Uniform, Low-Resistive Ni-Pt Silicide Fabricated by Partial Conversion With Low Metal-Consumption Ratio

Abstract

We applied partial conversion (PC) with a low metal-consumption ratio (MCR) as the initial silicidation, fabricating uniform and low-resistive Ni-Pt silicide regardless of the device patterns across a wafer. The key to PC in Ni-Pt silicidation was leaving the Ni-Pt alloy on the silicide after the initial silicidation. This process enriched the Pt of the Ni-Pt silicide because the Pt was supplied from the unconsumed Ni-Pt alloy on the silicide during the initial silicidation. The resistivity of Ni-Pt silicide was as low as that of NiSi at MCRs of less than 80%, suppressing the formation of nickel di-silicide (NiSi2) on the even narrow active line. We concluded that Pt on the silicide/Si interface and the grain boundaries of silicides can restrain Ni diffusion toward the ; direction into the Si substrate, which suppresses the formation of NiSi2.