2011 Volume 8 Issue 1 Pages 33-37
Work function modulation of PtSi by alloying with Yb to achieve ultra-low contact resistance for advanced CMOS was investigated. PtxYbySi was formed by depositing Pt(6-18nm)/Yb(2-14nm)/n-Si(100) stacked structure followed by 400-800°C/1-30min silicidation in N2 ambient. It was found that barrier height for electron(ΦBn) was decreased as the silicidation temperature and time increased, and ΦBn was reduced to 0.52eV by depositing Pt(6nm)/Yb(14nm) followed by 800°C/30min silicidation. It was found that Yb diffusion toword the silicide/Si interface was enhanced, compared to the sample formed by 500-600°C silicidation, which leads to further decrease of ΦBn. The estimated effective work function of PtSi decreased from 4.92eV to 4.57eV.