Abnormal bipolar-like resistance change behavior induced by symmetric electroforming in Pt/TiO2/Pt resistive switching cells.

Abnormal bipolar-like resistive changes are reported in TiO(2) thin films sandwiched between Pt top and bottom electrodes. The abnormal behavior is shown relying on the applied voltage range. That is, normal bipolar switching is also shown in the same sample with the optimized voltage range. In the abnormal mode, both set- and reset-like changes in resistance take place under the same polarity of the applied voltage. This abnormal behavior is considered to be due to symmetric electroforming which is assumed to activate electrochemical reactions involving oxygen vacancies at both Pt/TiO(2) interfaces. We analyze the abnormal behavior in terms of the interfacial resistive switching taking place on both interfaces nearly simultaneously.