Quantitative strain analysis of misfit dislocations in a Ge/Si heterostructure interface by geometric phase analysis

Misfit dislocations in a Ge/Si heterostructure were investigated experimentally in the present work. The misfit dislocations were demonstrated to be pure edge dislocations, with distances of about 10 nm between misfit dislocations. The strain fields around the misfit dislocation core were mapped using a combination of geometric phase analysis and high-resolution transmission electron microscopy. The strain measurement results were compared with the Peierls–Nabarro and Foreman models of dislocation networks. Based on the comparison results, the Foreman model can better describe the strain fields of the misfit dislocations in the Ge/Si heterostructure.

► Misfit dislocations in a Ge/Si heterostructure interface were analyzed quantitatively. ► Strain field in the region of a misfit dislocation core was mapped by geometric phase analysis. ► The strain measurement result was compared with theoretical predictions. ► The Foreman model with a=4 was determined as the most appropriate misfit dislocation model.