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

Highlights: • Epitaxial NiO thin films prepared by thermal oxidation of single crystalline (100) Ni substrates. • A RRAM capacitor with a Ni/NiO/Ni structure made of 100-nm-thick NiO thin films. • A conducting atomic force microscopy (CAFM) image of the 5-nm-thick NiO thin film. • Conducting filament nanobit array with a data storage density of about 16.7 Tbit/in². -- Abstract: We report on the formation of conducting 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 conducting atomic force microscope (CAFM) showed that the NiO thin films had uniform resistance without conducting 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/in² was achieved by arranging the CF nanodots.