Mechanism of Bias-Temperature Instability: Results from Positive Gate Stress

Hole trap generation under positive gate stressing of the ultra-thin oxynitride gate p-MOSFET is investigated. The experimental evidence is shown to be consistent with the hole trapping framework proposed for NBTI. Deep-level hole traps pinned by the Si-SiO2 conduction band discontinuity and the slow repassivation of Nit account for long-term device degradation. Generation of shallow hole traps is revealed via the increased Delta|V th| following a fast positive-negative-positive voltage ramp. The results offer potential insights into understanding the role of processing (e.g. plasma induced oxide damage) on the NBTI of the p-MOSFET.