A detailed analysis of the formation of Pt 2 Si and PtSi silicides is proposed, based on x-ray photoelectron spectroscopy ͑XPS͒, transmission electron microscopy ͑TEM͒, and electrical characterizations. Published kinetics of the Pt 2 Si and PtSi transformations under ultrahigh vacuum condition are consolidated on the basis of XPS measurements performed during an in situ annealing at a constant heating rate. At room temperature, an incomplete Pt x Si reaction is clearly identified by XPS depth profiling. Using rapid thermal annealing at 300, 400, and 500 °C, the sequential Pt-Pt 2 Si-PtSi reaction chain is found to be completed within 2 min. Outdiffusion of silicon to the top surface is shown to be responsible for the formation of a thin SiO 2 capping layer at 500 °C. Pileup of oxygen occurring at the Pt 2 Si/Pt reaction front is clearly identified as an inhibiting factor of the silicidation mechanism. Another incomplete reaction scheme limited to the unique formation of Pt 2 Si is exemplified in the case of ultra thin silicon-on-insulator films. Finally, current drive measurements on PtSi Schottky contacts have allowed us to identify 300 °C as the optimum annealing temperature while TEM cross sections demonstrate the formation of a smooth and continuous PtSi/Si interface at 300 °C.

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