Impact of metal gate electrode on Weibull distribution of TDDB in HfSiON gate dielectrics

The slope parameter of Weibull plot of Tbd, beta, strongly depends on gate electrode material for metalgate/HfSiON gate stacks in n-FETs. Furthermore beta of Tbd under bipolar stress is larger than that under DC stress. From these results, it is found that the balance of injected carriers is strongly related to beta in terms of the origin of large beta for metal-gate/high-k.