Effect of oxygen content on resistive switching memory characteristics of TiO _x films

This work reports a strong oxygen-content dependence of the resistive switching characteristics in TiO _x films grown by sputtering Ti under an oxygen ambient at flow rates (F _Q) from 0.4 to 2.0 sccm. Remarkable improvements in the resistive switching parameters of the Al/TiO _x/Pt memory devices, including dispersions of set/reset voltages, on/off ratio, and data retention, are obtained at F _Q = 1. 1 sccm. Based on the results of Rutherford backscattering and X-ray photoelectron spectroscopy, we show that the resistive switching characteristics of Al/TiO _x/Pt devices are determined by the stoichiometry of the TiO _x films and by the number of mobile oxygen ions in the films.