Growth device and method for reducing edge stress of silicon carbide crystal

Abstract

The embodiment of the invention provides a growth device and method for reducing edge stress of a silicon carbide crystal, and relates to the technical field of silicon carbide crystal growth. The crucible comprises a crucible body and a crucible cover covering the crucible body, and the crucible cover and the crucible body jointly define a raw material area and a growth area which are communicated with each other; silicon carbide powder is contained in the raw material area, and a guide cylinder is arranged in the growth area; the guide cylinder comprises a first containing surface and a second containing surface, the second containing surface contains a seed crystal, meanwhile, a plurality of growth grooves are formed in the second containing surface, and the growth grooves are used for allowing edges of silicon carbide crystals to grow in and form edge crystals in the growth grooves. According to the present invention, the growth groove is formed, such that the crystal entering the growth groove can apply the local high concentration stress on the flow guide cylinder so as to crack and break the flow guide cylinder, such that the crystal stress release is achieved, and the generation of the base sagittal plane dislocation is reduced.

Description

Technical Field

[0001] This invention relates to the field of silicon carbide crystal growth technology, and more specifically, to a growth apparatus and method for reducing edge stress in silicon carbide crystals. Background Technology

[0002] In the physical vapor transport method of silicon carbide crystals, in order to optimize the transport path of the gaseous raw material in the crucible, a graphite guide tube is usually set in the crucible. The guide tube is set around the seed crystal to guide the gaseous raw material from the edge of the crucible to the middle area and finally transport it to the surface of the seed crystal.

[0003] When the crystal growth process ends and the cooling process begins, due to the difference in thermal expansion coefficients between the silicon carbide crystal and the graphite guide tube, the graphite guide tube has a relatively larger shrinkage amount and a relatively faster shrinkage speed. As a result, the crystal edge is squeezed by the guide tube during the cooling process, generating more basis plane dislocations, which in turn affects the crystal quality. Summary of the Invention

[0004] The present invention aims to provide a growth apparatus and method for reducing edge stress in silicon carbide crystals, thereby addressing the technical problem that the crystal edge is squeezed by the guide tube during the cooling process, resulting in more basis vector dislocations and affecting crystal quality.

[0005] The embodiments of the present invention can be implemented as follows: In a first aspect, the present invention provides a growth apparatus for reducing edge stress in silicon carbide crystals, comprising: Crucible body; A crucible lid is placed on the crucible body, and the crucible lid and the crucible body together define a connected raw material area and a growth area. The raw material area contains silicon carbide powder, and the growth area is provided with a guide tube; the guide tube includes a first enclosing surface and a second enclosing surface, the second enclosing surface enclosing a seed crystal, such that the outer edge of the seed crystal abuts against the second enclosing surface; The second containment surface has a ring array of multiple growth grooves, which extend axially from one end of the guide tube to the other end and are used to allow the edge of silicon carbide crystal to grow in and form edge crystals within the growth grooves; The growth groove includes a first sharp portion; When the edge crystals are formed in the growth tank, the first sharp part generates concentrated stress. The first containment surface has a ring array of multiple fracture grooves, which are arranged in pairs. Each pair of fracture grooves is symmetrically opened on both sides of the corresponding growth groove in the circumferential direction. The fracture groove includes a second sharp portion, and a cracking path is formed between the second sharp portion and the first sharp portion.

[0006] In an optional embodiment, the number of the first sharp parts is multiple, and a thrust part is formed between adjacent first sharp parts.

[0007] In an optional embodiment, the growth groove further includes a transition section, one end of which is connected to the second containment surface, and the other end is connected to the thrust section and defines the first sharp portion with the thrust section.

[0008] In an optional implementation, the transition portion is a plane or a curved surface; When the transition portion is a curved surface, the end of the transition portion near the second enclosing surface is tangent to the second enclosing surface.

[0009] In an optional embodiment, the thrust portion includes a first thrust surface and a second thrust surface connected to each other; The angle between the first thrust surface and the second thrust surface is γ ,10°≤ γ ≤180°.

[0010] In an optional embodiment, the arc connecting the center of the adjacent growth tank and the center of the guide tube is . α The arc of each pair of rupture grooves connecting to the center of the guide tube is... β ;in, .

[0011] In an optional implementation, .

[0012] In an optional embodiment, the thickness of the guide tube is... H The depth of the fracture groove is h 1. The depth of the growth tank is: h 2; in, , .

[0013] In an optional implementation, , .

[0014] In a second aspect, the present invention provides a method for reducing edge stress in silicon carbide crystals, based on the growth apparatus for reducing edge stress in silicon carbide crystals according to any one of the foregoing embodiments, comprising: Install a flow guide tube and a seed crystal inside the crucible, and fill it with silicon carbide powder; The heating structure is activated to heat the crucible and begin crystal growth. The edge of the silicon carbide crystal grows into the growth tank and forms an edge crystal within the growth tank. The crucible body is cooled to room temperature, and the flow guide tube cracks and breaks under the action of the edge crystals. Separate the crucible body from the guide tube, and remove the guide tube and the silicon carbide crystal; Separate the guide tube from the silicon carbide crystal to complete the removal of the silicon carbide crystal.

[0015] The beneficial effects of the silicon carbide crystal growth and removal method and the growth apparatus for reducing edge stress of silicon carbide crystals provided in the embodiments of the present invention include: The growth apparatus for reducing edge stress of silicon carbide crystals provided by the present invention has multiple growth grooves arranged in a ring array on the second enclosing surface of the guide tube. During the growth process, the edge of the silicon carbide crystal can grow into the growth groove. As a result, during the cooling and shrinking process of the guide tube, the crystal that has entered the growth groove can apply local high concentrated stress to the guide tube, causing the guide tube to crack and break, thereby releasing the crystal stress and reducing the generation of basis plane dislocations. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 Front cross-sectional view of the growth apparatus for reducing edge stress of silicon carbide crystals provided in this embodiment. Figure 1 ; Figure 2 Front cross-sectional view of the growth apparatus for reducing edge stress of silicon carbide crystals provided in this embodiment. Figure 2 ; Figure 3 This is a top view of the guide tube and seed crystal in the growth apparatus for reducing edge stress of silicon carbide crystals provided in this embodiment 1. Figure 4 for Figure 3 A magnified view of a portion of the central P section; Figure 5 This is a schematic diagram of the growth tank structure in the growth apparatus for reducing edge stress of silicon carbide crystals provided in Embodiment 1. Figure 1 ; Figure 6 This is a schematic diagram of the growth tank structure in the growth apparatus for reducing edge stress of silicon carbide crystals provided in Embodiment 1. Figure 2 ; Figure 7 This is a schematic diagram of the growth tank structure in the growth apparatus for reducing edge stress of silicon carbide crystals provided in Embodiment 1. Figure 3 ; Figure 8 A front cross-sectional view of the guide tube in the growth apparatus for reducing edge stress of silicon carbide crystals provided in Embodiment 1. Figure 1 ; Figure 9 A front view of the guide tube in the growth apparatus for reducing edge stress of silicon carbide crystals provided in Embodiment 1. Figure 1 ; Figure 10 A front cross-sectional view of the guide tube in the growth apparatus for reducing edge stress of silicon carbide crystals provided in Embodiment 1. Figure 2 ; Figure 11 A front view of the guide tube in the growth apparatus for reducing edge stress of silicon carbide crystals provided in Embodiment 1. Figure 2 ; Figure 12 This is a flowchart of a method for reducing edge stress in silicon carbide crystals provided in this embodiment.

[0018] Icons: 100 - Crucible body; 110 - Raw material zone; 120 - Growth zone; 130 - Silicon carbide powder; 140 - Seed crystal; 200 - Crucible lid; 300-Guide tube; 310-First enclosing surface; 311-Fracturing groove; 3111-Second sharp point; 320-Second enclosing surface; 321-Growth groove; 3211-First sharp point; 3212-Thrust section; 3212a-First thrust surface; 3212b-Second thrust surface; 3213-Transition section; 330-Support member; A1 - Crack path. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0021] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0022] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0023] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0024] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0025] The following detailed description, through embodiments and in conjunction with the accompanying drawings, details the steps, implementation principles, and technical effects of the growth apparatus and method for reducing edge stress in silicon carbide crystals provided by the present invention, as well as the overall structure, working principle, and technical effects of the accompanying growth apparatus for reducing edge stress in silicon carbide crystals.

[0026] Example 1: Please see Figure 1 This embodiment provides a growth apparatus for reducing edge stress of silicon carbide crystals to grow silicon carbide crystals and form ingots. It includes a crucible body 100 and a crucible cover 200 covering the crucible body 100. The crucible cover 200 and the crucible body 100 define a communicating raw material area 110 and a growth area 120. The raw material area 110 contains silicon carbide powder 130, and the growth area 120 is provided with a guide tube 300. The guide tube 300 is detachably installed in the growth area 120 by a support member 330, which is a graphite support. The flow guide tube 300 includes a first containing surface 310 and a second containing surface 320. A gap is formed between the first containing surface 310 and the inner wall of the crucible body 100, which provides space for stress release in the flow guide tube 300. The second containing surface 320 contains a seed crystal 140 such that the outer edge of the seed crystal 140 abuts against the second containing surface 320. A plurality of growth grooves 321 are formed in a ring array on the second containing surface 320. The growth grooves 321 extend axially from one end of the flow guide tube 300 to the other end and are used to allow the edge growth of silicon carbide crystals to enter and form edge crystals in the growth grooves 321.

[0027] In this embodiment, silicon carbide powder 130 is heated and sublimated in raw material zone 110 to form gaseous raw material. After the gaseous raw material enters growth zone 120, it finally reaches the surface of seed crystal 140 under the action of guide tube 300 and begins crystal growth.

[0028] Please see Figure 1 and Figure 2 Furthermore, the flow guide 300 is a cylindrical structure made of graphite, located inside the crucible body 100 at the end away from the silicon carbide powder 130 and fixed by the support 330, having opposing outer and inner sidewalls; specifically, the first containing surface 310 is the outer sidewall, the second containing surface 320 is the inner sidewall, and a dense graphite structure exists between the outer and inner sidewalls. During the silicon carbide crystal growth process, the purpose of setting up the flow guide is mainly to precisely control the temperature gradient and gas phase transport by guiding the airflow, thereby suppressing impurities, reducing defects, and ultimately achieving efficient growth of high-quality single crystals; therefore, in some embodiments, such as Figure 1 As shown, the first containing surface 310 and the second containing surface 320 are vertically arranged and form the vertical sidewall of the guide tube 300; in other embodiments, such as Figure 2 As shown, the first containment surface 310 and the second containment surface 320 can be inclined to form the inclined guide tube 300 sidewall, so as to further guide the gaseous raw material to be transported to the seed crystal 140; the guide tube 300 is mainly designed to optimize the path of the gaseous raw material, and is not limited here.

[0029] In this embodiment, since multiple growth grooves 321 are formed in a ring array on the inner wall, when the crystal is in the growth state, the growth grooves 321 can allow the crystal edge to grow in. While consuming the unstable airflow at the crystal edge, reducing the polymorphic probability at the crystal edge, and reducing the polycrystalline mass and the number of dislocations, edge crystals are formed in the growth grooves 321. When the crystal growth process ends and the cooling process begins, the guide tube 300 contracts as the temperature decreases. At this time, the edge crystals located in the growth grooves 321 can apply a local stress to the guide tube 300, thereby causing the guide tube 300 to crack and break under the action of the edge crystals. Since the guide tube 300 no longer compresses the crystal, the crystal stress is released, thereby reducing the generation of basis vector plane dislocations and ensuring the crystal quality.

[0030] It should be noted that after the silicon carbide crystal growth is completed and the flow guide tube 300 is separated from the ingot, the edge crystals will remain on the outer edge of the ingot and will be removed in the subsequent ingot rounding process, without affecting the quality of the ingot.

[0031] Understandably, the shape of the edge crystal matches the shape of the growth tank 321. During the cooling process, in order for the edge crystal to effectively cause the guide tube 300 to crack and break, the growth tank 321 includes a first sharp part 3211. When edge crystals are formed in the growth tank 321, the first sharp part 3211 generates concentrated stress, which causes the guide tube 300 to crack and break at the stress concentration part of the first sharp part 3211.

[0032] Furthermore, the number of first sharp portions 3211 can be multiple, so as to cause the guide tube 300 to crack and break; at the same time, a thrust portion 3212 is formed between adjacent first sharp portions 3211 to increase the interaction area between the edge crystal and the guide tube 300; after the silicon carbide crystal growth is completed and the crucible body 100 enters the cooling process, since the guide tube 300 has a relatively larger shrinkage amount and a relatively faster shrinkage speed, the edge crystal can form a radial thrust acting on the guide tube 300 in the thrust portion 3212, so as to cause the guide tube 300 to crack and break at the stress concentration part of the first sharp portion 3211.

[0033] Specifically, the number of first sharp parts 3211 is 2, 4, etc.

[0034] Furthermore, the thrust unit 3212 includes a first thrust surface 3212a and a second thrust surface 3212b connected together, and the included angle between the first thrust surface 3212a and the second thrust surface 3212b is . γ ,10°≤ γ ≤180°.

[0035] Please see Figure 5 and Figure 7 , Figure 5 The included angle between the first thrust surface 3212a and the second thrust surface 3212b is shown. γ This is a schematic diagram of the structure at 90° (for ease of description and understanding). Figures 5 to 7 Only a portion of the seed crystal 140 structure is shown in the figure. At this time, a thrust part 3212 with an inverted triangular structure is formed between the first thrust surface 3212a and the second thrust surface 3212b. This allows the edge crystal and the guide tube 300 to have a sufficient working area, while the guide tube 300 can also generate sufficient stress at the position of the first sharp part 3211, so that the guide tube 300 can crack and break under the action of the edge crystal.

[0036] It is understandable that the angle between the first thrust surface 3212a and the second thrust surface 3212b... γ When the angle is between 0° and 90°, a similar shape is formed between the first thrust surface 3212a and the second thrust surface 3212b. γThe thrust section 3212, which forms an inverted triangle at 90°, differs only in that the interaction area between the edge crystal and the guide tube 300 is changed. Operators can select the included angle according to actual working needs. γ Specific angles within the range of 10° to 90°.

[0037] In some embodiments, a chamfer is provided at the connection between the first thrust surface 3212a and the second thrust surface 3212b to further increase the interaction area between the edge crystal and the guide tube 300.

[0038] Figure 7 The included angle between the first thrust surface 3212a and the second thrust surface 3212b is shown. γ The diagram shows a 180° view of the structure. At this point, the first thrust surface 3212a and the second thrust surface 3212b are connected flush, so that there is a larger working area between the edge crystal and the guide tube 300, thereby increasing the thrust of the edge crystal on the guide tube 300 during the cooling process.

[0039] In this embodiment, the growth groove 321 further includes a transition portion 3213, one end of which is connected to the second containment surface 320, and the other end is connected to the thrust portion 3212 and defines the first sharp portion 3211.

[0040] Similar to the thrust section 3212, after the crucible body 100 enters the cooling process, the edge crystals can form a thrust acting on the guide tube 300 in the transition section 3213, so as to cause the guide tube 300 to crack and break at the stress concentration point of the first sharp section 3211.

[0041] For further details, please refer to Figure 5 and Figure 6 The transition section 3213 is a plane or a curved surface; wherein, Figure 5 This shows a schematic diagram of the structure of the fracture groove 311 when the transition section 3213 is a plane. Figure 6 A schematic diagram of the structure of the fracture groove 311 when the transition part 3213 is a curved surface is shown.

[0042] Please continue reading. Figure 5 When the transition section 3213 is planar, it connects the second containment surface 320 and the thrust section 3212. The transition section 3213 and the guide tube 300 form a variable angle radially. This variable angle can be adjusted according to actual arrangement needs. For example, when the angle between the first thrust surface 3212a and the second thrust surface 3212b... γ When the angle is 90°, the variable included angle is relatively small; when the angle between the first thrust surface 3212a and the second thrust surface 3212b is 90°, the variable included angle is relatively small. γ When the angle is greater than 90°, the variable included angle can be increased at any time.

[0043] During the crystal growth process, edge crystals that connect to silicon carbide crystals can be generated in the growth groove 321. In order to reduce the disturbance of the silicon carbide crystal edge caused by opening the growth groove 321, the growth groove 321 should be connected to the guide tube 300 (i.e. the second containment surface 320) relatively smoothly, so as to reduce the influence of the corners caused by opening the growth groove 321 on the edge gas phase of silicon carbide crystal.

[0044] For example, while the transition portion 3213 is a curved surface, one end of the transition portion 3213 near the second containing surface 320 is tangent to the second containing surface 320. Figure 6 The dashed line in the middle shows the tangent position where the transition section 3213 is tangent to the second containment surface 320, so that the growth groove 321 and the guide tube 300 are connected relatively smoothly, thereby reducing the influence of the corners generated by opening the growth groove 321 on the edge gas phase of the silicon carbide crystal.

[0045] Please see Figure 3 and Figure 4 In order to facilitate the separation of the guide tube 300 and the crystal ingot, in this embodiment, a plurality of fracture grooves 311 are arranged in an annular array on the first enclosing surface 310. The plurality of fracture grooves 311 are arranged in pairs, and each pair of fracture grooves 311 is symmetrically opened on both sides of the corresponding growth groove 321 in the circumferential direction. The fracture groove 311 includes a second sharp part 3111, and a cracking path A1 is formed between the second sharp part 3111 and the first sharp part 3211.

[0046] The correspondence here means that each growth groove 321 corresponds to two (i.e. a pair) cracking grooves 311. The pair of cracking grooves 311 are symmetrically opened on both sides of the corresponding growth groove 321 in the circumferential direction, and cracking paths A1 are generated between them and the growth groove 321 respectively.

[0047] It should be noted that the cracking groove 311 on the first containment surface 310 and the growth groove 321 on the second containment surface 320 should be arranged to be staggered in the radial direction in order to avoid excessively weakening the strength of the guide tube 300, which could lead to cracking or damage of the guide tube 300 during crystal growth.

[0048] In this embodiment, the growth groove 321 has two first sharp parts 3211. It is understood that in a pair of crack grooves 311, a cracking path A1 is generated between the second sharp part 3111 of a single crack groove 311 and the adjacent first sharp part 3211 in the corresponding growth groove 321.

[0049] Specifically, in a pair of fracture grooves 311, the arc connecting the center of adjacent growth grooves 321 and the center of the guide tube 300 is... α The arc of the connection between each pair of rupture grooves 311 and the center of the guide tube 300 is... β , .

[0050] Understandable, radian α With radians β The relationship is related to the formation of crack path A1, when At that time, due to the short distance between the second sharp part 3111 and the first sharp part 3211, the structural strength of the guide tube 300 is excessively weakened, causing the cracking path A1 to appear prematurely during the crystal growth stage, resulting in cracking and breakage of the guide tube 300, thus affecting crystal growth; when At that time, because there is a long distance between the second sharp part 3111 and the first sharp part 3211, the guide tube 300 has excessive structural strength, which makes it impossible to form a cracking path A1 between the second sharp part 3111 and the first sharp part 3211 during the cooling stage of the crucible body 100, affecting the subsequent separation of the guide tube 300 and the crystal.

[0051] For example, .

[0052] In this embodiment, the thickness of the guide tube 300 is H The depth of the fracture groove 311 is h 1. The depth of the growth groove 321 is... h 2; among which, , .

[0053] Understandable, the depth of the fracture groove 311 h 1 and the depth of the growth tank 321 h 2. The structural strength of the guide tube 300 and the ease with which the guide tube 300 cracks under the action of edge crystals are related, and the operator can make adaptive adjustments according to the actual work needs.

[0054] For example, , .

[0055] Please see Figure 8 and Figure 9 In some embodiments, the rupture groove 311 is continuously opened along the axial direction of the first containing surface 310, thereby enabling the guide tube 300 to break smoothly during the crystal cooling process.

[0056] Please see Figure 10 and Figure 11 In other embodiments, in order to avoid the continuous cracking groove 311 from excessively weakening the structural strength of the guide tube 300, the cracking groove 311 can also be opened intermittently along the axial direction of the first containing surface 310 to prevent the guide tube 300 from cracking during the crystal growth stage.

[0057] The growth apparatus for reducing edge stress in silicon carbide crystals provided by this invention can produce at least the following technical effects: On the one hand, by providing a growth groove 321 on the second containment surface 320 of the guide tube 300, when the crystal is in the growth state, the growth groove 321 allows the crystal edge to grow in. While consuming the unstable airflow at the crystal edge, reducing the polymorphic probability at the crystal edge, and reducing the polycrystalline mass and the number of dislocations, edge crystals are formed in the growth groove 321. Thus, when the crystal growth process ends and the cooling process begins, local stress is generated inside the growth groove 321 under the action of the edge crystals. Since the guide tube 300 is made of graphite, which is a brittle material, the guide tube 300 can crack and break under the action of the edge crystals. At this time, since the guide tube 300 no longer compresses the crystal, the crystal stress is released, thereby reducing the generation of basis vector plane dislocations and ensuring the crystal quality.

[0058] On the other hand, since the guide tube 300 can crack and break under the action of the edge crystal during the crystal cooling process, it is convenient for operators to separate the guide tube 300 and the silicon carbide crystal in the future. This reduces the risk of crystal cracking, edge chipping or even personal injury caused by improper operation of the guide tube 300 when the crystal is removed.

[0059] Example 2: This embodiment provides a method for reducing edge stress in silicon carbide crystals. Based on the growth apparatus for reducing edge stress in silicon carbide crystals provided in Embodiment 1, the method reduces the compression of the silicon carbide crystal edge by the guide tube 300, thereby reducing the generation of crystal basis vector dislocations and ensuring crystal quality.

[0060] Please see Figure 12 In this embodiment, the method for reducing edge stress of silicon carbide crystals includes: S1. Install the guide tube 300 and seed crystal 140 inside the crucible, and fill it with silicon carbide powder 130. Similar to existing technologies, in this embodiment, the crucible body 100 provides a growth space for silicon carbide crystals. The guide tube 300 and the seed crystal 140 are disposed in the crucible body 100. The guide tube 300 is made of graphite and is used to optimize the transmission path of the gaseous raw materials in the crucible, so as to guide the gaseous raw materials from the edge of the crucible body 100 to the middle area, and finally to the surface of the seed crystal 140.

[0061] S2. The heating structure is activated to heat the crucible body 100 to begin crystal growth. The edge of the silicon carbide crystal grows into the growth tank 321 and forms an edge crystal within the growth tank 321.

[0062] In this embodiment, the crucible body 100 is heated by the heating structure, causing the silicon carbide powder 130 to sublimate into a gaseous raw material. Under the condition of temperature gradient, the gaseous raw material migrates to the surface of the seed crystal 140. Finally, the gaseous raw material is deposited and grown in an orderly manner on the surface of the seed crystal 140 according to the single crystal structure, and finally forms a large-sized silicon carbide single crystal ingot, i.e., a crystal ingot.

[0063] The silicon carbide crystal growth method provided in this embodiment allows the silicon carbide crystal edge to grow into the growth groove 321 opened on the guide tube 300 during the silicon carbide crystal growth process. This can consume the unstable airflow at the crystal edge, reduce the polymorphism probability at the crystal edge, and thus reduce the polycrystalline quality and the number of dislocations.

[0064] S3. Cool the crucible body 100 until it reaches room temperature. The guide tube 300 cracks and breaks under the action of the edge crystals.

[0065] It should be noted that, in order to avoid the crystal from developing thermal stress due to excessive internal and external temperature differences, which could lead to crystal quality defects, the crucible body 100 and the crystal should be gradually cooled down to room temperature. A slow, controllable, and uniform temperature drop rate should be achieved. The cooling method is not specified here.

[0066] In this embodiment, during the cooling and shrinking process of the guide tube 300, the crystal entering the growth tank 321 can apply local high concentrated stress to the guide tube 300, thereby causing the guide tube 300 to crack and break, thus releasing the crystal stress and reducing the generation of basis vector plane dislocations.

[0067] S4. Separate the crucible body 100 from the guide tube 300, and remove the guide tube 300 and the silicon carbide crystal.

[0068] Similar to existing technologies, the crucible body 100 and the guide tube 300 are detachably connected, with the guide tube 300 disposed within the crucible body 100 via a support member 330; therefore, the operator can remove the guide tube 300 from the crucible manually or mechanically.

[0069] S5. Separate the guide tube 300 from the silicon carbide crystal, remove the silicon carbide crystal, and complete the removal of the silicon carbide crystal.

[0070] In the method for reducing edge stress of silicon carbide crystals provided in this embodiment, the guide tube 300 can be smoothly cracked and broken under the action of the edge crystal, so that the guide tube 300 does not need to be broken by manual knocking. This reduces the risk of crystal cracking, edge chipping or even personal injury caused by improper operation of separating the guide tube 300 when the operator takes out the crystal.

[0071] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A growth apparatus for reducing edge stress in silicon carbide crystals, characterized in that, include: Crucible body (100); A crucible lid (200) is placed on the crucible body (100), and the crucible lid (200) and the crucible body (100) together define a connected raw material zone (110) and a growth zone (120). The raw material area (110) contains silicon carbide powder (130), and the growth area (120) is provided with a guide tube (300); the guide tube (300) includes a first containing surface (310) and a second containing surface (320), the second containing surface (320) contains a seed crystal (140) so that the outer edge of the seed crystal (140) abuts against the second containing surface (320); The second containment surface (320) has a ring array of multiple growth grooves (321), which extend axially from one end of the guide tube (300) to the other end and are used to allow the edge growth of silicon carbide crystals to enter and form edge crystals in the growth grooves (321); The growth groove (321) includes a first sharp point (3211); When the edge crystals are formed in the growth groove (321), the first sharp part (3211) generates concentrated stress; The first containment surface (310) has a ring-shaped array of multiple fracture grooves (311), and the multiple fracture grooves (311) are arranged in pairs. Each pair of fracture grooves (311) is symmetrically opened on both sides of the corresponding growth groove (321) in the circumferential direction. The rupture groove (311) includes a second sharp part (3111), and a cracking path (A1) is formed between the second sharp part (3111) and the first sharp part (3211).

2. The growth apparatus for reducing edge stress of silicon carbide crystals according to claim 1, characterized in that, The number of the first sharp part (3211) is multiple, and a thrust part (3212) is formed between adjacent first sharp parts (3211).

3. The growth apparatus for reducing edge stress of silicon carbide crystals according to claim 2, characterized in that, The growth groove (321) further includes a transition section (3213), one end of which is connected to the second containment surface (320), and the other end is connected to the thrust section (3212) and defines the first sharp part (3211) by the thrust section (3212).

4. The growth apparatus for reducing edge stress of silicon carbide crystals according to claim 3, characterized in that, The transition section (3213) is a plane or a curved surface; When the transition portion (3213) is a curved surface, the end of the transition portion (3213) near the second containing surface (320) is tangent to the second containing surface (320).

5. The growth apparatus for reducing edge stress of silicon carbide crystals according to claim 3, characterized in that, The thrust section (3212) includes a first thrust surface (3212a) and a second thrust surface (3212b) connected to each other. The angle between the first thrust surface (3212a) and the second thrust surface (3212b) is γ ,10°≤ γ ≤180°.

6. The growth apparatus for reducing edge stress of silicon carbide crystals according to claim 1, characterized in that, The arc of the connection between the center of the adjacent growth tank (321) and the center of the guide tube (300) is α The arc of each pair of the rupture grooves (311) connected to the center of the guide tube (300) is... β ;in, .

7. The growth apparatus for reducing edge stress of silicon carbide crystals according to claim 6, characterized in that, 。 8. The growth apparatus for reducing edge stress of silicon carbide crystals according to claim 1, characterized in that, The thickness of the guide tube (300) is H The depth of the fracture groove (311) is h 1. The depth of the growth tank (321) is... h 2; in, , .

9. The growth apparatus for reducing edge stress of silicon carbide crystals according to claim 8, characterized in that, , 。 10. A method for reducing edge stress in silicon carbide crystals, characterized in that, The growth apparatus for reducing edge stress of silicon carbide crystals according to any one of claims 1-9 includes: Install a flow guide tube (300) and a seed crystal (140) inside the crucible, and fill it with silicon carbide powder (130). The heating structure is activated to heat the crucible body (100) to begin crystal growth. The edge of the silicon carbide crystal grows into the growth tank (321) and forms an edge crystal within the growth tank (321). Cool the crucible body (100) until it reaches room temperature, and the flow guide tube (300) cracks and breaks under the action of the edge crystals; Separate the crucible body (100) from the guide tube (300), and remove the guide tube (300) and the silicon carbide crystal; Separate the guide tube (300) from the silicon carbide crystal to complete the removal of the silicon carbide crystal.

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