Method for prolonging lifetime of carriers of silicon carbide epitaxial layer

Abstract

The invention discloses a method for prolonging lifetime of carriers of a silicon carbide epitaxial layer. By mainly adoption of a combination of a low-speed high-carbon-silicon ratio process and a high-speed low-carbon-silicon-ratio process, a required thick layer silicon carbide epitaxial layer is grown periodically; compared with the single low-speed high-carbon-silicon ratio process, the growth rate of the epitaxial layer is improved effectively by the method disclosed in the invention; and meanwhile, by combination with high-temperature annealing treatment, carbon vacancy is eliminated by carbon element migration in a chemical vapor deposition thermodynamic equilibrium condition, so that carbon vacancy effective restoration in the in-situ growth process is realized, and the lifetime of the carriers of the silicon carbide epitaxial layer is prolonged. The epitaxial material grown by the epitaxial method provided by the invention does not need ion implantation or high-temperature oxidization post treatment after epitaxy completeness, and the method is compatible with the existing commercial silicon carbide epitaxial furnace base process, so that the method has extremely high popularization value.

Description

technical field [0001] The invention relates to a silicon carbide epitaxial growth method, in particular to a method for improving the carrier lifetime of the silicon carbide epitaxial layer. Background technique [0002] Among different wide-bandgap semiconductor materials, silicon carbide (SiC) is a very potential epitaxial material, which has the characteristics of high thermal conductivity, high breakdown field strength, high saturation electron drift rate and radiation resistance. 4H-SiC is the material with the best performance among SiC polytypes. It has a larger band gap, bulk electron mobility, and smaller anisotropy. It is the material of choice for the development of power electronic devices. [0003] Compared with traditional silicon devices, the biggest advantage of 4H-SiC power electronic devices is that they can work at high voltage and ultra-high voltage. Therefore, epitaxial materials suitable for 4H-SiC power electronic devices have been developing towards...

AI Technical Summary

Problems solved by technology

If the epitaxy rate below 10μm / h is used to ensure the carrier lifetime of SiC epitaxial wafers, the productivity of SiC epitaxial wafers will be greatly reduced.

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