Abinitioinvestigation of the dislocation structure and activation energy for dislocation motion in silicon carbide

Abstract
The structures of straight 90° glide partial dislocations in SiC are calculated using an ab initio local density functional cluster method. Si partials containing core Si atoms are found to be strongly reconstructed with a Si-Si bond of comparable length to that in bulk silicon. The C partial possessing core C atoms is more weakly reconstructed with a bond length 16% longer than that in bulk diamond. The formation and migration energies of kinks on the partials are calculated and indicate that the C partial is the more mobile. The calculations also predict that n-type doping leads to an increase in the mobility of C partials whereas p-type doping increases the mobility of Si partials.