Interaction of NBTI with Hot Carriers in PMOSFET's for Advanced CMOS Technologies

Abstract

PMOSFET's behavior at elevated temperatures has been studied with respect to hot carrier stress. It is found that the hot carrier (HC) stress damage at V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</sub> =V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</sub> 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 interaction of NBTI with hot carriers at low and high gate voltage show that the damage behavior is quite different, the low gate voltage stress resulting in an increase in transconductance, while the NBTI dominated high gate voltage and high temperature stress shows a decrease in transconductance.