-point semiconductor crystal materials such as SiC crystals, which mainly includes four steps: heating, crystal growth, annealing, and cooling. Taking SiC crystals as an example, in the PVT method, the raw materials for growing SiC crystals (i.e., SiC powder) are placed in a graphite crucible and sublimated into gaseous components by heating. These gaseous components will then condense on the surface of the SiC seed crystal with a lower temperature fixed to the top of the graphite crucible and grow to form SiC crystals. The grown SiC crystals will then undergo annealing and be taken out of the crystal growth furnace after being cooled to room temperature, so that they can be made into substrates through subsequent processes such as cutting, thinning, polishing, and cleaning.

[0004] Among these processes, the annealing process is particularly important, which can not only eliminate the thermal stress generated by the crystal during the growth process, but also reduce the deformation stress generated by the crystal during the cooling process, thereby reducing the risk of crystal cracking, increasing the substrate processing yield and improving the quality of the substrate.

[0005] At present, the annealing process is divided into annealing in a crystal growth furnace and annealing outside a crystal growth furnace. For annealing in a crystal growth furnace, the thermal field of annealing is consistent with the thermal field of crystal growth. However, the thermal field design of crystal growth requires a certain temperature gradient to ensure normal crystal growth, while the thermal field design of annealing requires the temperature gradient to be as small as possible to facilitate the release of stress. Therefore, direct annealing of the crystal in a crystal growth furnace is not conducive to reducing crystal stress, and may increase the risk of crystal cracking and reduce substrate processing yield and substrate quality. For annealing outside a crystal growth furnace, not only does it require additional annealing equipment, process flow and cycle, but it also causes energy waste and increases production costs. Summary of the invention

[0006] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0007] The object of the present disclosure is to provide a crystal growth device that can reduce the risk of crystal cracking during crystal annealing and improve the processing yield and quality of a substrate made of the crystal.

[0008] In order to achieve the above object, according to one aspect of the present disclosure, a crystal growth device is provided, comprising: A crucible for containing raw materials and seed crystals therein; an annealing chamber, in which a first thermal field structure for providing a first thermal field is disposed; a growth chamber in which a second thermal field structure for providing a second thermal field is disposed, wherein the radial temperature gradient and the axial temperature gradient of the first thermal field are respectively smaller than the radial temperature gradient and the axial temperature gradient of the second thermal field, and the annealing chamber and the growth chamber can be communicated with each other; and The driving device is used for driving the crucible to move between the growth chamber and the annealing chamber which are in a connected state, so as to grow a crystal on a seed crystal in the growth chamber and to anneal the grown crystal in the annealing chamber.

[0009] In some embodiments, the crystal growth equipment may further include an isolation device, which can be switched between a first state and a second state, and is in the first state during the crystal growth stage and in the second state after the crystal growth stage ends, wherein when the isolation device is in the first state, the annealing chamber is isolated from the growth chamber, and when the isolation device is in the second state, the annealing chamber is connected to the growth chamber.

[0010] In some embodiments, the isolation device may be a gate valve disposed between the annealing chamber and the growth chamber.

[0011] In some embodiments, the annealing chamber may be located above the growth chamber.

[0012] In some embodiments, the first thermal field structure may include a first side insulation felt, a first top insulation felt and a first heating device, wherein the first side insulation felt is arranged at the circumferential wall of the annealing chamber, the first top insulation felt is arranged at the top wall of the annealing chamber, and the first heating device is arranged radially inward of the first side insulation felt.

[0013] In some embodiments, the annealing chamber may include a support table fixed to a peripheral wall of the annealing chamber for supporting the first side insulation felt thereon.

[0014] In some embodiments, the first thermal field structure may further include a second top insulation felt, which is disposed at the top of the crucible and has a shape matching that of the first top insulation felt.

[0015] In some embodiments, the second thermal field structure may include a second side insulation felt, a bottom insulation felt and a second heating device, wherein the second side insulation felt is arranged at the circumferential wall of the growth chamber, the bottom insulation felt is arranged at the bottom of the growth chamber, and the second heating device is arranged radially inward of the second side insulation felt.

[0016] In some embodiments, the bottom insulation felt may be provided with a temperature measuring hole, which penetrates the bottom insulation felt to measure the bottom temperature of the crucible.

[0017] In some embodiments, the driving device may include a lifting rod that passes through the top wall of the annealing chamber in a vertical direction and is connected to the top of the crucible to drive the crucible to move between the growth chamber and the annealing chamber by moving up and down in the vertical direction.

[0018] In some embodiments, the driving device can also be used to drive the crucible to rotate.

[0019] In some embodiments, the crucible may include a crucible body and a crucible cover, the crucible cover being detachably connected to the crucible body, the crucible body being used to accommodate a raw material therein, and the crucible cover being used to connect a seed crystal at a lower portion thereof.

[0020] In some embodiments, the power of the first thermal field structure can be automatically adjusted to maintain the radial temperature gradient and the axial temperature gradient of the first thermal field.

[0021] In some embodiments, the annealing chamber and the growth chamber may be two separate parts and connected in a detachable manner.

[0022] According to another aspect of the present disclosure, a crystal growth method is also provided, which is performed using the crystal growth device according to any of the above embodiments.

[0023] According to the above technical solution, by setting a growth chamber and an annealing chamber with different temperature gradients of their respective thermal fields, and by enabling the two chambers to be connected and enabling the crucible to move between the two chambers, in the crystal growth stage, the crucible can be placed in the growth chamber so that the crystal growth can be carried out in a thermal field with an expected temperature gradient, thereby ensuring the normal growth of the crystal. In the annealing stage, the crucible can be moved from the growth chamber to the annealing chamber so that the annealing can be carried out in a thermal field with a relatively small temperature gradient. Thus, the stress of the grown crystal can be better released, thereby reducing the risk of crystal cracking, and improving the processing yield and quality of the substrate made of the grown crystal. Moreover, the waste heat of the thermal field of the growth chamber can enter the annealing chamber, thereby reducing energy consumption and saving production costs. In addition, the crystal growth stage, the annealing stage, and the transition stage from the crystal growth stage to the annealing stage are all carried out in the internal chamber of the crystal growth device, so there is no need to add annealing equipment, and thus the process flow and cycle can be reduced, thereby also saving production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The features and advantages of the embodiments of the present disclosure will become more easily understood through the following description with reference to the accompanying drawings. The drawings are not drawn to scale and some features may be enlarged or reduced to show details of specific parts. In the drawings: Figure 1 It is a schematic structural diagram of a crystal growth device according to an embodiment of the present disclosure.

[0025] Figure 2 It is a schematic structural diagram of a crystal growth device according to another embodiment of the present disclosure, wherein it schematically shows a state of the crystal growth device in a crystal growth stage.

[0026] Figure 3 Schematically shows Figure 2 The crystal growth apparatus shown in FIG. 1 is in a state at the end of the crystal growth stage but before entering the annealing stage.

[0027] Figure 4 Schematically shows Figure 2 The crystal growth apparatus shown in FIG. 1 is in the annealing stage.

[0028] In the drawings, the same or corresponding technical features, parts or components are represented by the same or corresponding reference numerals. DETAILED DESCRIPTION

[0029] The present disclosure is described in detail below with reference to the accompanying drawings by means of exemplary embodiments. It should be noted that the following detailed description of the present disclosure is only for illustrative purposes and is by no means a limitation of the present disclosure.

[0030] It should be noted that, for the sake of clarity, not all features of a specific implementation are described and illustrated in the specification and drawings. Furthermore, in order to avoid unnecessary details that obscure the technical solution focused on by the present disclosure, only the device structures and parts closely related to the technical solution of the present disclosure are described and illustrated in the specification and drawings, while other details that are not closely related to the technical content of the present disclosure and are known to those skilled in the art are omitted.

[0031] As discussed before, when annealing is performed in a crystal growth furnace, the thermal field used is the same thermal field used when growing crystals. However, for the thermal field design of crystal growth, to ensure normal crystal growth, the temperature gradient must reach a certain size and not be too small; and for the thermal field design of annealing, in order to avoid crystal cracking, the temperature gradient should be as small as possible. Therefore, when the crystal is annealed directly in the crystal growth furnace, that is, when annealing is performed in the original position of the crystal growth, the crystal stress may not be effectively released, which may increase the risk of crystal cracking and reduce the substrate processing yield and substrate quality. If annealing is performed outside the crystal growth furnace, not only will it be necessary to increase annealing equipment, increase process flow and cycle, but it will also cause energy waste and increase production costs.

[0032] In this regard, according to an embodiment of the present disclosure, a crystal growth device is provided. Figures 1 to 4 , the crystal growth device 1 is described in detail. It should be noted that the following description is carried out by taking the growth of SiC crystal as an example, but the present disclosure is not limited thereto.

[0033] First, refer to Figure 1 The crystal growth apparatus 1 includes a crucible 10 , an annealing chamber 20 , a growth chamber 30 and a driving device 40 .

[0034] The crucible 10 is used to accommodate a raw material 10 a and a seed crystal 10 b therein so as to grow a crystal in the crucible 10 and anneal the grown crystal.

[0035] For example, the raw material 10a may be SiC powder, and the seed crystal 10b may be a SiC seed crystal. The seed crystal 10b may be located at the top of the crucible 10 to form SiC crystals by growing gaseous components (e.g., Si, Si2C, SiC2, etc.) sublimated by heating the raw material 10a on the surface of the seed crystal 10b in the crucible 10.

[0036] The annealing chamber 20 is provided with a first thermal field structure 200 for providing a first thermal field. The growth chamber 30 is provided with a second thermal field structure 300 for providing a second thermal field. The radial temperature gradient and the axial temperature gradient of the first thermal field are respectively smaller than the radial temperature gradient and the axial temperature gradient of the second thermal field, and the annealing chamber 20 and the growth chamber 30 can communicate with each other.

[0037] That is to say, the growth chamber 30 and the annealing chamber 20 are two different chambers, and the thermal fields that the two chambers can provide are different. Reflected in the temperature gradient, the radial and axial temperature gradients of the thermal field of the annealing chamber 20 are both smaller than the radial and axial temperature gradients of the thermal field of the growth chamber 30. In this way, when crystal growth is performed in the growth chamber 30, the radial temperature gradient and the axial temperature gradient of the second thermal field can reach a certain size suitable for normal crystal growth; and when the grown crystal is annealed in the annealing chamber 20, the radial temperature gradient and the axial temperature gradient of the first thermal field can be smaller than the radial temperature gradient and the axial temperature gradient of the second thermal field, so as to be suitable for annealing. For example, the radial temperature gradient of the second thermal field can be 0.5°C / cm~1°C / cm, and the axial temperature gradient can be 0.5°C / cm~2°C / cm; while the radial temperature gradient of the first thermal field can be 0.1°C / cm~0.2°C / cm, and the axial temperature gradient can be 0.2°C / cm~0.3°C / cm.

[0038] In addition, the annealing chamber 20 and the growth chamber 30 can be connected to each other, which means that the annealing chamber 20 can be always connected to the growth chamber 30 (for example, Figure 1 Alternatively, the annealing chamber 20 may be connected to the growth chamber 30 only under certain conditions (for example, the embodiment described later). Figures 2 to 4 Implementation shown in ).

[0039] The driving device 40 is used to drive the crucible 10 to move between the growth chamber 30 and the annealing chamber 20 which are in a connected state, so as to grow a crystal on the seed crystal 10 b in the growth chamber 30 and anneal the grown crystal in the annealing chamber 20 .

[0040] When the growth chamber 30 and the annealing chamber 20 are in a connected state, the crucible 10 is allowed to move between the growth chamber 30 and the annealing chamber 20 by the driving device 40. In this way, in the crystal growth stage, the crucible 10 can be placed in the growth chamber 30 so that the crystal growth can be carried out in the second thermal field where the radial temperature gradient and the axial temperature gradient are both in the expected size, thereby ensuring the normal growth of the crystal. In the annealing stage, the crucible 10 can be driven by the driving device 40 to move from the growth chamber 30 to the annealing chamber 20 so that the annealing can be carried out in the first thermal field where the radial temperature gradient and the axial temperature gradient are relatively small, thereby enabling the stress of the grown crystal to be better released, thereby reducing the risk of crystal cracking, and improving the processing yield and quality of the substrate made of the grown crystal.

[0041] Moreover, since the growth chamber 30 and the annealing chamber 20 are connected to each other, especially after the crystal growth stage is over and when entering the annealing stage, the growth chamber 30 and the annealing chamber 20 are in a connected state, the residual heat of the second thermal field generated by the growth chamber 30 during crystal growth can enter the annealing chamber 20, so that the temperature of the annealing chamber 20 increases. Therefore, the first thermal field structure 200 can consume less energy to make the annealing chamber 20 reach the first thermal field for annealing, thereby reducing energy consumption and saving production costs.

[0042] In addition, since the crystal growth stage, annealing stage and the transition stage from the crystal growth stage to the annealing stage are all carried out in the internal chamber of the crystal growth equipment 1, there is no need to add annealing equipment, and thus the process flow and cycle can be reduced, thereby saving production costs.

[0043] It is conceivable that the power of the first thermal field structure 200 can be automatically adjusted to maintain the radial temperature gradient and the axial temperature gradient of the first thermal field.

[0044] The residual heat of the second thermal field of the growth chamber 30 will enter the annealing chamber 20, and the residual heat will change over time. For example, the residual heat will gradually increase at the beginning, and then gradually decrease to zero at a certain time. By enabling the power of the first thermal field structure 200 to be automatically adjusted, the temperature gradient of the first thermal field of the annealing chamber 20 can be made more stable, which is conducive to improving the quality of crystal annealing.

[0045] It is also conceivable that the annealing chamber 20 and the growth chamber 30 may be two separate parts and connected in a detachable manner.

[0046] In this way, the crystal growth device 1 can be easily installed and removed, especially the crucible 10 can be easily installed in the crystal growth device 1 and removed from the crystal growth device 1. The connection between the annealing chamber 20 and the growth chamber 30 can be sealed by a sealing ring, for example, to ensure the airtightness of the chamber.

[0047] In some embodiments, reference Figures 2 to 4 The crystal growth device 1 may further include an isolation device 50, which is capable of switching between a first state and a second state, and is in the first state during the crystal growth stage, and is in the second state after the crystal growth stage ends, wherein when the isolation device 50 is in the first state, the annealing chamber 20 is isolated from the growth chamber 30, and when the isolation device 50 is in the second state, the annealing chamber 20 is connected to the growth chamber 30.

[0048] That is, the annealing chamber 20 and the growth chamber 30 can be isolated and connected by the isolation device 50, and when the crucible 10 is in the growth chamber 30 for crystal growth, the growth chamber 30 is separated from the annealing chamber 20 by the isolation device 50 (e.g., Figure 2 After the crystal growth is completed, the growth chamber 30 is connected to the annealing chamber 20 through the isolation device 50 (as shown in Figure 3 and Figure 4 ), so that the crucible 10 is moved from the growth chamber 30 to the annealing chamber 20 for annealing.

[0049] In this way, during the crystal growth stage, the enclosed space where the crucible 10 is located is only the growth chamber 30, rather than the internal chamber formed by the growth chamber 30 and the annealing chamber 20. Therefore, the second thermal field structure 300 can consume less energy to make the growth chamber 30 have a second thermal field suitable for normal crystal growth, thereby reducing energy consumption and saving production costs. After the crystal growth stage is over, as the growth chamber 30 and the annealing chamber 20 become connected to each other, the residual heat of the second thermal field of the growth chamber 30 can still be allowed to enter the annealing chamber 20, thereby further reducing energy consumption and further saving production costs.

[0050] It is conceivable that after the crucible 10 is moved into the annealing chamber 20 , the temperature of the second thermal field can be gradually lowered, for example, the second thermal field structure 300 stops heating the growth chamber 30 , and the temperature of the first thermal field of the annealing chamber 20 is maintained solely by the first thermal field structure 200 .

[0051] During the annealing stage, the annealing chamber 20 may still be connected to the growth chamber 30 to utilize as much residual heat as possible from the growth chamber 30. However, it is also conceivable that the annealing chamber 20 may be isolated from the growth chamber 30 by the isolation device 50 again.

[0052] In some embodiments, Figures 2 to 4 As shown in FIG. 5 , the isolation device 50 may be a gate valve disposed between the annealing chamber 20 and the growth chamber 30 .

[0053] The gate valve can be Figure 2 and Figure 3 As shown in FIG. 1 , the growth chamber 30 moves in the horizontal direction, for example, shrinks and expands, to cut off the connection between the growth chamber 30 and the annealing chamber 20 and to restore the cut-off connection. In this way, the isolation and connection conversion between the growth chamber 30 and the annealing chamber 20 can be simply achieved while keeping the growth chamber 30 and the annealing chamber 20 fixed, so that the crystal growth apparatus 1 can be made more stable and simpler in structure.

[0054] It is contemplated that the isolation device 50 may take any other suitable form.

[0055] In some embodiments, Figure 2 As shown in FIG. 8 , the annealing chamber 20 may be located above the growth chamber 30 .

[0056] In this way, it is convenient to perform annealing after the crystal growth stage by moving the crucible 10 only a short distance, thereby simplifying the path of movement of the crucible 10 in the transition from crystal growth to annealing, and thus reducing the risk of the grown crystal being damaged during the transfer of the crucible 10. In addition, since heat generally rises naturally, by arranging the annealing chamber 20 above the growth chamber 30, it is also beneficial for the residual heat in the growth chamber 30 to enter the annealing chamber 20, so that the residual heat can be used more effectively, and thus the energy consumption can be further reduced.

[0057] However, it is contemplated that the annealing chamber 20 may also be located below the growth chamber 30 .

[0058] In some embodiments, when the annealing chamber 20 is located above the growth chamber 30, as shown in FIG. Figures 1 to 4As shown in the figure, the first thermal field structure 200 may include a first side thermal insulation felt 2001, a first top thermal insulation felt 2002a and a first heating device 2003, the first side thermal insulation felt 2001 is arranged at the circumferential wall of the annealing chamber 20, the first top thermal insulation felt 2002a is arranged at the top wall of the annealing chamber 20, and the first heating device 2003 is arranged on the radial inner side of the first side thermal insulation felt 2001.

[0059] The first heating device 2003 can heat the interior of the annealing chamber 20 , and the first side insulation felt 2001 and the first top insulation felt 2002a can form an internal insulation layer of the annealing chamber 20 , thereby forming a first thermal field in the annealing chamber 20 .

[0060] It is conceivable that Figure 2 As shown in FIG. 1 , the annealing chamber 20 may include a support table 20 a fixed to a circumferential wall of the annealing chamber 20 for supporting the first side insulation felt 2001 thereon.

[0061] The support platform 20a may be an annular support platform extending along the circumferential direction of the annealing chamber 20 and may be fixed to the circumferential wall by welding. Through the support platform 20a, the first side insulation felt 2001 may be stably arranged at the circumferential wall of the annealing chamber 20.

[0062] It is also contemplated that the first top insulation blanket 2002a may be secured to the top wall of the annealing chamber 20 by studs and nuts.

[0063] In some embodiments, Figures 1 to 4 As shown in , the first thermal field structure 200 may further include a second top thermal insulation felt 2002b, which is disposed at the top of the crucible 10, and the shape of the second top thermal insulation felt 2002b matches the shape of the first top thermal insulation felt 2002a.

[0064] In this case, in the crystal growth stage, when the crucible 10 is in the growth chamber 30, the second top insulation felt 2002b can be used as the top insulation layer of the growth chamber 30 because it is arranged at the top of the crucible 10, and in the annealing stage, when the crucible 10 is moved from the growth chamber 30 to the annealing chamber 20, since the shape of the second top insulation felt 2002b matches the shape of the first top insulation felt 2002a, the second top insulation felt 2002b and the first top insulation felt 2002a can together constitute the top insulation layer of the annealing chamber 20. In this way, the insulation effects of the growth chamber 30 and the annealing chamber 20 can be improved at the same time with a simple structure.

[0065] In some embodiments, Figures 1 to 4As shown in, the second thermal field structure 300 may include a second side insulation felt 3001, a bottom insulation felt 3002 and a second heating device 3003, the second side insulation felt 3001 is arranged at the circumferential wall of the growth chamber 30, the bottom insulation felt 3002 is arranged at the bottom of the growth chamber 30, and the second heating device 3003 is arranged on the radial inner side of the second side insulation felt 3001.

[0066] The second heating device 3003 can heat the interior of the growth chamber 30 , and the second side insulation felt 3001 and the bottom insulation felt 3002 can form an internal insulation layer of the growth chamber 30 , thereby forming a second thermal field in the growth chamber 30 .

[0067] It is conceivable that Figure 2 As shown in FIG. 1 , the bottom insulation felt 3002 may be provided with a temperature measuring hole 3002a, which penetrates the bottom insulation felt 3002 to measure the bottom temperature of the crucible 10. The diameter of the temperature measuring hole 3002a may be, for example, 10 mm to 30 mm, so as to make the hole diameter as small as possible while meeting the space required for temperature measurement, so as to reduce the adverse effect on the insulation effect.

[0068] It can be understood that the power of the first thermal field structure 200 and the power of the second thermal field structure 300 can be considered as the power of the first heating device 2003 and the power of the second heating device 3003 respectively.

[0069] In some embodiments, the annealing chamber 20 is located above the growth chamber 30. Figures 1 to 4 As shown in the figure, the driving device 40 may include a lifting rod 401, which passes through the top wall of the annealing chamber 20 in the vertical direction and is connected to the top of the crucible 10, so as to drive the crucible 10 to move between the growth chamber 30 and the annealing chamber 20 by moving up and down in the vertical direction.

[0070] Since the lifting rod 401 itself has a simple structure and occupies a small space, it is not easy to interfere with other components when moving in the annealing chamber 20 and the growth chamber 30, and basically does not affect the isolation of the annealing chamber 20 and the growth chamber 30 by the isolation device 50 such as the gate valve.

[0071] The lifting rod 401 can be connected to the top of the crucible 10 by, for example, a threaded connection. However, it is conceivable that the lifting rod 401 can also be connected to the crucible 10 by any other suitable means.

[0072] In some embodiments, the driving device 40 can also be used to drive the crucible 10 to rotate. Figure 2As shown in the figure, the driving device 40 can drive the crucible 10 to rotate by rotating the lifting rod 401. The rotation can be performed throughout the crystal growth stage and the annealing stage. For example, the driving device 40 can drive the crucible 10 to rotate at a rotation speed of 0.1 rpm to 3 rpm, thereby making the crystal growth temperature and annealing temperature more uniform, which is beneficial to improving the quality of the grown crystal and the effect of crystal annealing.

[0073] In some embodiments, Figure 2 As shown in FIG. 1 , the crucible 10 may include a crucible body 101 and a crucible cover 102 , which is detachably connected to the crucible body 101 , the crucible body 101 being used to accommodate a raw material 10a for growing crystals therein, and the crucible cover 102 being used to connect a seed crystal 10b at its lower portion.

[0074] The crucible body 101 can be connected to the crucible cover 102 by a threaded connection, for example. For example, corresponding external threads and internal threads are respectively provided on the outer side of the crucible body 101 and the inner side of the crucible cover 102 to achieve a threaded connection between the two. The seed crystal 10b can be bonded to the lower surface of the crucible cover 102 by an adhesive, for example.

[0075] According to another aspect of the present disclosure, a crystal growth method is also provided, and the crystal growth method is performed using the crystal growth device 1. Figures 2 to 4 The crystal growth method will be exemplarily described with reference to the crystal growth apparatus 1 shown in FIG.

[0076] In the crystal growth stage, the lifting rod 401 is positioned so that the position of the seed crystal 10b in the crucible 10 connected thereto is, for example, 30 cm to 50 cm lower than the upper edge of the second heating device 3003 of the growth chamber 30, and the gate valve is closed. In this stage, first, the growth chamber 30 and the annealing chamber 20 are evacuated simultaneously, and when the vacuum degree is lower than 1×10^-1Pa, argon and nitrogen are introduced into the growth chamber 30 and the annealing chamber 20 to maintain the pressure in the chamber at 40000Pa to 80000Pa. Then, the second heating device 3003 is started for heating, and the temperature rise slope is controlled at 100°C / h~500°C / h. When the bottom temperature of the crucible 10 rises to 2100°C~2300°C, the pressure in the cavity begins to be reduced, and the pressure in the cavity is maintained at 100Pa~1000Pa for crystal growth. After the crystal growth is completed (for example, the growth time is 30h~300h), the pressure in the cavity is increased to 40000Pa~80000Pa.

[0077] Then, slowly open the gate valve, for example, it takes 5min to 120min for the gate valve to be fully opened from the fully closed state, then slowly lift the lifting rod 401 at a lifting speed of 1mm / h to 500mm / h until the second top insulation felt 2002b and the first top insulation felt 2002a are assembled and then stop lifting. During this process, the bottom temperature of the crucible 10 is maintained at 1800°C to 1900°C by starting the first heating device 2003 and controlling the power of the first heating device 2003. Then, slowly close the second heating device 3003 (for example, reduce the power of the second heating device 3003 from the current power to 0 through 1h to 5h). Then, control the power of the first heating device 2003 to maintain the bottom temperature of the crucible 10 at 1800°C to 1900°C, and perform crystal annealing for a duration of 5h to 24h. Then, the crucible 10 is cooled to room temperature at a cooling rate of 100° C. / h to 200° C. / h, and the crystal is taken out.

[0078] In the present disclosure, although the present disclosure has been described with reference to exemplary embodiments, it should be understood that the present disclosure is not limited to the specific embodiments described and shown in detail herein. Those skilled in the art may make various changes to the exemplary embodiments without departing from the scope defined by the claims of the present disclosure.

[0079] The features mentioned and / or shown in the above description of the exemplary embodiments of the present disclosure may be combined in the same or similar manner into one or more other embodiments, combined with the features in other embodiments or substituted for the corresponding features in other embodiments. The technical solutions obtained by these combinations or substitutions shall also be deemed to be included in the protection scope of the present disclosure.

Claims

1. A crystal growth device, characterized in that: include: A crucible for containing raw materials and seed crystals therein; an annealing chamber, in which a first thermal field structure for providing a first thermal field is disposed; a growth chamber in which a second thermal field structure for providing a second thermal field is disposed, wherein the radial temperature gradient and the axial temperature gradient of the first thermal field are respectively smaller than the radial temperature gradient and the axial temperature gradient of the second thermal field, and the annealing chamber and the growth chamber are capable of communicating with each other; and A driving device is used to drive the crucible to move between the growth chamber and the annealing chamber which are in a connected state, so as to grow a crystal on the seed crystal in the growth chamber and anneal the grown crystal in the annealing chamber.

2. The crystal growth device according to claim 1, characterized in that It also includes an isolation device, which can be switched between a first state and a second state, and is in the first state during the crystal growth stage, and is in the second state after the crystal growth stage is over, wherein when the isolation device is in the first state, the annealing chamber is isolated from the growth chamber, and when the isolation device is in the second state, the annealing chamber is connected to the growth chamber.

3. The crystal growth device according to claim 2, characterized in that: The isolation device is a gate valve arranged between the annealing chamber and the growth chamber.

4. The crystal growth apparatus according to any one of claims 1 to 3, characterized in that The annealing chamber is located above the growth chamber.

5. The crystal growth device according to claim 4, characterized in that: The first thermal field structure includes a first side insulation felt, a first top insulation felt and a first heating device, the first side insulation felt is arranged at the circumferential wall of the annealing chamber, the first top insulation felt is arranged at the top wall of the annealing chamber, and the first heating device is arranged on the radial inner side of the first side insulation felt.

6. The crystal growth device according to claim 5, characterized in that The annealing chamber includes a support table fixed to the circumferential wall of the annealing chamber for supporting the first side insulation felt thereon.

7. The crystal growth apparatus according to claim 5, characterized in that The first thermal field structure further includes a second top insulation felt, which is disposed at the top of the crucible and has a shape matching that of the first top insulation felt.

8. The crystal growth apparatus according to claim 4, characterized in that The second thermal field structure includes a second side insulation felt, a bottom insulation felt and a second heating device, the second side insulation felt is arranged at the circumferential wall of the growth chamber, the bottom insulation felt is arranged at the bottom of the growth chamber, and the second heating device is arranged on the radial inner side of the second side insulation felt.

9. The crystal growth apparatus according to claim 8, characterized in that The bottom insulation felt is provided with a temperature measuring hole, and the temperature measuring hole penetrates the bottom insulation felt to measure the bottom temperature of the crucible.

10. The crystal growth apparatus according to claim 4, characterized in that The driving device includes a lifting rod, which passes through the top wall of the annealing chamber in a vertical direction and is connected to the top of the crucible, so as to drive the crucible to move between the growth chamber and the annealing chamber by moving up and down in the vertical direction.

11. The crystal growth apparatus according to any one of claims 1 to 3, characterized in that The driving device is also used to drive the crucible to rotate.

12. The crystal growth apparatus according to any one of claims 1 to 3, characterized in that The crucible includes a crucible body and a crucible cover, the crucible cover is detachably connected to the crucible body, the crucible body is used to accommodate the raw material therein, and the crucible cover is used to connect the seed crystal at the lower part thereof.

13. The crystal growth apparatus according to any one of claims 1 to 3, characterized in that The power of the first thermal field structure can be automatically adjusted to maintain the radial temperature gradient and the axial temperature gradient of the first thermal field.

14. The crystal growth apparatus according to any one of claims 1 to 3, characterized in that The annealing chamber and the growth chamber are two separate parts and are connected in a detachable manner.

15. A crystal growth method, characterized in that: The method is carried out using the crystal growth apparatus according to any one of claims 1 to 14.

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