AB-INITIO INVESTIGATION OF THE DISLOCATION-STRUCTURE AND ACTIVATION-ENERGY FOR DISLOCATION-MOTION IN SILICON-CARBIDE

The structures of straight 90 degrees glide partial dislocations in Si C are calculated using an ab initio local density functional cluster m ethod. Si partials containing core Si atoms are found to be strongly r econstructed with a Si-Si bond of comparable length to that in bulk si licon. The C partial possessing core C atoms is more weakly reconstruc ted with a bond length 16% longer than that in bulk diamond. The forma tion and migration energies of kinks on the partials are calculated an d indicate that the C partial is the more mobile. The calculations als o 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.