Thickness-dependent resistive switching memory characteristics of NiO nanodisks fabricated by AAO nanotemplate

Forming and set/reset operating voltages are critical issues encountered with a decrease in resistive random-access memory (RRAM) sizes. This study investigated the thickness-dependent resistive switching properties of NiO nanodisks. The NiO RRAM nanodisks, with a diameter of 100 nm and varying thicknesses, were fabricated on Pt/Ta/SiO₂/Si substrates using anodic aluminum oxide templates through the RF sputtering process. In the electroforming process, the forming voltage of the NiO nanodisk effectively reduced with a decrease in the thickness. The electric field enhancement in localized regions appeared to contribute to the reduction in the forming voltage. In addition, the set/reset operating voltage of the NiO nanodisk RRAM decreased with a decrease in the thickness. We conclude that the use of the C-AFM tip strengthened the local electric field in NiO nanodisk RRAM cells, leading to the reduction of the set/reset voltage with a decrease in the thickness.