Study of the process-structure-property correlation in CVD-SiC coatings on graphite substrates

This study investigates the chemical vapor deposition (CVD) of SiC coatings on high-purity graphite susceptors, which serve as critical components in the epitaxial growth systems of III-V semiconductor materials (specifically GaN/SiC heterostructures). Using CH₃SiCl₃-H₂ as precursor with Ar carrier gases, we systematically examined the coupled effects of: Temperature (1100-1350 °C), Pressure (40-150 mbar), and ratios (6-12). Advanced characterization (XRD, SEM, XPS, nanoindentation) combined with computational fluid dynamics (CFD) simulations revealed: Kinetic regime transition at 1180 °C, Pressure-dependent roughness evolution (Ra = 0.8 μm at 50 mbar and 2.1 μm at 200 mbar), Stoichiometric control (Si/C = 1 at H₂/MTS = 10). Maximum hardness (42.12GPa) for -oriented 3 C-SiC. The optimized coatings demonstrated exceptional stability during MOCVD cycles (1100℃ GaN growth), maintaining: Surface roughness Ra = 1.55 μm (initial:1.47 μm), No interfacial degradation (SEM/TEM). These findings provide fundamental insights into CVD-SiC growth mechanisms while establishing practical guidelines for semiconductor-grade graphite susceptor production.