Modeling of heat transfer and kinetics of physical vapor transport growth of silicon carbide crystals

Wide-bandgap silicon carbide (SiC) substrates are needed for fabrication of electronic and optoelectronic devices and circuits that can function under high temperature, high-power high-frequency conditions. The bulk growth of SiC single crystal by physical vapor transport (PVT), modified Lely method involves sublimation of a SiC powder charge, mass transfer through an iner t gas environment, and condensation on a seed. Temperature distribution in the growth system and growth rate profile on the crystal surface are critic al to the quality and size of the grown SiC single crystal. Modeling of SiC growth is considered important for the design of efficient systems and red uction of defect density and micropipes in as-grown crystals. A comprehensi ve process model for SiC bulk growth has been developed that incorporates t he calculations of radio frequency (RF) heating, heat and mass transfer and growth kinetics. The effects of current in the induction coil as well as t hat of coil position on thermal field and growth rate have been studied in detail. The growth rate has an Arrhenius-type dependence on deposition surf ace temperature and a linear dependence on the temperature gradient in the growth chamber.