A Comprehensive Study of Enhanced Characteristics with Localized Transition in Interface-type Vanadium-based Devices

Abstract In this research, we investigated the conduction mechanism in metal-insulator transition materials. Among these metal-insulator transition (MIT) materials (NbOx, NiOx, VOx, and TaS2), vanadium oxide based-selectors have been widely investigated because of their high switching speed (∼10ns transition time), sufficient nonlinearity (>103) and endurance stability (∼1010). Abnormal temperature-dependent degradation in the high resistive state was observed, as was studied in detail by a current fitting analysis and explored theoretically by electric (E-IMT) and thermal (T-IMT) modeling. Results suggest the existence of a metal-insulator transition region located between the electrode and the localized filament. To improve the localized transition efficiency, we propose an enhanced-type MIT architecture to bypass the E-IMT and T-IMT universal rule with the novel structure of vanadium top electrode device. As compared to a vanadium oxide middle-layer device, the electrical transition efficiency is improved by 2x as evidenced by thermal-cycling material analysis, as well as boosting endurance reliability to 107 at 65 oC. Finally, for the first time, a potential neuromorphic computing application featuring a damping oscillator has been demonstrated in this enhanced-type MIT architecture, and a high damping ratio with 10x smaller area and 5x smaller on energy as compared CMOS devices. This presents a promising milestone for ultra-low power neuromorphic system design and solutions in the near future.