Numerical Study on the Growth Rate of Silicon Carbide Single Crystals in a High Temperature Chemical Vapor Deposition System

The growth rate of SiC crystals in a high temperature chemical vapor deposition system was simulated numerically using a computational fluid dynamics (CFD) method. The effects of the SiH₄ flow rate, H₂ carrier flow rate and reactor length on the temperature, flow velocity and growth rate of SiC were examined using a simple grid and complicated grid model. The growth mechanism involving the formation of a condensed Si liquid cluster, its reaction with hydrocarbon and the growth of a SiC crystal were explicitly assumed. The strong dependence of SiH4 and the reactor length on the degree of Si supersaturation and the resulting growth rate of SiC was calculated, which is consistent with the postulation that the formation of a Si cluster in the gas phase is a limiting factor determining the growth rate of SiC. A growth rate of 15.7 mm/hr for a SiC crystal in HTCVD was obtained when the CH₄ flow rate was 240 sccm.