A phenomenological description of strain relaxation in GexSi1−x/Si(100) heterostructures

We describe how in situ observation of strain relaxation of Gex Si1−x /Si(100) heterostructures in a transmission electron microscope enable us to obtain the fundamental parameters which describe the nucleation, propagation, and interaction of misfit dislocations. Activation energies and prefactors are obtained for the nucleation and propagation processes for x in the range 0.20–0.35, and a simple model to account for dislocation interactions is developed. These measured parameters are then incorporated into a predictive model of strain relaxation which successfully reproduces experimental data. This model relies only upon parameters which can be directly measured.