Factors Determining the Resistive Switching Behavior of Transparent InGaZnO-Based Memristors

The overarching goal herein is to identify the factors dominating the performance of a-IGZO-based memristors. Despite the highest on/off ratio, greater than 10⁴ with a preferred minimal set/reset bias achieved from a-IGZO-based memristors, it is observed that the switching performance and stability/reliability of the devices is significantly dominated by the V_O^·· density and metallization material, depending on their reactivity with IGZO. As the first governing factor, ensuring optimal V_O^·· concentration in the switching layer IGZO (V_O^··/O_O^x ratio 24.3% in this study) is crucial to obtain the tractable formation and rupture of conduction filament. Neither higher nor lower V_O^·· density than the optimized results in detrimental reliability issues, which may be ascribed to an uncontrollable filament in an abundant vacancy environment or a weak conducting path, respectively. As the second governing mechanism determining the memristor performance and reliability, it is suggested that metallization materials need to be carefully selected based on the thermodynamic redox potential and interfacial stability of the metallization material with IGZO. Metallization materials with larger reduction potential and interfacial stability are found to yield higher switching on/off ratio and greater device performance reliability.