Nonvolatile Memory Devices Prepared from Sol-Gel Derived Niobium Pentoxide Films

Abstract

We report on the resistive switching nonvolatile memory (RSNM) properties of niobium pentoxide (Nb2O5) films prepared using sol-gel chemistry. A sol-gel derived solution of niobium ethoxide, a precursor to Nb2O5, was spin-coated on to a platinum (Pt)-coated silicon substrate, and was then annealed at approximately 620 and 450 degrees C to form a Nb2O5 film of polycrystalline and amorphous structure, respectively. A top electrode consisting of Ag, W, Au, or Pt was then coated onto the Nb2O5 films to complete the fabrication. After a forming process of limited current compliance up to 10 mA, known as "electroforming", a resistive switching phenomenon, independent of voltage polarity (unipolar switching), was observed at low operating voltages (0.59 +/- 0.05 V-RESET and 1.03 +/- 0.06 V-SET) with a high ON/OFF current ratio above 10(8). The reported approach offers opportunities for preparing Nb2O5-based resistive switching memory devices from solution process.