Sol–Gel-Processed Y₂O₃–Al₂O₃ Mixed Oxide-Based Resistive Random-Access-Memory Devices

Herein, sol–gel-processed Y₂O₃–Al₂O₃ mixed oxide-based resistive random-access-memory (RRAM) devices with different proportions of the involved Y₂O₃ and Al₂O₃ precursors were fabricated on indium tin oxide/glass substrates. The corresponding structural, chemical, and electrical properties were investigated. The fabricated devices exhibited conventional bipolar RRAM characteristics without requiring a high-voltage forming process. With an increase in the percentage of Al₂O₃ precursor above 50 mol%, the crystallinity reduced, with the amorphous phase increasing owing to internal stress. Moreover, with increasing Al₂O₃ percentage, the lattice oxygen percentage increased and the oxygen vacancy percentage decreased. A 50% Y₂O₃–50% Al₂O₃ mixed oxide-based RRAM device exhibited the maximum high-resistance-state/low-resistance-state (HRS/LRS) ratio, as required for a large readout margin and array size. Additionally, this device demonstrated good endurance characteristics, maintaining stability for approximately 100 cycles with a high HRS/LRS ratio (>10⁴). The HRS and LRS resistances were also retained up to 10⁴ s without considerable degradation.