Stabilizing Resistive Switching Characteristics by Inserting Indium-Tin-Oxide Layer as Oxygen Ion Reservoir in HfO₂-Based Resistive Random Access Memory

This paper investigates the issues of oxygen accumulation and variation in the high-resistance state of HfO ₂ -based resistive random access memory (RRAM), with improvement attained by inserting a thin oxygen-vacancy-rich layer of indium-tin-oxide (ITO) film. By acting as the oxygen ion reservoir, this ITO thin film on the TiN electrode can further stabilize resistance switching (RS) characteristics. In terms of reliability, ac endurance, and retention tests confirm stable RS characteristics for the Pt/HfO ₂ /ITO/TiN device. Finally, a conducting model was proposed to explain the influence of the ITO thin layer and clarify the physical mechanism of electrical improvements.