High-purity silicon carbide powder and preparation method therefor

Abstract

The application discloses high-purity silicon carbide powder and a preparation method therefor and belongs to the field of preparation of semiconductor materials. The preparation method for the high-purity silicon carbide powder comprises the following steps: providing beta silicon carbide powder and / or alpha silicon carbide powder as an initial silicon carbide powder material; recrystallizing theinitial silicon carbide powder material, so as to prepare a silicon carbide polycrystalline block; and subjecting the silicon carbide polycrystalline block to decarburization purification, thereby preparing the high-purity silicon carbide powder, wherein a temperature of recrystallization is not low 2,500 DEG C. According to the high-purity silicon carbide powder and the preparation method therefor, the purity of the prepared high-purity silicon carbide powder is improved by a recrystallization method, impurity removal by a hydrometallurgy or pickling step is not required, and the high-puritysilicon carbide powder is light in pollution, low in toxicity and high in operability; by a decarburization purification step of introducing oxygen gas to pure silicon carbide powder at a temperatureof 600 DEG C to 799 DEG C, the decarburization effect of the carbonized polycrystalline block is good, the prepared high-purity silicon carbide powder is low in degree of oxidation, and the influenceon an oxygen impurity is low when the high-purity silicon carbide powder is applied to growth of silicon carbide monocrystals; and by the preparation method, the high-purity silicon carbide powder with purity not lower than 99.9999% can be prepared, and the particle size of the high-purity silicon carbide powder is controllable.

Description

technical field [0001] The application relates to a high-purity silicon carbide powder and a preparation method thereof, belonging to the field of semiconductor material preparation. Background technique [0002] With the development of third-generation semiconductor technology, the production scale of third-generation semiconductor silicon carbide materials is gradually expanding. At the same time, with the in-depth research on the application of silicon carbide materials, the market has higher and higher requirements for silicon carbide substrates. Resistivity, as one of the important parameters reflecting the performance of silicon carbide substrates, is mainly affected by the impurity content in silicon carbide wafers. The main sources of impurities in silicon carbide ingots include crucible insulation materials used for growth, protective gases used in the growth process, and silicon carbide powder used for growing ingots. Therefore, reducing the impurity content in s...

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Problems solved by technology

In the prior art, in order to improve the purity of the prepared silicon carbide powder, impurities are often removed by hydrometallurgy or solvent pickling. This method of removing impurities is large in pollution and toxicity, and it is easy to introduce new impurities, and the effect of removing impurities is poor. It is difficult to further reduce the content, and it is difficult to produce high-purity silicon carbide powder with a purity greater than 99.999%; and the particle size distribution range of the high-purity silicon carbide powder prepared by the existing method is large, and it is difficult to control

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