A new smart V<inf>th</inf>-extraction methodology considering recovery and mobility degradation due to NBTI

Abstract

In the recent literature several measurement methods were introduced to characterize the Vth-degradation of NBTI considering the recovery phenomenon. To our knowledge each method has a severe problem or at least a significant disadvantage. Either there are long delay times, the accuracy is not satisfactory or it is not possible to implement the method with customary equipment. A compromise is to do a one point measurement in the subthreshold region and calculate Vth based on the assumption that the subthreshold slope is not or only marginally affected by NBTI. In this paper we disprove the universality of this assumption. Vth determination using a one point measurement can lead to imprecise values. This extraction method disregards mobility degradation after NBTI impacting Vth, which we have clearly obtained in our measurements. We introduce a new smart Vth extraction methodology offering both shortest possible delay times with customary equipment and consideration of mobility degradation effects.