Reduction in charged defects associated with oxygen vacancies in hafnia by magnesium incorporation: First-principles study

Charged defects in a gate insulating oxide significantly degrade electric properties of the field-effect transistors. We report on our analysis of the effects of Mg incorporation into HfO2 upon reduction in the positive charges associated with oxygen vacancies V_O⁺². Our comprehensive study using first-principles calculations revealed that a Mg atom substituted for Hf is stable in charge negative Mg_Hf^-2 and strongly binds with V_O⁺², neutralizing the defect. This contributes to the suppressing of the electron traps at the defect site, improving the reliability of Hf-based gate oxides