Method to extract parameters of power law for nano-scale SiON pMOSFETs under negative bias temperature instability

摘要

This paper proposes a fast and accurate method to extract parameters of the power law for nano-scale SiON pMOSFETs under negative bias temperature instability (NBTI), which is useful for an accurate estimation of NBTI lifetime. Experimental results show that accurate extraction of the time exponentnof the power law was obstructed by either fast trapping of minority carriers or damage recovery during measurement of threshold voltageVth. These obstructing effects were eliminated using ΔVths obtained from fast and slow measurement-stress-measurement (MSM) procedures. The experimental SiON pMOSFETs hadn ≈ 1/4, an activation energyEa = 0.04 eV for the fast recoverable degradation, andEa = 0.2 eV for the slow permanent degradation. Based on these experimental observations, a method to estimate NBTI lifetime is proposed.