Decoupling effects of the resistive-switching behavior on the polarization reversal in ultrathin ferroelectric Hf_0.5Zr_0.5O₂ films

HfO₂-based ferroelectrics attract considerable attention as their nanoscale ferroelectricity and CMOS compatibility, fulfilling demands of emerging memory technologies. However, as films scale down, resistive-switching behavior becomes increasingly pronounced, intertwining with polarization-switching process and affecting ferroelectric switching—factors often overlooked yet crucial for device optimization. Characterizing resistive-switching behavior and oxygen vacancy motion using tailored electric-pulse schemes, we decouple the resistive-switching behavior from the overall switching process in ultrathin Hf_0.5Zr_0.5O₂ films, which would otherwise erroneously inflate polarization values and increase coercive fields. Building on this, we elucidate endurance degradation mechanisms from perspectives of resistive switching and defect migration. Furthermore, we demonstrate mitigated resistive-switching activity by designing HfO₂-based devices with symmetric oxide electrodes, achieving reduced coercive fields and improved cycling performances. This work provides crucial insights into origins of inflated polarizations and reliability challenges in HfO₂-based devices while offering a viable strategy to enhance ferroelectric properties for advanced applications.