On-axis Si-face 4H-SiC epitaxial growth with enhanced polytype stability by controlling micro-steps during the H2 etching process
In situ H2 etching and homoepitaxial growth of 4H-SiC were performed on on-axis Si-face substrates using low-pressure chemical vapor deposition. We investigated the effect of various etching temperatures and durations on the surface of the on-axis substrates and used optimized etching characteristics to enhance the polytype stability of the epitaxial layer. It was found that the micro-steps at the etched surface of the on-axis substrates play a vital role in enhancing the stability of the 4H-SiC polytype. Homoepitaxial 4H-SiC with up to 99% stability was successfully grown with spread-out micro-steps without step-bunching during the etching process.