The dislocation structure that forms the caterpillar-shaped etch pit upon molten KOH etching was investigated by transmission electron microscopy employing a weak-beam dark-field method. The observed dislocation has the Burgers vector 1/3[12•0], and its structure was transformed from a basal plane dislocation to a threading edge dislocation. In the basal plane dislocation region, it propagated parallel to the [10•0] direction. On the basis of the measured dislocation structure, the caterpillar pit formation was explained. The process of dislocation formation was discussed by analyzing the relationship between sample types and the detection of the caterpillar pits.

Microscopic Structure of Stepwise Threading Dislocation in 4H-SiC Substrate. Y.Ishikawa, Y.Sugawara, H.Saitoh, K.Danno, H.Suzuki, T.Bessho, Y.Kawai, N.Shibata: Japanese Journal of Applied Physics, 2012, 51[4], 041301