Reliability improvement on HfO/sub 2/ nMOSFETs by replacing polySi gate with TaSiN gate

This paper reports significantly improved charge trapping lifetime of HfO/sub 2/ nMOSFETs by using TaSiN gate instead of polySi gate. It demonstrates that the trapping induced threshold voltage shift is much more of a concern than TDDB in determining the device operating lifetime. A trapping model with a continuous distribution in trapping capture cross section has been used to extrapolate the device lifetime. Charge pumping results suggest the improvement on trapping lifetime is due to reduced bulk trap density in TaSiN gated HfO/sub 2/ nMOSFETs.