Nitrogen impurity effects on nickel silicide formation at low temperatures – New “nitrogen co-plasma” approach

Nickel based silicide films were prepared by annealing nickel–platinum layers deposited on n doped Si substrates. We report on the evolution of the phase formation and the redistribution of contaminants on blanket wafers during silicide formation as a function of the nitrogen gas flow introduces during Ni(Pt) deposition. Nitrogen incorporation creates a contamination as-deposited layer which modifies phase formation and changes nickel diffusion. Nitrogen is not incorporated in silicide formed. After a second anneal, the monosilicide forms excepted for high nitrogen quantity introduced where the Ni 3Si 2 is always observed. Monosilicide thermal stability is also improved by nitrogen co-plasma.