Dislocation core reconstruction and its effect on dislocation mobility in silicon

Abstract

Through atomistic calculations of kink nucleation and migration in the core of partial dislocations in silicon we demonstrate that symmetry-breaking structural reconstructions will strongly affect dislocation mobility. Core reconstructions give rise to multiple kink species, and, relative to kinks in an unreconstructed dislocation, an increase in kink formation and migration energies. These factors provide additional resistance to dislocation motion which scales with the energy reconstruction. Our results indicate that the observed variations of dislocation mobility in going from elemental to IV–IV, and further to III–V and II–VI zinc-blende semiconductors, can be attributed in part to the weakening of core reconstruction across the series.