Stacking Fault Formation via 2D Nucleation in PVT Grown 4H-SiC

Synchrotron white beam x-ray topography (SWBXT), synchrotron monochromatic beam x-ray topography (SMBXT), and high resolution transmission electron microscopy (HRTEM) studies have been carried out on stacking faults in PVT grown 4H-SiC crystal. Their fault vectors were determined by SWBXT to be 1/3<-1100>, 1/2<0001>, 1/6<-2203>, 1/12<4-403>, 1/12<-4403>. HRTEM studies reveal their similarity in stacking sequences as limited numbers of bilayers of 6H polytype structure. Simulation results of the two partial dislocations associated with the stacking faults in SMBXT images reveal the opposite sign nature of their Burgers vectors. A mechanism for stacking fault formation via 2D nucleation is postulated.