The effects of Ta on the formation of Ni-silicide in Ni 0.95xTa x0.05/Si systems

Abstract

We investigated a comparative study on the silicide formation in the Ni 0.95Ta 0.05/Si alloy systems and Ni/Si systems. Ni and Ni 0.95Ta 0.05 films were deposited on Si(1 0 0) substrate by DC magnetron sputtering and processed at various silicidation temperatures. The sheet resistance of the silicide from the Ni 0.95Ta 0.05/Si alloy systems was obtained at lower values than those in pure Ni/Si systems at any temperature. Using RBS and TEM analyses, we confirmed the presence of a Ta rich layer at the top of the Ni-silicide layer and the presence of small amounts of Ta in the silicide layer. The stability of the silicide layer for the Ni 0.95Ta 0.05 systems is explained by the presence of the Ta rich layer on top of the Ni-silicide layer, as well as by the presence of the small amount of Ta in the Ni-silicide layer. The Ni-silicide using Ni 0.95Ta 0.05/Si system displayed a stable sheet resistance value of ∼5 Ω/sq which was maintained during the anneal process at 600 °C.