A model was suggested for the splitting of dislocated pipes at a crystal growth front. According to this model, pipe splitting occurred via the generation of a dislocation semi-loop at the pipe and crystal surfaces and its subsequent expansion into the crystal interior. The strain energy of such a dislocation semi-loop, and the stress field of a dislocated pipe perpendicular to a flat crystal surface, were calculated. Those parameter values were identified for which expansion of the dislocation semi-loop was energetically favorable and the pipe splitting therefore became irreversible. A mechanism was proposed for the formation of a stable semi-loop, resulting in splitting, and possible subsequent overgrowth of the dislocated pipe.

Split and Sealing of Dislocated Pipes at the Front of a Growing Crystal. M.Y.Gutkin, A.G.Sheinerman: Physica Status Solidi B, 2004, 241[8], 1810-26