Thermal stability of Ni(Pt) silicide films formed on poly-Si

The stability of Ni silicide films formed with a thin interlayer of Pt onto poly-Si layer has been investigated in a wide range of silicidation temperatures between 350 and 900 °C and post-silicidation heat treatments between 500 and 1000 °C, using different characterization techniques to analyze the surface, cross-section interfaces and electrical characteristics. Formation of uniform and stable Ni(Pt)Si/poly-Si layered structures with low sheet resistances of about 5 Ω/sq. were observed up to 700 °C annealing temperature, except those obtained at 350 °C that presented a sheet resistance of 22 Ω/sq. At high temperatures, as-silicided and heat treated samples exhibited a drastic increase of the sheet resistance at 800/850 °C, respectively, due to the layer inversion and degradation of the morphology.