Impact of surface preparation on nickel–platinum alloy silicide phase formation

Nickel based silicide films were prepared by annealing nickel–platinum layers deposited on n-doped Si substrates. We report on the evolution of the crystallography, the phase formation and the redistribution of contaminants on blanket wafers during silicide formation as a function of the silicon surface preparation prior to Ni(Pt) deposition. In situ argon sputtering etch creates a contamination layer which modifies phase texture during the formation of the first Ni silicide phases. Using remote pre-clean results in a predominant Ni2Si phase with preferential grain orientation after a first anneal. After a second anneal, the monosilicide forms, regardless of what nickel rich silicide phase was initially formed and regardless of the surface preparation prior to metal deposition.