The Role of High-Field Stress in the Negative-Bias Temperature Instability

In this paper, a fast drain-current measurement methodology which supports the standard threshold voltage and transconductance extractions associated with the fast dynamic negative-bias temperature instability (NBTI) is presented. Using this methodology, we show that production quality transistors exhibit only minimal degradation after a brief stress at moderate to high dielectric fields (contrary to the excessive degradation reported in the recent literature). The degradation at stress conditions which are consistent with many recent NBTI studies is shown to be dominated by high-field stress, instead of NBTI. The ability to extract transconductance from fast drain-current measurements helps to identify the existence of a latent electron trapping/detrapping component which provides further support of a degradation mechanism dominated by high-field stress. This high-field-stress component, while dominating, has not been accounted for in most of the recent NBTI literature.