Evaluation of the WO x Film Properties for Resistive Random Access Memory Application

The formation condition, microstructure, and growth kinetics of the WO x layer for WO x resistive random access memory are investigated. To understand the optimal condition for the rapid thermal oxidation process which forms the WO x layer, various annealing temperature and annealing time are systemically studied through transmission electron microscopy, X-ray diffraction, Raman spectra analyses and electrical characterizations. The growth kinetics for WO x under rapid thermal oxidation is found similar to the one for thermal oxidation on silicon. The electrical forming voltages of the WO x cells are also found independent from the oxide thickness, which further suggests the switching behavior of WO x resistive random access memory takes place at the interface but not the bulk.