Energetic and kinetic aspects of the growth of pseudomorphic SiGe islands

We investigate some principal thermodynamic and kinetic aspects of the growth of pseudomorphic SiGe-islands on Si(0 0 1)-substrates. We use different sets of samples grown by liquid phase epitaxy with different thermodynamic parameters. This approach permits growth rather close to thermodynamic equilibrium conditions contrary to other growth techniques. We determine with atomic force microscopy, the island density and the coverage of islands on the substrates. The systematic analysis yields a consistent description of the evolution of island density and island coverage with time in dependence of important parameters like cooling rate, saturation temperature and Germanium concentration. In addition, we compare sample sets grown very close to thermodynamic equilibrium with sample sets deliberately grown farther away from equilibrium. This comparison allows us to detect and analyze quantitatively the onset of kinetic effects. This study enables us to draw the borderline between energetically and kinetically controlled growth.