Oxidation behaviour of nickel silicides investigated by AES and XPS

The oxygen interaction with Ni silicide surfaces in a wide range of composition, from NiSi2 to Ni3Si, has been investigated at room temperature by AES and XPS techniques. It has been found that the Si oxidation is enhanced over that of pure Si in all the Ni-Si compounds, and that the strongest oxidation occurs in Ni richer silicides. In general, oxygen bonds with Si leaving the metal unoxidized, but in Ni3Si evidence for the occurrence of Ni oxidation has been found at high exposures.