Effects of plasma treatment time on surface characteristics of indium-tin-oxide film for resistive switching storage applications

In this paper, we implement a post-oxidation method to modify surface characteristics of indium tin oxide (ITO) films by using an O-2 inductively coupled plasma (ICP) treatment. Based on field emission scanning electron microscope (FE-SEM) and atomic force microscope (AFM) analysis, we found that the surface morphologies of the ITO films become slightly flatter after the O-2 plasma treatment. The optical characteristics and X-ray diffraction (XRD) experiments of either pure ITO or O-2 plasma treated ITO films were also verified. Even though the XRD results showed no difference from bulk crystallizations, the oxygen concentrations increased at the film surface after O-2 plasma treatment, according to the XPS inspection results. Moreover, this study investigated the effects of two different plasma treatment times on oxygen concentration in the ITO films. The surface sheet resistance of the plasma treated ITO films became nearly non-conductive when measured with a 4-point probe. Finally, we applied the O-2 plasma treated ITO films as the insulator in resistive random access memory (RRAM) to examine their potential for use in resistive switching storage applications. Stable resistance switching characteristics were obtained by applying the O-2 plasma treatment to the ITO-based RRAM. We also confirmed the relationship between plasma treatment time and RRAM performance. These material analyses and electrical measurements suggest possible advantages in using this plasma treatment technique in device fabrication processes for RRAM applications. (C ) 2017 Elsevier B.V. All rights reserved.