Oxygen-related defects in amorphous HfO2 gate dielectrics

Formation energies and electronic properties of oxygen defects in amorphous HfO2 gate dielectrics are investigated by employing the first-principles method based on the density functional theory. We have found that the fori-nation energy of neutral oxygen vacancy in amorphous HfO2 distributes from 4.7 to 6.1 eV, most of which is lower than the value for cubic HfO2, 6.0 eV. The decrease of the formation energy is due to the small coordination number of oxygen atom in the amorphous structure. It is also found that the atomic oxygen incorporation is more favorable in amorphous HfO2 than in crystal HfO2.