Silicon carbide crystal growth method and device and silicon carbide crystal

Abstract

The embodiment of the invention provides a silicon carbide crystal growth method and device and a silicon carbide crystal, relates to the technical field of silicon carbide crystal growth, and aims at solving the technical problem that in the prior art, due to the fact that gas phase flow cannot be dynamically adjusted, crystal defects are easily caused. The method comprises the steps that S1, seed crystals and silicon carbide powder are arranged in a crucible, and the crucible is connected with a gas phase flow adjusting assembly; s2, pumping air from the crucible, filling inert gas into the crucible, and heating the crucible to enable the silicon carbide crystals to enter a growth stage; and S3, in a crystal growth stage, controlling the opening degree of a gas-phase flow channel through a gas-phase flow adjusting assembly so as to adjust the flow of gas reaching the seed crystal until the growth of the silicon carbide crystal is finished. The method can effectively improve the crystal growth rate in the early and middle stages of crystal growth and avoid the carbon wrapping defect of the crystal in the later stage of crystal growth.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon carbide crystal growth, and in particular to a silicon carbide crystal growth method, a device and a silicon carbide crystal. Background Art

[0002] As a representative of the third-generation semiconductor materials, silicon carbide is widely used in power electronics, radio frequency devices, optoelectronic devices and other fields due to its excellent properties such as large bandgap, high saturated electron mobility, strong breakdown field and high thermal conductivity.

[0003] In traditional silicon carbide crystal growth processes, single-layer fixed-aperture graphite plates or segmented structures are often used to regulate the gas flow rate in the crucible. Since the gas flow rate cannot be dynamically adjusted, it is impossible to adapt to the gas flow rate requirements of different stages of crystal growth (nucleation, growth, and cooling). For example, in the later stages of crystal growth, the silicon element in the silicon carbide powder in the lower crucible gradually decreases. At this time, the carbon content in the powder is much greater than the silicon element. As the reaction proceeds, the carbon element will continue to evaporate upward, resulting in carbon encapsulation defects in the crystal. Summary of the Invention

[0004] The purpose of the present invention includes providing a silicon carbide crystal growth method, device and silicon carbide crystal to improve the technical problem in the prior art that the gas phase flow rate cannot be dynamically adjusted, which easily leads to crystal defects.

[0005] The embodiments of the present invention can be implemented as follows: In a first aspect, the present invention provides a method for growing a silicon carbide crystal, comprising: Placing seed crystals and silicon carbide powder in a crucible, and connecting the crucible to a gas phase flow regulating assembly; After the crucible is evacuated, it is filled with inert gas, and the crucible is heated to allow the silicon carbide crystal to enter the growth stage; During the crystal growth stage, the opening of the gas flow channel is controlled by the gas flow regulating component to adjust the gas flow reaching the seed crystal until the silicon carbide crystal growth is completed.

[0006] In an optional embodiment, a method for controlling the opening of a gas phase flow channel by a gas phase flow regulating component to adjust the gas flow reaching the seed crystal includes: In the early stage of crystal growth, the gas phase flow channel is controlled to be in an intermediate state; In the middle stage of crystal growth, the opening of the gas phase flow channel is dynamically adjusted according to the crystal growth temperature, so that the gas phase flow channel is in an intermediate state or a fully open state; In the later stage of crystal growth, the opening of the gas phase flow channel is controlled to decrease gradually until the gas phase flow channel is in a completely closed state.

[0007] In an optional embodiment, in the early stage of crystal growth, the opening of the gas phase flow channel is controlled to be 40%-60%.

[0008] In an optional embodiment, the crystal growth mid-stage includes a first stage and a second stage in terms of time sequence, and when the first stage is completed, the crystal growth temperature reaches the target growth temperature; Under the first stage conditions, the gas phase flow channel opening is controlled to increase gradually until the gas phase flow channel opening is 100%; Under the second stage conditions, the gas phase flow channel opening is controlled to decrease gradually until the gas phase flow channel opening is 40%-60%.

[0009] In a second aspect, the present invention provides a silicon carbide crystal growth device, comprising: A crucible comprising an upper crucible and a lower crucible, wherein a first cavity is formed in the upper crucible, and a top of the first cavity is used to fix a seed crystal; a second cavity is formed in the lower crucible, and the second cavity is used to accommodate silicon carbide powder; the upper crucible is rotatable relative to the lower crucible; A gas phase flow regulating component is provided between the first cavity and the second cavity and is used to regulate the gas flow from the second cavity into the first cavity when the upper crucible and the lower crucible rotate relative to each other.

[0010] In an optional embodiment, the gas phase flow regulating assembly includes a first regulating unit connected to the upper crucible and a second regulating unit connected to the lower crucible; The first regulating unit is rotatably connected to the second regulating unit. When the first regulating unit rotates relative to the second regulating unit, the gas phase flow regulating component regulates the flow of gas entering the first cavity from the second cavity.

[0011] In an optional embodiment, the first adjusting unit includes an upper graphite plate, the upper graphite plate is fixedly connected to the upper crucible, and a plurality of first through holes are formed on the upper graphite plate; The second adjusting unit includes a lower graphite plate, the lower graphite plate is fixedly connected to the lower crucible, and a plurality of second through holes are formed on the lower graphite plate; The first through holes and the second through holes together form a gas phase flow channel. When the first adjustment unit rotates relative to the second adjustment unit, the connection area between the multiple first through holes and the multiple second through holes changes to achieve opening adjustment of the gas phase flow channel.

[0012] In an optional embodiment, the first adjustment unit further includes a plurality of fixed blocks connected to the upper graphite plate and sliding blocks provided on the fixed blocks; The second adjustment unit further includes an annular groove formed on the lower graphite plate; The sliding block is slidably disposed in the annular groove so that the upper graphite plate and the lower graphite plate are rotatably connected.

[0013] In an optional embodiment, the silicon carbide crystal growth apparatus further comprises: A bracket assembly, the bracket assembly comprising a fixed bracket and a rotating bracket; Wherein, the fixing bracket is fixedly connected to the upper crucible and is used to fix the upper crucible; The rotating bracket is used to support the lower crucible and to drive the lower crucible to rotate relative to the upper crucible.

[0014] In a third aspect, the present invention provides a silicon carbide crystal, which is prepared using the silicon carbide crystal growth method described in any one of the aforementioned embodiments or the silicon carbide crystal growth device described in any one of the aforementioned embodiments.

[0015] The beneficial effects provided by the embodiments of the present invention include: The silicon carbide crystal growth method and device provided by the present invention dynamically adjust the gas flow reaching the seed crystal during the crystal growth stage by controlling the gas flow regulating component. On the one hand, it prevents the seed crystal from sublimating or burning through due to excessive gas flow in the early stage of crystal growth. On the other hand, it prevents the gas phase with a high carbon content from continuing to flow upward in the later stage of crystal growth, thereby reducing the formation of carbon inclusions on the crystal in the later stage of crystal growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 Flowchart of the silicon carbide crystal growth method provided in Example 1; Figure 2 A silicon carbide ingot prepared based on the silicon carbide crystal growth method provided in Example 1; Figure 3 A silicon carbide ingot prepared based on the silicon carbide crystal growth method provided in Comparative Example 1; Figure 4 It is an enlarged schematic diagram of the carbon wrapping in Comparative Example 1; Figure 5 A front cross-sectional view of the silicon carbide crystal growth apparatus provided in Example 2; Figure 6 for Figure 5 A partial enlarged view of part A in the middle; Figure 7 A schematic structural diagram of the lower graphite plate in the silicon carbide crystal growth device provided in Example 2; Figure 8 This is a schematic diagram of the coordination of the first through hole and the second through hole in the silicon carbide crystal growth device provided in Example 2.

[0018] Icon: 100-crucible; 110-upper crucible; 111-first cavity; 120-lower crucible; 121-second cavity; 130-seed crystal; 140-silicon carbide powder; 200 - gas phase flow regulating assembly; 210 - first regulating unit; 211 - upper graphite plate; 212 - first through hole; 213 - fixed block; 214 - sliding block; 215 - limit pin; 220 - second regulating unit; 221 - lower graphite plate; 222 - second through hole; 223 - annular groove; 300-bracket assembly; 310-fixed bracket; 320-rotating bracket. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0021] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0022] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the invention is usually placed when in use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation on the present invention.

[0023] In addition, the terms "first", "second", etc., if used, are merely used to distinguish and describe, and should not be understood as indicating or implying relative importance.

[0024] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0025] The following describes in detail the detailed steps, implementation principles and technical effects of the silicon carbide crystal growth method provided by the present invention, as well as the overall structure, working principle and technical effects of the corresponding silicon carbide crystal growth device through examples and in combination with the accompanying drawings.

[0026] Example 1: See also Figure 1 , this embodiment provides a method for growing silicon carbide crystals, comprising the following steps: S1. Place a seed crystal 130 and silicon carbide powder 140 in a crucible 100, and connect the crucible 100 to a gas phase flow regulating assembly 200; S2, after evacuating the crucible 100, filling it with an inert gas, and heating the crucible 100 to allow the silicon carbide crystal to enter a growth stage; S3. During the crystal growth stage, the gas flow regulating assembly 200 is used to control the opening of the gas flow channel to adjust the gas flow reaching the seed crystal 130 until the growth of the silicon carbide crystal is completed.

[0027] In this embodiment, the gas phase flow regulating component 200 has a fully closed state, an intermediate state and a fully open state in the process of controlling the opening of the gas phase flow channel. The above intermediate state can be understood as that the gas phase flow channel is only partially opened, and its opening is between 0%-100%.

[0028] The method of controlling the opening of the gas phase flow channel by the gas phase flow regulating component to adjust the gas flow reaching the seed crystal may specifically be: In the early stage of crystal growth (process formulation stage, the first 45 hours), in order to prevent the seed crystal 130 from sublimating or burning through due to excessive gas flow, the gas flow channel is controlled to be in an intermediate state.

[0029] Furthermore, in the early stage of crystal growth, the opening of the gas phase flow channel is controlled to be 40%-60%.

[0030] For example, the opening degree of the gas phase flow channel may be 50%.

[0031] In the middle stage of crystal growth (crystal growth stage), the opening of the gas phase flow channel is dynamically adjusted according to the crystal growth temperature, so that the gas phase flow channel is in an intermediate state or a fully open state.

[0032] In this embodiment, the mid-stage of crystal growth includes a first stage and a second stage in terms of timing, and when the first stage is completed, the crystal growth temperature reaches the target growth temperature; that is, in the first stage, the crystal growth temperature gradually increases until it reaches the maximum target growth temperature (at which time the crystal growth rate reaches the maximum value), and in the second stage, the crystal growth temperature is maintained at the above-mentioned maximum target growth temperature or gradually decreases.

[0033] Specifically, under the conditions of the first stage, the opening of the gas phase flow channel is controlled to increase gradually, and the opening of the gas phase flow channel is gradually increased from 50% in the early stage of crystal growth to 100%; Under the second stage conditions, the opening of the gas phase flow channel is controlled to decrease gradually from 100% in the first stage to 40%-60%; illustratively, the second stage can decrease to 50%.

[0034] In the later stage of crystal growth, the opening of the gas phase flow channel is controlled to decrease gradually until the gas phase flow channel is in a completely closed state.

[0035] Specifically, in the late stage of crystal growth, the opening of the gas phase flow channel gradually decreases from 50% in the second stage of the middle stage of crystal growth to 0%, that is, the gas phase flow channel is in a completely closed state.

[0036] In this embodiment, in the later stage of crystal growth, since the silicon element in the silicon carbide powder 140 in the crucible 100 gradually decreases, the carbon element content in the powder is much greater than the silicon element. This will cause the carbon element gas phase to flow upward in the later stage, resulting in the presence of carbon inclusion defects in the crystal. Therefore, at this time, the gas phase flow channel is controlled to gradually be in a completely closed state to prevent the gas phase with a higher carbon content from continuing to flow upward, thereby inhibiting the formation of carbon inclusions on the crystal surface.

[0037] The silicon carbide crystal growth method provided in this embodiment can produce at least the following technical effects: This embodiment provides a method for growing silicon carbide crystals, which can control the opening of the gas flow channel according to different stages of silicon carbide crystal growth, thereby matching the corresponding gas flow requirements; in the early and middle stages of crystal growth, it can increase the growth rate of the crystal; in the late stage of crystal growth, it can reduce gas phase elements with a high carbon content, thereby inhibiting the formation of carbon inclusions on the crystal surface.

[0038] Comparative Example 1: See also Figures 2 to 4 The difference between Comparative Example 1 and Example 1 is that during the growth of the silicon carbide crystal, the gas flow reaching the seed crystal 130 is not adjusted, and the other process flows refer to Example 1.

[0039] Comparison of Example 1 and Comparative Example 1 shows that the surface of the ingot formed by the silicon carbide crystal prepared by the present invention is free of corrosion and carbon inclusions.

[0040] Figure 3 、 Figure 4 The arrow in the middle points to the carbon inclusion.

[0041] Example 2: The present invention provides a silicon carbide crystal growth device, which is based on the silicon carbide crystal growth method provided in Example 1 and is mainly used for preparing silicon carbide single crystal substrates based on the physical vapor transport method.

[0042] See also Figure 5 In the present invention, the silicon carbide crystal growth device includes a crucible 100 and a gas flow regulating assembly 200 arranged in the crucible 100; wherein the crucible 100 includes an upper crucible 110 and a lower crucible 120, a first cavity 111 is formed in the upper crucible 110, and the top of the first cavity 111 is used to fix the seed crystal 130; a second cavity 121 is formed in the lower crucible 120, and the second cavity 121 is used to accommodate silicon carbide powder 140.

[0043] In this embodiment, by providing the above-mentioned gas phase flow regulating component 200, the gas phase flow rate from the first cavity 111 to the second cavity 121 or the gas phase flow rate from the second cavity 121 to the first cavity 111 can be dynamically controlled during the growth of the silicon carbide crystal, thereby effectively improving the crystal growth rate in the early and middle stages of crystal growth and avoiding carbon encapsulation defects in the crystal in the late stage of crystal growth.

[0044] Please continue reading Figure 5 In this embodiment, the above-mentioned gas-phase flow regulating component 200 is arranged between the first cavity 111 and the second cavity 121, and includes a first regulating unit 210 connected to the upper crucible 110 and a second regulating unit 220 connected to the lower crucible 120; the first regulating unit 210 and the second regulating unit 220 can rotate relative to each other. When the first regulating unit 210 rotates relative to the second regulating unit 220 or the second regulating unit 220 rotates relative to the first regulating unit 210, the gas-phase flow regulating component 200 realizes the regulation of the gas-phase flow between the first cavity 111 and the second cavity 121.

[0045] See also Figure 5 、 Figure 6 and Figure 7 Specifically, the first adjustment unit 210 includes an upper graphite plate 211, a plurality of fixed blocks 213 connected to the upper graphite plate 211, and a sliding block 214 arranged on the fixed block 213; the second adjustment unit 220 includes a lower graphite plate 221 and an annular groove 223 opened on the lower graphite plate 221.

[0046] In this embodiment, the sliding block 214 on the upper graphite plate 211 forms a sliding connection with the annular groove 223 on the lower graphite plate 221 , so that the upper graphite plate 211 is rotatably connected to the lower graphite plate 221 .

[0047] During the specific assembly process, the lower graphite plate 221 may be a split structure, thereby facilitating the processing of the annular groove 223 and the assembly connection between the sliding block 214 and the annular groove 223 .

[0048] For example, see Figure 7 The lower graphite plate 221 can be formed by splicing two symmetrically arranged semicircular graphite plates. Each semicircular graphite plate is grooved separately. After the grooving is completed, the sliding block 214 and the fixed block 213 are connected, and then the two semicircular graphite plates are spliced and fixed. Finally, the upper graphite plate 211 and the fixed block 213 are connected through the limit pin 215 to complete the connection between the upper graphite plate 211 and the lower graphite plate 221.

[0049] Please continue reading Figure 5 In this embodiment, the outer diameter of the upper graphite plate 211 is slightly smaller than the outer diameter of the upper crucible 110, and is threadedly connected to the inner wall of the upper crucible 110 through multiple fixing blocks 213; the outer diameter of the lower graphite plate 221 is the same as that of the lower crucible 120, and is threadedly connected to the lower crucible 120; the connection between the upper crucible 110 and the lower crucible 120 is achieved through the connection between the upper graphite plate 211 and the lower graphite plate 221. At the same time, in order to ensure the sealing of the connection, a corresponding sealing structure can be provided at the connection between the upper crucible 110 and the lower crucible 120, such as padding graphite paper at the joint.

[0050] See also Figure 7 and Figure 8 A plurality of first through holes 212 and second through holes 222 are respectively provided on the upper graphite plate 211 and the lower graphite plate 221. It can be understood that since the upper graphite plate 211 and the lower graphite plate 221 are in contact with each other, a gas phase flow channel for the gas phase to pass through can be formed between the first through holes 212 and the second through holes 222, and by controlling the overlap of the first through holes 212 and the second through holes 222, the opening of the gas phase flow channel can be controlled.

[0051] See also Figure 8 , Figure 8 The solid line portion represents the first through hole 212 on the upper graphite plate 211 , and the dotted line portion represents the second through hole 222 on the lower graphite plate 221 , wherein the overlapping portion of the first through hole 212 and the second through hole 222 is a gas phase flow channel.

[0052] It can be understood that when the first through hole 212 and the second through hole 222 completely overlap, the gas flow channel opening is 100%, and the gas in the crucible 100 can enter the second cavity 121 through the first cavity 111, or enter the first cavity 111 through the second cavity 121; on the contrary, when the first through hole 212 and the second through hole 222 are completely staggered, the gas flow channel opening is 0%, and the gas in the first cavity 111 cannot enter the second cavity 121 through the gas flow regulating component 200, and the gas in the second cavity 121 cannot enter the first cavity 111 through the gas flow regulating component 200.

[0053] In particular, when the first through hole 212 and the second through hole 222 are partially staggered, the gas phase flow rate can be infinitely adjusted by changing the opening of the gas phase flow channel.

[0054] Furthermore, when the first through holes 212 and the second through holes 222 are arranged regularly, the opening of the gas flow channel can be determined by determining the relative angle between the upper graphite plate 211 and the lower graphite plate 221, thereby dynamically controlling the size of the gas flow rate.

[0055] In this embodiment, the first through holes 212 and the second through holes 222 are provided in a ring array on the upper graphite plate 211 and the lower graphite plate 221 , and are arranged in multiple layers from the inside out with the upper graphite plate 211 and the lower graphite plate 221 as the center.

[0056] In addition, when the first through hole 212 and the second through hole 222 are arranged in a ring-shaped multi-layer, in order to avoid the difficulty in determining the opening of the gas phase flow channel due to dense openings, in this embodiment, the first through hole 212 and the second through hole 222 are arranged along the radial direction of the upper graphite plate 211 and the lower graphite plate 221, with the diameter gradually increasing from the inside to the outside.

[0057] It should be noted that, for example, when the opening of the gas phase flow channel is 50%, it refers to 50% of the overall opening of the gas phase flow channel formed by the first through hole 212 and the second through hole 222. If the apertures of the first through hole 212 and the second through hole 222 are set to be variable, the through hole with a smaller aperture may be in a completely closed state, while the through hole with a larger aperture is in a partially open state.

[0058] In this embodiment, the silicon carbide crystal growth device also includes a support assembly 300, which includes a fixed support 310 and a rotating support 320; wherein, the fixed support 310 is connected to the upper crucible 110 and is used to fix the upper crucible 110 so that it remains relatively fixed; the rotating support 320 is used to support the lower crucible 120 and is used to drive the lower crucible 120 to rotate relative to the upper crucible 110.

[0059] It is understandable that the fixed bracket 310 is connected to an external fixed structure; the rotating bracket 320 is connected to a corresponding driving mechanism and a data acquisition mechanism, which can obtain the rotation angle of the crucible 120 driven by the rotating bracket 320 in real time.

[0060] This embodiment provides a silicon carbide crystal growth device, and the specific assembly process is as follows: (1) Assembling process of gas phase flow regulating assembly 200: The fixed block 213 and the sliding block 214 are connected to the annular groove 223 on the lower graphite plate 221 in a sliding manner. Then, the fixed block 213 and the upper graphite plate 211 are fixed by the limit pin 215 so that the upper graphite plate 211 can be rotatably arranged on the lower graphite plate 221, thereby completing the assembly of the gas phase flow regulating assembly 200.

[0061] (2) The process of connecting the gas phase flow regulating assembly 200 and the crucible 100: the lower graphite plate 221 is threadedly connected to the lower crucible 120, and then the upper crucible 110 is threadedly connected to the upper graphite plate 211, thereby completing the connection between the gas phase flow regulating assembly 200 and the crucible 100.

[0062] (3) The process of connecting the crucible 100 and the support assembly 300: The crucible 100 is placed on the rotating support 320, and then the upper crucible 110 is kept fixed by the fixed support 310.

[0063] The silicon carbide crystal growth device provided in this embodiment can produce at least the following technical effects: The silicon carbide crystal growth device provided in this embodiment realizes stepless dynamic adjustment of the gas phase flow channel opening by causing the rotating bracket 320 to drive the lower crucible 120 to rotate relative to the upper crucible 110, thereby causing the lower graphite plate 221 to rotate relative to the upper graphite plate 211, thereby being able to adaptively match different gas flow rates for different stages of crystal growth, thereby avoiding crystal defects such as carbon encapsulation, and at the same time, can also increase the growth rate of the crystal growth stage.

[0064] Example 3: This embodiment provides a silicon carbide crystal, which is prepared based on the silicon carbide crystal growth method provided in Example 1 or the silicon carbide crystal growth device provided in Example 2, and has the characteristics of high growth rate and less carbon wrapping.

[0065] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for growing silicon carbide crystals, characterized in that: include: A seed crystal (130) and silicon carbide powder (140) are placed in a crucible (100), and the crucible (100) is connected to a gas phase flow regulating component (200); After evacuating the crucible (100), an inert gas is filled in, and the crucible (100) is heated to allow the silicon carbide crystal to enter a growth stage; During the crystal growth stage, the opening of the gas phase flow channel is controlled by the gas phase flow regulating component (200) to regulate the gas flow reaching the seed crystal (130) until the growth of the silicon carbide crystal is completed.

2. The method for growing silicon carbide crystals according to claim 1, wherein: A method for regulating the gas flow reaching a seed crystal (130) by controlling the opening of a gas phase flow channel through a gas phase flow regulating component (200) includes: In the early stage of crystal growth, the gas phase flow channel is controlled to be in an intermediate state; In the middle stage of crystal growth, the opening of the gas phase flow channel is dynamically adjusted according to the crystal growth temperature, so that the gas phase flow channel is in an intermediate state or a fully open state; In the later stage of crystal growth, the opening of the gas phase flow channel is controlled to decrease gradually until the gas phase flow channel is in a completely closed state.

3. The method for growing silicon carbide crystals according to claim 2, wherein: In the early stage of crystal growth, the opening of the gas phase flow channel is controlled to be 40%-60%.

4. The method for growing silicon carbide crystals according to claim 2, wherein: The crystal growth mid-stage includes a first stage and a second stage in terms of time sequence, and when the first stage is completed, the crystal growth temperature reaches the target growth temperature; Under the first stage conditions, the gas phase flow channel opening is controlled to increase gradually until the gas phase flow channel opening is 100%; Under the second stage conditions, the gas phase flow channel opening is controlled to decrease gradually until the gas phase flow channel opening is 40%-60%.

5. Silicon carbide crystal growth device, characterized in that include: A crucible (100), the crucible (100) comprising an upper crucible (110) and a lower crucible (120), wherein a first cavity (111) is formed in the upper crucible (110), and a top of the first cavity (111) is used to fix a seed crystal (130); a second cavity (121) is formed in the lower crucible (120), and the second cavity (121) is used to accommodate silicon carbide powder (140), and the upper crucible (110) is rotatable relative to the lower crucible (120); A gas phase flow regulating component (200) is provided between the first cavity (111) and the second cavity (121), and is used to regulate the gas flow rate entering the first cavity (111) from the second cavity (121) when the upper crucible (110) and the lower crucible (120) rotate relative to each other.

6. The silicon carbide crystal growth apparatus according to claim 5, characterized in that The gas phase flow regulating assembly (200) comprises a first regulating unit (210) connected to the upper crucible (110) and a second regulating unit (220) connected to the lower crucible (120); The first regulating unit (210) is rotatably connected to the second regulating unit (220), and when the first regulating unit (210) rotates relative to the second regulating unit (220), the gas phase flow regulating assembly (200) regulates the flow of gas entering the first cavity (111) from the second cavity (121).

7. The silicon carbide crystal growth device according to claim 6, characterized in that The first adjustment unit (210) comprises an upper graphite plate (211), the upper graphite plate (211) is fixedly connected to the upper crucible (110), and a plurality of first through holes (212) are formed on the upper graphite plate (211); The second adjustment unit (220) comprises a lower graphite plate (221), the lower graphite plate (221) is fixedly connected to the lower crucible (120), and a plurality of second through holes (222) are formed on the lower graphite plate (221); The first through holes (212) and the second through holes (222) together form a gas phase flow channel. When the first regulating unit (210) rotates relative to the second regulating unit (220), the connection area between the plurality of first through holes (212) and the plurality of second through holes (222) changes, thereby achieving opening adjustment of the gas phase flow channel.

8. The silicon carbide crystal growth device according to claim 7, characterized in that The first adjustment unit (210) further includes a plurality of fixed blocks (213) connected to the upper graphite plate (211) and sliding blocks (214) arranged on the fixed blocks (213); The second adjustment unit (220) further includes an annular groove (223) formed on the lower graphite plate (221); The sliding block (214) is slidably disposed in the annular groove (223) so that the upper graphite plate (211) and the lower graphite plate (221) are rotatably connected.

9. The silicon carbide crystal growth apparatus according to claim 5, wherein: The silicon carbide crystal growing device further comprises: A bracket assembly (300), the bracket assembly (300) comprising a fixed bracket (310) and a rotating bracket (320); Wherein, the fixing bracket (310) is fixedly connected to the upper crucible (110) and is used to fix the upper crucible (110); The rotating bracket (320) is used to support the lower crucible (120) and to drive the lower crucible (120) to rotate relative to the upper crucible (110).

10. Silicon carbide crystal, characterized in that The silicon carbide crystal is prepared by the silicon carbide crystal growth method according to any one of claims 1 to 4 or the silicon carbide crystal growth device according to any one of claims 5 to 7.

Images