Impacts of TaC Coating on SiC PVT Process Control and Crystal Quality

Tantalum carbide (TaC) coating, produced in an ultrahigh temperature chemical vapor deposition (CVD) process, exhibited high thermal and chemical stabilities, low emissivity, and high purity. The present research investigated through modeling the TaC emissivity and reactivity impacts on the temperature, C/Si ratio and growth rate in SiC physical vapor transport (PVT) process. The TaC coating effect was further validated by SiC crystal shape and quality through a series of growth experiments. As our study revealed, TaC coating can act as a protection and isolation layer to extend graphite component life, improve radial temperature uniformity, maintain SiC sublimation stoichiometry, suppress impurity migration, and reduce energy consumption. Ultimately a TaC-coated graphite crucible set is expected to improve SiC PVT process control and product quality.