MECHANISM OF ATOMIC LAYER EPITAXY OF ALAS

A systematic study on atomic layer epitaxy (ALE) of AlAs thin films ha s been carried out by using ethyldimethylamine alane as an Al source. Self-limiting growth modes accompanied by one, two and three monolayer s per ALE cycle have been clearly presented. Each growth mode shows un ique dependence of growth temperature on carbon contents. We discuss t hat one monolayer self-limiting growth proceeds with the conventional adsorbate inhibition model, whereas the self-limiting growth with two and three monolayers can only be explained by the formation of metalli c Al layers. We also point out that atomic configuration of the layer may depend on the substrate temperature. Kinetic consideration is also given to examine these models. (C) 1998 Elsevier Science B.V. All rig hts reserved.