Multi-level resistive switching observations in asymmetric Pt/Ta2O5−x/TiOxNy/TiN/Ta2O5−x/Pt multilayer configurations

We examine multilevel (ML) resistance switching properties in a Pt/Ta2O5−x/TiOxNy/TiN/Ta2O5−x/Pt matrix, in which two bipolar resistive switching elements Pt/Ta2O5−x/TiOxNy and TiN/Ta2O5−x/Pt are anti-serially and electrically connected. The ML features for the three assigned, distinguishable resistance states are clearly identified by using an I–V device operation scheme, indicating that the middle TiN and TiOxNy electrodes are crucial for adjusting ML resistance states. Experimental observations suggest that the ML switching events rely on electrically induced oxygen ion drifts at interfaces between the top/bottom Ta2O5−x and middle TiN/TiOxNy layers.