Highly Uniform and Reliable Resistance Switching Properties in Bilayer WOx/NbOx RRAM Devices

Abstract

Memory performances, especially uniformity and reliability of resistance random access memory (RRAM) devices with W/NbOx/Pt structures were investigated. Scaling down the active device area (phi=?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 WOx/NbOx 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 (>104?s, 85 degrees C), stable cycling endurance (107 cycles), almost 100% device yield and excellent switching uniformity are obtained.