Pt2Si and PtSi formation with high-purity Pt thin films

Abstract

Formation rates of Pt2Si and PtSi have been measured using 1.8-MeV 4He+ backscattering spectroscopy. Both silicide layers were grown with t1/2 time dependence, but the formation of PtSi starts only after all available Pt has reacted for the formation of Pt2Si, in disagreement with previously reported results. The activation energies have the common value 1.5±0.1 eV. Auger electron spectroscopy data confirmed the deposited Pt film purity and show that the contaminants contained in the sputter-deposited Pt layer segregate at the Pt2Si/Pt interface. It is postulated that this interfacial impurity buildup can affect the formation rate of Pt2Si and the further evolution of the system.