Basal plane dislocations were an important category of extended defects in SiC epilayers. They act as nucleation sites for single layer Shockley-type stacking faults which account for the degradation of the bipolar devices operating under forward bias. It was well documented that most of the basal plane dislocations in the SiC epilayers propagate from the substrates. However, two characteristic types of basal plane dislocations were suggested to be due to either nucleation or multiplication during epitaxy, including interfacial dislocations and short basal plane dislocation arrays connected to the epilayer surface by threading segments. Combining molten KOH etching, plan-view transmission X-ray topography, and photoluminescence mapping, both types were determined to be two parts of one defect produced by the sideway glide of a basal plane dislocation under the influence of shear stress. During the glide, the down-step end of the basal plane dislocation frequently produces a series of short basal plane dislocation segments at the moving growth front. These basal plane dislocation segments will grow into an array of dislocation half loops. At the same time, the sideway glide of the basal plane dislocation in the epilayer leaves an edge-type basal plane dislocation segment at the epilayer/substrate interface, which was the interfacial dislocation. The defect morphology provided the evidence of significant level of shear stresses present in SiC homo-epitaxy of typical power device structures. The magnitude of such stresses was estimated.

Glide and Multiplication of Basal Plane Dislocations during 4H-SiC Homoepitaxy. X.Zhang, M.Skowronski, K.X.Liu, R.E.Stahlbush, J.J.Sumakeris, M.J.Paisley, M.J.O'Loughlin: Journal of Applied Physics, 2007, 102[9], 093520