Stability of oxides grown on tantalum silicide surfaces

The oxidation of TaSi2 and Ta2Si surfaces prepared under ultrahigh vacuum conditions has been studied by x-ray photoemission spectroscopy. For both silicides, Si and Ta oxides comprise the native oxide formed at room temperature. Annealing at 550 °C induces a solid state reaction within the native oxide. Ta2O5 is partially decomposed, and the liberated oxygen bonds to Si. This reaction and the influence of the silicide stoichiometry are discussed.