Investigation of the effect of oxygen partial pressure during reactive sputtering of tantalum oxide resistive random access memory switching layer

Abstract

Resistive Random Access Memory (ReRAM) is a novel non-volatile memory technology, with potential applications spanning high-density memory and embedded memory in various non-von Neumann computing architectures. This study investigated the dependency of ReRAM switching parameters on the stoichiometry of the tantalum oxide switching layer. Devices were fabricated using reactive sputtering where oxygen partial pressure was varied during deposition of the switching layer. X-ray photoelectron spectroscopy was employed to evaluate the resulting tantalum oxide film composition, showing distinct Ta sub-oxides for each oxygen partial pressure implemented during reactive sputtering. Electrical characterization revealed optimal device performance, with sub-3 V forming voltage and memory window >10 for ReRAM devices deposited with 0.14 mTorr pO₂. Devices fabricated at lower pO₂ and excessively high pO₂ failed to exhibit resistive switching behavior.