Hydrogen-related extrinsic oxide trap generation in thin gate oxide film during negative-bias temperature instability stress

摘要

This paper presents an extended model for the negative-bias temperature instability in p-MOSFET's with 3 nm gate oxide film. The devices, annealed with a standard forming gas (FG) process, have been subjected to an additional annealing process under high pressure, using both hydrogen and deuterium. We found that NBTI was accelerated by the high-pressure hydrogen (or deuterium) annealing compared to the standard FG annealing. This is attributed to the higher hydrogen (deuterium) density, and that in turn causes higher densities of oxide charges under NBTI stress. Our investigation of recovery and isotope effect shows that both interface-reaction and bulk-reaction, which can be plausible by extrinsic defect, are among the origins of NBTI degradation in ultrathin gate oxide.