Phase and layer stability of Ni- and Ni(Pt)-silicides on narrow poly-Si lines

Abstract

The phase and morphology stability of NiSi and Ni(Pt)Si formed on the poly-Si lines and wide pads have been studied. Differences in the NiSi2 nucleation temperature and the extent of layer inversion have been analyzed. The nucleation of NiSi2 was hindered on the narrow poly-Si lines as compared to that on the large area poly-Si pads at 750°C. Stress is believed to play an important role in the delayed nucleation of NiSi2. In addition, layer inversion was found to be less severe on the narrow poly-Si lines as compared to that on the poly-Si pads after being subjected to the same annealing condition. This is likely due to the limiting grain growth of the poly-Si in the narrow lines. Enhanced stability of Ni(Pt)Si was achieved up to 800°C on both poly-Si wide pads and narrow lines.