Resistive random access memory characteristics of NiO thin films with an oxygen-deficient NiO_0.95 layer

Herein, we characterize resistive random access memory (RRAM) devices containing an oxygen-deficient layer. The RRAM devices consist of multiple layered NiO thin films that consist of an oxygen-deficient NiO_0.95 layer, within a NiO/NiO_0.95/NiO layer structure. The NiO thin-film layers were deposited on Pt/Ta/SiO₂/Si substrates by radio frequency magnetron sputtering. The stoichiometry and thickness of the NiO triple-layer thin films were determined by Auger electron spectroscopy. We fabricated RRAM capacitors with a structure of Pt/NiO/NiO_0.95/NiO/Pt to investigate the resistive switching characteristics. The presence of an oxygen-deficient layer significantly lowers the forming and SET/RESET voltages compared to a Pt/NiO/Pt RRAM capacitor. This reduces the energy required to form conducting filaments in the oxygen-deficient layer. Moreover, the forming and SET/RESET voltages exhibit reduced dispersion due to the relatively high oxygen vacancy density in the oxygen-deficient NiO_0.95 layer.