Bulk Oxygen–Ion Storage in Indium–Tin–Oxide Electrode for Improved Performance of HfO₂-Based Resistive Random Access Memory

Indium-tin-oxide (ITO) is investigated as the top electrode material in HfO 2 -based resistive random access memory cells. Experimental results show that in contrast to a metal (Pt) electrode, an ITO electrode provides for self-limiting current flow during the forming and SET processes, so that no compliance limit is necessary. This provides for low-power consumption, high endurance (>10 7 cycles), and short SET/RESET transition times (~50 ns). We propose that this is because ITO is an oxygen-vacancy-rich material, providing bulk storage for oxygen ions rather than surface storage as a metal electrode.