ABSTRACT
Epitaxial growth of Si0.7Ge0.3/Si(001) under kinetically limited conditions results in the initial formation of shallow pyramidal pits with facets, similar to an inverted "hut" structure. Heteroepitaxial growth of semiconductor structures is important for the fabrication of many types of devices. However, due to the lattice mismatch, large strains develop in the epitaxial layer. This strain may be reduced through the formation of islands on the surface of the film when there is sufficient adatom mobility, and also through the injection of misfit dislocations at a critical thickness. The typical island morphologies formed through strain relieving mechanisms in the Ge/Si or SiGe/Si system may have broad or bilateral size distributions because the resulting morphology can consist of a mixture of hut clusters, domes, or elongated islands depending on the growth conditions. The strain-stabilized structures appear to be self-limiting in size with respect to further growth and annealing at 550°C, unlike the usual hut/dome clusters seen in the SiGe/Si system.
