Tuning strain relaxation by surface morphology: Surfactant-mediated epitaxy of germanium on silicon

In this paper, we summarize the results on the surfactant-mediated epitaxy (SME) of germanium on (0 0 1) and (1 1 1) silicon substrates. Then, we discuss, how the surfactant-controlled development of micro-facets determines the strain relaxation process. We place particular emphasis on the different types of strain-compensating dislocation networks that form at the Ge/Si(0 0 1) interface in epitaxy with and without Sb as a surfactant. At elevated temperatures, high Sb-coverage promotes the generation of a regular array of edge type misfit dislocations, which allows for abrupt instead of gradual strain relaxation in the initial stage of growth.