Aluminum doping property in SiC epilayers grown at high growth rate using chloride-based CVD

摘要

The systematic study of p-doping SiC epitaxy layer was performed on 4H-SiC (0001) 4° off-axis substrates using a high growth rate planetary hot-wall chloride-based CVD system. The influence of C/Si ratio, main hydrogen flow rate and Cl/Si ratio on aluminum (Al)-doping concentration and intra wafer uniformity has been investigated. The concentration increases with the C/Si ratio and main hydrogen flow rate while decreases with the Cl/Si ratio. The doping uniformity as the embodiment of the shape of aluminum depletion profile with substrate rotation averaging is mainly affected by main hydrogen flow, and more or less unaffected by C/Si ratio and Cl/Si ratio. The main hydrogen flow rate optimizes the Al-depletion curve within reactor, resulting in an improvement of intra wafer incorporation uniformity.