Micro-pipes and dislocations in single crystals were studied by means of chemical etching. Micro-pipes were shown to be interconnected with other structural defects. The Si and C faces were preferentially and isotropically attacked, respectively, by molten KOH. This was explained in terms of the differing surface free energies of the Si and C faces. The revelation of micro-pipes was more pronounced on Si faces. An hexagonal pattern of micro-pipes was revealed due to the rapid etching which was provided by a large undersaturation at the surface. It was shown that etching from a melt led to a disintegration of the crystal at the micro-pipe, via a spiral dissolution mechanism which was due to etching under near-to equilibrium conditions. The temperature dependence of the etching rate obeyed an Arrhenius dependence, with an apparent activation energy of about 12 to 15kcal/mol; as deduced from etching-rate and weight-loss data.

Anisotropy of Dissolution and Defect Revealing on SiC Surfaces. M.Syväjärvi, R.Yakimova, A.L.Hylén, E.Janzén: Journal of Physics - Condensed Matter, 1999, 11[49], 10041-6