Interface engineering of BiFeO3 ferro-resistive memories for sustainable high diode current

Abstract

Resistive switching, arising from the polarization modulation of the interfacial Schottky barrier in ferroelectric devices, holds promise for information storage applications. However, the performance reliability of such memory devices faces challenges, especially when the diode current is maximized for rapid data processing. Here, we demonstrate a substantial enhancement in the stability of diode current by meticulously selecting electrodes to establish a defect-free interface. This deliberate design effectively mitigates interfacial charge injection to screen the polarization of the ferroelectric BiFeO₃ thin film, thereby significantly enhancing the performance of the prototype memory devices. The BiFeO₃ devices featuring the epitaxial SrRuO₃ electrodes exhibit excellent stability in terms of coercive voltage and current rectification ratio during alternating pulse cycling while maintaining a high diode current density of 0.83 A/cm² at a bias voltage of -2.2 V. Conversely, metal electrodes facilitates trap formation at the interface for charge injection, which potentially screens the domain switching field and leads to an increased coercive voltage in BiFeO₃ devices. Additionally, injected charges can defuse into the interior of the ferroelectric thin film, precipitating polarization degradation and even device breakdown. This work elucidates the critical role of a defect-free interface in achieving sustainable high diode current for ferro-resistive memory.