Enhancement of dielectric constant in HfO2 thin films by the addition of Al2O3

Hf O 2 films with an enhanced dielectric constant, prepared through phase transition engineering by the addition of Al2O3, were deposited by plasma-enhanced atomic layer deposition adopting a supercycle concept. After an annealing step at 700°C, the tetragonal phase, which is a high-temperature phase of HfO2, was stabilized completely at room temperature and the crystallographic direction was changed to the preferred (002) orientation. As a result, Hf aluminate film with a (002)-oriented tetragonal phase had a dielectric constant of 47, approximately twice as large as the reported value of HfO2 film with a monoclinic phase.