Origin of traps and charge transport mechanism in hafnia

In this study, we demonstrated experimentally and theoretically that oxygen vacancies are responsible for the charge transport in HfO2. Basing on the model of phonon-assisted tunneling between traps, and assuming that the electron traps are oxygen vacancies, good quantitative agreement between the experimental and theoretical data of current-voltage characteristics was achieved. The thermal trap energy of 1.25 eV in HfO2 was determined based on the charge transport experiments.