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.