Effect of Scaling $\hbox {WO}_{x}$ -Based RRAMs on Their Resistive Switching Characteristics

We investigated the effect of scaling down the device area of WOx resistive random-access memory (RRAM) devices on their switching characteristics. Device dimensions were successfully scaled down to 50 nm using a via-hole structure with additional Al₂O₃ sidewall process. As compared to the microscale devices, the nanoscale devices exhibited a distinct switching mechanism and better memory performance, such as improved switching uniformity, larger memory window, and stable endurance characteristics for up to 10⁷ cycles. This improvement can be explained by a uniform interfacial switching mechanism in nanoscale device; this is in contrast with the defect-induced filamentary switching mechanism observed in microscale devices. In this way, the intrinsic switching properties of RRAMs were obtained by scaling down of the device area, indicating that RRAMs hold considerable promise for future applications.