FIRST STAGE OF THE FORMATION OF SILVER THIN FILMS ON THE As-PASSIVATED Si(111)-(1×1) SURFACE

The As-terminated Si surface has an ideally flat monolayer of As atoms at the outermost layer, showing a nonreconstructed (1×1) symmetry with one extra valence electron on each As atom, and setting a passivation, on the silicon surface, remarkable for its stablity up to temperatures above 600°C and under Ag deposition. Angle-resolved photoelectron spectroscopy (ARUPS) of valence bands in the main Brillouin zone directions of the As–Si(111) surface, and X-ray photoelectron diffraction (XPD), recorded with the LURE synchrotron light, provide the principal results presented in this work. No arsenic diffusion into the metallic overlayer is detected by photoemission, in a wide range of temperatures, proving the stability of the Ag/As–Si(111) interface, and allowing a first study of the structural and electronic properties of this flat interface. The formation of the silver–metal films on the semiconductor surface has been investigated, in particular the growth mode in the one-monolayer range and the building of the semiconductor–metal interface, and the evolution of the film during the silver deposition up to a few monolayers.