Highly uniform and reliable resistance switching properties in bilayer WOx/NbOx RRAM devices

Memory performances, especially uniformity and reliability of resistance random access memory (RRAM) devices with W/NbO x /Pt structures were investigated. Scaling down the active device area ( ø = 250 nm) can significantly minimize extrinsic defects related to nonuniform switching and also demonstrate low‐voltage SET/RESET operations due to increased Joule heating. Electromigration of oxygen ions under the bipolar electric field, bilayer formation, and lightning‐rod effect localized at WO x /NbO x interface can explain the improved switching behavior in this novel stack. Excellent device characteristics such as lower switching voltage, fast switching speed (100 ns), high‐temperature retention (>10 4 s, 85 °C), stable cycling endurance (10 7 cycles), almost 100% device yield and excellent switching uniformity are obtained.