Ti-Doped GaO_x Resistive Switching Memory with Self-Rectifying Behavior by Using NbO_x/Pt Bilayers

Crossbar arrays (CBAs) with resistive random access memory (ReRAM) constitute an established architecture for high-density memory. However, sneak paths via unselected cells increase the total power consumption of these devices and limit the array size. To eliminate such sneak-path problems, we propose a Ti/GaO_x/NbO_x/Pt structure with a self-rectifying resistive-switching (RS) behavior. In this structure, to reduce the operating voltage, we used a Ti/GaO_x stack to increase the number of trap sites in the RS GaO_x layer through interfacial reactions between the Ti and GaO_x layers. This increase enables easier carrier transport with reduced electric fields. We then adopted a NbO_x/Pt stack to add rectifying behavior to the RS GaO_x layer. This behavior is a result of the large Schottky barrier height between the NbO_x and Pt layers. Finally, both the Ti/GaO_x and NbO_x/Pt stacks were combined to realize a self-rectifying ReRAM device, which exhibited excellent performance. Characteristics of the device include a low operating voltage range (-2.8 to 2.5 V), high on/off ratios (∼20), high selectivity (∼10⁴), high operating speeds (200-500 ns), a very low forming voltage (∼3 V), stable operation, and excellent uniformity for high-density CBA-based ReRAM applications.