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

Abstract

HfO2 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 degrees 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.