Induction of ferroelectricity in nanoscale ZrO2 thin films on Pt electrode without post-annealing

Large stable ferroelectricity in nanoscale undoped zirconia (ZrO2) thin films prepared without post-annealing has been demonstrated for the first time. Remanent polarizations up to 12 μC cm−2 were obtained in the as-deposited ZrO2 thin films prepared by remote plasma atomic layer deposition at 300 °C substrate temperature on the Pt electrode. Ferroelectric crystallization of the films was achieved without post-annealing, which is highly beneficial to the application of the films in non-volatile memories and ultralow-power nanoelectronics. The existence of the ferroelectric orthorhombic phase with noncentrosymmetric space group Pbc21 in the as-deposited ZrO2 thin films was confirmed by high-resolution transmission electron microscopy.