Interaction of Gd and N incorporation on the band structure and oxygen vacancies of HfO₂ gate dielectric films

The interaction of Gd and N incorporation on the band gap, band offset, and oxygen vacancies of HfO2 high-k gate dielectric films has been investigated. The results show that introducing N (9.7% and 17.4%) and Gd into HfO2 does not dramatically reduce the band gap due to the counteracting effect of Gd doping. Most importantly, Gd and N co-doping increases the conduction band offset of HfO2 and leads to a much better band offset symmetry compared to undoped or Gd-monodoped HfO2. Compared with Gd, N plays a more significant role in improving the band-offset symmetry. The oxygen vacancies are greatly suppressed by Gd and N co-doping under the suitable doping amounts.