Nonvolatile memory devices prepared from sol-gel derived niobium pentoxide films

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 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 10⁸. The reported approach offers opportunities for preparing Nb₂O₅-based resistive switching memory devices from solution process.