Mechanism of Contact Resistance Reduction in Nickel Silicide Films by Pt Incorporation

Platinum (Pt) incorporation into nickel silicide (NiSi) films improves silicide characteristics such as lower contact resistance RC at silicide/Si interface and higher thermal stability. The impact of Pt incorporation is widely accepted and recognized in research field; however, the role of Pt in NiSi films has not been fully clarified so far. In this paper, the spatial distributions of Pt and dopants (i.e., arsenic and boron) in silicide films are studied at an atomic level analysis using local electrode atom probe. In particular, Pt and dopant distributions were investigated in detail both at silicide/Si interface and at silicide-grain boundary. Silicide-grain size was also analyzed at various Pt concentrations in silicide films, and the relationship between the Pt concentration and physical properties of Ni 1 - x Pt x Si films is pointed out. Finally, for further CMOS device scaling, the benefit of higher concentration of Pt incorporation into Ni 1-x Pt x Si films is described.