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

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 exponent n of the power law was obstructed by either fast trapping of minority carriers or damage recovery during measurement of threshold voltage Vth. These obstructing effects were eliminated using ΔVths obtained from fast and slow measurement-stress-measurement (MSM) procedures. The experimental SiON pMOSFETs had n ≈ 1/4, an activation energy Ea = 0.04 eV for the fast recoverable degradation, and Ea = 0.2 eV for the slow permanent degradation. Based on these experimental observations, a method to estimate NBTI lifetime is proposed.