Preparation method of high-purity silicon carbide

Abstract

The invention relates to a preparation method of high-purity silicon carbide, and belongs to the technical field of semiconductor materials. In order to solve the problems of low purity and severe environmental pollution of silicon carbide obtained by the prior art, the invention provides a preparation method of high-purity silicon carbide. The method is as below: completely wrapping the surface of a raw material silica or metal silicon or a mixture of the two with a carbon source containing carbon element, so as to prepare raw material particles; and reacting the raw material particles under high temperature to produce the silicon carbide. The silicon carbide prepared by the method in the invention has high purity, also can reduce energy consumption and pollutant emissions, and is friendly to the environment.

Description

technical field [0001] The invention relates to a method for preparing high-purity silicon carbide, which belongs to the technical field of semiconductor materials. Background technique [0002] In recent years, silicon carbide (SiC), which has a larger band gap than commonly used silicon, has been used for semiconductor substrates for manufacturing semiconductor devices. Therefore, a semiconductor device using silicon carbide has the advantages of high breakdown voltage, low on-resistance, and less performance degradation in a high-temperature environment. However, the use of silicon carbide as a material for manufacturing semiconductor devices has higher requirements on the purity content of silicon carbide, that is to say, higher requirements are placed on the preparation of silicon carbide. [0003] The preparation method of silicon carbide in the prior art adopts a layer of quartz sand on the heating element, and then a layer of coal or petroleum coke is spread on the ...

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Problems solved by technology

[0003] And the preparation method of silicon carbide in the prior art adopts to spread a layer of quartz sand on the heating element, then spread a layer of coal or petroleum coke on the periphery of the quartz sand, and then spread a layer of quartz sand on the outside of the coal or petroleum coke. , and then lay a layer of coal or stone tar. The thickness of each layer of quartz sand and coal petroleum coke layer is different. After laying, it will be heated at high temperature for at least 7 days. , because quartz sand and carbon contain a large amount of impurities such as metals, these impurities also undergo chemical reactions in a high-temperature heating environment to generate smoke of various colors such as yellow and red, which are directly discharged into the atmosphere without any treatment. Serious environmental pollution; and these impurities have a greater impact on the purity of SiC itself, and the use of this method to prepare silicon carbide, due to the different distances between the raw material and the heating element, will also make the generated silicon carbide The purity is different and affects the carbonization. purity of silicon

Therefore, the silicon carbide prepared by this method pollutes the environment very much, and the purity of silicon carbide is not high, and the purity cannot reach more than 99%, which is not conducive to the materials used to prepare semiconductor devices.

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