Engineering Hf0.5Zr0.5O2 Ferroelectric/Anti- Ferroelectric Phases With Oxygen Vacancy and Interface Energy Achieving High Remanent Polarization and Dielectric Constants

In this study, a decreased oxygen vacancy concentration [V_o] and an increased ZrO₂-HfO₂ interface area were experimentally and theoretically demonstrated to favor the formation of the ferroelectric orthorhombic phase (FE o-phase), whereas an increased [V_o] and a decreased ZrO₂-HfO₂ interface area (by forming alloy) favored the anti-ferroelectric tetragonal phase (AFE t-phase). High remanent polarization (2P $_{r} = 51\,\,\mu \text{C}$ /cm²) was achieved, and therefore, a high tunneling electroresistance (TER) ratio (46) was obtained in metal-ferroelectric-metal (MFM) superlattice structures. Moreover, the optimized AFE phase film exhibited a high dielectric constant 50, as measured by non-hysteretic C-V, by using metal-insulator-metal (MIM) capacitors with the ZrO₂-HfO₂ alloy. The thermal budget used in this study was as low as 450°C.