Performance stability and functional reliability in bipolar resistive switching of bilayer ceria based resistive random access memory devices

Memory devices based on Ti/CeO2-x:CeO2/ITO stacks with bilayer structure fabricated by rf-magnetron sputtering demonstrate promising bipolar resistive switching behavior with relatively low-voltage operation and small distribution of switching parameters. These devices show much reliable repeatability and good endurance (>104 switching cycles) without any significant degradation in their performance. The cycle-to-cycle and device-to-device distribution of resistance switching parameters, such as resistances in the low and high resistance states, set and reset voltages have been investigated and discussed. Resistive switching behavior in our devices has been proposed to originate from the electric field induced drift of defects (specifically oxygen vacancies) preferably along grain boundaries in the bilayer structure of active dielectric layer.