Method for preparing high-purity silicon carbide powder

Abstract

The invention provides a method for preparing high-purity silicon carbide powder. The method is characterized by comprising the following steps: (1) selecting high-purity silicon powder and high-purity carbon powder; (2) carrying out primary purification and secondary purification on the high-purity carbon powder, a graphite crucible and a heat-insulation structure, wherein the primary purification adopts vacuum degassing purification and the secondary purification adopts high-temperature purification under inert gas; (3) putting the high-purity carbon powder subjected to the secondary purification in step (2) and the high-purity silicon powder in step (1) into the graphite crucible subjected to the secondary purification in step (2); reacting to obtain the high-purity silicon carbide powder. According to the method provided by the invention, the carbon powder, the graphite crucible and the heat-insulation structure are pre-treated, so that the nitrogen content of the high-purity carbon powder and the content of metal impurities are reduced; compared with a method of carrying out wet-process metallurgical treatment after silicon carbide is synthesized, the method is more environmentally friendly and has simpler procedures; meanwhile, impurities are not introduced from the graphite crucible and the heat-insulation structure when the silicon carbide powder is synthesized.

Description

technical field [0001] The invention relates to the technical field of crystal material preparation, in particular to a high-purity silicon carbide powder and a preparation method thereof. Background technique [0002] As one of the most important third-generation semiconductor materials, silicon carbide single crystal is widely used in civil lighting, screens, etc. Display, aerospace, high temperature radiation environment, oil exploration, radar communication and automotive electronics and other fields. Silicon carbide single crystal is usually prepared from silicon carbide powder by sublimation method, so the purity, particle size and crystal form of silicon carbide powder used in sublimation method have a significant impact on the quality of silicon carbide single crystal. [0003] At present, the most commonly used SiC powder synthesis method in production is the self-propagating high-temperature synthesis method, which is to heat high-purity carbon powder and silicon ...

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Problems solved by technology

[0007] The present invention aims at the problem that the purity of silicon carbide powder synthesized in the prior art is not high, and provides a kind of preparation method of high-purity silicon carbide powder, and described preparation method comprises the following steps: (1) select high-purity silicon powder and high-purity Carbon powder; (2) primary purification and secondary purification are carried out to high-purity carbon powder, graphite crucible and insulation structure, wherein, primary purification adopts vacuum degassing purification, and secondary purification adopts high-temperature purification under inert gas; (3) will The high-purity carbon powder obtained by the secondary purification of step (2) and the high-purity silicon powder obtained in step (1) are placed in the graphite crucible obtained by the secondary purification of step (2), and react to obtain high-purity silicon carbide powder

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