Bonding states and electrical properties of ultrathin $HfOxNy$ gate dielectrics Available to Purchase

Hafnium oxynitride $(HfOxNy)$ gate dielectric was prepared using reactive sputtering followed by postdeposition annealing at $650 °C$ in a $N2$ ambient. Nitrogen incorporation in the dielectric was confirmed by x-ray photoelectron spectroscopy analysis. In comparison to $HfO2$ of the same physical thickness, $HfOxNy$ gate dielectric showed lower equivalent oxide thickness (EOT) and lower leakage density $(J).$ Even after a high-temperature postmetal anneal at $950 °C,$ an EOT of 9.6 Å with $J$ of $0.8 mA/cm2$ $@−1.5 V$ was obtained. In contrast, $J$ of $∼20 mA/cm2$ $@−1.5 V$ for $HfO2$ with an EOT of 10 Å was observed. The lower leakage current and superior thermal stability of $HfOxNy$ can be attributed to the formation of silicon–nitrogen bonds at the gate dielectric/Si interface and strengthened immunity to oxygen diffusion by the incorporated nitrogen.