Special features of the formation of Ge(Si) islands on the relaxed Si1-xGex/Si(001) buffer layers

The results of studying the growth of self-assembled Ge(Si) islands on relaxed Si1-xGex/Si(001) buffer layers (x approximate to 25%), with a low surface roughness are reported. It is shown that the growth of self-assembled islands on the buffer SiGe layers is qualitatively similar to the growth of islands on the Si (001) surface. It is found that a variation in the surface morphology (the transition from dome- to hut-shaped islands) in the case of island growth on the relaxed SiGe buffer layers occurs at a higher temperature than for the Ge(Si)/Si(001) islands. This effect can be caused by both a lesser mismatch between the crystal lattices of an island and the buffer layer and a somewhat higher surface density of islands, when they are grown on an SiGe buffer layer.