Stacking fault formation in n+ 4H-SiC epilayers (n = 9 x 1019/cm3) deposited on the 4H-SiC substrates (n = 5 x 1018/cm3) was observed by means of conventional and high-resolution transmission electron microscopy. Formation of faults occurred during annealing in Ar (1150C, 1.5h). All of the faults were identical double layer Shockley faults formed by the glide of partial dislocations on 2 neighboring basal planes. The sign of the Burgers vector for several of the partial dislocations bounding the faults at the epilayer/substrate interface was determined by high-resolution transmission electron microscopy. Approximately half of the dislocations had a sign which corresponded to the extra half-plane inserted into the epilayer, while the other half resulted in the removal of the same half-plane from the film. In one case, 2 faults bounded by opposite-sign dislocations were separated by only 80nm. This result was inconsistent with mechanical stresses, due to the doping difference between the epilayer and the substrate, as being a driving force for fault expansion.

Stacking Fault Formation in Highly Doped 4H-SiC Epilayers during Annealing. H.J.Chung, J.Q.Liu, M.Skowronski: Applied Physics Letters, 2002, 81[20], 3759-61