Ti/Ni bilayers on silicon: Sputter-induced intermixing, rapid thermal annealing and ternary silicide formation

Sputtering of titanium on Ni/Si(100) leads to strong NiSi intermixing with no annealing treatment, an effect which we attribute to secondary electron heating. The major consequence is to reduce the formation temperature of the ternary silicide Ti4Ni4Si7 relative to the Ni/Ti/Si(100) couple from above 600°C to 470°C. The effect is suppressed by the presence of more than 2 at.% interfacial oxygen or by careful heat sinking. Differences between the two sequences are consistent with the different interface sensitivities to oxygen.