Fluorine interface treatments within the gate stack for defect passivation in 28 nm high-k metal gate technology

A novel method of fluorine incorporation into the gate dielectric by gaseous thermal NF3 interface treatments for defect passivation have been investigated in 28 nm high-k metal gate technology with respect to improvement in device reliability. The thermal treatment suppresses physical interface regrowth observed in previous plasma-assisted fluorine treatments. Detailed defect characterization by spectroscopic charge pumping is used to characterize the influence of fluorine on trap states in the interfacial oxide layer. Comprehensive structural as well as electrical characterization linked with bias temperature instability measurements indicates the potential of improving reliability in high-k metal gate technology by gaseous introduction of fluorine into the gate dielectric.