The interaction between oxygen vacancies and La atoms in the La-doped HfO2 dielectric were studied using first principles total energy calculations. La dopants in the vicinity of a neutral oxygen vacancy (VO) show lower formation energy compared to the La defects far from VO centres. La doping in HfO2 leads to the shift of the defect states of oxygen vacancies towards the conduction band edge. A statistical average of this shift over several possible configurations of La atoms and VO shows that the incorporation of La effectively passivates the VO induced defect states leading to the reduction of the gate leakage current and improvement of the device reliability.

Interaction of Oxygen Vacancies and Lanthanum in Hf-Based High-k Dielectrics: an ab initio Investigation. E.Nadimi, R.Öttking, P.Plänitz, M.Trentzsch, T.Kelwing, R.Carter, M.Schreiber, C.Radehaus: Journal of Physics - Condensed Matter, 2011, 23[36], 365502