Extensive Studies for Effects of Nitrogen Incorporation into Hf-based High-A Gate Dielectrics

摘要

Effects of nitrogen incorporation into Hf-based high-/c gate dielectrics have been extensively studied via first-principles calculations. Particular emphasis is given to the relationship between incorporation of N atoms and oxygen vacancies (Vos). Three important aspects are outlined in this paper. The first one is the intrinsic effect of N atoms in reducing the leakage current mediated by Vo related gap states. The second one is the suppression of electron charge traps at Vo due to the strong repulsive Coulomb potential from N3~ ions located around Vo. The third one is the acceleration of the Vo formation around N ions. From these analyses, we infer that the amount of N incorporation should be tuned in the fabrication of reliable gate insulators.