Atomistic Modeling of Misfit Dislocation Network Variants for Ge/Si(111) Interfaces

Abstract

For Ge layers on Si(111) surfaces the energy of coherent and semicoherent interfaces with misfit dislocations is numerically analyzed by use of the atomistic anharmonic bond charge model and the Stillinger-Weber approach. For the semicoherent interface, three configurations are considered, differing in the dissociation of the misfit dislocations into Shockley partials and in the partial dislocation patterns. The calculations yield a slight energetic preference of the so-called B variant while the literature reports observation of all three configurations. The deduced critical thickness for the coherent interface is in fair accordance with experimental estimates.