Photoemission study of the initial stage of Er/Si(100) interface formation

Abstract

The initial stage of Er/Si(100) interface formation has been investigated by usingsynchrotron radiation photoelectron spectroscopy combined with low-energyelectron diffraction. Both the valence band and the core level peaks of the Siphotoemission spectra shift rigidly with increasing Er coverage in thesubmonolayer region. Upon depositing 0.6 monolayers of Er on the Si(100) surfaceat room temperature, the surface Fermi level is ultimately pinned at 0.29 eVabove its initial value, which is equivalent to a Schottky barrier height of 0.67 eV.No evidence is found for the formation of Er silicides at the as-depositedsurfaces. Annealing of the Er-covered Si(100) surfaces at 600ºC results in theappearance of a new peak located 1.2 eV below the Si 2p peak, indicatingthe presence of some sort of Er silicide. Meanwhile, the Er 4f spectrummeasured for samples upon annealing exhibits a well-resolved fine structure,implying that only monospecies of Er silicide may exist on the surface.