Scaling of submonolayer island sizes in surfactant-mediated epitaxy of semiconductors

Abstract

We study submonolayer island size distributions in the epitaxy of Si and Ge on the Si(111) surface with Bi as a surfactant. We show that sizes of Si islands at different growth temperatures scale to a standard scaling function that peaks at the mean island size. Size distribution of Ge islands demonstrates qualitatively different behavior: With the decreasing temperature the most probable size in the population of Ge islands shifts towards small island sizes so that the peaked scaling function degenerates to a decreasing one. The observed scaling phenomena are found to be inherent to the mechanism of growth which involves exchange and de-exchange processes of deposited atoms with the surfactant and the strong passivation of step edges in the presence of the surfactant.