Comparison of Negative Bias Temperature Instability in HfSiO(N)/TaN and SiO(N)/poly-Si pMOSFETs

In contrast to previous studies, the VT degradation during NBTI stress demonstrates power law time dependence as predicted by the R-D model as well as Arrhenius T activation for different nitrided/non-nitrided HfSiO(N)/TaN and SiO(N)/poly-Si devices. It is shown that measurement delay causes an increase in n. Different higher values of n reported earlier are artifacts of measurement delay. All splits of devices follow NBTI scaling scheme, EA,NBTI=n*EA,Diffusion regardless of the different gate stack materials. The difference in EADiffusion and EA,NBTI between HfSiO(N)/TaN and SiO(N)/poly-Si devices is attributed to different diffusion medium for hydrogen. Identical mechanism (primarily DeltaNIT driven) for VT degradation at longer stress time can be predicted for nitrided/non-nitrided HfSiO(N)/TaN and SiO(N)/poly-Si devices.