The partial dislocations that bordered triangle or parallelogram-shaped stacking faults, formed during the degradation of p-n diodes fabricated on 4H–SiC wafers, were determined - using transmission X-ray topography - to be dislocation loops with the Burgers vector, 1/3<10▪0>, a Shockley partial type which was consistent with previously reported transmission electron microscopy results. Some were separated from axial screw dislocations also present in the sample; thus indicating that the axial dislocations were not involved in loop nucleation; while others were seen to have interacted during their growth with the axial screw dislocations; distorting their shapes from those of ideal parallelograms.

Dislocation Loops Formed during the Degradation of Forward-Biased 4H–SiC p-n Junctions. W.M.Vetter, J.Q.Liu, M.Dudley, M.Skowronski, H.Lendenmann, C.Hallin: Materials Science and Engineering B, 2003, 98[3], 220-4