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

$\mathrm{Hf}{\mathrm{O}}_2$ films with an enhanced dielectric constant, prepared through phase transition engineering by the addition of ${\mathrm{Al}}_2{\mathrm{O}}_3$ , were deposited by plasma-enhanced atomic layer deposition adopting a supercycle concept. After an annealing step at $700°\mathrm{C}$ , the tetragonal phase, which is a high-temperature phase of $\mathrm{Hf}{\mathrm{O}}_2$ , 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 $\mathrm{Hf}{\mathrm{O}}_2$ film with a monoclinic phase.