Multilevel operation of GdO_x-based resistive switching memory device fabricated by post-deposition annealing

Resistive switching memory has been studied actively for next-generation computing. Several binary oxides, such as HfO₂ and Ta₂O₅, are widely adapted as resistive switching layers; however, there are several limitations to obtaining an energy- and area-efficient operation with sufficient reliability. Rare-earth oxide materials exhibit interesting resistive switching properties because of their reactivities with active anion species. In this study, atomic-layer-deposited GdO_x films were investigated as an active switching layer for resistive switching memory. Post-deposition annealing of as-grown GdO_x films enhanced the tunability of the resistance states, which can be useful for the multilevel operation of nonvolatile memory and neuromorphic computing applications. The effects of the crystallization and hygroscopic nature of the GdO_x film are investigated for elucidating the change in the resistive switching characteristics and its underlying mechanism.