The interaction of Ni-Pt alloy with silicon

Diffusion and segregation effects during the formation of silicides in the interaction of an Ni-Pt alloy with Si and Si substrates were investigated by means of 4He+ megaelectronvolt Rutherford backscattering spectrometry, Auger electron spectroscopy coupled with Ar+ ion sputtering and glancing angle X-ray diffraction as functions of the heat treatment (150–850°C). The Ni-Pt alloy film was deposited onto silicon by codeposition using a system of electron guns. After low temperature annealing of the sample the nickel segregates and NiSi is formed at the original silicon-alloy interface. Further annealing promotes the interdiffusion of platinum into the NiSi. The barrier heights measured on n-type silicon confirm these observations. At low temperatures or after short annealing times the barrier height is 0.70eV. Further annealing increases this value until saturation is reached at, for Pt45Ni55 alloy, 0.77 eV. At high temperatures the contact degrades.