Surface Processes in ALE and MBE Growth of ZnSe: Correlation of RHEED Intensity Variation with Surface Coverage

Abstract

The surface processes in ALE (atomic layer epitaxy) and MBE (molecular beam epitaxy) are investigated both by numerical calculation for the surface coverage based on the model proposed by the authors and by in situ observation of the RHEED intensity variation. The sublimation process is dominated by the Se sublimation from the surface and the adsorption process is influenced by the desorption of Se from both the surface and the precursor states in the range of practical ALE and MBE growth temperatures. To achieve the layer-by-layer growth during ALE the substrate temperature should be set below 300°C. It is also shown that the RHEED intensity variation corresponds to the change in surface coverage during ALE and MBE growth as determined via comparison of the model calculation for surface coverage with the experimental RHEED data.