Impact of Off-State Stress and Negative Bias Temperature Instability on Degradation of Nanoscale pMOSFET

This letter investigates the impact of dynamic stress on the degradation of a nanoscale p-channel metal-oxide-semiconductor field-effect transistor (pMOSFET). Experimental results indicate that the off-state stress generated donorlike interface traps N_it and electron oxide traps, localized near the drain. The on-state stress produced the negative bias temperature instability which generated N_it´s and positive oxide charges Q_ox distributed uniformly in the channel. Although the electrons trapped by the off-state stress decreased the threshold voltage |V_th|, they were detrapped readily by the subsequent on-state stress. A dynamic stress caused the nanoscale pMOSFET to build up N_it and positive Q_ox, which increased the |V_th| significantly. These new observations indicate that the combined dynamic process can significantly influence the reliability of scaled CMOS inverter circuits.