Epitaxy of two-dimensional ErSi xGe 2− x on Si(111) (5×5)–Ge observed by LEED and HREELS

Abstract

Low energy electron diffraction (LEED) and high resolution electron energy loss spectroscopy (HREELS) have been used to characterize the film formed upon deposition of an Er monolayer on a Si(111) (5×5)–Ge surface and annealing at 500°C. The properties of the clean surface, as well as its reactivity towards H adsorption, are found to be essentially the same as for the well-documented two-dimensional ErSi 2 silicide surface grown epitaxially on clean Si(111). From that it is deduced that the structure of the film must be similar to ErSi 2, i.e. a hexagonal erbium monolayer located underneath a buckled layer of mixed SiGe composition. The main effect of Ge substitution is reflected in a change of the dielectric properties of the film, as is clearly observed with HREELS.