Oxygen ion drift-driven dual bipolar hysteresis curves in a single Pt/Ta2O5−x/TiOxNy framework

We describe abnormal dual bipolar resistive switching events in simple Pt/Ta2O5−x/TiOxNy and Pt/Ta2O5−x/TiN matrices in which the typical switching directions (SD) are initially clockwise (CW). The negative difference region in a high resistance state before reaching the typical “CW set” process enables the SD transition to a counterclockwise direction. It thereby emphasizes the occurrence of a highly stable secondary bipolar resistive switching curve. The origin of two different switching modes is described by adapting a bias-dependent oxygen ion accumulation and depletion process at TiOxNy and TiN electrode interfaces and by performing various structural analyses.