Effect of Electrochemically Active Top Electrode Materials on Nanoionic Conductive Bridge Y₂O₃ Random-Access Memory

Abstract

Herein, sol–gel-processed Y2O3 resistive random-access memory (RRAM) devices were fabricated. The top electrodes (TEs), such as Ag or Cu, affect the electrical characteristics of the Y2O3 RRAM devices. The oxidation process, mobile ion migration speed, and reduction process all impact the conductive filament formation of the indium–tin–oxide (ITO)/Y2O3/Ag and ITO/Y2O3/Cu RRAM devices. Between Ag and Cu, Cu can easily be oxidized due to its standard redox potential values. However, the conductive filament is easily formed using Ag TEs. After triggering the oxidation process, the formed Ag mobile metal ions can migrate faster inside Y2O3 active channel materials when compared to the formed Cu mobile metal ions. The fast migration inside the Y2O3 active channel materials successfully reduces the SET voltage and improves the number of programming–erasing cycles, i.e., endurance, which is one of the nonvolatile memory parameters. These results elucidate the importance of the electrochemical properties of TEs, providing a deeper understanding of how these factors influence the resistive switching characteristics of metal oxide-based atomic switches and conductive-metal-bridge-filament-based cells.

Keywords

• sol–gel
• Y₂O₃
• RRAM
• CBRAM
• top electrodes