Improved reset breakdown strength in a HfO_x-based resistive memory by introducing RuO_x oxygen diffusion barrier

We investigated the reset breakdown phenomenon of HfO_x-based resistive memory for reliable switching operation in a fully CMOS compatible stack. Through the understanding on the effect of electrode materials and device area, our findings show that observed failure is attributed to additional oxygen vacancies close to the electrode interface, where switching is occurred. Therefore, RuO_x serving as an oxygen diffusion barrier was introduced to suppress the generation of unwanted oxygen vacancies by preventing out-diffusion of oxygen through the electrode. As a result, significantly enhanced breakdown strength in HfO_x/RuO_x stack is achieved and resulting in improved cycle endurance with larger on/off ratio.