High-quality silicon carbide epitaxial growth technology

Abstract

The invention discloses a high-quality silicon carbide epitaxial growth technology. A plurality of silicon carbide buffer layers are sequentially homogeneously grown on a silicon carbide substrate bya chemical vapor deposition process, and a silicon carbide epitaxial layer is grown on the uppermost buffer layer, wherein the growth rate of all the buffer layers increases stepwise from bottom to top, and the growth rate of the top buffer layer is not higher than the growth rate of the epitaxial layer. Multiple buffer layers are formed through the stepped control of the growth rate, and a plurality of interfaces formed by the brief growth interruption among the buffer layers sequentially reduce the propagation of defects, so the extended propagation of the defects of the substrate to the epitaxial layer is blocked, the number of the defects in the epitaxial layer is reduced, the epitaxial quality is improved, and the characteristics and the yield of functional devices manufactured basedon above obtained epitaxial wafers are improved.

Description

technical field [0001] The invention relates to semiconductor manufacturing technology, in particular to a high-quality silicon carbide epitaxial growth process. Background technique [0002] Silicon carbide semiconductor has excellent characteristics such as large bandgap width, excellent stability, high thermal conductivity, high critical breakdown field strength, high saturation electron drift velocity, etc. It is the best choice for making high temperature, high frequency, high power and strong radiation power electronic devices ideal semiconductor material. Compared with traditional silicon devices, silicon carbide devices can work normally under the electric field strength 10 times that of silicon devices. The silicon carbide material used to make silicon carbide devices is usually a silicon carbide epitaxial wafer grown on a silicon carbide substrate. [0003] At present, the epitaxial growth of silicon carbide has been commercialized, and the method of CVD (chemica...

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Problems solved by technology

[0004] However, in the above-mentioned epitaxial process, since there are only two interfaces between the substrate and the buffer layer, and the buffer layer and the epitaxial layer in the whole epitaxial growth process, there are many dislocation defects in the silicon carbide substrate, such as threading screw dislocation defects, penetrating Edge dislocation defects and basal layer fault defects, etc., because the epitaxial growth of silicon carbide is homoepitaxial growth, the above two interfaces cannot completely eliminate the propagation of defects in the substrate to the epitaxial layer, so the dislocation defects in the substrate will be As the growth extends to the epitaxial layer, there are still a certain number of defects in the epitaxial layer, resulting in a decrease in the quality of the epitaxial layer

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