Influence of fabrication parameters on the Schottky barrier modulation of Mo/MoOx/IGZO/Ti/Mo memristor

This study investigates the impact of annealing and plasma treatments on the electrical and structural properties of Mo/MoOx/IGZO/Ti/Mo memristors, with focus on the effective Schottky barrier modulation at the MoOx/IGZO interface. The IGZO memristors demonstrate reliable analog switching with area-dependent resistance states, showcasing the potential of interface engineering in improving memristor performance. The role of oxygen vacancies as key contributors to the conduction in IGZO is explored, emphasizing their formation and distribution under varying conditions. X-ray photoelectron spectroscopy and scanning transmission electron microscopy analyses reveal that annealing redistributes oxygen within IGZO, lowering the effective Schottky barrier at the bottom interface where resistive switching (RS) takes place, and improving device-to-device variability. On the other hand, an oxygen plasma treatment on the active Schottky electrode can control whether the equilibrium state of the devices is at the low resistive state (LRS) or at the high resistive state (HRS). Additionally, employing a top contact with high oxygen affinity increases the ILRS/IHRS ratio of the memristors. Long-term passivation studies show that parylene-C significantly improves device yield after more than five years of ambient aging. These findings provide a deeper understanding of the mechanisms governing RS in IGZO-based memristors and highlight the critical interplay between fabrication steps and device functionality. In total, more than 90 devices were characterized, strengthening the statistical relevance of the findings.