Utilization of a cross-section CAFM to investigate resistive switching behaviors in a Pt/YMnO₃/Pt device

Recently, the filament mechanism has been proposed to explain the resistive switching (RS) behaviors of metal/oxide/metal (MOM) devices, which are highly regarded as promising candidates for future non-volatile memory applications. The major technical difficulties in filament investigation lie in its tiny size and ambiguous position, which is always embedded in the interface of a MOM device. As a feature of this work, the conductive path formed in the YMnO₃ (YMO)/Pt interface during the RS process was directly observed through cross-section conduct atomic force microscopy (CAFM). By the voltage source 2-wire and the current source 4-wire measurements, the RS properties of the YMO/Pt interface and YMO film were further distinguished and studied in a special Pt/YMO/Pt step sample. Moreover, fitting results based on current–voltage curves exhibit the high resistance state (HRS) and low resistance state (LRS), in accordance with the Schottky emission and Ohm's law, respectively. The resistances of the HRS increase with the temperature decrease, while those of the LRS demonstrate a reverse trend in the same process, indicating semiconductor and metal characteristics, respectively. Combining the results of energy dispersive spectroscopy, the RS mechanism was attributed to the conductive path in association with the Mn vacancies created in the annealing process. (paper)