Micropipe bundling and twisting in SiC crystals was revealed by using synchrotron X-ray phase sensitive radiography. The computer simulation of micro-pipe evolution during the crystal growth suggested that the bundled and twisted micro-pipes arise under the influence of stress fields from other neighboring micro-pipes. The annihilation of twisted dipoles was attributed to their transformation into semi-loops. Reactions of micro-pipe coalescence lead to the generation of micro-pipes and/or the annihilation of initial micro-pipes, resulting in the decrease in their average density.

Micropipe Evolution in Silicon Carbide. M.Y.Gutkin, A.G.Sheĭnerman, T.S.Argunova, E.N.Mokhov, J.H.Je, Y.Hwu, W.L.Tsai, G.Margaritondo: Applied Physics Letters, 2003, 83[11], 2157-9