SURFACE SEGREGATIONS DURING EPITAXIAL-GROWTH OF FE/AU MULTILAYERS ON GAAS(001)

The epitaxial growth process of Fe/Au multilayers on GaAs(001) substrates at temperatures of between 300 and 573 K has been studied using reflection high-energy electron diffraction and Auger electron spectroscopy. The growth mode is identified as the layer-by-layer type. Surface segregations of As, Ga, Fe or Au atoms that constitute substrates and underlayers were observed during the growth processes of these multilayers, depending on the deposition condition. These surface segregations can be removed by sputter etching for a short period, and resegregation is not observed afterwards. Differences in the mechanisms of these and conventional surface segregations are discussed.