Advanced gate stacks with fully silicided (FUSI) gates and high-κ dielectrics: Enhanced performance at reduced gate leakage

The key result in this work is that FUSI/HfSixOy gate stacks offer both significant gate leakage reduction (due to high-κ) and drive current improvement at Tinv ∼ 2 nm (due to: (i) elimination of poly depletion effect, ∼ 0.5 nm, and (ii) the high mobility of HfSi xOy). We also demonstrate that threshold voltage for both PFETs and NFETs can be adjusted from midgap to the values of Vt(PFET)∼ -0.4 V and Vt(NFET) ∼ + 0.3 V by poly-Si predoping by implantation (Al or As) and FUSI alloying. Significantly improved charge trapping (Vt stability) was found in the case of NiSi/ HfSixOy compared to the same gate electrode with HfD2 dielectric. ©2004 IEEE.