Si-Passivation of Epitaxial SiGe: Kinetics and Impact on Morphology

Abstract

In this work a process was developed to passivate epitaxial SiGe on Si (001) substrates by a very thin Si layer. The Si-passivation was characterized in terms of deposition kinetics and of impact on the SiGe morphology during annealing. Different passivation durations allowed determining the time-dependence of the deposited thickness. A non-linear behavior was found resulting in a non-constant growth rate which decreases rapidly during the first seconds of passivation. Concerning the morphology of annealed SiGe, we showed that it can be strongly influenced by Si-passivation. The undulations appearing due to strain relaxation decrease in amplitude with increasing passivation duration until disappearance. In contrast, the morphology observed at the pattern edge, caused by thermal rounding, was not stabilized with similar passivation and annealing conditions.