Roles of Stacking Faults in the Phase Transformation of SiC

The role of stacking faults in the 3C→4H phase transformation in SiC was investigated by employing powder samples having different initial stacking fault densities and by intentionally adding 5mol% Al to suppress the effect of inherent impurities. The Al addition induced the predominant formation of 4H-polytype, and the grown 4H grains appeared to have a platelet shape. Stacking faults present in the 3C phase served as nucleation sites for the formation of 4H-polytype, but the rate of 4H growth after nucleation was higher in 3C-SiC having a smaller initial stacking fault density. Roles of stacking faults in the phase transformation and its mechanism are discussed.