Modulation of ferroelectricity and antiferroelectricity of nanoscale ZrO2 thin films using ultrathin interfacial layers

In this study, tailoring the microstructures and ferroelectric(FE)/antiferroelectric(AFE) properties of nanoscale ZrO₂ thin films is demonstrated with an intentional introduction of sub-nanometre interfacial layers. The ferroelectricity of ZrO₂ thin films is significantly enhanced by the HfO₂ interfacial layers, while the TiO₂ interfacial layers lead to a dramatic transformation of ZrO₂ from ferroelectricity into antiferroelectricity. The HfO₂ and TiO₂ interfacial layers boost the formation of the polar orthorhombic phase with (111)-texture and the non-polar tetragonal phase with (110)-texture in the FE/AFE ZrO₂ thin films, respectively, as evidenced by grazing incidence, out-of-plane, and in-plane X-ray diffraction measurements. Furthermore, the modulation of ferroelectricity and antiferroelectricity of nanoscale ZrO₂ thin films by the HfO₂/TiO₂ interfacial layers can be achieved without high-temperature annealing, which is highly advantageous to process integration. The findings demonstrate the important role of the interfaces in the effective tuning of FE/AFE properties of nanoscale thin films.