Controlled oxygen vacancy electrode reservoir for robust WO3-based memory devices

Abstract

Oxide-based memristors are promising candidates as neuromorphic hardware in energy-efficient edge computing applications for the Internet of Things (IoT). However, achieving simultaneously optimized memristive and synaptic performance with low-temperature fabrication, compatible with complementary metal-oxide-semiconductor (CMOS) processes, remains a challenge. Here, we demonstrate a dual-function electrode selection strategy—controlled oxygen vacancy electrode reservoir—implemented in a simple, low-temperature-fabricated indium tin oxide (ITO)/WO3/TiN thin film system. We systematically vary the oxygen stoichiometry in the ITO top electrode, which serves not only as an electrical contact, but also as a dynamic oxygen reservoir. A high oxygen-vacancy concentration in the ITO enables optimized memristive performance of low electroforming and operation voltages, and robust memristive and synaptic endurance. This electrode-focused defect engineering approach offers a versatile route to advanced memristor design, enabling many applications in IoT and neuromorphic systems.