Investigation of HfO 2 /Ti based vertical RRAM - Performances and variability

An easy-to-fabricate, low-cost, sidewall TiN/HfO 2 /Ti vertical resistive RAM (VRRAM) device is proposed. Devices with bottom electrode thickness down to 10nm were fabricated and characterized. Forming, SET and RESET voltages of respectively 2V, 0.5V and −0.5V were measured. A stable memory window of one decade was maintained after 10 5 s at 200°C. The impact of scaling on the operating voltages and memory resistance levels was evaluated, showing a SET and RESET voltage reduction as the cell diameter is reduced. Finally the cycle-to-cycle resistance variability was addressed.