A kind of silicon carbide crystal and preparation method thereof

Abstract

The application discloses a preparation method of silicon carbide crystal, which belongs to the field of semiconductor material preparation. The method includes: providing a reaction chamber, a crystal growing chamber and a material removing mechanism, the reaction chamber includes a raw material chamber and a waste chamber, and the silicon carbide raw material is loaded into the raw material chamber; The raw material gas generated by the sublimation of the raw material in the chamber is transmitted to the crystal growth chamber through the gas phase transmission channel for crystal growth. When the sublimation rate of the silicon carbide raw material is the first sublimation rate, the material removal mechanism is activated, and the material removal mechanism is used to remove the reaction chamber. The waste generated after the sublimation of the inner raw material is transferred to the waste chamber, and the remaining raw material in the raw material chamber continues to sublime for crystal growth under the crystal growth conditions. Silicon carbide crystals. The present application can improve the sublimation rate and utilization rate of raw materials, and reduce crystal defects.

Description

technical field [0001] The application relates to a silicon carbide crystal and a preparation method thereof, belonging to the field of semiconductor material preparation. Background technique [0002] At present, in the preparation of silicon carbide crystals, the physical vapor transport (referred to as PVT method) technology is mainly used. m C n Then, driven by the axial temperature gradient, it is transferred to the seed crystal to crystallize and grow into a silicon carbide crystal. PVT method is a complex process, and many parameters must be comprehensively controlled, such as growth temperature, temperature gradient, direct distance between seed crystal and growth material, gas pressure, etc. If any one parameter is not well controlled, the stability of crystal growth Sex will be destroyed. [0003] In the later stage of the growth of silicon carbide crystals, the non-stoichiometric decomposition of the silicon carbide raw material will occur, and more silicon ato...

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Problems solved by technology

Graphitization of silicon carbide raw materials is a common instability factor, which will increase the possibility of crystal graphitization and the formation of other defects, so that the crystal growth rate is largely limited

[0004] The current solution is to add additional solid silicon to the graphite crucible, which can compensate for the lack of silicon in the growth material and prevent the graphitization of the growth material to a certain extent, but this will lead to the formation of liquid silicon droplets and the formation of polymorphic structures. The second is to use tantalum crucibles to create an environment for adsorbing carbon, which can significantly inhibit the graphitization of growth raw materials, but the price of tantalum crucibles is too high to be used on a large scale

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