The formation of single and multiple stacking faults that sometimes gave rise to 3C–SiC bands was observed in a highly doped n-type 4H–SiC epilayer following dry thermal oxidation. Transmission electron microscopy following oxidation revealed single stacking faults and bands of 3C–SiC in a 4H–SiC matrix within the 4H–SiC epilayer. These bands, parallel to the (00•1) basal plane, were not detected in un-oxidized control samples. In addition to the 3.22eV peak of 4H–SiC, Cathodoluminescence spectroscopy at 300K after oxidation revealed a spectral peak at 2.5eV photon energy that was not present in the sample prior to oxidation. The polytypic transformation was tentatively attributed to the motion of Shockley partial dislocations on parallel (00•1) slip planes. The generation and motion of these partials may were induced by stresses caused either by the heavy doping of the epilayer or nucleation from defect.

Observation of 4H–SiC to 3C–SiC Polytypic Transformation during Oxidation. R.S.Okojie, M.Xhang, P.Pirouz, S.Tumakha, G.Jessen, L.J.Brillson: Applied Physics Letters, 2001, 79[19], 3056-8