Improving Performance by Doping Gadolinium Into the Indium-Tin–Oxide Electrode in HfO2-Based Resistive Random Access Memory

This letter investigates the characteristics of doping gadolinium (Gd) in an indium-tin-oxide (ITO) electrode in HfO
₂
-based resistive random access memory (RRAM). Identical bottom electrodes and insulators were made but then capped by either pure ITO or a Gd:ITO top electrode. Doping Gd in the ITO electrode produces lower operation currents in both high-resistance state (HRS) and low-resistance state (LRS) as well as enlarging the memory window. This excellent performance suggests a remarkable potential to improve RRAM applications. Schottky emission mechanism dominates both HRS and LRS according to current fitting results, and is confirmed by temperature effect experiments. The resistive switching behavior of the Gd:ITO device is explained by our model and is also confirmed by material analysis and electrical measurements. Furthermore, reliability tests verify the Gd:ITO device's capability to perform data storage as a nonvolatile memory.