Ordered growth of Ge islands above a misfit dislocation network in a Ge layer on Si(111)

Abstract

A flat Ge layer on Si(111) with a buried dislocation network at the Si/Ge interface is used as substrate. This flat Ge film was grown with Sb as surfactant. During subsequent growth and coarsening of two-dimensional Ge islands, ordering of the islands with respect to the underlying dislocation network (which has a periodicity of ∼100 Å) is observed using scanning tunneling microscopy (STM). During coarsening, preferred growth of the islands occurs near the minima of the height undulations induced by the buried dislocation network. This ordering effect is explained by strain induced preferred diffusion towards these areas and energetically favorable binding at these positions above the dislocations.