Multi-level operation in VO2-based resistive switching devices

Vanadium dioxide (VO2) is widely studied for its prominent insulator–metal transition (IMT) near room temperature, with potential applications in novel memory devices and brain-inspired neuromorphic computing. We report on the fabrication of in-plane VO2 metal–insulator–metal structures and reproducible switching measurements in these two-terminal devices. Resistive switching can be achieved by applying voltage or current bias, which creates Joule heating in the device and triggers the IMT. We analyze the current/voltage-induced resistive switching characteristics, including a pronounced intermediate state in the reset from the low to the high resistance state. Controllable switching behavior is demonstrated between multiple resistance levels over several orders of magnitude, allowing for multibit operation. This multi-level operation of the VO2-bridge devices results from exploiting sub-hysteresis loops by Joule heating.