Mechanisms of surface morphology formation during Ge growth on Si(100) at high temperatures

The formation of island ensembles during the Ge deposition on the Si(100) surface at high temperatures is studied using scanning tunneling and electron microscopies. It is found that the island size and shape distributions, which are known to be bimodal at the Ge growth temperatures below 700°C, become monomodal at temperatures above 800°C. The strain relaxation processes at temperatures below 800°C usually occurs by means of the mass transfer from small to neighboring large islands, leading to highly inhomogeneous island distributions in size and along the surface. The monomodal island size distribution is formed under a Ge deposition flux in the conditions of a long deposited-atom surface diffusion length, which provides the atom incorporation in the most preferable surface places. This produces islands to be uniform in size and homogeneously distributed along the surface.