Thermal stability of Ni-Pt-Ta alloy silicides on epi-Si1-xCx

We investigated the silicide formation in Ni/epi-Si1-xCx systems. Ni-Pt and Ni-Pt-Ta films were deposited on epi-Si1-xCx/Si substrates by DC magnetron sputtering and processed at various temperatures. The sheet resistance of the silicide from the Ni alloy/epi-Si1-xCx systems was maintained at low values compared to that from Ni/Si systems. By TEM and EDS analyses, we confirmed the presence of a Pt alloy layer at the top of the Ni-silicide layer. The stability of the silicide layer in the Ni alloy/epi-Si1-xCx system is explained by not only the Pt rich layer on the top of the Ni-silicide layer, but also by the presence of a small amount of Pt in the Ni-silicide layer or at the grain boundaries. And both the thermal stability and the morphology of silicide were greatly improved by the addition of Ta in Ni-Pt films