An investigation was made of hexagonal silicon carbide with low dislocation density to reveal inherent dislocation types and structures using the bulk-sensitive synchrotron X-ray topography. This topographic study revealed that: (1) basal-plane dislocations with the Burgers vector of 1/3<11▪0> preferred to be screw dislocations along <11▪0> in straight shape. (2) threading dislocations containing the Burgers vector component of <00▪1> were mostly mixed dislocations containing that of 1/3<11▪0>. (3) threading edge dislocations with the Burgers vector of 1/3<11▪0> were of short lengths, about 30–100μm. (4) all these dislocations were connected to convert, combine and dissociate to each other. The dislocation types and structures were discussed in terms of Peierls energy and elastic interaction. Moreover, it was proposed that the source of dislocations with the Burgers vector of 1/3<11▪0> was due to the propagation from a seed crystal rather than due to the Frank–Read mechanism.

Topographic Study of Dislocation Structure in Hexagonal SiC Single Crystals with Low Dislocation Density. D.Nakamura, S.Yamaguchi, I.Gunjishima, Y.Hirose, T.Kimoto: Journal of Crystal Growth, 2007, 304[1], 57-63