Phase and Layer Stability of Ni- and Ni(Pt)-Silicides on Narrow Poly-Si Lines

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 NiSi 2 nucleation temperature and the extent of layer inversion have been analyzed. The nucleation of NiSi 2 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 NiSi 2 . 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.