Silicidation in Ni-Si System

Silicide formation induced by thermal annealing in Ni/Si thin film system has been investigated using glancing incidence X-ray diffraction. Silicide formation takes place at 600degC with Ni₂Si, NiSi and NiSi₂ phases co-existing with Ni. Complete conversion of intermediate silicide phases to the final NiSi₂ phase takes place at 900degC. A comparison of the experimental results in terms of annealing temperature, Ni thickness, and dopant impurities with Ni-Si phases is presented. Nickel silicide (NiSi) is emerging to be the choice material for contact application in semiconductor device processing for sub_65 nm technology node and beyond. The focus of present work is to facilitate better understanding of the influence of thermal budget on nickel silicide solid-state reaction. Requirements for low temperature anneal and improving within wafer sheet resistance uniformity pose challenges for conventional lamp-based rapid thermal processing (RTP) due to lamp response effects on temperature controllability. Evolution of the nickel-rich silicide phase as a function of temperature is recorded using X-ray diffraction (XRD) techniques. It is postulated that lowering the Ni₂Si/Si interface energy favors the delay of the agglomeration of the NiSi.