Etching-dependent reproducible memory switching in vertical SiO2 structures

Vertical structures of SiO2 sandwiched between a top tungsten electrode and conducting nonmetallic substrate were fabricated by dry and wet etching methods. Both structures exhibit similar voltage-controlled memory behaviors, in which short voltage pulses (1 mu s) can switch the devices between high- and low-impedance states. Through the comparison of current-voltage characteristics in structures made by different methods, filamentary conduction at the etched oxide edges is most consistent with the results, providing insights into similar behaviors in metal/SiO/metal systems. High ON/OFF ratios of over 10(4) were demonstrated.