Coexistence of bipolar and unipolar resistive switching in Al-doped ceria thin films for non-volatile memory applications

The Ti/CeO2/Al/CeO2/Pt stacks as a ReRAM device exhibits bipolar and unipolar resistive switching behaviors. The OFF/ON resistance ratio (>10(2)) in both modes is almost similar but operating voltages are slightly smaller in the former than in the later. These devices could switch between the two operating modes merely by choosing the polarity of RESET voltage. In addition, the requirement of identical current compliance during the SET process of both modes provides an additional advantage of simplicity in device operation. The conduction mechanisms of high resistance state and low resistance state are Schottky emission and Ohmic conduction. On the basis of analyses of current-voltage characteristics and temperature dependence of resistance, resistive switching mechanism originated from a combined effect of field induced diffusion of oxygen and Al ions in the sandwiched ceria matrix. (C) 2015 Elsevier B.V. All rights reserved.