Effect of Operating Conditions on Switching Variations in Ag/Ti/SiOx/Au RRAM Devices

In this work, Ag/Ti/SiOx/Au RRAM devices were fabricated, and their electrical characteristics were investigated under different operating conditions to understand the stochastic nature. For increasing compliance (250 µA – 1 mA), the devices exhibit coexistence of volatile and non-volatile behaviour from cycle-to-cycle that broadens the overall switching voltages variability. This trend results from stochasticity in filament formation and rupture from volatile and non-volatile switching. Furthermore, the variability enhances through increasing the reset voltage. The increased electric field and Joule heating at a higher reset voltage (– 1.5 V) cause larger filament rupture during the reset operation that varies from cycle-to-cycle than at lower reset voltage biases, thereby increasing variability. The combination of ± 1.5 V sweep bias at 5 mA compliance appears to be the optimal operating parameters for our devices to achieve higher switching-voltage variability. The variability of these devices under different operating electrical parameters can be utilized as a source of entropy for security applications.