Shapes of the Micron-Sized SiGe Islands Grown on Si(100) in Dewetting Conditions

The shape of the islands formed during the Ge deposition on Si(100) surfaces in dewetting conditions is analyzed on the basis of surface layer energy minimization. An analytical expression for the total energy is derived for the sphere segment-shaped islands with contact angles up to 180° with respect to the substrate. It is found that the island shape is determined by the balance between the surface energy of the Si substrate areas located around the islands and the elastic energy of the areas around the island/substrate interface.