Reflection high-energy electron diffraction (RHEED) oscillations in phase-locked epitaxy of ZnSe

RHEED oscillations are frequently used to monitor layer thicknesses in mole cular beam epitaxy (MBE). In the case of the growth of ZnSe and ZnSe-based alloys it has been found that the oscillation of the specular beam intensit y is influenced by a phenomenon denoted as "material contrast". The aim of the present study has been to separate the contribution due to material con trast from the oscillatory contribution in the specular beam intensity. For this purpose, a simple model for both the contributions has been applied. Parameters of the model are discussed in the case of phase-locked epitaxy. It can be concluded from these parameters, which phase angle of the shutter operation yields the flattest surface. The properties of two differently g rown superlattices have been shown to validate the interpretation. (C) 1999 Elsevier Science B.V. All rights reserved.