Nickel silicide and titanium silicide formation -- A comparison

Silicides have been used in CMOS technology for some years mainly to reduce sheet resistance in the source and drain regions. This paper discusses in detail the formation of nickel silicide (NiSi) and titanium silicide (TiSi2). The composition of silicides formed using sputtered and evaporated metals are compared. Metal films (titanium or nickel) on silicon deposited by DC magnetron sputtering or electron beam evaporation were vacuum annealed to form corresponding metal silicide thin films. The problem of oxygen contamination during silicidation is also discussed. Analyses of the silicide thin films formed were carried out using Auger Electron Spectroscopy (AES) depth profiles, Atomic Force Microscopy (AFM) surface scans, and surface profilometry for measurement of feature heights. The average surface roughness of the silicide thin films is also compared, and it was observed that nickel silicide thin films were much smoother than titanium silicide thin films.