Interface barrier-driven memristive switching in Al2O3/BFO heterostructures for advanced memory applications

In this study, Pt/BiFeO3/Al2O3/ITO heterostructures are fabricated using a sputtering technique, and the role of the interface barrier in influencing the resistive switching (RS) mechanism is investigated. Al2O3/BFO heterostructures are successfully fabricated with uniform granular morphology on a commercial ITO substrate. These devices exhibit self-rectifying analog memristive behavior, positioning them as promising candidates for neuromorphic computing applications. Devices incorporating an Al2O3 layer show intrinsic rectifying characteristics and distinct analog resistance states. Al2O3/BFO devices demonstrate better performance, primarily due to the accumulation and migration of oxygen vacancies (O∗∗). These bilayer devices present two clear switching behaviors: filamentary switching and area-dependent switching. Through systematic exploration of devices with varying device sizes, area-dependent switching, driven by interface barriers, emerges as the dominant mechanism with different resistance loads at different device features. Conductive atomic force microscopy (CAFM) is employed to examine switching behavior at the nanoscale, offering critical insights for future nanoscale device applications. The conduction mechanism in Al2O3/BFO devices is also analyzed to better understand the charge transport process. These devices exhibit stable endurance up to 9 × 105 cycles at room temperature, along with excellent projected data retention of up to 10 years at 85 °C with minimal resistance variation.