Controlling Electrochemical Metallization in Low-Temperature Microwave-Grown MoS2 RRAM through Ultrathin MoO3 Interfacial Engineering

Abstract

Resistive random-access memory (RRAM) has attracted significant attention as a next-generation nonvolatile memory technology owing to its simple structure, fast switching speed, and compatibility with back-end-of-line (BEOL) integration. Among emerging switching media, two-dimensional molybdenum disulfide (MoS₂) offers unique advantages arising from its atomically thin structure and interface-dominated transport characteristics. However, the integration of MoS₂-based memory devices is often limited by the high synthesis temperatures required for conventional growth methods. Here, we demonstrate MoS₂-based RRAM devices employing directly grown MoS₂ films synthesized by microwave plasma-enhanced sulfurization at a process temperature below 400 °C without transfer processes. The switching behavior was found to strongly depend on the top electrode material. Inert Au electrodes exhibited vacancy-mediated resistive switching with stable retention but limited endurance, whereas active Ag and Cu electrodes showed electrochemical metallization (ECM)-type behavior associated with metal ion migration and conductive filament formation. To improve switching stability, an ultrathin 1 nm MoO₃ interlayer was introduced between Ag and MoS₂ to regulate Ag migration while preserving the ECM switching mechanism. The optimized Ag/MoO₃ (1 nm)/MoS₂/Au device exhibited stable SET/RESET voltages of approximately 0.6/–1.9 V, retention exceeding 10⁴ s, and endurance approaching 10³ cycles (∼950 cycles). Depth-resolved X-ray photoelectron spectroscopy further confirmed the reversible redistribution of Ag species during switching, supporting a filamentary ECM mechanism. This work demonstrates a practical low-temperature approach for improving the reliability of MoS₂-based RRAM devices through interfacial ion-transport control, providing a BEOL-compatible pathway toward scalable resistive memory integration.