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

Abstract

This paper reports significantly improved charge trapping lifetime of HfOz nMOSFETs by using TaSiN gate instead of polySi gate. It will demonstrate that the trapping induced threshold voltage shift is much more of a concem 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 HfO2 nMOSFETs.

Charge Trapping & NBTI in High k Gate Dielectric Stacks

“…Lastly, the model is observed to be compatible with charge trapping data reported by other research groups (13,18).…”

Frequency dependent charge pumping — A defect depth profiling tool?

“…As such, the need to better understand these defects became extremely important. One methodology that became popular for this purpose is frequency dependent charge pumping (FD-CP) as a tool for profiling bulk defect spatial distributions [2][3][4][5][6][7][8][9][10][11][12]. FD-CP is thought to have a well-defined relationship between charge pumping (CP) frequency and physical defect depth in the gate dielectric.…”