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.