NBTI-enhanced hot carrier damage in p-channel MOSFETs

The behavior of p-MOS devices at elevated temperatures has been studied with respect to hot carrier stress. It is found that the hot carrier stress damage at V/sub g/=V/sub d/ increases as temperature increases, contrary to conventional hot carrier behavior. The cause of the damage is identified as being negative bias temperature instability (NBTI)-related, which is greatly accelerated under hot carrier stress conditions. A comparison of the AC hot carrier lifetimes at T=25 and 125 degrees C shows that the damage behavior is quite different, the low-temperature stress resulting in an increase in drive current, while the NBTI-dominated high-temperature stress shows a decrease in drive current. It is concluded that this can be the major source of hot carrier damage at elevated temperatures (>or=100 degrees C) in the AC stressing of p-MOS transistors.<
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