Anodic $\hbox {Nb}_{2}\hbox {O}_{5}$ Nonvolatile RRAM

We report nonvolatile resistive switching in anodic niobium pentoxide thin-film memory cells. Highly dielectric Nb₂O₅ films were prepared at room temperature by the anodic oxidation of submicrometer-thick Nb films sputtered onto an Si wafer. After the electroforming process, Au/Nb₂O₅/Nb/Si sandwich memory cells demonstrate reproducible direct current and pulse mode switching between two resistance states with a resistance on-off ratio around 10³. Low and high resististive states show ohmic conductivity and field-assisted Poole-Frenkel-type conductivity, respectively. Nonvolatile resistance storage was traced within 40 days to quantify retention characteristics of the Nb₂O₅ memristor. The low-temperature anodic oxidation of Nb was found to be feasible to fabricate high-density cross-point memory with 3-D stack structures.