The homoepitaxial growth mechanism of SiC was studied using both experiment and computational fluid dynamics (CFD) simulation in a vertical hot-wall CVD reactor with high-speed wafer rotation, and the influence of the C/Si ratio on the epitaxial growth rate and carrier doping concentration on the wafer surface were explored. The study reveals that the molar ratio of carbon-containing to silicon-containing species above the wafer surface (referred to as the effective C/Si ratio) deviates from the C/Si ratio at the gas inlet. This discrepancy is believed to be related to the gas species redistribution during the gas transport and diffusion, as well as parasitic deposition of precursors in the gas injector and/or on the hot-wall. The impact of the effective C/Si ratio on the growth rate and doping concentration was investigated. It is demonstrated that the growth rate, doping concentration and their uniformities are primarily influenced by the effective C/Si ratio at the wafer surface rather than the C/Si ratio at the gas inlet. By optimizing the growth conditions, high-quality 6-inch (1 inch=2.54 cm) epitaxial wafer is achieved with thickness and doping uniformity of 1.15% and 2.68%, respectively. 8-inch SiC epitaxial wafer with similar thickness and doping uniformities is obtained. Moreover, SiC epilayer (thickness exceeding 50 μm) with high growth rate is also demonstrated.