【Device Papers】Forming-free resistive switching characteristics of RF-sputtered Ga₂O₃-based memristors

      Researchers from the Tech University of Korea have published a dissertation titled "Forming-free resistive switching characteristics of RF-sputtered Ga₂O₃-based memristors" in Materials Science in Semiconductor Processing.

Abstract

      Gallium oxide (Ga₂O₃) is a promising material for non-volatile memory due to its wide bandgap and defect-tolerant properties. This study systematically investigates the effects of rapid thermal annealing atmosphere and temperature on Pt/Ga₂O₃/Pt memristors fabricated on sapphire substrates. Structural and chemical analyses reveal that while high-temperature annealing promotes crystallization of sputtered Ga₂O₃ films, the annealing atmosphere critically governs the kinetics of defects. X-ray photoelectron spectroscopy confirms that N₂ annealing increases oxygen-vacancy concentration, whereas O₂ annealing suppresses vacancies and restores stoichiometric Ga–O bonding. These defects strongly influence electrical transport and resistive switching behavior. Notably, N₂-annealed memristors inherently exhibit a defect-induced low-resistance initial state, which can be transformed into a well-defined high-resistance state through an initial-RESET process, thereby enabling forming-free memristive operation without a conventional electroforming step. In contrast, O₂-annealed devices show enhanced insulation and improved off-state stability. The on/off ratio systematically increases with annealing temperature, reaching 8.45 × 10⁷ for O₂ annealing at 1000 °C, while optimal performance for N₂ annealing occurs at 800 °C. All devices demonstrate stable bipolar switching and robust data retention up to 10⁴ s.

DOI：

https://doi.org/10.1016/j.mssp.2026.110648