A conducting atomic force microscopy study of conducting filament nanobits in the epitaxial NiO thin film prepared precisely controlled by the oxidation time of the single crystalline Ni substrates

We report on the formation of conducing filament (CF) nanodots and the resistive random access memory (RRAM) characteristics of epitaxial NiO thin films with good crystallinity obtained by oxidation of the single crystal Ni substrates. The thickness of the epitaxial NiO thin films with good crystallinity was precisely controlled by the oxidation time. The local current mapping using conducing atomic force microscope (CAFM) showed that the NiO thin films had uniform resistance without conducing defects inside. In particular, it was confirmed that CF nanodots with a diameter of several nanometers in the 5-nm-thick NiO thin film and the storage density of about 16.7 Tbit/in(2) was achieved by arranging the CF nanodots.