Observation of inhomogeneous oxygen distribution in electric-field-cycled Hf _0.5 Zr _0.5 O ₂ thin films prepared by atomic layer deposition

This study investigates the impact of ion distribution, with a particular focus on oxygen ions, on the stability and phase transformation processes of the hafnium zirconium oxide (HZO) ferroelectric phase. Using atomic layer deposition (ALD) to prepare HZO thin films, this research analyzes the microscopic particle distribution of various fatigue aging states from an elemental distribution perspective through spherical aberration-corrected electron microscopy. The results reveal that while the distribution of Hf and O ions remains relatively uniform in fresh samples, notable differences emerge in the distribution of oxygen ions in HZO samples after wake-up and fatigue processes. These findings suggest that the variation in oxygen ion distribution plays a crucial role in the phase stability and transition dynamics of HZO ferroelectric materials.