Thin film growth effects related to the propensity for clustering

Control of the morphology of epitaxial thin films is a prerequisite for device applications. Particularly crucial is the formation of smooth and defect-free hetero-interfaces at elevated temperatures where cluster formation is thermodynamically favored. In particular knowledge of the early stage of clustering is crucial as nucleation often results in aggregates of a few atoms which could still be integrated during further growth. Only few data exist for this stage to date due to small cluster sizes and the transient time behavior which complicate measurements with most standard surface techniques. An alternative approach is described to study the early stage of cluster growth as a by-product in late stage growth experiments. When applicable, like in the case of Ga clustering on GaAs(001) as discussed in this paper, simpler technical access and higher precision in the determination of a time scale favor this method.