Crucible device for silicon carbide single crystal growth
By using porous graphite structures and crystal stabilizers in silicon carbide single crystal growth apparatus, the problems of impurity inclusions and non-uniform crystal forms in silicon carbide single crystals were solved, and the growth of high-quality silicon carbide single crystals was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SU ZHOU QING YAN BAN DAO TI KE JI YOU XIAN GONG SI
- Filing Date
- 2025-06-23
- Publication Date
- 2026-05-26
AI Technical Summary
In the current silicon carbide single crystal growth process, impurity particles and carbon inclusions are easily formed inside the single crystal, resulting in a non-uniform crystal structure, which affects the quality of the single crystal and the efficiency of industrial production.
A crucible device for silicon carbide single crystal growth is adopted, including a crucible body, a crucible lid, a porous graphite plate and a porous graphite cylinder. By combining a small graphite crucible and a crystal form stabilizer, the porous structure filters impurity gases and controls the crystal form, thereby reducing the formation of carbon inclusions.
It effectively reduces impurity particles, inclusions, and carbon inclusions in silicon carbide single crystals, ensuring a single crystal form, reducing microtube and dislocation defects, and improving single crystal quality and growth rate.
Smart Images
Figure CN224280550U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of silicon carbide single crystal growth technology, and in particular to a crucible device for silicon carbide single crystal growth. Background Technology
[0002] Silicon carbide (SiC) single crystals, as a typical representative of third-generation wide-bandgap semiconductor materials, stand out due to their unique physical properties. The main methods for preparing SiC single crystals include Physical Vapor Transport (PVT), High-Temperature Chemical Vapor Deposition (HTCVD), and Liquid Phase Method; among these, PVT is currently the mainstream method for growing SiC single crystals. Specifically, PVT involves first bonding a SiC seed crystal to a graphite crucible lid, and then filling the graphite crucible with SiC powder as the growth material. The crucible is then placed in a specific heating furnace for heating, with the seed crystal temperature controlled between 2100℃ and 2200℃. The SiC powder sublimates and decomposes upon heating, forming gaseous components. These gaseous components are transported to the seed crystal under the driving force of the axial temperature gradient inside the graphite crucible, where they crystallize and grow into a SiC single crystal. However, due to the unavoidable presence of various impurities in SiC powder, these impurities sublimate along with the SiC powder at high temperatures, forming impurity particle inclusions on the growth surface of the silicon carbide seed crystal and inside the single crystal, leading to defects such as microtubes and dislocations. Simultaneously, in the middle and later stages of crystal growth, the gas escaping from the silicon carbide powder is primarily silicon-rich gas. This silicon-rich gas reacts with the graphite crucible, causing the surface of the graphite crucible to become powdery. At this time, solid carbon particles in the SiC powder also continuously accumulate. Both the powdery carbon particles on the graphite crucible surface and the carbon particles accumulated in the SiC powder rise with the gas flow and adhere to the silicon carbide seed crystal, forming carbon inclusions on the growth surface of the silicon carbide single crystal. This further induces defects such as microtubes and dislocations, significantly affecting the performance of single-crystal devices and the yield of large-scale single-crystal production.
[0003] Existing technologies typically employ methods such as supplementing the silicon atmosphere during crystal growth to reduce carbon inclusion formation and thus improve the quality of silicon carbide single crystals. For example, silicon powder is added to the raw materials to increase the silicon-to-carbon ratio, thereby reducing carbon particle aggregation and inhibiting carbon inclusion formation. However, these methods cannot flexibly control the silicon sublimation time and the amount of silicon added, ultimately resulting in only a minor improvement in the quality of silicon carbide single crystals, which is detrimental to industrial production. Furthermore, the crystal structure of silicon carbide single crystals grown using these methods is also difficult to control.
[0004] This invention provides a crucible device for growing silicon carbide single crystals, which solves the problems in the prior art where impurity particles, carbon inclusions, and non-uniform crystal forms easily form inside the single crystal when growing silicon carbide single crystals using existing crucible devices. Summary of the Invention
[0005] The object of the present utility model is to provide a crucible device for growing silicon carbide single crystals, so as to solve the problems existing in the prior art that when growing silicon carbide single crystals using the existing crucible device, impurity particle inclusions and carbon inclusions are easily formed inside the single crystal, and the crystal form is not single, etc.
[0006] The technical solution of the present utility model is: a crucible device for growing silicon carbide single crystals, including a crucible body, a crucible cover buckled on the crucible body, a porous graphite plate and a porous graphite cylinder arranged inside the crucible body, and a heating component arranged on the peripheral side of the crucible body;
[0007] A seed crystal is fixedly arranged on the inner side surface of the crucible cover;
[0008] The porous graphite cylinder is coaxially arranged with the crucible body, and the bottom of the porous graphite cylinder abuts against the bottom wall of the crucible body; a partition component is arranged at the upper end of the porous graphite cylinder; a filling cavity for accommodating silicon carbide powder is formed between the outer side surface of the porous graphite cylinder, the inner wall of the crucible body and the lower end of the partition component;
[0009] The porous graphite plate is placed above the porous graphite cylinder;
[0010] A small graphite crucible is further arranged inside the crucible body;
[0011] The small graphite crucible is placed inside the porous graphite cylinder, and a crystal form stabilizer is accommodated inside the small graphite crucible.
[0012] Preferably, the crucible body is designed in a "convex" shape with a wide bottom and a narrow top;
[0013] The height of the porous graphite cylinder is not less than the internal height of the bottom of the crucible body; the outer diameter of the porous graphite cylinder is the same as the maximum inner diameter of the upper part of the crucible body;
[0014] The maximum diameter of the porous graphite plate is not less than the inner diameter of the porous graphite cylinder.
[0015] Preferably, the thickness of the porous graphite cylinder is 3 mm to 10 mm, the inner diameter is 60 mm to 150 mm, and the height is 100 mm to 200 mm;
[0016] The porosity of both the porous graphite cylinder and the porous graphite plate is 50% to 70%;
[0017] The thickness of the crucible body and the crucible cover is 5 to 20 mm.
[0018] Preferably, the heating element is a graphite heating cylinder; the graphite heating cylinder is coaxially arranged with the crucible body; the thickness of the graphite heating cylinder is 5-20 mm.
[0019] Preferably, a graphite hard felt is further disposed between the crucible body and the heating component.
[0020] Preferably, the graphite hard felt is disposed on the periphery of the upper part of the crucible body.
[0021] Compared with the prior art, the advantages of this utility model are:
[0022] (1) The present invention provides a crucible device for growing silicon carbide single crystals. The crucible device sets up a small graphite crucible and contains a crystal stabilizer. It also combines a porous graphite cylinder and a porous graphite plate to filter the gas components generated by sublimation. This can effectively reduce the formation of impurity particles and carbon inclusions in the silicon carbide single crystal during the growth process, while inhibiting crystal transformation, and ensuring the growth of silicon carbide ingots with a single crystal form. This effectively reduces defects such as microtubes and dislocations caused by carbon inclusions in the silicon carbide single crystal, and improves the quality of the silicon carbide single crystal. Through the special design of the crucible body structure, the growth rate of silicon carbide single crystals can also be effectively improved. This solves the problems in the prior art where impurity particles and carbon inclusions are easily formed inside the single crystal when using the existing crucible device to grow silicon carbide single crystals, resulting in a non-single crystal form. Attached Figure Description
[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments:
[0024] Figure 1 This is a schematic diagram of the crucible device described in Embodiment 1 of this utility model;
[0025] Figure 2 This is a schematic diagram of the crucible device described in Embodiment 2 of this utility model;
[0026] Figure 3 This is a schematic diagram of the crucible device described in Embodiment 3 of this utility model;
[0027] Figure 4 This is an image of the silicon carbide ingot described in Embodiment 3 of this utility model;
[0028] The components include: 1. Crucible body; 2. Crucible lid; 3. Porous graphite cylinder; 4. Porous graphite plate; 5. Silicon carbide powder; 6. Small graphite crucible; 7. Heating element; 8. Graphite hard felt; 9. Seed crystal; 10. Partition assembly. Detailed Implementation
[0029] The present invention will be further described in detail below with reference to specific embodiments:
[0030] Implementation Method 1
[0031] A commonly used crucible device for silicon carbide single crystal growth in the prior art, such as Figure 1 As shown, the crucible device includes a crucible body 1 and a crucible lid 2 fastened to the crucible body 1; a heating element 7 is arranged around the periphery of the crucible body 1; wherein, the heating element 7 is a graphite heating cylinder, and the thickness of the graphite heating cylinder is 10mm; a seed crystal 9 is fixedly arranged inside the crucible lid 2; a porous graphite cylinder 3, a porous graphite plate 4, and a partition assembly 10 are arranged inside the crucible body 1; and the porous graphite cylinder 3 is coaxially arranged with the crucible body 1, and is porous The bottom of the graphite cylinder 3 abuts against the bottom wall of the crucible body 1; the partition assembly 10 is disposed at the upper end of the porous graphite cylinder 3, and the outer side of the partition assembly 10 abuts against the inner wall of the crucible body 1; thus, a filling cavity for accommodating silicon carbide powder 5 is formed between the outer side of the porous graphite cylinder 3, the inner wall of the crucible body 1, and the lower end of the partition assembly 10; the porous graphite plate 4 is placed above the porous graphite cylinder 3, and the inner sidewall of the porous graphite plate 4 abuts against the inner sidewall of the partition assembly 10. The function of the partition assembly 10 is to limit the flow path of the gaseous components formed by the sublimation of silicon carbide powder 5, that is, the gaseous components formed by the sublimation of silicon carbide powder 5 can only first pass through the porous graphite cylinder 3 for filtration into the interior of the porous graphite cylinder 3, and then undergo a second filtration through the porous graphite plate 4, and then flow to the silicon carbide seed crystal 9.
[0032] In this embodiment, the porous graphite cylinder 3, the porous graphite plate 4, and the partition assembly 10 are all coated with tantalum carbide coatings on their surfaces and in their pores. The porous graphite cylinder 3 has a height of 150 mm, an inner diameter of 85 mm, and an outer diameter of 95 mm. The porous graphite plate 4 has a thickness of 5 mm and a diameter of 90 mm. The porosity of both the porous graphite cylinder 3 and the porous graphite plate 4 is set to 50%. In other embodiments, the porous graphite cylinder 3, the porous graphite plate 4, and the partition assembly 10 are coated with rare metal carbide or nitride coatings on their surfaces and in their pores. The rare metal is one or more of tantalum, titanium, niobium, hafnium, tungsten, zirconium, and vanadium. The heating element 7 can also be selected from other components that can meet the heating requirements. In other embodiments, the thickness of the porous graphite cylinder 3 needs to be controlled within the range of 3mm to 10mm, the inner diameter needs to be controlled within the range of 60mm to 150mm, and the height needs to be controlled within the range of 100mm to 200mm; the porosity of both the porous graphite cylinder 3 and the porous graphite plate 4 is 50% to 70%; the thickness of the crucible body 1 and the crucible cover 2 needs to be controlled within the range of 5 to 20mm; and the thickness of the graphite heating cylinder is 5 to 20mm.
[0033] Silicon carbide single crystals were grown using the above-mentioned crucible apparatus. After 150 hours of growth, a silicon carbide ingot with a thickness of 20.1 mm was obtained. The silicon carbide ingot was then sliced to obtain a silicon carbide substrate with a small number of radial inclusion defects.
[0034] Implementation Method 2
[0035] The difference between this implementation method and implementation method one is that: Figure 2 As shown, a small graphite crucible 6 is also provided inside the crucible body 1; the small graphite crucible 6 is placed inside the porous graphite cylinder 3, and the interior of the small graphite crucible 6 contains a crystal form stabilizer. The crystal form stabilizer is cerium silicide; however, in other embodiments, the crystal form stabilizer can also be other reagents such as cerium oxide that can stabilize the crystal form.
[0036] Using the above-mentioned crucible apparatus, silicon carbide single crystals were grown. After 150 hours of growth, a silicon carbide ingot with a thickness of 20.5 mm and very few inclusion defects was obtained.
[0037] Implementation Method 3
[0038] A crucible apparatus for silicon carbide single crystal growth, such as Figure 3 As shown, the crucible device includes a crucible body 1, a crucible cover 2 fastened to the crucible body 1, a heating element 7 disposed around the crucible body 1, and a seed crystal 9 fixedly disposed inside the crucible cover 2. The crucible body 1 is designed in a "convex" shape, wider at the bottom and narrower at the top. The connecting plate connecting the bottom and top of the crucible body 1 acts as a partition assembly 10, meaning the top cover plate at the bottom of the crucible body 1 acts as a partition assembly 10. At this time, the porous graphite cylinder 3 and the crucible body... The porous graphite cylinder 3 is coaxially arranged, with its bottom abutting against the bottom wall of the crucible body 1, and its height equal to the height of the bottom of the crucible body 1. The outer diameter of the porous graphite cylinder 3 is the same as the maximum inner diameter of the upper part of the crucible body 1. A filling cavity for accommodating silicon carbide powder 5 is formed between the outer side of the porous graphite cylinder 3 and the bottom of the crucible body 1. A porous graphite plate 4 is placed above the porous graphite cylinder 3, and the maximum diameter of the porous graphite plate 4 is equal to the outer diameter of the porous graphite cylinder 3. In other embodiments, the height of the porous graphite cylinder 3 should not be lower than the internal height of the bottom of the crucible body 1; the outer diameter of the porous graphite cylinder 3 should be the same as the maximum inner diameter of the upper part of the crucible body 1; and the maximum diameter of the porous graphite plate 4 should not be less than the inner diameter of the porous graphite cylinder 3.
[0039] The heating element 7 is a graphite heating cylinder, which is coaxially arranged with the crucible body 1. A graphite hard felt 8 is also disposed between the crucible body 1 and the graphite heating cylinder; furthermore, the graphite hard felt 8 is disposed on the upper periphery of the crucible body 1. A small graphite crucible 6 is also disposed inside the crucible body 1; the small graphite crucible 6 is placed inside a porous graphite cylinder 3, and the interior of the small graphite crucible 6 contains a crystal stabilizer. In other embodiments, the size of the graphite hard felt 8 is adjustable; that is, the graphite hard felt 8 can also be disposed on the upper part of the crucible body 1 and extend from the upper part of the crucible body 1 to a certain height at the bottom of the crucible body 1; by changing the size of the graphite hard felt, the morphology of the silicon carbide ingot can be adjusted, thereby improving the crystal quality.
[0040] Silicon carbide single crystal growth was performed using the above-mentioned crucible apparatus. After 150 hours of crystal growth, as follows... Figure 4 As shown, a silicon carbide ingot with a thickness of 23.3 mm and no inclusion defects was obtained.
[0041] Compared to Embodiment 1, the crucible device provided in Embodiment 2 adds a small graphite crucible inside the crucible body, and places a crystal stabilizer inside the small graphite crucible. During the heating process, the gaseous components of the crystal stabilizer decompose and sublimate, and the gaseous components formed by the thermal sublimation of silicon carbide powder and filtered through a porous graphite cylinder, mix in the porous graphite cylinder, and then flow to the seed crystal after passing through a second filter of a porous graphite plate. By using two filtration stages to better remove particulate impurities, especially carbon particulate impurities in the gaseous components, and combined with the crystal stabilizer, it is possible to grow a single-crystal silicon carbide ingot while reducing carbon inclusions in the silicon carbide single crystal; significantly reducing defects such as microtubes and dislocations caused by carbon inclusions in the silicon carbide single crystal, and improving the quality of the grown silicon carbide single crystal. Comparing Embodiment 2 with Embodiment 3, it can be seen that designing the crucible body into a "convex" shape with a narrow upper part and a wide lower part can play a role in guiding the flow of gas components to the seed crystal more smoothly, thereby improving the growth rate of silicon carbide single crystal.
[0042] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. It is obvious to those skilled in the art that this utility model is not limited to the details of the above exemplary embodiments, and that it can be implemented in other specific forms without departing from the spirit or basic characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description, and therefore, all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within this utility model.
Claims
1. A crucible device for growing silicon carbide single crystals, comprising a crucible body (1), a crucible lid (2) buckled on the crucible body (1), a porous graphite plate (4) and a porous graphite cylinder (3) arranged inside the crucible body (1), and a heating component (7) arranged on the peripheral side of the crucible body (1); A seed crystal (9) is fixedly arranged on the inner side surface of the crucible lid (2); The porous graphite cylinder (3) is coaxially arranged with the crucible body (1), and the bottom of the porous graphite cylinder (3) abuts against the bottom wall of the crucible body (1); a partition component (10) is arranged at the upper end of the porous graphite cylinder (3); a filling cavity for accommodating silicon carbide powder (5) is formed between the outer side surface of the porous graphite cylinder (3), the inner wall of the crucible body (1) and the lower end of the partition component (10); The porous graphite plate (4) is placed above the porous graphite cylinder (3); characterized in that A small graphite crucible (6) is further arranged inside the crucible body (1); The small graphite crucible (6) is placed inside the porous graphite cylinder (3), and a crystal form stabilizer is accommodated inside the small graphite crucible (6); 2. The apparatus according to claim 1, wherein: The crucible body (1) is designed in a "convex" shape with a wide bottom and a narrow top; The height of the porous graphite cylinder (3) is not less than the internal height of the bottom of the crucible body (1); the outer diameter of the porous graphite cylinder (3) is the same as the maximum inner diameter of the upper part of the crucible body (1); The maximum diameter of the porous graphite plate (4) is not less than the inner diameter of the porous graphite cylinder (3); 3. The apparatus according to claim 2, wherein: The thickness of the porous graphite cylinder (3) is 3 mm to 10 mm, the inner diameter is 60 mm to 150 mm, and the height is 100 mm to 200 mm; The porosity of both the porous graphite cylinder (3) and the porous graphite plate (4) is 50% to 70%; The thickness of the crucible body (1) and the crucible lid (2) is 5 to 20 mm; 4. The crucible apparatus for silicon carbide single crystal growth according to claim 2, characterized in that: The heating component (7) is a graphite heating cylinder; the graphite heating cylinder is coaxially arranged with the crucible body (1); the thickness of the graphite heating cylinder is 5 to 20 mm; 5. The crucible apparatus for silicon carbide single crystal growth according to claim 2, characterized in that: A graphite hard felt (8) is further arranged between the crucible body (1) and the heating component (7); 6. The crucible apparatus for silicon carbide single crystal growth according to claim 5, characterized in that: The graphite hard felt (8) is arranged on the peripheral side of the upper part of the crucible body (1).