Effect of impurities on the PtSi–Si interface and the PtSi surface

Platinum silicides have been prepared by depositing Pt thin films under UHV and controlled impurity ambients. The interfaces and surfaces have been characterized by Rutherford backscattering spectroscopy, cross sectional TEM techniques and SEM. Clean depositions yielded planar interfaces whereas increasing oxygen contamination produced nonuniform interfaces and surfaces. No differences in interfacial and surface uniformity, reaction rates, and phase growth sequence were observed between samples cleaned with normal device processing steps and UHV sputter cleaned and annealed samples provided the Pt films were impurity free. The influence of interfacial oxides on silicide kinetics has also been determined.