Silicon carbide single crystal growth apparatus for liquid phase method and working method thereof
By setting up inner and outer graphite crucibles and T-shaped components in the silicon carbide single crystal growth apparatus, the problem of impurity accumulation at the bottom of the inner crucible was solved, and stable growth of silicon carbide single crystals and high-quality crystal growth were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 常州臻晶半导体有限公司
- Filing Date
- 2026-04-03
- Publication Date
- 2026-06-05
AI Technical Summary
During the liquid phase growth of silicon carbide single crystals, impurities in the graphite crucible dissolve and diffuse at high temperatures, accumulating at the bottom of the inner crucible and affecting the crystal growth quality. This is especially true when the liquid level decreases, as the crystal growth region approaches the area with the highest impurity concentration.
A silicon carbide single crystal growth apparatus was designed, including an inner graphite crucible and an outer crucible. The bottom of the inner crucible is provided with a central hole, and the outer crucible can be lowered and communicated with the inner crucible. By controlling the graphite crucible shaft to drive the outer crucible to descend, impurities flow into the outer crucible. At the same time, a T-shaped component is set to stir the solution and maintain the uniformity of the solution.
It effectively reduces the impurity content at the bottom of the inner crucible, ensures stable growth of silicon carbide single crystals, avoids growth interruption, maintains solution homogeneity, and improves crystal quality.
Smart Images
Figure CN122147496A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of chemical metallurgy technology, specifically relating to single crystal growth, and more particularly to a silicon carbide single crystal growth apparatus and its working method for liquid phase method. Background Technology
[0002] Silicon carbide, as a representative of third-generation semiconductor materials, has been widely used in new energy vehicles, 5G communications, smart grids and other fields due to its excellent properties such as wide bandgap, high breakdown field strength and high thermal conductivity.
[0003] For example, in the publication "Apparatus and working method for stable growth of silicon carbide single crystal by liquid phase method" with publication number "CN121065809A", impurities in the graphite crucible will continuously dissolve and diffuse into the melt under long-term high temperature, thus accumulating at the bottom of the inner crucible. As the liquid level decreases, the crystal growth area gradually approaches the area with the highest impurity concentration at the bottom, thereby affecting the crystal growth quality.
[0004] Therefore, how to solve the above problems is a problem that urgently needs to be solved by those skilled in the art.
[0005] It should be noted that the information disclosed in this background section is only for understanding the background technology of the present application concept, and therefore, the above description is not considered to constitute prior art information. Summary of the Invention
[0006] This disclosure provides at least one embodiment of a silicon carbide single crystal growth apparatus for liquid phase method and its operating method.
[0007] In a first aspect, embodiments of this disclosure provide a silicon carbide single crystal growth apparatus for liquid-phase method, comprising: an inner graphite crucible, which is hoisted by a graphite fixing component; an outer graphite crucible, which is disposed around the inner graphite crucible and supported and rotated by a graphite crucible shaft; and a graphite seed crystal rod, which extends into the inner graphite crucible and contacts the liquid surface of the solution; a central hole communicating with the outer graphite crucible is provided at the bottom of the inner graphite crucible; when crystallization occurs on the inner wall of the inner graphite crucible, the control module controls the graphite crucible shaft to drive the outer graphite crucible to descend, so that the solution at the bottom of the inner graphite crucible, carrying impurities, flows into the outer graphite crucible through the central hole.
[0008] In one optional embodiment, a T-shaped component is provided at the bottom of the outer graphite crucible; wherein the upper part of the T-shaped component is located inside the inner graphite crucible, and the lower part of the T-shaped component passes through the central hole and is connected to the outer graphite crucible; the T-shaped component rotates with the outer graphite crucible to stir the solution in the inner graphite crucible.
[0009] In one optional embodiment, the upper part of the T-shaped component is a stirring part, and the lower part of the T-shaped component is a connecting part; wherein the connecting part of the T-shaped component is a cylinder with a cross-sectional area of S1; the cross-sectional area of the inner graphite crucible is S2, and the cross-sectional area of the outer graphite crucible is S3; wherein S1 = S3 - S2.
[0010] In one alternative embodiment, the diameter of the connecting portion is smaller than the inner diameter of the central hole.
[0011] In one optional embodiment, a graphite shielding cylinder is provided around the outer graphite crucible; wherein the upper part of the graphite fixing member is connected to the graphite shielding cylinder, and the lower part of the graphite fixing member is connected to the inner graphite crucible for hoisting the inner graphite crucible.
[0012] In one optional embodiment, a graphite insulation felt is provided around the graphite shielding cylinder; a graphite heater is provided between the graphite shielding cylinder and the graphite outer crucible.
[0013] In one alternative embodiment, the upper part of the graphite seed rod is connected to a first driver; wherein the first driver is used to control the rotation and lifting of the graphite seed rod.
[0014] Secondly, this disclosure also provides a method for operating a silicon carbide single crystal growth apparatus for liquid phase method, comprising: hoisting an inner graphite crucible using a graphite fixing member, wherein the bottom of the inner graphite crucible has a central hole; supporting an outer graphite crucible using a graphite crucible shaft and positioning the outer graphite crucible around the inner graphite crucible; inserting a graphite seed crystal rod into the inner graphite crucible to contact the liquid surface of the solution, and rotating and pulling it to grow silicon carbide single crystals on it; when crystallization occurs on the inner wall of the inner graphite crucible, the graphite crucible shaft drives the outer graphite crucible to descend, causing the solution at the bottom of the inner graphite crucible, carrying impurities, to flow into the outer graphite crucible through the central hole.
[0015] In one optional embodiment, a T-shaped component is provided at the bottom of the outer graphite crucible, and the upper part of the T-shaped component is located inside the inner graphite crucible; wherein the graphite crucible shaft drives the outer graphite crucible to rotate, causing the T-shaped component to stir the solution in the inner graphite crucible.
[0016] In one optional embodiment, the connecting part of the T-shaped component is set as a cylinder, and its cross-sectional area S1 = S3 - S2 is made to eliminate the difference in cross-sectional area between the inner graphite crucible and the outer graphite crucible, so that when the outer graphite crucible descends, the silicon carbide single crystal on the graphite seed crystal rod is always in contact with the liquid surface of the solution; wherein, S2 is the cross-sectional area of the chamber of the inner graphite crucible 1; and S3 is the cross-sectional area of the chamber of the outer graphite crucible 2.
[0017] The beneficial effects of this invention are as follows: The silicon carbide single crystal growth apparatus and its working method for liquid phase method involve setting an outer graphite crucible around an inner graphite crucible, and having a central hole at the bottom of the inner graphite crucible that communicates with the outer graphite crucible. When crystallization is observed on the inner wall of the inner graphite crucible, the outer graphite crucible is lowered by controlling the graphite crucible shaft. This allows the solution at the bottom of the inner graphite crucible, carrying impurities, to flow into the outer graphite crucible through the central hole. Consequently, the liquid surface of the solution in the inner graphite crucible is moved away from the crystallization site, and the impurity content at the bottom of the inner crucible is reduced, thus enabling stable growth of the silicon carbide single crystal. Furthermore, by setting a T-shaped component, not only can the solution in the inner graphite crucible be stirred, but also, during the descent of the outer graphite crucible, the graphite seed crystal rod only needs to descend synchronously with the outer graphite crucible to ensure that the silicon carbide single crystal remains in contact with the liquid surface of the solution.
[0018] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained through the structures particularly pointed out in the description and the drawings.
[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description
[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the structure of an inner graphite crucible, an outer graphite crucible, and a graphite fixing member provided in an embodiment of this disclosure.
[0022] Figure 2 This is a schematic diagram of a silicon carbide single crystal growth apparatus for liquid phase method provided in an embodiment of this disclosure.
[0023] Figure 3 This is a schematic diagram of the structure of a silicon carbide single crystal growth apparatus for liquid phase method after the graphite outer crucible is lowered, as provided in an embodiment of this disclosure.
[0024] In the picture: 1. Graphite inner crucible; 11. Graphite fixing component; 12. Center hole; 2. Graphite outer crucible; 21. Graphite crucible shaft; 22. T-shaped component; 221. Stirring section; 222. Connecting section; 3. Graphite seed crystal rod; 4. Graphite shielding cylinder; 5. Graphite insulation felt; 6. Graphite heater. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions 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, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0026] It should be noted that similar reference numerals 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. Furthermore, in the figures, the thickness of parts may be exaggerated or reduced for the purpose of effectively depicting the technical content.
[0027] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0028] like Figures 1 to 3 As shown, at least one embodiment provides a silicon carbide single crystal growth apparatus for liquid phase method, including: an inner graphite crucible 1, a graphite fixing member 11, an outer graphite crucible 2, a graphite crucible shaft 21, and a graphite seed crystal rod 3.
[0029] Specifically, the graphite inner crucible 1 is hoisted using the graphite fixing component 11.
[0030] Specifically, the outer graphite crucible 2 is placed around the inner graphite crucible 1 and mounted on the graphite crucible shaft 21; the graphite crucible shaft 21 serves to support the outer graphite crucible 2 and to drive the outer graphite crucible 2 to rotate.
[0031] Specifically, the graphite seed crystal rod 3 is used to extend into the graphite inner crucible 1 and contact the liquid surface of the solution, and to grow silicon carbide single crystals by rotating and pulling.
[0032] In related technologies, during the growth of silicon carbide single crystals, the large gradient within the solution leads to a mismatch in growth rates, causing the liquid surface to crystallize on the inner wall of the crucible, which in turn affects solution flow and crystal growth. Simultaneously, under prolonged high temperatures, impurities in the graphite crucible continuously dissolve and diffuse into the melt, accumulating at the bottom of the inner crucible. As the liquid level decreases, the crystal growth region gradually approaches the area with the highest impurity concentration at the bottom, thus affecting the quality of crystal growth.
[0033] To address the aforementioned issues, in some embodiments, a central hole 12 communicating with the outer graphite crucible 2 is provided at the bottom of the inner graphite crucible 1. When crystallization occurs on the inner wall of the inner graphite crucible 1, the graphite crucible shaft 21 drives the outer graphite crucible 2 to descend, allowing the solution at the bottom of the inner graphite crucible 1, carrying impurities, to flow into the outer graphite crucible 2 through the central hole 12. This not only lowers the solution level away from the crystallization site but also reduces the impurity content at the bottom of the inner crucible.
[0034] In this embodiment, initially, the outer graphite crucible 2 and the inner graphite crucible 1 are abutted against each other to block the central hole 12. When the operator observes crystallization on the inner wall of the inner graphite crucible 1, pressing the button causes the control module to control the graphite crucible shaft 21 to lower the outer graphite crucible 2, creating a chamber between the outer graphite crucible 2 and the inner graphite crucible 1. This allows the solution in the inner graphite crucible 1 to enter the chamber. Since the height of the inner graphite crucible 1 remains unchanged, the liquid level of the solution in the inner graphite crucible 1 will decrease to move away from the crystallization site, thus enabling the silicon carbide single crystal to grow stably.
[0035] like Figure 2 As shown, in some embodiments, a T-shaped member 22 is provided at the bottom of the graphite outer crucible 2; wherein the upper part of the T-shaped member 22 is located inside the graphite inner crucible 1, and the lower part of the T-shaped member 22 passes through the central hole 12 and is connected to the graphite outer crucible 2; the T-shaped member 22 rotates with the graphite outer crucible 2 to stir the solution in the graphite inner crucible 1.
[0036] In this embodiment, the T-shaped component 22 rotates synchronously with the outer graphite crucible 2, so that the T-shaped component 22 can stir the solution in the inner graphite crucible 1, so that the solute concentration in the solution remains uniform for a long time.
[0037] In some embodiments, the upper part of the graphite seed rod 3 is connected to a first driver; wherein the first driver is used to control the rotation and lifting of the graphite seed rod 3.
[0038] In this embodiment, the graphite seed crystal rod 3 is rotated and pulled by the first driver, thereby forming the desired silicon carbide single crystal on the graphite seed crystal rod 3.
[0039] In some embodiments, when crystallization occurs on the inner wall of the graphite inner crucible 1, the graphite crucible shaft 21 drives the graphite outer crucible 2 to descend, while the first driver drives the graphite seed crystal rod 3 to descend, and keeps the graphite outer crucible 2 and the graphite seed crystal rod 3 synchronized.
[0040] In some embodiments, optionally, the mounting part of the first driver is connected to the upper part of the linkage rod, and the mounting part of the graphite crucible shaft 21 is connected to the lower part of the linkage rod. The linkage rod is controlled by the second driver to move up and down. That is, when the graphite outer crucible 2 needs to be lowered, it is only necessary to control the second driver to drive the linkage rod to lower, so that the graphite outer crucible 2 and the graphite seed crystal rod 3 can be lowered synchronously.
[0041] To avoid interruption of silicon carbide single crystal growth, the silicon carbide single crystal on the graphite seed rod 3 needs to be in constant contact with the liquid surface of the solution. In some embodiments, the upper part of the T-shaped member 22 is a stirring part 221, and the lower part of the T-shaped member 22 is a connecting part 222. The connecting part 222 of the T-shaped member 22 is a cylinder with a cross-sectional area of S1. The cross-sectional area of the chamber of the inner graphite crucible 1 is S2, and the cross-sectional area of the chamber of the outer graphite crucible 2 is S3. Wherein, S1 = S3 - S2.
[0042] In this embodiment, since the cross-sectional area of the inner graphite crucible 1 is smaller than that of the outer graphite crucible 2, when the outer graphite crucible 2 descends by X millimeters, the liquid level of the solution in the inner graphite crucible 1 will drop by more than X millimeters, causing the silicon carbide single crystal on the graphite seed rod 3 to lose contact with the liquid surface of the solution. Therefore, in this embodiment, by setting the connecting part 222 of the T-shaped component 22 as a cylinder and making its cross-sectional area S1=S3-S2, even though the connecting part 222 occupies part of the space in the outer graphite crucible 2, the difference in cross-sectional area between the inner graphite crucible 1 and the outer graphite crucible 2 is eliminated, so that when the outer graphite crucible 2 descends, the silicon carbide single crystal on the graphite seed rod 3 is always in contact with the liquid surface of the solution.
[0043] In some embodiments, the diameter of the connecting portion 222 is smaller than the inner diameter of the central hole 12.
[0044] Optionally, the diameter of the connecting part 222 is 1-2 mm smaller than the inner diameter of the central hole 12, and the diameter of the stirring part 221 is 10-20 mm larger than the inner diameter of the central hole 12.
[0045] In some embodiments, the stirring section 221 is always submerged in the solution.
[0046] In some embodiments, the connecting part 222 is threadedly connected to the bottom of the graphite outer crucible 2.
[0047] In some embodiments, the length of the connecting portion 222 is optionally L mm, such that the stirring portion 221 is H mm away from the bottom of the graphite inner crucible 1.
[0048] In this embodiment, the graphite outer crucible 2 can be lowered multiple times, as long as the total distance of descent is less than H millimeters.
[0049] In some embodiments, a graphite shielding cylinder 4 is provided around the graphite outer crucible 2; wherein the upper part of the graphite fixing member 11 is connected to the graphite shielding cylinder 4, and the lower part of the graphite fixing member 11 is connected to the graphite inner crucible 1 to suspend the graphite inner crucible 1.
[0050] In this embodiment, the position of the inner graphite crucible 1 does not change during the descent of the outer graphite crucible 2.
[0051] In some embodiments, a graphite insulation felt 5 is provided around the graphite shielding cylinder 4; a graphite heater 6 is provided between the graphite shielding cylinder 4 and the graphite outer crucible 2.
[0052] At least one embodiment also provides a method of operating a silicon carbide single crystal growth apparatus for liquid phase method, comprising: hoisting a graphite inner crucible 1 by means of a graphite fixing member 11, wherein the bottom of the graphite inner crucible 1 has a central hole 12; supporting a graphite outer crucible 2 by means of a graphite crucible shaft 21, and placing the graphite outer crucible 2 around the graphite inner crucible 1; extending a graphite seed crystal rod 3 into the graphite inner crucible 1 to contact the liquid surface of the solution, and growing silicon carbide single crystals on it by rotation and lifting; when crystallization occurs on the inner wall of the graphite inner crucible 1, the graphite crucible shaft 21 drives the graphite outer crucible 2 to descend, so that part of the solution in the graphite inner crucible 1 flows into the graphite outer crucible 2 through the central hole 12, that is, the liquid surface of the solution descends away from the crystallization site.
[0053] For the specific structure and implementation process of the silicon carbide single crystal growth apparatus used in the liquid phase method, please refer to the relevant discussion in the above embodiments, which will not be repeated here.
[0054] In this embodiment, by setting a graphite outer crucible 2 around the graphite inner crucible 1, and opening a central hole 12 at the bottom of the graphite inner crucible 1 that communicates with the graphite outer crucible 2, when crystallization is observed on the inner wall of the graphite inner crucible 1, it is only necessary to control the graphite crucible shaft 21 to drive the graphite outer crucible 2 down, so that the liquid surface of the solution in the graphite inner crucible 1 is far away from the crystallization site, thereby enabling the silicon carbide single crystal to grow stably.
[0055] In some embodiments, a T-shaped member 22 is provided at the bottom of the outer graphite crucible 2, and the upper part of the T-shaped member 22 is located inside the inner graphite crucible 1; wherein the graphite crucible shaft 21 drives the outer graphite crucible 2 to rotate, causing the T-shaped member 22 to stir the solution in the inner graphite crucible 1.
[0056] In this embodiment, the T-shaped component 22 rotates synchronously with the outer graphite crucible 2, so that the T-shaped component 22 can stir the solution in the inner graphite crucible 1, so that the solute concentration in the solution remains uniform for a long time.
[0057] In some embodiments, when crystallization occurs on the inner wall of the graphite inner crucible 1, the graphite crucible shaft 21 drives the graphite outer crucible 2 to descend, while the first driver drives the graphite seed crystal rod 3 to descend, and keeps the graphite outer crucible 2 and the graphite seed crystal rod 3 synchronized.
[0058] To avoid interruption of silicon carbide single crystal growth, the silicon carbide single crystal on the graphite seed rod 3 needs to be in constant contact with the liquid surface of the solution. In some embodiments, the connecting portion 222 of the T-shaped member 22 is set as a cylinder with a cross-sectional area of S1; the cross-sectional area of the chamber of the graphite inner crucible 1 is S2; and the cross-sectional area of the chamber of the graphite outer crucible 2 is S3; wherein, S1 = S3 - S2.
[0059] In this embodiment, since the cross-sectional area of the inner graphite crucible 1 is smaller than that of the outer graphite crucible 2, when the outer graphite crucible 2 descends by X millimeters, the liquid level of the solution in the inner graphite crucible 1 will drop by more than X millimeters, causing the silicon carbide single crystal on the graphite seed rod 3 to lose contact with the liquid surface of the solution. Therefore, in this embodiment, by setting the connecting part 222 of the T-shaped component 22 as a cylinder and making its cross-sectional area S1=S3-S2, even though the connecting part 222 occupies part of the space in the outer graphite crucible 2, the difference in cross-sectional area between the inner graphite crucible 1 and the outer graphite crucible 2 is eliminated, so that when the outer graphite crucible 2 descends, the silicon carbide single crystal on the graphite seed rod 3 is always in contact with the liquid surface of the solution.
[0060] In summary, the silicon carbide single crystal growth apparatus and its operating method for the liquid phase method, by setting an outer graphite crucible 2 around an inner graphite crucible 1, and having a central hole 12 at the bottom of the inner graphite crucible 1 communicating with the outer graphite crucible 2, allows the silicon carbide single crystal to grow stably when crystallization is observed on the inner wall of the inner graphite crucible 1. This is achieved by controlling the graphite crucible shaft 21 to lower the outer graphite crucible 2, allowing the solution at the bottom of the inner graphite crucible 1, carrying impurities, to flow into the outer graphite crucible 2 through the central hole 12. This keeps the liquid surface of the solution in the inner graphite crucible 1 away from the crystallization site and reduces the impurity content at the bottom of the inner crucible, thus enabling stable growth of the silicon carbide single crystal. Furthermore, by setting a T-shaped component 22, not only can the solution in the inner graphite crucible 1 be stirred, but also, during the descent of the outer graphite crucible 2, the graphite seed crystal rod 3 only needs to descend synchronously with the outer graphite crucible 2 to ensure that the silicon carbide single crystal remains in contact with the liquid surface of the solution.
[0061] In this document, when it is said that the first component is located on the second component, this can mean that the first component can be directly formed on the second component, or that the third component can be inserted between the first component and the second component.
[0062] In this document, when an element or layer is referred to as being “located,” “joined to,” “connected to,” “attached to,” or “coupled to” another element or layer, it may be directly located, joined, connected, attached to, or coupled to the other element or layer, or there may be an intermediate element or layer.
[0063] In the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.
[0064] Spatially relative terms, such as “inside,” “outside,” “below,” “below,” “down,” “above,” “up,” etc., may be used herein to describe the relationship between one element or feature illustrated in the figures and another element or feature. In addition to the orientations depicted in the figures, spatially relative terms may be intended to cover different orientations of the apparatus in use or operation.
[0065] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.
Claims
1. An apparatus for growing silicon carbide single crystals using a liquid-phase method, characterized in that, include: The graphite inner crucible (1) is hoisted using a graphite fixing component (11); The graphite outer crucible (2) is set around the graphite inner crucible (1) and is supported and rotated by the graphite crucible shaft (21); Graphite seed rod (3) is used to extend into the graphite inner crucible (1) and contact the liquid surface of the solution; The bottom of the graphite inner crucible (1) is provided with a central hole (12) that communicates with the graphite outer crucible (2). When crystals appear on the inner wall of the graphite inner crucible (1), the control module controls the graphite crucible shaft (21) to drive the graphite outer crucible (2) to descend, so that the solution at the bottom of the graphite inner crucible (1), carrying impurities, flows into the graphite outer crucible (2) through the central hole (12).
2. The silicon carbide single crystal growth apparatus for liquid-phase method as described in claim 1, characterized in that, The bottom of the graphite outer crucible (2) is provided with a T-shaped component (22); wherein The upper part of the T-shaped component (22) is located inside the graphite inner crucible (1), and the lower part of the T-shaped component (22) passes through the central hole (12) and is connected to the graphite outer crucible (2). The T-shaped component (22) rotates with the outer graphite crucible (2) to stir the solution in the inner graphite crucible (1).
3. The silicon carbide single crystal growth apparatus for liquid-phase method as described in claim 2, characterized in that, The upper part of the T-shaped component (22) is a stirring part (221), and the lower part of the T-shaped component (22) is a connecting part (222); wherein The connecting part (222) of the T-shaped component (22) is a cylinder with a cross-sectional area of S1; The cross-sectional area of the chamber of the inner graphite crucible (1) is S2, and the cross-sectional area of the chamber of the outer graphite crucible (2) is S3; Where S1 = S3 - S2.
4. The silicon carbide single crystal growth apparatus for liquid-phase method as described in claim 3, characterized in that, The diameter of the connecting part (222) is smaller than the inner diameter of the central hole (12).
5. The silicon carbide single crystal growth apparatus for liquid-phase method as described in claim 1, characterized in that, A graphite shielding cylinder (4) is provided around the graphite outer crucible (2); wherein The upper part of the graphite fixing member (11) is connected to the graphite shielding cylinder (4), and the lower part of the graphite fixing member (11) is connected to the graphite inner crucible (1) for hoisting the graphite inner crucible (1).
6. The silicon carbide single crystal growth apparatus for liquid-phase method as described in claim 5, characterized in that, The graphite shielding cylinder (4) is surrounded by a graphite insulation felt (5). A graphite heater (6) is provided between the graphite shielding cylinder (4) and the graphite outer crucible (2).
7. The silicon carbide single crystal growth apparatus for liquid-phase method as described in claim 1, characterized in that, The upper part of the graphite seed rod (3) is connected to the first driver; wherein The first driver is used to control the rotation and lifting of the graphite seed rod (3).
8. A method of operating a silicon carbide single crystal growth apparatus for liquid-phase method as described in any one of claims 1-7, characterized in that, include: The graphite inner crucible (1) is hoisted by a graphite fixing piece (11), wherein the bottom of the graphite inner crucible (1) has a central hole (12). The graphite outer crucible (2) is supported by the graphite crucible shaft (21), and the graphite outer crucible (2) is placed around the graphite inner crucible (1); The graphite seed crystal rod (3) is inserted into the graphite inner crucible (1) and brought into contact with the liquid surface of the solution. It is then rotated and pulled to grow silicon carbide single crystals on it. When crystals appear on the inner wall of the graphite inner crucible (1), the graphite crucible shaft (21) drives the graphite outer crucible (2) to descend, so that the solution at the bottom of the graphite inner crucible (1), carrying impurities, flows into the graphite outer crucible (2) through the central hole (12).
9. The operating method of the silicon carbide single crystal growth apparatus for liquid-phase method as described in claim 8, characterized in that, A T-shaped component (22) is provided at the bottom of the outer graphite crucible (2), and the upper part of the T-shaped component (22) is located inside the inner graphite crucible (1); wherein The graphite crucible shaft (21) drives the graphite outer crucible (2) to rotate, causing the T-shaped component (22) to stir the solution in the graphite inner crucible (1).
10. The method of operating the silicon carbide single crystal growth apparatus for liquid-phase method as described in claim 9, characterized in that, The connecting part (222) of the T-shaped component (22) is set as a cylinder, and its cross-sectional area S1=S3-S2, so as to eliminate the difference in cross-sectional area between the inner graphite crucible (1) and the outer graphite crucible (2), so that when the outer graphite crucible (2) descends, the silicon carbide single crystal on the graphite seed crystal rod (3) is always in contact with the liquid surface of the solution; Wherein, S2 is the cross-sectional area of the inner graphite crucible 1; and S3 is the cross-sectional area of the outer graphite crucible 2.