Positive bias and temperature stress induced two-stage drain current degradation in HfSiON nMOSFET's

Abstract

Positive bias and temperature (PBTI) stress induced drain current degradation in HfSiON gate dielectric nMOSFETs is investigated by using a transient measurement technique. The degradation exhibits two stages, featuring different degradation rate and stress temperature dependence. The drain current degradation in the first stage is attributed to the charging of pre-existing high-k dielectric traps while the degradation in the second stage is mainly due to additional high-k trap creation. Process effect on high-k trap growth is evaluated.