The evolution of hollow-core defects in vapour-phase grown bulk crystals during subsequent liquid-phase epitaxial treatment was investigated for a wide range of supersaturation conditions. Hollow macrodefects were already found to decompose into a number of micropipes at supersaturations close to zero. The elimination of pure screw-dislocation based micropipes required a higher supersaturation. The micropipes were observed to dissociate into individually acting non-hollow core dislocations. Following decomposition, the activity of growth centers based upon a micropipe was usually reduced, and a new center could dominate the growth surface. A model for the mechanism of micropipe transformation was proposed which was based upon Burton-Cabrera-Frank theory, and the Chernov theory of morphological stability.

On The Mechanisms of Micropipe and Macrodefect Transformation in SiC during Liquid Phase Treatment. B.M.Epelbaum, D.Hofmann: Journal of Crystal Growth, 2001, 225[1], 1-5