A new fast switching NBTI characterization method that determines subthreshold slope degradation during stress

For PMOSFET devices NBTI is a serious reliability concern. Because of recovery effects careful stress and measurement methods must be used to determine threshold voltage (V_T) degradation. These methods typically assume that mobility and subthreshold slope (SS) degradation are minimal. Recent paper have pointed out that this assumption may not be valid. This paper discusses a new fast switching NBTI measurement technique that alternates between two V_GS measurement conditions to determine the SS as a function of stress time. In this new method the SS is determined during stress to correctly compensate the V_T degradation for SS degradation. In addition, this paper presents SS and V_T NBTI degradation data from a 2 nm low and high nitrogen and a 6 nm DGO PMOS device to demonstrate the value of this new method.