Multi-layered NiOy/NbOx/NiOy fast drift-free threshold switch with high Ion/Ioff ratio for selector application

NbO 2 has the potential for a variety of electronic applications due to its electrically induced insulator-to-metal transition (IMT) characteristic. In this study, we find that the IMT behavior of NbO 2 follows the field-induced nucleation by investigating the delay time dependency at various voltages and temperatures. Based on the investigation, we reveal that the origin of leakage current in NbO x is partly due to insufficient Schottky barrier height originating from interface defects between the electrodes and NbO x layer. The leakage current problem can be addressed by inserting thin NiO y barrier layers. The NiO y inserted NbO x device is drift-free and exhibits high I on /I off ratio (>5400), fast switching speed (<2 ns), and high operating temperature (>453 K) characteristics which are highly suitable to selector application for x-point memory arrays. We show that NbO x device with NiO x interlayers in series with resistive random access memory (ReRAM) device demonstrates improved readout margin (>2 9 word lines) suitable for x-point memory array application.