Multifunctional resistive switching behaviors employing various electroforming steps

We examine the electroforming-dependent multifunctional resistive switching features by operating a merged Pt/Ta2O5-x/Ta-Ta/Ta2O5-x/Pt switching device under particular bias and polarity conditions. The basic Pt/Ta2O5-x/Ta resistive switching cell comprising the completely merged device shows two different bipolar switching behaviors with an initial forming process under different bias polarities. Therefore, two switching elements can be merged in various ways to produce diverse functionalities such as asymmetric complementary resistive switching (CRS) and typical CRS, achieved through control of the forming process. A possible mechanism to explain the unique features observed is discussed in terms of bias-driven oxygen ion drift and Joule-heating-based filamentary path models. This work suggests a suitable electroforming route for advancing symmetric CRS characteristics.