Characterization of gadolinium oxide thin films with CF ₄ plasma treatment for resistive switching memory applications

The effect of the CF ₄ plasma treatment on the gadolinium oxide (Gd _x O _y ) thin films for the resistive random access memory (RRAM) applications was investigated. The material properties of the fluorine incorporated Gd _x O _y 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/Gd _x O _y /W RRAM devices with the CF ₄ 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 10 ⁴ s. The CF ₄ plasma treated Gd _x O _y RRAMs can sustain a resistance ratio of 10 ² for more than 800 times stable set/reset cycling, suitable for future low-voltage and high-performance nonvolatile memory operation.