Electrically Stable, Solution-Processed Amorphous Oxide IZO Thin-Film Transistors Through a UV-Ozone Assisted Sol-Gel Approach

Metal acetylacetonates are conventional sol-gel precursors used to deposit thin amorphous metal oxide films of In-Zn-O (IZO) suitable for thin-film field effect transistors (TFTs). In this paper, we couple this traditional approach with a postdeposition UV-ozone treatment to effectively reduce carbon impurities prior to any thermal treatment steps. Therefore, we find that the rate of bulk metal oxide formation is enhanced, thus enabling a significant reduction of the processing temperature necessary to achieve high-mobility transistors. Optimized TFT structures processed at 300 °C show n-type mobility of 35 cm²/Vs with on and off ratio of 10⁷. Moreover, positive bias stress tests of such devices are found to exhibit one the lowest threshold voltage shifts of any solution-processed amorphous TFT fabricated without a passivation layer.