Porous partition plate and silicon carbide crystal growth device
By coating a porous separator plate with a carbide coating and combining it with a ring design, the problem of easy corrosion of porous carbon materials at high temperatures was solved, achieving high-quality growth and uniformity of silicon carbide crystals and reducing production costs.
Patent Information
- Application Number
- CN202422629124.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-29
- Publication Date
- 2025-11-25
- Estimated Expiration
- 2034-10-29
AI Technical Summary
In the prior art, porous carbon materials are easily corroded by Si during the growth of silicon carbide single crystals, leading to failure. Furthermore, the pore size distribution is uneven, resulting in high production costs and making it difficult to achieve uniform carbide coating growth under high-temperature conditions.
A porous partition plate is used, with through holes on the main body and coated with a carbide coating, such as tantalum carbide coating. Combined with the design of annular grooves and bosses, a sealed atmosphere is formed to block carbon impurities and reduce the rise of carbon particles. A porous graphite plate is used as the substrate to ensure uniform distribution of gaseous substances.
It improves the crystal quality and lattice purity of silicon carbide crystals, reduces surface and grain boundary defects, extends the service life of porous materials, reduces production costs, and ensures the uniformity and stability of the growth process.
Smart Images
Figure CN223592882U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of silicon carbide crystal growth technology, and in particular to a porous separator plate and a silicon carbide crystal growth device. Background Technology
[0002] The growth of silicon carbide single crystals is relatively difficult, and physical vapor deposition (PVD) is currently the most common method. The growth process typically involves placing silicon carbide powder at the bottom of a crucible and fixing a silicon carbide seed crystal at the top. A porous carbon material containing graphite is placed inside the crucible to separate the silicon carbide powder and the seed crystal. During crystal growth, the silicon carbide powder is heated to a certain temperature and sublimates, forming a gaseous phase. This sublimated gaseous phase passes through the porous carbon material and is transported to the surface of the seed crystal for deposition and crystal growth. By using the porous carbon material to separate the silicon carbide powder and the seed crystal, the pore structure of the porous carbon material can effectively regulate the growth rate of the silicon carbide crystal, reduce surface and grain boundary defects, and improve crystal quality and lattice purity.
[0003] Currently, the pore size of porous carbon materials is typically 20-100 μm, resulting in high manufacturing costs, significant technical challenges, and uneven pore size distribution. Furthermore, in the high-temperature environment of PVT-grown SiC single crystals, under ultra-high temperatures of 2200-2400 degrees Celsius and a corrosive Si atmosphere, carbon materials are corroded by Si, leading to failure. Therefore, an ideal solution is to uniformly form a carbide protective layer, such as a tantalum carbide coating, on the surface of porous carbon materials. However, achieving a uniform coating of a certain thickness within the extremely fine and tortuous pore size of 20-100 μm without clogging the micropores presents significant technical difficulties and very high manufacturing costs. Utility Model Content
[0004] This invention provides a porous separator plate and a silicon carbide crystal growth device, which solves the problem that in the existing technology, the carbon material is corroded by Si and damaged in the high-temperature environment of PVT growth of SiC single crystals at ultra-high temperature of 2200-2400 degrees Celsius and corrosive Si atmosphere, leading to failure.
[0005] This utility model provides the following technical solution:
[0006] On one hand, this application provides a porous partition plate, including a main body with through holes and a carbide coating on the outside of the main body.
[0007] In one possible implementation, the carbide coating is one of tantalum carbide coating, zirconium carbide coating, tungsten carbide coating, niobium carbide coating, and hafnium carbide coating.
[0008] In one possible implementation, an annular groove is provided on the upper side of the main board body, and an annular boss is provided on the lower side of the main board body, so that a sealed atmosphere is formed after the multi-hole partition plates are assembled, and when multiple multi-hole partition plates are provided, a gap is left between the main boards.
[0009] In one possible implementation, the depth of the annular groove is greater than the protrusion length of the annular boss, so that a gap is left between the main body panels.
[0010] In one possible implementation, the through holes are evenly spaced and have a consistent diameter.
[0011] In one possible implementation, the through holes are evenly spaced and the diameter of the holes gradually increases from the outside to the inside.
[0012] In one possible implementation, the motherboard body has a thickness of 4-10 mm, a hole diameter of 1-3 mm, and a hole spacing of 1-2 mm.
[0013] In one possible implementation, the main body is a porous graphite plate.
[0014] On the other hand, this application provides a silicon carbide crystal growth apparatus, including a graphite crucible, a furnace cavity formed inside the graphite crucible, an annular step formed in the middle of the furnace cavity, a plurality of porous partition plates mounted on the annular step, and the through holes of adjacent porous partition plates being staggered, and a furnace cover installed on the top of the graphite crucible.
[0015] In one possible implementation, a flow guide sleeve is installed between the furnace cover and the porous partition plate.
[0016] It should be understood that a porous graphite plate is used as a substrate to form a circular substrate. A downward-facing annular groove is set near the edge of the substrate. The peripheral wall of the annular groove protrudes downward from the plate to form a sealed atmosphere with the peripheral wall of the crucible on the lower side. Three supporting protrusions are set in the annular groove, so that a gap is formed between the upper and lower main plates. The annular groove of the upper main plate extends into the annular groove of the lower main plate to form a sealed atmosphere between the two main plates. During the rising of the gas phase material, it plays a role in blocking carbon impurities, reducing the number of carbon particles rising to the single crystal growth area, and reducing defects formed in the product.
[0017] In this application, the amount of carbon particle impurities rising can be reduced by controlling the airflow, thereby improving the crystal quality, making the temperature uniformity of the raw material zone better, maintaining the uniformity of the airflow rate during the growth process, improving the crystal shape, and avoiding polycrystalline formation at the outer edge of the crystal. Attached Figure Description
[0018] Figure 1This is a schematic diagram of the structure of a silicon carbide crystal growth apparatus provided in an embodiment of the present invention;
[0019] Figure 2 A partial structural diagram of a porous partition plate with vertical through holes provided in an embodiment of this utility model;
[0020] Figure 3 A partial structural diagram of a porous partition plate provided in an embodiment of the present invention, showing the through holes tilted towards the edge;
[0021] Figure 4 This is a partial structural diagram of a porous partition plate provided in an embodiment of the present invention, showing the through holes tilted towards the axis.
[0022] Figure 5 One of the schematic diagrams showing different orientations of the through holes on the upper and lower main bodies of a porous partition plate according to an embodiment of this utility model;
[0023] Figure 6 This is a schematic diagram of the layer structure of a porous partition plate provided in an embodiment of the present invention.
[0024] Figure label:
[0025] 1. Furnace lid; 2. Flow guide sleeve; 3. Graphite crucible; 4. Main body; 5. Annular groove; 6. Annular boss; 7. Through hole; 8. Carbide coating. Detailed Implementation
[0026] The embodiments of the present invention will now be described with reference to the accompanying drawings.
[0027] In existing silicon carbide single crystal growth devices, porous partition plates are generally installed. The porous structure can effectively regulate the growth rate of silicon carbide crystals, reduce the amount of carbon particle impurities rising, thereby reducing surface defects and grain boundary defects of silicon carbide crystals, improving crystal quality and lattice purity, and porous graphite plates are generally used. However, in actual use, under ultra-high temperature of 2200-2400 degrees and corrosive Si atmosphere, carbon materials will be corroded by Si and damaged, leading to failure.
[0028] like Figure 1 , Figure 6 As shown, this application provides a porous separator plate, in which through holes 7 are formed on the main body 4 to allow gaseous substances to pass through, block carbon impurities, reduce the number of carbon particles rising to the single crystal growth area, and further, a carbide coating 8 is grown on its entire surface. The plate has a simple shape, simple production technology, low production cost, and is easy to make coatings, which can extend the service life of porous carbon materials and reduce defects formed in the product.
[0029] Specifically, this application provides a porous partition plate, including a main body 4. The main body 4 has through holes 7. The cross-sectional shape of the through holes 7 is not limited and can be one or more combinations of round, square, and triangular holes. In this application, the through holes 7 are round. A carbide coating 8 is applied to the outside of the main body 4. The outer surface of the main body 4 includes the upper and lower surfaces, side surfaces, and the inner surface of the through holes 7. The carbide coating 8 can be fabricated using methods such as chemical vapor deposition, slurry impregnation, or molten salt deposition. After the main body 4 is installed into the crucible cavity, it divides the crucible cavity into upper and lower parts. Silicon carbide powder is placed in the lower part of the crucible cavity. When the silicon carbide powder is heated to 2100 degrees Celsius, it begins to sublimate, forming a gaseous substance. These sublimated gaseous substances pass through the main body 4. Carbon impurities formed in the raw materials during long-term operation are blocked at the bottom by the main body 4, reducing the number of carbon particles rising to the single crystal growth area. The growth rate of silicon carbide crystals can be adjusted by the size and distribution of the through holes 7 in the main body 4, reducing surface defects and grain boundary defects of silicon carbide crystals, reducing the amount of carbon particle impurities rising, and improving crystal quality and lattice purity. By setting the carbide coating 8, the carbon material of the main body 4 can be prevented from directly contacting corrosive Si, thereby preventing the carbon material from being corroded by Si and causing damage and failure.
[0030] Furthermore, the carbide coating 8 is one of tantalum carbide coating, zirconium carbide coating, tungsten carbide coating, niobium carbide coating, and hafnium carbide coating. Specifically, it can be prepared on the surface of the substrate by methods such as chemical vapor deposition (CVD) and physical vapor deposition (PVD) to improve the performance and service life of the substrate. Moreover, the above coatings have corrosion resistance, chemical stability, and high temperature stability. In a corrosive Si atmosphere, the tantalum carbide coating can effectively prevent the substrate from being corroded and protect the integrity and performance of the substrate.
[0031] Specifically, the methods for producing carbide coating 8 include: chemical vapor deposition, slurry impregnation, molten salt method, etc.
[0032] Furthermore, an annular groove 5 is formed on the main body 4, and the annular groove 5 is arranged near the edge of the main body 4. The lower side of the main body 4 protrudes to form an annular boss 6 in accordance with the annular groove 5. When the main body 4 is placed in the crucible cavity, the annular boss 6 fits against the lower inner wall of the crucible cavity to ensure stable assembly of the main body 4 and to provide a certain sealing atmosphere. When multiple main bodies 4 are stacked, the annular boss 6 below the lowermost main body 4 fits against the lower inner wall of the crucible cavity, while the annular boss 6 below the uppermost main body 4 extends into... In the annular groove 5 of the lower main board body 4, since the depth of the annular groove 5 is greater than the extension length of the annular boss 6, a gap will be left between the upper main board body 4 and the lower main board body 4. The annular boss 6 of the upper main board body 4 extends into the annular groove 5 of the lower main board body 4 to form a sealed atmosphere, so that when the gaseous substance moves upward, it needs to pass through the through hole 7 of the main board body 4, so that a sealed atmosphere is formed after the porous partition plate is assembled. When multiple porous partition plates are set, a gap is left between the main board bodies 4 of different porous partition plates.
[0033] Specifically, such as Figure 2-5 As shown, in this application, two porous partition plates are stacked. The annular protrusion 6 of the lower main board body 4 extends 4mm out of the main board body, and the annular groove 5 of the lower main board body 4 is 2mm deep and 6mm wide. The annular protrusion 6 of the upper main board body 4 extends 4mm out of the main board body and is 6mm wide. The annular groove 5 and annular protrusion 6 of the lower main board body and the annular groove 5 and annular protrusion 6 of the upper main board body are axially aligned, so that the annular protrusion 6 of the upper main board body 4 can extend into the annular groove 5 of the lower main board body 4. The annular protrusion 6 of the upper main board body 4 and the annular groove 5 of the lower main board body 4 fit together to form a certain sealing atmosphere. A 2mm gap is left between the lower side surface of the upper main board body 4 and the upper side surface of the lower main board body 4.
[0034] Furthermore, the through holes 7 are evenly spaced and have a consistent diameter, which can maintain the stability of growth conditions in the standard silicon carbide crystal growth process, ensure that the crystal grows at the predetermined rate and morphology, and ensure that the raw material gas is evenly distributed throughout the growth area. This helps to reduce the concentration gradient and temperature gradient during the growth process, thereby improving the uniformity and quality of the crystal.
[0035] Furthermore, the through holes 7 are evenly spaced and the diameter of the holes gradually increases from the outside to the inside. When it is necessary to optimize the material concentration distribution at the silicon carbide crystal growth interface, the flow rate and distribution of the raw material gas can be adjusted by changing the diameter of the through holes 7, thereby affecting the material transport and reaction process at the growth interface.
[0036] Furthermore, such as Figure 2 As shown, the through holes 7 can be set vertically. When multiple layers of porous partition plates are stacked, the positions of the through holes 7 in different layers are staggered, as shown in the figure. Figure 3-4As shown, it can also be set at a 45° angle toward the center or toward the edge, such as... Figure 5 As shown, when setting up a multi-layer motherboard body, the orientation of the through holes 7 on the motherboard body can be freely set. A multi-hole partition plate with both vertical and inclined orientations can be set at the same time, or a multi-hole partition plate with both orientations towards the center and the edge can be set at the same time.
[0037] Specifically, heating components are installed at the bottom and side walls of the crucible. The sublimation rate of the gaseous substance in the middle of the crucible is slower than that at the edge. When the through hole 7 at the edge of the main body 4 is smaller than the through hole 7 in the middle of the main body 4, the gaseous substance passing through the smaller through hole 7 at the edge of the main body 4 after sublimation is balanced with the gaseous substance passing through the larger through hole 7 in the middle of the main body 4, thereby making the overall sublimation of the gaseous substance more uniform.
[0038] Furthermore, the main body 4 has a thickness of 4-10mm, which provides better mechanical strength and thermal stability, enabling it to withstand higher temperatures and pressures. The aperture is 1-3mm, which directly affects the flow rate and velocity of the gas phase through the partition, as well as the ease of coating the carbide coating 8. When the aperture is 1-3mm, the carbide coating 8 can be easily coated, reducing the processing difficulty of the coating process. Moreover, by setting up staggered holes in the multi-layer main body 4, the passage of gaseous substances can be reduced without affecting the amount of carbon particle impurities rising. The hole spacing of the porous partition plate is 1-2mm, which reduces the processing difficulty while ensuring the mechanical strength of the main body 4, and achieves uniform gas distribution.
[0039] Furthermore, the main body 4 is a porous graphite plate, which can maintain stable performance even under high temperature conditions.
[0040] Specifically, such as Figure 2 As shown, a porous graphite plate is used as the substrate to form a circular substrate. A downward-facing annular groove 5 is provided on the upper side near the edge of the substrate, and an annular protrusion 6 is provided on the lower side near the edge of the substrate. The annular protrusion 6 protrudes downward from the plate to form a sealed atmosphere with the lower crucible peripheral wall, so that a gap is formed between the upper main plate 4 and the lower main plate 4, and the annular protrusion 6 of the upper main plate 4 extends into the annular groove 5 of the lower main plate 4 to form a sealed atmosphere between the two main plates 4. During the rising of the gas phase material, carbon impurities can be blocked, reducing the number of carbon particles rising to the single crystal growth area and reducing the number of carbon-encapsulated defects in the product, improving crystal quality, improving the temperature uniformity of the raw material area, maintaining the uniformity of the gas flow rate during the growth process, improving the crystal shape, and avoiding polycrystalline formation at the outer edge of the crystal.
[0041] like Figure 1-6As shown, a silicon carbide crystal growth apparatus includes a graphite crucible 3, which serves as the main container for crystal growth. The graphite crucible 3 possesses excellent high-temperature resistance and chemical stability, enabling it to withstand the high-temperature environment during crystal growth. A furnace cavity is formed inside the graphite crucible 3, with an annular step in the center. This annular step provides support for the installation of porous partition plates. Multiple porous partition plates are mounted on the annular step, with the through holes 7 of adjacent partition plates staggered to increase airflow disturbance within the furnace cavity, promoting uniform sublimation and transport of the raw materials, thereby contributing to uniform crystal growth. A furnace cover 1 is installed on the top of the graphite crucible 3. During the silicon carbide crystal growth process, high-purity silicon carbide powder is placed inside the graphite crucible 3 as the raw material. The furnace cavity is heated to a high temperature (typically between 2100℃ and 2500℃), where the raw material sublimates and decomposes into gaseous substances such as Si, Si₂C, and SiC₂, and solid C. These gaseous materials are transported to the low-temperature region inside the furnace cavity through the through holes 7 of the porous partition plate, and are deposited and grown into silicon carbide crystals on the seed crystal. Due to the presence of the porous gas partition plate, the airflow speed under the thermal gradient condition will be reduced, and the bottom carbon particles will rise to the top SiC single crystal growth area with the airflow, thus greatly reducing the number of carbon encapsulation defects.
[0042] Furthermore, such as Figure 1 As shown, a flow guide sleeve 2 is installed between the furnace cover 1 and the porous partition plate, which allows the gaseous material to converge towards the center, reducing the formation of eddies and dead zones, and making the airflow more evenly distributed in the furnace cavity, eventually depositing and growing silicon carbide crystals on the seed crystal.
[0043] Specifically, the inside of the guide sleeve 2 is an inverted conical cavity, and the diameter gradually decreases from bottom to top.
[0044] The above are merely specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. In the absence of conflict, the embodiments and features in the embodiments of this utility model can be combined with each other. Therefore, the protection scope of this utility model should be determined by the scope of the claims.
Claims
1. A porous partition plate, characterized in that, The system includes a main board body, an annular groove on the upper side of the main board body, and an annular boss on the lower side of the main board body to form a sealed atmosphere after the multi-hole partition plates are assembled. When multiple multi-hole partition plates are provided, gaps are left between the main board bodies. The main board body has through holes and a carbide coating is provided on the outer side of the main board body.
2. A porous partition plate according to claim 1, characterized in that, The carbide coating is one of tantalum carbide coating, zirconium carbide coating, tungsten carbide coating, niobium carbide coating, and hafnium carbide coating.
3. A porous partition plate according to claim 1, characterized in that, The depth of the annular groove is greater than the protrusion length of the annular boss, so that there is a gap between the main body panels.
4. A porous partition plate according to claim 1, characterized in that, The through holes are evenly spaced and have a consistent diameter.
5. A porous partition plate according to claim 1, characterized in that, The through holes are evenly spaced and the diameter of the holes gradually increases from the outside to the inside.
6. A porous partition plate according to claim 4 or 5, characterized in that, The main board body has a thickness of 4-10mm, a hole diameter of 1-3mm, and a hole spacing of 1-2mm.
7. A porous partition plate according to claim 1, characterized in that, The main body is a porous graphite plate.
8. A silicon carbide crystal growth apparatus, based on the porous partition plate according to any one of claims 1-7, characterized in that, The device includes a graphite crucible, which has a furnace cavity inside. An annular step is formed in the middle of the furnace cavity. Multiple porous partition plates are mounted on the annular step, and the through holes of adjacent porous partition plates are staggered. A furnace cover is installed on the top of the graphite crucible.
9. A silicon carbide crystal growth apparatus according to claim 8, characterized in that, A flow guide sleeve is installed between the furnace cover and the porous partition plate.