Role of Nitrogen Atoms in Reduction of Electron Charge Traps in Hf-Based High- $\kappa$ Dielectrics

Effects of nitrogen incorporation on suppression of electron charge traps in Hf-based high- kappa gate dielectrics have been studied by first-principles calculations, focusing on interactions between N atoms and electrons trapped at oxygen vacancies (V_O´s). Our total energy calculations revealed that the formation energy of a doubly occupied state of V_O is significantly increased in HfO_xN_y compared to that in HfO₂ . This clearly indicates that the electron charge traps at V_O´s are considerably suppressed by N incorporation