Composition of nanometer-scaled self-assembled SiGe islands

Quantitative relation between composition of self-assembled SiGe islands and critical size for shape evolution was established. The critical size, at which Ge islands change from pyramids to domes, increases with increasing of Si concentration in islands. Based on the critical size obtained from AFM characterization of SiGe islands, the composition of nanometer-scaled SiGe islands was calculated from the dependence of critical size of shape transition on the Si concentration.