Tailoring the metal-oxide interface for improving fatigue performance in HfO2-based ferroelectrics

Hafnia-based ferroelectrics have attracted significant interest for their scalability and compatibility with complementary metal-oxide-semiconductor (CMOS) technology for memory applications. However, the imprint and fatigue behaviour remain critical challenges, particularly in electrode-integrated devices. By investigating Y-doped HfO ₂ films with various top electrodes (Pt, Cu, W, Mo, Ni, and Al), this study reveals that the fatigue performance is determined by the interplay between the metal work function and chemical stability through extended Frenkel pairs formation at the interface. Moreover, YHO with Ni top electrodes undergoes a unique ferroelectric failure from ferroelectric switching to filamentary conduction under electrical cycling, driven by extended Frenkel pair defects redistribution. Electrodes with high extended Frenkel pair formation energy enable YHO capacitors to maintain nearly unchanged ferroelectric polarization after 10 ⁸ switching cycles. Our findings show that charged defect formation, rather than intrinsic work function, determines interfacial band bending and the Schottky barrier. This work highlights the importance of interface engineering for enhancing the fatigue performance and the reliability of HfO ₂ -based ferroelectrics for memory applications.