Dominant Device Instability Mechanism in Scaled Metal–Oxide–Semiconductor Field-Effect Transistors with Hafnium Oxide Dielectric

The negative-bias temperature instability (NBTI) and positive-bias temperature instability (PBTI) of metal–oxide–semiconductor field-effect transistors (MOSFETs) with high dielectric constant ( k ) gate dielectrics have been studied by varying the physical thickness of high- k dielectric. Both PBTI and NBTI were reduced with decrease in the high- k dielectric thickness, but NBTI reduction saturated in the thin high- k region. Since residual NBTI is sufficiently large to cause device instability, NBTI is still a dominant reliability concern in scaled MOSFETs.