Silicon carbide crystal growth crucible, seed crystal and crystal growth method

Abstract

The invention provides a silicon carbide crystal growth crucible, a seed crystal and a crystal growth method, belongs to the technical field of silicon carbide crystal growth, and solves the problem that the surface quality is reduced after diameter expansion of silicon carbide crystals in the prior art. The crucible comprises a crucible body, a first area is arranged in the crucible body, the first area is arranged in the circumferential direction of the inner side wall of the crucible body, and the side, away from the side wall of the crucible body, of the first area communicates with a second area; the seed crystal fixing assembly comprises two clamping pieces, and the two clamping pieces are arranged at an interval in the vertical direction so as to form a third area; and the heating assembly comprises a first heating mechanism and a second heating mechanism. By adjusting the power ratio of the first heating mechanism to the second heating mechanism, the upper and lower surfaces of the seed crystal form certain positive saturation, so that decomposition of the upper and lower surfaces is inhibited, surface defects are reduced, and the surface uniformity of the silicon carbide crystal after diameter expansion is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of silicon carbide crystal growth, and specifically, relates to a silicon carbide crystal growth crucible, a seed crystal, and a crystal growth method. Background Art

[0002] Physical Vapor Transport (PVT) is currently the most commonly used method for growing SiC single crystals. However, the existing PVT method still faces many technical difficulties in practical applications, especially the slow expansion speed, low expansion yield, and difficulty in increasing crystal size.

[0003] During the expansion process of silicon carbide crystals, ensuring the uniformity of their growth is a difficult point. At present, most institutions adopt the design of the expansion ring structure, and then control the change of the thermal field, so that the diameter of the crystal continues to increase during the epitaxy from the thin seed crystal. For the distribution of the temperature field and the air flow field, the expansion process requires higher precision than the normal equal diameter growth crystal to avoid the crystal from expanding too fast or too slow, and the growth rate is inconsistent in different parts, resulting in crystal defects. Secondly, the brittle nature of 4H-SiC requires careful handling of materials during the expansion process to avoid cracks or other structural defects during the expansion process. This requires a more conservative strategy in the design and operation of the expansion ring. The main reason is that the expansion ring may produce excessive stress on the edge of the crystal, and a large amount of edge polycrystals are caused by the contact between the expansion ring and the crystal. This poses a challenge to the control of mechanical stress during the expansion process. In addition, during the expansion process, the mechanical stress of the crystal may increase, leading to the formation of cracks or other defects. Therefore, controlling the pressure and growth rate of the expansion ring to reduce stress concentration is an important technical bottleneck at present. Furthermore, after using the expansion ring, defects or unevenness may appear on the crystal surface, requiring post-processing to improve the surface quality, which increases the complexity and cost of the overall process.

[0004] Based on the above content, the technical problem to be solved by this application is: the surface quality of silicon carbide crystal is reduced after diameter expansion. Summary of the invention

[0005] The purpose of this application is to address the above-mentioned problems existing in the prior art and to propose a silicon carbide crystal growth crucible, seed crystal and crystal growth method, which solves the problem of reduced surface quality of silicon carbide crystals after diameter expansion in the prior art, improves the surface uniformity of silicon carbide crystals after diameter expansion, and reduces surface defects.

[0006] The objectives of the present application can be achieved through the following technical solutions: A silicon carbide crystal growth crucible, comprising: a crucible body, a first zone is provided in the crucible body, the first zone is used to accommodate raw materials, the first zone is arranged circumferentially along the inner side wall of the crucible body, and the first zone is connected to a second zone toward the side away from the side wall of the crucible body, the second zone is used for crystal growth; a seed crystal fixing assembly, the seed crystal fixing assembly comprises two clamping members, the two clamping members are arranged at intervals in the vertical direction to form a third zone, the third zone is used to accommodate seed crystals, and the third zone is connected to the second zone; and a heating assembly, the heating assembly comprises: a first heating mechanism, the first heating mechanism acts on the first zone for sublimation of the raw materials; a second heating mechanism, the second heating mechanism acts on the third zone for crystal growth; wherein the power of the first heating mechanism and the second heating mechanism is adjustable to form a temperature difference between the first zone, the third zone and the second zone. It can be understood that the crucible body is generally made of graphite. The first zone is used to accommodate raw materials. The raw materials here are preferably pre-sintered raw materials to avoid scattering to the second zone due to gravity factors. The second zone is mainly an area for gas phase transmission after the raw materials are heated. One side of the second zone is connected to the first zone, and the other side is connected to the third zone, so that crystal growth can be carried out on the seed crystal. In addition, the third zone covers the outer diameter edge of the seed crystal and the vertical extension area of ​​the seed crystal. The second heating mechanism can heat the third zone and the seed crystal in the third zone. And by setting a first heating mechanism to heat the first zone and a second heating mechanism to heat the third zone, the two zones can be controlled to provide appropriate temperatures respectively, and the second zone is not heated, so that a temperature difference is formed between the three zones. The silicon carbide raw material in the crucible body is sublimated toward the edge of the seed crystal after high-temperature heating, and is directly deposited on the m-plane and the a-plane when cooled, so that the silicon carbide seed crystal expands rapidly, wherein the m-plane and the a-plane are part of the outer peripheral surface of the silicon carbide seed crystal. If the silicon carbide seed crystal is a regular dodecagon, it has 12 side faces and 2 end faces, and the m-plane and the a-plane have 6 side faces respectively; and the upper and lower surfaces of the seed crystal can be formed with a certain positive saturation by adjusting the power ratio of the first heating mechanism and the second heating mechanism, thereby inhibiting the decomposition of the upper and lower surfaces, reducing surface defects, and improving the surface uniformity of the silicon carbide crystal after expansion.

[0007] In the above-mentioned silicon carbide crystal growth crucible, the first heating mechanism includes: a first heater, the first heater is arranged on the outer periphery of the side wall of the crucible body, and the first heater acts on the first zone; a second heater, the second heater is arranged on the outside of the crucible body, and the second heater is at least 2 and respectively located on both sides of the first zone in the vertical direction, and the second heater acts on the first zone. It can be understood that by subdividing the first heating mechanism into the first heater and the second heater, the heating can be controlled separately, so that the raw materials in the first zone are heated as evenly as possible. Exemplarily, the second heater is annular and is arranged above and below the crucible body respectively. The shape of the annular second heater is preferably substantially the same as the shape of the first zone, or the heating surface of the second heater in the vertical direction fully covers the cross-section of the first zone.

[0008] In the above-mentioned silicon carbide crystal growth crucible, the second heating mechanism includes a third heater, the third heater is arranged outside the crucible body, and the third heater acts on the third zone in an annular heating manner. It can be understood that the third zone is independently heated by arranging the third heater, and the third heater can be annular, so that the heating surface formed by it can annularly cover the third zone, and the heat transfer is more uniform.

[0009] In the above-mentioned silicon carbide crystal growth crucible, the first zone is arranged in an annular shape to accommodate an annular raw material. It can be understood that by arranging the first zone in an annular shape to match the shape of the inner wall of the crucible body, the effective filling rate of the raw material in the crucible body is increased, and sufficient material is provided for growing large-sized silicon carbide crystals.

[0010] The purpose of the present application is also to provide a silicon carbide seed crystal, which is applied to the silicon carbide crystal growth crucible as described above, wherein the thickness of the seed crystal ranges from 15 mm to 20 mm. It is understandable that the thickness of the existing seed crystal is generally about 350 microns, and by thickening the seed crystal and adjusting the thickness to the range of 15 mm to 20 mm, the high temperature decomposition part can be compensated.

[0011] In the above silicon carbide seed crystal, the cross section of the seed crystal is a regular 6*N polygon, where N≥1. It is understandable that a regular hexagon is one of the shapes, and in some embodiments, the cross section of the seed crystal may also be a regular dodecagon, a regular octagon, etc. When the number of sides increases, the shape tends to be more circular, and the area size of the crystal growth becomes larger.

[0012] In the above silicon carbide seed crystal, the minimum outer diameter of the seed crystal is larger than the outer diameter of the third zone. It can be understood that by configuring the minimum outer diameter of the seed crystal to be larger than the outer diameter of the third zone, the seed crystal can be assembled to protrude from the third zone in its length direction, and the third heater is configured at the periphery of the third zone, and the heating effect of the third heater is mainly concentrated in the third zone. Therefore, the edge temperature in the length direction of the seed crystal is lower than the temperature in the middle part, and it is not easy to decompose and can grow safely.

[0013] Another object of the present application is to provide a silicon carbide crystal growth method, which is applied to the silicon carbide crystal growth crucible as described above, and includes the following steps: preparing silicon carbide pre-sintered raw materials and filling seed crystals into the crucible body; heating the first zone and the third zone, and controlling the temperature of the first zone and the third zone to be greater than the temperature of the second zone, so that the raw material in the first zone sublimates to the second zone and is deposited and grown.

[0014] In the above-mentioned silicon carbide crystal growth method, heating the first zone and the third zone and controlling the temperature of the first zone and the third zone to be greater than the temperature of the second zone includes: configuring the power ratio of the first heater, the second heater and the third heater to be 6:x:y, wherein x∈[5,7] and y∈[2,4].

[0015] It can be understood that x and y are real numbers. By configuring the power ratio of the first heater, the second heater and the third heater to 6:x:y, the temperature of the second zone can be the lowest, and the temperatures of the first zone and the third zone can be higher. Among them, a regular dodecagonal seed crystal processed from an 8-inch crystal is selected. When the power ratio is set to first heater: second heater: third heater = 7:7:6, the middle of the seed crystal is overheated and decomposes rapidly. The edge of the seed crystal also decomposes seriously, and the diagonal diameter is decomposed from 200mm to 185mm; when the power ratio is set to first heater: second heater: third heater = 6:7:4 or 6:7:3 or 5 When the heating ratio is 1:7:4, the middle of the seed crystal decomposes slightly, the edge of the seed crystal shows no obvious signs of growth or decomposition, and the crystal expands rapidly, which is the optimal heating ratio; when the ratio is set to first heater: second heater: third heater = 6:7:2 or 5:7:2, a small amount of crystallization occurs on the upper and lower surfaces of the seed crystal, and a small amount of polycrystal appears at the contact with the graphite column, which can be removed by rough grinding. The edge of the seed crystal grows rapidly, and the diagonal diameter expands from 200mm to 245mm; if the ratio is set to first heater: second heater: third heater = 6:7:0, a large amount of crystallization occurs on the upper and lower surfaces of the seed crystal, and the edge of the seed crystal shows no obvious signs of growth or decomposition.

[0016] In the above-mentioned silicon carbide crystal growth method, the power ratio is set to the first heater: the second heater: the third heater = 6:7:0. The obtained crystal is processed and expanded once to expand the outer diameter of the seed crystal from the existing 8 inches to about 9.7 inches. The expansion process is stable, and the iteration time required to expand the C surface of silicon carbide from 8 inches to 10 inches is about one twentieth of that of the existing solution.

[0017] In the above-mentioned silicon carbide crystal growth method, the preparation of silicon carbide pre-sintered raw materials and filling the crucible body with seed crystals includes: processing the pre-sintered raw materials into a ring shape to obtain a ring-shaped pre-sintered raw material that matches the inner wall of the crucible body. It can be understood that by cutting or molding the pre-sintered raw materials into a ring shape, a specific size can be formed so as to fit the inner wall of the crucible body, providing sufficient raw materials for crystal growth and diameter expansion, and because the surface of the ring-shaped raw materials is sufficiently flat, the physical vapor transport process is more uniform, and the surface of the crystal grown on the seed crystal is also more uniform.

[0018] Compared with the prior art, this application has the following beneficial effects: 1. The present application sets a first heating mechanism to heat the first zone, and sets a second heating mechanism to heat the third zone, so that the two zones can be controlled to provide appropriate temperatures respectively, and the second zone is not heated, so that a temperature difference is formed between the three zones. The silicon carbide raw material in the crucible body is sublimated toward the edge of the seed crystal after high-temperature heating, and is directly deposited on the m-plane and the a-plane when cooled, so that the silicon carbide seed crystal expands rapidly; and the power ratio of the first heating mechanism and the second heating mechanism can be adjusted to form a certain positive saturation on the upper and lower surfaces of the seed crystal, thereby inhibiting the decomposition of the upper and lower surfaces, reducing surface defects, and improving the surface uniformity of the silicon carbide crystal after expansion; 2. The present application can compensate for the high-temperature decomposition part by thickening the seed crystal and adjusting the thickness to the range of 15 mm to 20 mm, thereby preventing the seed crystal from breaking during the crystal growth and diameter expansion process; 3. In the present application, the cross section of the seed crystal is set to be a regular dodecagon, a regular octagon, etc. When the number of sides increases, the shape tends to be circular, and the area size of the crystal growth is larger; 4. In the present application, by setting the heating power ratio to first heater: second heater: third heater = 6:7:4 or 6:7:3, the seed crystal is slightly decomposed in the middle, there is no obvious growth or decomposition sign at the edge of the seed crystal, the crystal expands rapidly, and the crystal surface uniformity is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a simplified structural schematic diagram of the silicon carbide crystal growth crucible of the present application; Figure 2 yes Figure 1The schematic diagram of the simplified structure after the seed crystal is placed in the structure shown; Figure 3 yes Figure 2 Schematic diagram of the simplified structure after crystal growth of the structure shown; Figure 4 is a schematic diagram of the cross-sectional structure of a silicon carbide seed crystal exemplified in the present application; Figure 5 It is a schematic diagram of the process of the silicon carbide crystal growth method of the present application; In the figure, 100, crucible body; 110, first zone; 120, second zone; 200, seed crystal fixing assembly; 210, clamping member; 220, third zone; 300, heating assembly; 310, first heating mechanism; 311, first heater; 312, second heater; 320, second heating mechanism; 321, third heater; Z, seed crystal; J, crystal growth layer. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0021] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0022] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0023] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0024] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0025] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only embodiment.

[0026] Please refer to the attached drawings in the instruction manual. Figure 1The silicon carbide crystal growth crucible of the present application includes a crucible body 100, a seed crystal fixing assembly 200 and a heating assembly 300. The crucible body 100 is provided with a first zone 110, which is arranged circumferentially along the inner side wall of the crucible body 100, and the first zone 110 is connected to the second zone 120 toward the side away from the side wall of the crucible body 100. The seed crystal fixing assembly 200 includes two clamping members 210, which are arranged at intervals in the vertical direction to form a third zone 220, and the third zone 220 is connected to the second zone 120. The heating assembly 300 includes a first heating mechanism 310 and a second heating mechanism 320, the first heating mechanism 310 acts on the first zone 110, and the second heating mechanism 320 acts on the third zone 220. It can be understood that the crucible body 100 is generally made of graphite, and the first zone 110 is used to accommodate raw materials. The raw materials here are preferably pre-sintered raw materials to avoid scattering to the second zone 120 due to gravity factors. The second zone 120 is mainly an area for gas phase transmission after the raw materials are heated. One side of the second zone 120 is connected to the first zone 110, and the other side is connected to the third zone 220, so that crystal growth can be carried out on the seed crystal Z. And by setting the first heating mechanism 310 to heat the first zone 110, and setting the second heating mechanism 320 to heat the third zone 220, the two zones can be controlled to provide suitable temperatures respectively, and the second zone 120 is not heated, so that a temperature difference is formed among the three zones. The silicon carbide raw material in the crucible body 100 is sublimated toward the edge of the seed crystal Z after high-temperature heating, and is directly deposited on the m-plane and the a-plane when cooled, so that the silicon carbide seed crystal Z expands rapidly; and the power ratio of the first heating mechanism 310 and the second heating mechanism 320 can be adjusted to form a certain positive saturation on the upper and lower surfaces of the seed crystal Z, thereby inhibiting the decomposition of the upper and lower surfaces, reducing surface defects, and improving the surface uniformity of the silicon carbide crystal after expansion.

[0027] Continue to refer to Figure 1 In some embodiments, the first heating mechanism 310 includes a first heater 311 and a second heater 312. The first heater 311 is arranged on the outer periphery of the side wall of the crucible body 100, and the first heater 311 acts on the first zone 110. The second heater 312 is arranged on the outside of the crucible body 100, and there are at least two second heaters 312, which are respectively located on both sides of the first zone 110 in the vertical direction, and the second heater 312 acts on the first zone 110. It can be understood that by subdividing the first heating mechanism 310 into the first heater 311 and the second heater 312, the heating can be controlled separately, so that the raw materials in the first zone 110 are heated as uniformly as possible. Exemplarily, the second heater 312 is annular and is arranged above and below the crucible body 100, respectively. The shape of the annular second heater 312 is preferably substantially the same as that of the first zone 110, or the heating surface of the second heater 312 in the vertical direction fully covers the cross section of the first zone 110.

[0028] In some embodiments, the second heating mechanism 320 includes a third heater 321, which is disposed outside the crucible body 100, and the third heater 321 performs circumferential heating on the third zone 220. It can be understood that the third zone 220 is independently heated by providing the third heater 321, and the third heater 321 can be annular, so that the heating surface formed by it can circumferentially cover the third zone 220, and the heat transfer is more uniform.

[0029] In some embodiments, the first area 110 is arranged in a ring shape to accommodate a ring-shaped raw material. It is understood that by arranging the first area 110 in a ring shape, so as to match the shape of the inner wall of the crucible body 100, the effective filling rate of the raw material in the crucible body 100 is increased, and sufficient material is provided for growing large-sized silicon carbide crystals.

[0030] See also Figure 2 or Figure 3 The silicon carbide seed crystal Z of the present application is applied to the silicon carbide crystal growth crucible of the present application, and the thickness range of the seed crystal Z is configured to be 15mm to 20mm. It can be understood that the thickness of the existing seed crystal Z is generally about 350 microns. By thickening the thickness of the seed crystal Z and adjusting it to the range of 15mm to 20mm, the high-temperature decomposition part can be compensated.

[0031] See also Figure 4 In some embodiments, the seed crystal Z cross section is a regular 6*N polygon, N≥1. It can be understood that the regular hexagon is one of the shapes. In some embodiments, the seed crystal Z cross section can also be a regular dodecagon, a regular octagon, etc. When the number of sides increases, the shape tends to be circular, and the area size of the crystal growth is larger.

[0032] In some embodiments, the minimum outer diameter of the seed crystal Z is greater than the outer diameter of the third zone 220. It is understandable that by configuring the minimum outer diameter of the seed crystal Z to be greater than the outer diameter of the third zone 220, the seed crystal Z can be assembled to protrude from the third zone 220 in its length direction, and the third heater 321 is configured at the periphery of the third zone 220, and the heating effect of the third heater 321 is mainly concentrated in the third zone 220. Therefore, the edge temperature of the seed crystal Z in the length direction is lower than the temperature of the middle part, and it is not easy to decompose and can grow safely.

[0033] See also Figure 5 The silicon carbide crystal growth method of the present application, applied to the silicon carbide crystal growth crucible of the present application, comprises the following steps: S100, preparing silicon carbide pre-sintering raw materials, and filling seed crystals Z into the crucible body 100; S200 , heating the first zone 110 and the third zone 220 , controlling the temperature of the first zone 110 and the third zone 220 to be greater than the temperature of the second zone 120 , so that the raw material in the first zone 110 sublimates toward the second zone 120 and performs deposition and crystal growth.

[0034] S210 , configuring the power ratio of the first heater 311 , the second heater 312 , and the third heater 321 to be 6:x:y, x∈[5,7], y∈[2,4].

[0035] It can be understood that x and y are real numbers. By configuring the power ratio of the first heater 311, the second heater 312 and the third heater 321 to 6:x:y, the temperature of the second zone 120 can be the lowest, and the temperatures of the first zone 110 and the third zone 220 can be higher. Among them, a regular dodecagonal seed crystal Z processed from an 8-inch crystal is selected. When the power ratio is set to the first heater 311: the second heater 312: the third heater 321 = 7:7:6, the middle of the seed crystal Z is overheated and decomposes rapidly. The edge of the seed crystal Z also decomposes seriously, and the diagonal diameter is decomposed from 200mm to 185mm; Figure 3 As shown, when the power ratio is set to the first heater 311: the second heater 312: the third heater 321 = 6:7:4 or 6:7:3 or 5:7:4, the middle of the seed crystal Z is slightly decomposed, the edge of the seed crystal Z has no obvious signs of growth or decomposition, and the surface of the crystal growth layer J obtained by the crystal expansion growth is relatively uniform; when the ratio is set to the first heater 311: the second heater 312: the third heater 321 = 6:7:2 or 5:7:2, a small amount of crystallization occurs on the upper and lower surfaces of the seed crystal Z, a small amount of polycrystals appear at the contact with the graphite column, the polycrystals can be removed by rough grinding, the edge of the seed crystal Z grows rapidly, and the diagonal diameter expands from 200 mm to 245 mm; when the ratio is set to the first heater 311: the second heater 312: the third heater 321 = 6:7:0, the upper and lower surfaces of the seed crystal Z are largely crystallized, and the edge of the seed crystal Z has no obvious signs of growth or decomposition.

[0036] In some embodiments, the power ratio is set to first heater 311: second heater 312: third heater 321 = 6:7:0. The resulting crystal is processed and expanded once to expand the seed crystal Z from 8 inches to 9.7 inches. The expansion process is stable, and the iteration time required to expand the C surface of silicon carbide from 8 inches to 10 inches is about one twentieth of that of the existing solution.

[0037] In some embodiments, S100, preparing silicon carbide pre-sintering raw materials and filling the crucible body 100 with seed crystals Z includes: S110, processing the pre-sintered raw material into a ring shape to obtain a ring-shaped pre-sintered raw material that matches the inner wall of the crucible body 100. It can be understood that by cutting or molding the pre-sintered raw material into a ring shape, a specific size can be formed so as to fit the inner wall of the crucible body 100, providing sufficient raw material for crystal growth and diameter expansion, and because the surface of the ring-shaped raw material is sufficiently flat, the physical vapor transport process is more uniform, and the crystals finally grown on the seed crystal Z are also more uniform.

[0038] Beneficial effects: The present application sets a first heating mechanism 310 to heat the first zone 110, and sets a second heating mechanism 320 to heat the third zone 220, so that the two zones can be controlled to provide appropriate temperatures respectively, and the second zone 120 is not heated, so that a temperature difference is formed between the three zones. The silicon carbide raw material in the crucible body 100 is sublimated toward the edge of the seed crystal Z after high-temperature heating, and is directly deposited on the m-plane and the a-plane when cooled, so that the silicon carbide seed crystal Z crystal expands rapidly; and the upper and lower surfaces of the seed crystal Z can be formed to a certain positive saturation by adjusting the power ratio of the first heating mechanism 310 and the second heating mechanism 320, thereby inhibiting the decomposition of the upper and lower surfaces, reducing surface defects, and improving the surface uniformity of the silicon carbide crystal after expansion; by thickening the thickness of the seed crystal Z and adjusting it to a range of 15mm to 20mm, the high-temperature decomposition part can be compensated to prevent the seed crystal Z from breaking during the crystal growth and expansion process; By setting the cross section of the seed crystal Z to be a regular dodecagon, a regular octagon, etc., when the number of sides increases, its shape tends to be circular, and the area size of the crystal growth is larger; by setting the heating power ratio to the first heater 311: the second heater 312: the third heater 321 = 6:7:4 or 6:7:3, the seed crystal Z is slightly decomposed in the middle, there is no obvious sign of growth or decomposition at the edge of the seed crystal Z, and the crystal expands rapidly, and the crystal surface uniformity is high.

[0039] The specific embodiments described herein are merely examples of the spirit of the present application. A person skilled in the art of the present application may make various modifications or additions to the specific embodiments described or replace them in a similar manner, but this will not deviate from the spirit of the present application or exceed the scope defined by the attached claims.

Claims

1. A silicon carbide crystal growth crucible, characterized in that: include: A crucible body (100), wherein a first area (110) is provided in the crucible body (100), the first area (110) is used to accommodate raw materials, the first area (110) is arranged circumferentially along the inner side wall of the crucible body (100), and the first area (110) is connected to a second area (120) toward a side away from the side wall of the crucible body (100), and the second area (120) is used for crystal growth; A seed crystal fixing assembly (200), the seed crystal fixing assembly (200) comprising two clamping members (210), the two clamping members (210) being arranged at intervals in a vertical direction to form a third area (220), the third area (220) being used to accommodate the seed crystal, and the third area (220) being in communication with the second area (120); as well as A heating component (300), the heating component (300) comprising: A first heating mechanism (310), the first heating mechanism (310) acts on the first zone (110) to provide sublimation for the raw material; A second heating mechanism (320), the second heating mechanism (320) acts on the third zone (220) to facilitate crystal growth; The power of the first heating mechanism (310) and the second heating mechanism (320) is adjustable so as to form a temperature difference between the first zone (110), the third zone (220) and the second zone (120).

2. The silicon carbide crystal growth crucible according to claim 1, characterized in that: The first heating mechanism (310) comprises: A first heater (311), the first heater (311) being arranged on the outer periphery of the side wall of the crucible body (100), and the first heater (311) acting on the first zone (110); A second heater (312), the second heater (312) is arranged outside the crucible body (100), and there are at least two second heaters (312) which are respectively located on both sides of the first zone (110) in the vertical direction, and the second heater (312) acts on the first zone (110).

3. The silicon carbide crystal growth crucible according to claim 2, characterized in that: The second heating mechanism (320) comprises a third heater (321), the third heater (321) is arranged outside the crucible body (100), and the third heater (321) performs circumferential heating on the third zone (220).

4. The silicon carbide crystal growth crucible according to claim 1, characterized in that: The first zone (110) is arranged in a ring shape to accommodate ring-shaped raw materials.

5. A silicon carbide seed crystal, characterized in that: Applicable to the silicon carbide crystal growth crucible as described in any one of claims 1 to 4, the thickness of the seed crystal ranges from 15 mm to 20 mm.

6. The silicon carbide seed crystal according to claim 5, characterized in that: The seed crystal has a cross section in the form of a regular 6*N-gon, where N≥1.

7. The silicon carbide seed crystal according to claim 5, characterized in that: The minimum outer diameter of the seed crystal is greater than the outer diameter of the third region (220).

8. A method for growing a silicon carbide crystal, applied to the silicon carbide crystal growth crucible as claimed in claim 3 or 4, characterized in that: The following steps are involved: Preparing silicon carbide pre-sintering raw materials and filling seed crystals into the crucible body (100); The first zone (110) and the third zone (220) are heated, and the temperature of the first zone (110) and the third zone (220) are controlled to be greater than the temperature of the second zone (120), so that the raw material of the first zone (110) sublimates toward the second zone (120) and is deposited and grown.

9. The method for growing silicon carbide crystals according to claim 8, characterized in that: The heating of the first zone (110) and the third zone (220) and controlling the temperature of the first zone (110) and the third zone (220) to be greater than the temperature of the second zone (120) comprises: The power ratio of the first heater (311), the second heater (312) and the third heater (321) is configured to be 6:x:y, where x∈[5,7] and y∈[2,4].

10. The method for growing silicon carbide crystal according to claim 8, characterized in that: The steps of preparing silicon carbide pre-sintered raw materials and filling seed crystals into the crucible body (100) include: processing the pre-sintered raw materials into a ring shape to obtain a ring-shaped pre-sintered raw material that matches the inner wall of the crucible body (100).

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