Fabrication process controlled pre-existing and charge - discharge effect of hole traps in NBTI of high-k / metal gate pMOSFET

Abstract

This study aims to investigate the application of a technique to separate bulk hole trap effects from interface state degradation in NBTI to understand hole traps behavior including MOSFET fabrication process dependence. A gate last process is used to fabricate the pMOSFETs with HfSiON/TiN gate stacks. Results show that RTA is an effective method for reducing pre-existing hole traps, while nitridation is effective in the thermally de-activation of hole traps. The hole traps, which are thought to be due to the negatively charged interstitial oxygen, increase logarithmically with hole injection.