Crucible for SiC crystal growth
By designing the SiC long crystal crucible cover with a split structure, the problems of poor uniformity of seed crystal installation and difficulty in taking out are solved, and partial reuse and cost savings of the crucible cover are achieved.
Patent Information
- Application Number
- CN202421292075.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-06
- Publication Date
- 2025-04-01
- Estimated Expiration
- 2034-06-06
AI Technical Summary
In the existing SiC crystal growth technology, the uniformity of seed crystals on the top of the crucible is poor and the problem of not being easy to remove crystals after crystal growth.
A crucible for SiC crystal long crystal is designed, and its crucible cover adopts a split structure, including a first cover body and a fixed seat, and the seed crystal is placed in the accommodating cavity of the fixed seat and abuts against the first cover body to achieve uniform installation and positioning.
Through the crucible cover with a split structure, uniform installation and positioning of seed crystals can be achieved. After the crystal is grown, the fixed seat can be directly removed to remove the crystals to avoid damaging the crucible cover, and partial reuse is achieved, cost saving and process simplification.
Smart Images
Figure CN222700466U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of semiconductor material preparation equipment, in particular to a crucible for SiC crystal growth. Background Art
[0002] Silicon carbide (SiC) is a typical representative of the third generation of semiconductor materials. Compared with other semiconductor materials, SiC has superior properties such as higher breakdown electric field, higher thermal conductivity, and greater saturated electron drift velocity. It has an irreplaceable position in applications such as high temperature, high frequency, radiation resistance, and high power. The use of SiC semiconductor materials can reduce the size of devices, improve device performance, and reduce power consumption.
[0003] At present, physical vapor transport (PVT) is the mainstream preparation method for growing silicon carbide crystals. PVT crystal growth is mainly a reaction in a crucible. The basic principle is: place the silicon carbide raw material in the crucible, fix the seed crystal on the top of the crucible, sublimate the raw material under high temperature and low pressure, and the sublimated gas undergoes mass transfer and is finally transported to the seed crystal at the top of the crucible, where it crystallizes and grows downward. The seed crystal is usually pasted on the top of the crucible, and the uniformity of the pasting is difficult to guarantee. After the crystal growth is completed, the top graphite cover must be destroyed to remove the crystal, which makes the crystal removal process complicated and difficult, and increases the cost of using the crucible. Utility Model Content
[0004] The utility model aims to provide a crucible for SiC crystal growth, so as to solve the problems of poor uniformity of seed crystals pasted on the top of the crucible and difficulty in taking out the crystals after crystal growth.
[0005] To achieve this purpose, the utility model adopts the following technical solutions:
[0006] The utility model provides a crucible for SiC crystal growth, comprising a crucible body and a crucible cover, wherein the crucible cover comprises:
[0007] a first cover body, wherein the first cover body is embedded in the crucible body and seals the crucible body;
[0008] A fixed seat, wherein the fixed seat is provided with a receiving cavity, the top opening of the receiving cavity is used to place a seed crystal and connect to the first cover body, the bottom of the fixed seat is provided with a through hole connected to the receiving cavity, the seed crystal is arranged in the receiving cavity and covers the through hole, and the fixed seat is detachably connected to the first cover body so that the seed crystal can abut against the bottom end of the first cover body.
[0009] In one embodiment, the crucible cover further includes a second cover body, the second cover body is detachably connected to the first cover body, the fixing seat is detachably connected to the second cover body, and the seed crystal abuts against the second cover body.
[0010] In one embodiment, a mounting hole is provided at the bottom end of the first cover body, the second cover body is threadedly connected to the first cover body at the mounting hole, the bottom end of the second cover body protrudes from the bottom end of the first cover body, and the fixing seat is threadedly connected to the bottom end of the second cover body.
[0011] In one embodiment, the first cover body, the second cover body, the fixing seat and the crucible body are coaxially arranged, and the through hole and the crucible body are coaxially arranged.
[0012] In one embodiment, the first cover body has an axial through hole, and the second cover body has an axial matching hole connected to the axial through hole, and the axial through hole and the axial matching hole are coaxially arranged with the seed crystal.
[0013] In one of the embodiments, the SiC crystal growth crucible further comprises a rotating support, which is disposed at the bottom end of the crucible body and the two are coaxially arranged, and the rotating support is used to drive the crucible body to rotate coaxially.
[0014] In one embodiment, a plurality of the rotation supports are provided, the plurality of the rotation supports are coaxially arranged, and any two adjacent rotation supports are spaced apart in the axial direction and connected by a connecting member.
[0015] In one embodiment, the connecting member is a connecting ring, and the connecting ring is threadedly connected to any two of the rotating supports.
[0016] In one of the embodiments, a heat insulating member is provided in the axial gap between any two adjacent rotating supports.
[0017] In one embodiment, the rotation support is a hollow structure.
[0018] Beneficial effects of the utility model:
[0019] The crucible for SiC crystal growth provided by the utility model has a crucible cover as a split structure including a first cover body and a fixed seat, so that a seed crystal can be placed in a receiving cavity of the fixed seat and abut the first cover body after installation, thereby achieving installation and positioning of the seed crystal. Compared with the prior art in which the seed crystal is pasted on the crucible cover at the top of the crucible, the seed crystal has good uniformity after installation, and the fixed seat can be directly removed after crystal growth without destroying the first cover body, thereby achieving at least partial reuse of the crucible cover, saving costs, simplifying the process, and solving the problem that it is difficult to take out the crystal in the seed crystal pasting method. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a structural schematic diagram of a SiC crystal growth crucible provided in an embodiment of the utility model.
[0021] In the figure:
[0022] 100, seed crystal; 200, SiC raw material;
[0023] 1. Crucible body;
[0024] 2. Crucible cover; 21. First cover body; 211. Axial through hole; 22. Fixing seat; 221. Through hole; 23. Second cover body; 231. Axial matching hole;
[0025] 3. Rotation support; 31. Axial clearance; 32. Temperature measuring hole at the bottom;
[0026] 4. Connectors. DETAILED DESCRIPTION
[0027] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.
[0028] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0029] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.
[0030] In the description of this embodiment, the terms "upper", "lower", "right", etc., are based on the directions or positions shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.
[0031] The utility model provides a crucible for SiC crystal growth, such as Figure 1 As shown, the crucible for SiC crystal growth includes a crucible body 1 and a crucible cover 2. The crucible body 1 is used to hold SiC raw material 200. The crucible cover 2 is set on the crucible body 1 to seal the crucible body 1 and set the seed crystal 100. In the embodiment of the utility model, the crucible cover 2 includes a first cover body 21 and a fixed seat 22. The first cover body 21 is embedded and installed in the crucible body 1 and seals the crucible body 1; the fixed seat 22 is provided with a receiving cavity, the top opening of the receiving cavity is used to place the seed crystal 100 and connect the first cover body 21, and the bottom of the fixed seat 22 is provided with a through hole 221 connected to the receiving cavity. The seed crystal 100 is arranged in the receiving cavity and covers the through hole 221. The fixed seat 22 is detachably connected to the first cover body 21 so that the seed crystal 100 can abut against the bottom end of the first cover body 21.
[0032] The crucible for SiC crystal growth provided by the utility model takes a graphite crucible as an example, the crucible body 1 and the crucible cover 2 are both made of graphite, the inner cavity of the crucible body 1 is cylindrical, and the crucible cover 2 is cylindrical, and the crucible cover 2 is arranged as a split structure including a first cover body 21 and a fixed seat 22 and detachably connected, so that the seed crystal 100 can be placed in the accommodating cavity of the fixed seat 22 and abut against the first cover body 21 after installation, so as to achieve the installation and positioning of the seed crystal 100. Compared with the prior art in which the seed crystal 100 is pasted on the crucible cover 2 at the top of the crucible, the seed crystal 100 has good force uniformity after being arranged and installed by the fixed seat 22, and the fixed seat 22 can be directly removed after crystal growth without destroying the first cover body 21, so as to achieve at least partial reuse of the crucible cover 2, save costs, simplify the process, and solve the problem that the crystal is not easy to be taken out by pasting the seed crystal 100.
[0033] In one embodiment, the crucible cover 2 further includes a second cover 23 , the second cover 23 is detachably connected to the first cover 21 , the fixing seat 22 is detachably connected to the second cover 23 , and the seed crystal 100 abuts against the second cover 23 .
[0034] like Figure 1As shown, the first cover 21 is embedded in the crucible body 1 and connected to the second cover 23, and the fixing seat 22 is connected through the second cover 23 to install the seed crystal 100. Since the two ends of the second cover 23 are detachably connected to the first cover 21 and the fixing seat 22, the selective use and replacement of the second cover 23 can be realized. By setting the second cover 23, the distance between the SiC raw material 200 and the seed crystal 100 can be adjusted or adapted. The crucible body 1 does not need to be replaced in different crystal growth processes. For a crucible body 1 with a larger capacity, the distance between the seed crystal 100 and the SiC raw material 200 can be adjusted through the second cover 23 without adding more SiC raw material 200, which is conducive to saving raw material costs and simplifying the preparation process, and can effectively block heat transfer, reducing the irreversible damage of the crucible cover 2 as a whole. By setting the second cover 23, the crucible cover 2 is composed of at least three parts. After the crystal growth is completed, it is convenient to remove the graphite of the crystal growth part, further ensuring the reuse of the first cover 21, saving energy and cost.
[0035] In one embodiment, a mounting hole is provided at the bottom end of the first cover body 21, the second cover body 23 is connected to the first cover body 21 in the mounting hole, the bottom end of the second cover body 23 protrudes from the bottom end of the first cover body 21, and the fixing seat 22 is connected to the bottom end of the second cover body 23.
[0036] like Figure 1 As shown, the outer diameter of the part of the first cover 21 embedded in the crucible body 1 is equal to the inner diameter of the crucible body 1, so that the first cover 21 can be tightly embedded in the crucible body 1 to achieve sealing and fixing. The bottom end of the embedded part of the first cover 21 is provided with a mounting hole, and the mounting hole has an internal thread. The second cover 23 is cylindrical, and the upper and lower ends of the second cover 23 are respectively provided with external threads. The top of the second cover 23 is threadedly connected to the first cover 21 at the mounting hole, and the bottom end of the second cover 23 is threadedly connected to the fixing seat 22. The threaded connection method is convenient for disassembly and assembly, and it is convenient to adjust the depth of the thread screwing, so that the seed crystal 100 can abut between the bottom end of the second cover 23 and the bottom wall of the accommodating cavity of the fixing seat 22, which is conducive to ensuring the installation and positioning of the seed crystal 100. It should be noted that the inner diameter of the accommodating cavity is adapted to the outer diameter of the seed crystal 100 to avoid radial movement of the seed crystal 100 after installation. The number of second covers 23 can be arranged in sequence along the axial direction according to needs.
[0037] In one embodiment, the first cover 21 , the second cover 23 , the fixing seat 22 and the crucible body 1 are coaxially arranged, and the through hole 221 and the crucible body 1 are coaxially arranged.
[0038] It can be understood that the coaxial arrangement facilitates uniform heating of the seed crystal 100 and the SiC raw material 200, ensuring the quality of the crystal growth. The through hole 221 is coaxial with the crucible body 1, which facilitates the coaxial arrangement of the seed crystal 100 and the crucible body 1, reduces the positioning steps during the installation of the seed crystal 100, and helps reduce the difficulty of installation.
[0039] In one embodiment, the first cover body 21 has an axial through hole 211 , and the second cover body 23 has an axial matching hole 231 communicating with the axial through hole 211 . The axial through hole 211 and the axial matching hole 231 are coaxially arranged with the seed crystal 100 .
[0040] like Figure 1 As shown, the axial matching hole 231 is a blind hole, and the axial through hole 211 and the axial matching hole 231 are connected along the axial direction of the crucible body 1 to form an upper temperature measuring hole, which is convenient for detecting the temperature of the seed crystal 100 during the crystal growth process. Further, the bottom end of the upper temperature measuring hole (i.e., the bottom end of the axial matching hole 231) is set as close to the seed crystal 100 as possible.
[0041] In one embodiment, the SiC crystal growth crucible further includes a rotation support 3 , which is disposed at the bottom end of the crucible body 1 and the two are coaxially arranged, and the rotation support 3 is used to drive the crucible body 1 to rotate coaxially.
[0042] like Figure 1 As shown, the crucible body 1 is driven to rotate coaxially by the rotating support 3. On the one hand, the rotating support 3 has the effect of reducing heat transfer, which is conducive to connecting the rotating drive mechanism. On the other hand, it can avoid the problem of poor radial heating uniformity of the crucible body 1 and uneven crystal growth quality caused by coaxiality differences. Preferably, the rotating support 3 is made of graphite.
[0043] In one embodiment, a plurality of rotating supports 3 are provided, and the plurality of rotating supports 3 are coaxially arranged, and any two adjacent rotating supports 3 are spaced apart in the axial direction and connected through a connecting member 4 .
[0044] like Figure 1 As shown, taking the arrangement of three rotating supports 3 as an example, the three rotating supports 3 are coaxially and spaced apart in the axial direction below the crucible body 1, and the connecting member 4 is used to connect and transmit torque. By arranging the three rotating supports 3 at intervals, the heat transfer between the three rotating supports 3 can be reduced, and the three rotating supports 3 are connected by the connecting member 4. When any rotating support 3 is damaged, it can be replaced and adjusted separately, which reduces the overall irreversible damage of the rotating support 3, has a high reuse rate, and is conducive to saving material costs.
[0045] In one embodiment, the connecting member 4 is a connecting ring, which is threadedly connected to any two rotating supports 3 .
[0046] like Figure 1 The two ends of the connecting ring are respectively threadedly connected to the two rotating supports 3. The connecting ring adopts metal heat insulation material. The threaded connection method can adjust the spacing distance between the two rotating supports 3, and the coaxiality is high. The connecting ring is a ring structure with a small heat conduction area, which is conducive to reducing or blocking heat transfer.
[0047] In one embodiment, a heat insulating member is provided in the axial gap 31 between any two adjacent rotating supports 3. The heat insulating member can be a metal or non-metal material that has a heat insulating effect, can be a heat insulating pad, or a heat insulating device or heat insulating structure, which is used to isolate the heat transfer between two adjacent rotating supports 3. Generally, the heat insulating member is clamped between the two rotating supports 3, and the two rotating supports 3 adjust the force of clamping the heat insulating member by screwing the depth of the threads with the connecting member 4. The connecting member 4 can be arranged inside the heat insulating member, or outside the heat insulating pad. Figure 1 In the structure shown, the connecting member 4 is located inside the thermal insulation pad.
[0048] In one embodiment, the rotating support 3 is a hollow structure. A plurality of rotating supports 3 are coaxially arranged, and the rotating supports 3 with hollow structures are sequentially connected to the bottom end of the crucible body 1 and are formed with a lower temperature measuring hole 32, which is conducive to detecting the temperature of the crucible body 1, so as to monitor the temperature change of the SiC raw material 200 during the crystal growth process.
[0049] Using the SiC crystal growth crucible provided in the embodiment of the utility model, one of the SiC crystal growth experimental steps is as follows:
[0050] The crucible cover 2 adopts a split assembly structure. First, the second cover 23 is rotated into the bottom mounting hole of the first cover 21, the seed crystal 100 is placed in the accommodating cavity of the fixing seat 22 and positioned at the bottom through hole 221, the fixing seat 22 is rotated and installed on the bottom end of the second cover 23, and the seed crystal 100 is locked on the second cover 23 by the fixing seat 22, and the upward surface of the seed crystal 100 is in close contact with the bottom end of the second cover 23. The upper temperature measuring hole passes through the first cover 21 and goes deep into the second cover 23.
[0051] A split assembly structure is adopted for the rotating support 3, in which three rotating supports 3 are connected together by two metal connecting rings, so that a certain gap is left between adjacent rotating supports 3 for installing heat insulation parts, thereby reducing heat transfer. The rotating support 3 and the metal connecting ring are both hollow, and a plurality of hollow parts are connected to form a temperature measuring hole 32 below after the rotating support 3 and the metal connecting ring are connected.
[0052] During crystal growth, SiC raw material 200 is loaded into crucible body 1, and crucible cover 2 is embedded and installed in the top opening of crucible body 1 to seal crucible body 1. The temperature of SiC raw material 200 during crystal growth can be measured through the lower temperature measuring hole, and the temperature of seed crystal 100 during crystal growth can be measured through the upper temperature measuring hole.
[0053] After the crystal growth is completed, it is only necessary to remove the corresponding graphite material of the crystal growth part, that is, remove the second cover body 23, and then remove the fixing seat 22 to achieve crystal retrieval. The first cover body 21 is kept intact. Without completely destroying the crucible cover 2, crystal retrieval and at least part of the crucible cover 2 can be recycled and used multiple times, thereby reducing the cost of crystal retrieval.
[0054] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the scope of protection of the present invention. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the claims of the present invention.
Claims
1. A crucible for SiC crystal growth, comprising a crucible body (1) and a crucible cover (2), characterized in that: The crucible cover (2) comprises: A first cover (21), wherein the first cover (21) is embedded in the crucible body (1) and seals the crucible body (1); A fixing seat (22), wherein the fixing seat (22) is provided with a receiving cavity, the top opening of the receiving cavity is used to place the seed crystal (100) and connect to the first cover body (21), the bottom of the fixing seat (22) is provided with a through hole (221) connected to the receiving cavity, the seed crystal (100) is arranged in the receiving cavity and covers the through hole (221), and the fixing seat (22) is detachably connected to the first cover body (21) so that the seed crystal (100) can abut against the bottom end of the first cover body (21).
2. The SiC crystal growth crucible according to claim 1, characterized in that: The crucible cover (2) further comprises a second cover body (23), wherein the second cover body (23) is detachably connected to the first cover body (21), the fixing seat (22) is detachably connected to the second cover body (23), and the seed crystal (100) abuts against the second cover body (23).
3. The SiC crystal growth crucible according to claim 2, characterized in that: A mounting hole is provided at the bottom end of the first cover body (21); the second cover body (23) is threadedly connected to the first cover body (21) at the mounting hole; the bottom end of the second cover body (23) protrudes from the bottom end of the first cover body (21); and the fixing seat (22) is threadedly connected to the bottom end of the second cover body (23).
4. The SiC crystal growth crucible according to claim 3, characterized in that: The first cover body (21), the second cover body (23), the fixing seat (22) and the crucible body (1) are coaxially arranged, and the through hole (221) and the crucible body (1) are coaxially arranged.
5. The SiC crystal growth crucible according to claim 2, characterized in that: The first cover body (21) has an axial through hole (211), and the second cover body (23) has an axial matching hole (231) connected to the axial through hole (211), and the axial through hole (211) and the axial matching hole (231) are coaxially arranged with the seed crystal (100).
6. The SiC crystal growth crucible according to any one of claims 1 to 5, characterized in that: The SiC crystal growth crucible further comprises a rotating support (3), wherein the rotating support (3) is arranged at the bottom end of the crucible body (1) and the two are coaxially arranged, and the rotating support (3) is used to drive the crucible body (1) to rotate coaxially.
7. The SiC crystal growth crucible according to claim 6, characterized in that: A plurality of the rotating supports (3) are provided, and the plurality of the rotating supports (3) are coaxially arranged, and any two adjacent rotating supports (3) are spaced apart in the axial direction and connected via a connecting member (4).
8. The SiC crystal growth crucible according to claim 7, characterized in that: The connecting member (4) is a connecting ring, and the connecting ring is respectively threadedly connected to any two of the rotating supports (3).
9. The SiC crystal growth crucible according to claim 8, characterized in that: A heat insulating member is provided in the axial gap (31) between any two adjacent rotating supports (3).
10. The SiC crystal growth crucible according to claim 9, characterized in that: The rotating support (3) is a hollow structure.