Characterization of gadolinium oxide thin films with CF4 plasma treatment for resistive switching memory applications

The effect of the CF4 plasma treatment on the gadolinium oxide (GdxOy) thin films for the resistive random access memory (RRAM) applications was investigated. The material properties of the fluorine incorporated GdxOy films were analyzed by the X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS) and ultraviolet-visible spectroscopy (UV-VIS). Further, the set and reset voltages of the Pt/GdxOy/W RRAM devices with the CF4 plasma treatment were effectively reduced to −1.15 and 2.1 V respectively owing to the low Schottky barrier height. The formation of GdF bonds can prevent the oxygen atoms from out-diffusing through Pt grain boundaries into the atmosphere, leading to the superior retention characteristics for over 104 s. The CF4 plasma treated GdxOy RRAMs can sustain a resistance ratio of 102 for more than 800 times stable set/reset cycling, suitable for future low-voltage and high-performance nonvolatile memory operation.