First-principles studies of the intrinsic effect of nitrogen atoms on reduction in gate leakage current through Hf-based high-k dielectrics -: art. no. 143507

The atomistic effects of N atoms on the leakage current through HfO2 high-k gate dielectrics have been studied from first-principles calculations within the framework of a generalized gradient approximation (GGA). It has been found that the intrinsic effects of N atoms drastically reduce the electron leakage current. N atoms couple favorably with oxygen vacancies (V-O) in HfO2 and extract electrons from V-O. As a result, V-O energy levels are drastically elevated due to the charged-state change in V-O from neutral (V-O(0)) to positively charged (V-O(2+)). Accordingly, N incorporation removes the electron leakage path mediated by V-O related gap states. (C) 2005 American Institute of Physics.