Nukleation, Relaxation und Umverteilung von Si-Schichten in GaAs

: Brandt, O.; Crook, G.; Ploog, K.; Bierwolf, R.; Hohenstein, M.; Maier, M.; Wagner, J.

Abstract
We study the structural properties of Si layers of different thickness (0.1-1.3 nm) inserted in GaAs by solidsource molecular beam epitaxy. Using high- resolution electron microscopy, we demonstrate that the Si nucleation on GaAs takes place via the formation of Si nanoclusters in a highly regular arrangement. Thicker films (several monolayers) are found to be partially intermixed with GaAs. This intermixing is caused by the segregation of a considerable fraction of the deposited Si during overgrowth, as observed by secondary ion mass spectrometry. Finally, we show that the strain relief of Si films on GaAs occurs at a thickness of about 1.2 nm via the generation of stacking faults, whereas complete dislocations are not detected.