Excellent Selector Characteristics of Nanoscale VO2 for High-Density Bipolar ReRAM Applications

We herein present a nanoscale vanadium oxide (VO2) device with excellent selector characteristics such as a high ON/ OFF ratio (> 50), fast switching speed (< 20 ns), and high current density (> 10(6) A/ cm(2)). Owing to extrinsic defects, a large-area device with a 20-nm-thick VO2 layer underwent an electrical short. In contrast, after scaling the device active area (< 5 x 10(4) nm(2)), excellent switching uniformity was obtained. This can be explained by the reduced defects and the metal-insulator transition of the whole nanoscale VO2. By integrating a bipolar resistive random access memory device with the VO2 selection device, a significantly improved readout margin was obtained. The VO2 selection device shows good potential for cross-point bipolar resistive memory applications.