Full Silicidation of Silicon Gate Electrodes Using Nickel-Terbium Alloy for MOSFET Applications

The full silicidation of silicon gate electrodes using Ni-Tb alloy was investigated for metal oxide semiconductor field effect transistor (MOSFET) applications. Results showed that a dual-layer silicide gate consisting of a top NiTb silicide layer and a bottom NiSi layer was formed. Full silicidation using Nio BTbo 2 resulted in a gate work function of 4.41 eV. This is lower than a work function of 4.68 eV obtained from full Ni silicidation. The work function lowering was linked to structural changes in the underlying NiSi layer. No physical or electrical degradation was observed after forming gas annealing at 420DGC for 30 min. NiTb-silicided gate electrodes have work functions suitable for application in advanced transistor structures.