CN-122006647-A - Synthesizing device for optimizing high-temperature region position batch production of SiC powder and SiC powder production method

CN122006647ACN 122006647 ACN122006647 ACN 122006647ACN-122006647-A

Abstract

The invention relates to a synthesizing device for optimizing high-temperature area position batch production of SiC powder and a SiC powder production method, wherein a graphite structure is additionally arranged at the bottom of a crucible barrel, a hollow cavity structure is arranged in a graphite base, the crucible barrel and the graphite base are coaxially arranged, central axes of the crucible barrel and the graphite base are overlapped, a heat-insulating layer is arranged outside the crucible barrel to improve the high-temperature area position, radial temperature gradient is optimized, cracking of the bottom of the crucible and growth of SiC particles are effectively prevented, axial temperature gradient is regulated and controlled through process setting, the discharge ratio of the large-particle-size SiC powder can be improved, and the synthesizing of high-purity large-batch SiC powder with low carbon impurity content is facilitated.

Inventors

CHEN XIUFANG
WANG DESHENG
YANG XIANGLONG
XIE XUEJIAN
HU XIAOBO
XU XIANGANG

Assignees

山东大学

Dates

Publication Date: 20260512
Application Date: 20251226

Claims (10)

1. The utility model provides an optimize synthesizer of high temperature region position mass production SiC powder, this synthesizer includes a crucible section of thick bamboo, the top end opening of a crucible section of thick bamboo, the opening part is provided with the crucible lid, the bottom of a crucible section of thick bamboo is provided with graphite base and contacts each other, the inside hollow cavity structure that is equipped with of graphite base, a crucible section of thick bamboo and graphite base take coaxial arrangement mode to set up, the central axis coincidence of both, the outside of a crucible section of thick bamboo is provided with the heat preservation.
2. The synthesizer of claim 1 wherein the graphite base has a convex configuration in shape and the hollow cavity in the graphite base has a convex configuration with a smaller top and a larger bottom in longitudinal section.
3. The synthesizer of claim 2 wherein the cavity structure has a height of 80-90% of the total height of the graphite base.
4. The synthesizer of claim 1, wherein the graphite base has a side wall structure with an axial gradient, the height of the graphite base is 100-300 mm, the wall thickness of the graphite base is 10-30 mm, the long outer diameter of the graphite base is larger than the outer diameter of the crucible, and the short outer diameter is smaller than or equal to the outer diameter of the crucible.
5. The synthesizer of claim 1 wherein the crucible is 10 to 30mm thick, 550 to 750mm high and 300 to 550mm in diameter.
6. The synthesizer of claim 1 wherein an upper insulating layer is provided on the top end of the crucible barrel, a lower insulating layer is provided on the bottom end of the graphite base, an outer insulating layer is provided on the outer side wall of the crucible barrel and the side wall of the graphite base, and a double intermediate frequency induction heating coil is provided on the outer side of the insulating layer.
7. The synthesizer of claim 6 wherein the dual intermediate frequency induction heating coil comprises an upper induction coil and a lower induction coil, the upper induction coil and the lower induction coil being independently controllable and being adjustable in relative position, the upper induction coil and the lower induction coil being respectively externally connected to a high frequency ac power supply, an upper temperature measuring hole being provided through the upper insulation layer, and a lower temperature measuring hole being provided through the lower insulation layer.
8. A method for mass production of silicon carbide powder based on the synthesis apparatus of claim 1, comprising the steps of: S1, raw material pretreatment: carrying out dry ball milling mixing on silicon powder and carbon powder according to a molar ratio of 1:1-1:2 to obtain a uniformly mixed mixture; s2, crucible activation treatment: Heating the synthesis device through a double medium-frequency induction heating coil, and activating the synthesis device by high-temperature air firing under the protection of argon, wherein the temperatures of the top and the bottom of the crucible are respectively measured through an upper temperature measuring hole and a lower temperature measuring hole and are respectively recorded as T top and T bot ; s3, vacuum synthesis: 1) And (3) a vacuum impurity removal stage: Filling the mixture obtained in the step S1 into an activated crucible, and vacuumizing to ensure that the vacuum degree in the crucible reaches 10 -5 -10 -6 mbar; 2) beta-SiC synthesis stage: Heating to 1200-1600 ℃ and keeping the temperature for 10 hours to finish the solid phase diffusion reaction to generate beta-SiC crystalline phase, wherein the temperature uniformity of a reaction interface is ensured by dynamically balancing the thermal field distribution of upper and lower areas during the process, and free carbon inclusion is inhibited; 3) alpha-SiC crystal form conversion stage: Maintaining the argon flow at 20-300sccm, regulating the pressure in the crucible to 10-200mbar, regulating the power of the upper coil and the lower coil, heating to 2000-2400 ℃, controlling the temperature difference of T bot -T top to 150-200 ℃ and maintaining for 15h, so as to promote the conversion of beta-SiC into alpha-SiC, and generating SiC decomposition and the transportation process of gas phase components; s4, cooling, filling argon, and naturally cooling to room temperature.
9. The method according to claim 8, wherein in the step S2, the crucible body is heated to 1800-2400 ℃ for 10-30min, the argon flow is 10-500ccm, and the furnace pressure is 10-200mbar.
10. The production method according to claim 8, wherein in step 1) of step S3, a mechanical vacuum pump and a molecular pump are sequentially started to perform gradient vacuum pumping on the synthesis device, wherein the mechanical pump pumps for 1-10 hours to reduce the furnace pressure to 10 -1 -10 - 2 mbar, then the molecular pump continues to pump for 1-10 hours to enable the vacuum degree in the device to reach 10 -5 -10 -6 mbar, in step 2), 20-300sccm of high-purity argon gas is introduced, the power of an upper induction coil and a lower induction coil is regulated, the temperature of the material is increased to 1200-1600 ℃ at 80-120 ℃ per minute and kept at ttop= Tbot + -5 ℃, and in step S4, the temperature reduction rate is reduced to 350-450 ℃ within 5-15 hours.

Description

Synthesizing device for optimizing high-temperature region position batch production of SiC powder and SiC powder production method Technical Field The invention relates to a synthesis device for optimizing high-temperature region position batch production of SiC powder and a SiC powder production method, and belongs to the technical field of SiC powder preparation. Background Silicon carbide (SiC) is a third generation wide bandgap semiconductor material, and has been attracting attention in recent years because of its excellent properties such as large bandgap, high thermal conductivity, high critical breakdown field strength, large saturated carrier drift velocity, and small dielectric constant. Currently, physical Vapor Transport (PVT) is the dominant technique for preparing SiC single crystals. As a core raw material of PVT method, market demand for SiC powder continues to rise as SiC single crystals are widely used in the fields of semiconductors, new energy, and the like. At present, the industrial industry mainly adopts an improved self-propagating synthesis process and combines a single-coil PVT synthesis system to prepare SiC powder, but the method has two major technical bottlenecks, namely limited single synthesis amount, difficult to meet the requirement of large-scale production, and higher carbon impurity content in the product, and influences the subsequent single crystal growth quality. Therefore, the development of a SiC powder synthesis technology with high purity, low carbon impurities and large-scale preparation capability has important practical significance for promoting the development of the third-generation semiconductor industry. In order to solve the above-mentioned problems, patent document CN114832764a discloses a high-charge-amount silicon carbide powder device and a synthesis method thereof, the structure comprises a double-coil induction heater, a crucible and a thermal insulation structure, and a graphite ring or a graphite column structure is added inside the crucible. During operation, the carbon silicon powder raw materials are mixed, sectional heating is adopted, the double-coil induction heater is independently controlled, the relative position of the double-coil induction heater is adjustable, the regulation and control of the axial temperature gradient and the improvement of the radial temperature gradient are facilitated, however, the device still has the problems that the position of a high-temperature area is difficult to regulate and control, crystallization is easy to occur, the material taking is difficult, the regulation and control range of the temperature and the temperature gradient is limited, and the like, and the further application of the double-coil synthetic furnace is restricted. In view of the fact that the research on synthesizing SiC powder by adopting a double-coil induction heating technology is less at present, development of a novel double-coil high-temperature furnace synthesizing device capable of optimizing the position of a high-temperature region is needed to be urgently needed, so that large-scale and efficient preparation of SiC powder is facilitated. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a synthesis device for optimizing the mass production of SiC powder in a high-temperature region and a SiC powder production method. According to the synthesis device, the graphite structure is additionally arranged at the bottom of the crucible barrel, so that the position of a high-temperature region is improved, the radial temperature gradient is optimized, cracking of the bottom of the crucible and growth of SiC particles are effectively prevented, the axial temperature gradient is regulated and controlled through process setting, the discharge ratio of large-particle-size SiC powder can be improved, and the synthesis of high-purity large-batch SiC powder with low carbon impurity content is facilitated. The invention is realized by the following technical scheme: The utility model provides an optimize synthesizer of high temperature region position mass production SiC powder, this synthesizer includes a crucible section of thick bamboo, the top end opening of a crucible section of thick bamboo, the opening part is provided with the crucible lid, the bottom of a crucible section of thick bamboo is provided with graphite base and contacts each other, the inside hollow cavity structure that is equipped with of graphite base, a crucible section of thick bamboo and graphite base take coaxial arrangement mode to set up, the central axis coincidence of both, the outside of a crucible section of thick bamboo is provided with the heat preservation. According to the invention, the shape of the graphite base is a convex structure, and the longitudinal section of the cavity structure in the graphite base is a convex structure with a small upper part and a large lower part. According to the invention, the height