Lower-Temperature Epitaxial Growth of 4H-SiC Using CH₃Cl Carbon Gas Precursor

The advantages of the CH3Cl carbon precursor were investigated in order to achieve good-quality homoepitaxial layers of the 4H-SiC polytype at temperatures lower than what was considered practical (or even possible) with C3H8-based growth. It was observed that the process window for good epilayer morphology becomes narrower when the growth temperature is decreased. Successful growth experiments have been conducted in this work down to a temperature of 1290-13000C, with the growth rate in excess of 2 +m/hr and a mirror-like defect-free epilayer surface morphology. Growth on a 2” substrate produced promising growth rate homogeneity. The dependence of the growth rate on SiH4 flow followed a clear exponential dependence. This trend is tentatively attributed to Si vapor condensation. Photoluminescence results suggest that the crystalline quality of the epilayers grown at 13000C is comparable to that of 17000C growth.