Effect of nitrogen incorporation on the electronic structure and thermal stability of HfO2 gate dielectric.

The effect of nitrogen incorporation on the electronic structure and thermal stability of HfO₂ gate dielectric was investigated by using photoemission study and first-principles calculation. Hafnium oxynitride (HfON) dielectric shows higher thermal stability in comparison to pure HfO₂ on Si. Atomic N can passivate O vacancies in the dielectrics during nitridation process, but the N atoms incorporated into interstitial sites cause band gap reduction. Postnitridation annealing is required to activate interstitial N atoms to form stable N–Hf bonds, which will increase the band gap and band offset of as-nitrided dielectric film. [ABSTRACT FROM AUTHOR]