Method for preparing high-quality large silicon carbide single crystal and silicon carbide single crystal prepared by same

Abstract

The invention relates to a method for preparing a high-quality large silicon carbide single crystal and a silicon carbide single crystal prepared by the method. The method comprises the following steps: placing a seed crystal on a seed crystal frame coated with a carbon-enriched polymer and heating so that the carbon-enriched polymer is thermocured; heating in an inert atmosphere so that the carbon-enriched polymer is pyrolyzed and carbonized; and growing the silicon carbide crystal on the carbonized and bonded seed crystal by a seed crystal guide gas phase transport technology (PVT). The seed crystal and the seed crystal frame are tightly bonded by the carbon-enriched polymer and pyrolyzed and carbonized after being cured to form a dense middle carbon layer, thereby effectively improving the temperature field uniformity of the silicon carbide seed crystal and solving the problems of polycrystals, multinuclear intergrowth, multiform mixture, and the like caused by uneven temperature distribution; the growing silicon carbide crystal has a single crystal form, the size of the crystal is larger than 2 inches, and the n-type or p-type mixed silicon carbide crystal can be prepared by mixing impurities in the growing process of the seed crystal.

Description

Technical field [0001] The invention relates to the technical field of preparation of wide-bandgap semiconductor wafers, in particular to a method for preparing a high-quality large silicon carbide single crystal and a silicon carbide single crystal prepared by the method. Background technique [0002] Silicon carbide (SiC) is one of the core of the third-generation semiconductor materials. It not only has the advantages of large forbidden band width, high thermal conductivity, high carrier saturation migration speed, and high critical breakdown electric field strength, but also has excellent advantages Chemical stability, very suitable for the production of high temperature, high frequency, radiation resistance, high power and high density integrated electronic devices. SiC material has an important strategic position in the national defense and military, so it is highly valued by all countries. At present, a variety of SiC-based microelectronic devices have come out and are us...

AI Technical Summary

Problems solved by technology

The place where the hole is sandwiched between the seed crystal and the seed crystal frame has poor heat transfer and high temperature, while the place with carbon adhesion has good heat transfer and low temperature, and the temperature distribution on the surface of the seed crystal is also different. Growth of high-quality, single polytype silicon carbide single crystals

[0007] To sum up, the seed crystal fixing method used for SiC crystal growth in the prior art is difficult to ensure the uniformity of the radial temperature distribution of the seed crystal, and it is inevitable that there are differences in crystallization conditions in various regions in the early growth stage, and parasitic 6H, 15R, 4H polytype competitive growth cannot satisfy the stable growth of high-quality large SiC single crystal

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