Effect of $hbox{F}_{2}$ Postmetallization Annealing on the Electrical and Reliability Characteristics of HfSiO Gate Dielectric

摘要

The effects of fluorine (F2) annealing on the electrical and reliability characteristics of HfSiO MOSFETs were investigated. Compared with a control sample annealed in conventional forming gas (H2/N2=4%/96%), additional annealing in a fluorine ambient (F2/Ar=0.3%/99.7%) at 400 degC for 20 min improved the electrical characteristics such as lower interface trap density and higher transconductance. In addition, MOSFET samples annealed in a F2 ambient exhibited less degradation under hot-carrier stress and positive bias temperature stress. These improvements can be explained by fluorine incorporation at the high-k/Si interface, which was confirmed by an X-ray photoelectron spectroscopy analysis