Silicide formation with codeposited titanium-tantalum alloys on silicon.

The formation of disilicides of titanium and tantalum from Ti-Ta alloys codeposited on silicon and polysilicon have been investigated using x-ray diffraction techniques, resistance measurements, and Auger electron spectroscopy. Titanium and tantalum in the Ti-Ta alloy interacted separately with silicon, in the same temperature range, without any interdiffusion between the two metals and no ternary was detected. The growth of each metal silicides were sustained by continuous outdiffusion of silicon into the Ti-Ta alloy film until the metals were consumed in the silicide transformation. This accounted for the absence of phase separation and component accumulation.