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

• Published in: IEEE transactions on electron devices 2014-04, Vol.61 (4), p.1093-1100
• Main Authors: Singh, Thokchom Birendra, Jasieniak, Jacek Jaroslaw, de Oliveira Tozi, Leonardo, Easton, Christopher David, Bown, Mark
• Format: Article
• Language: English
• Subjects: Active matrix organic light emitting-diodes (AMOLEDs); amorphous oxide semiconductors; Annealing; charge carriers mobility; high uniformity; Impurities; Logic gates; Metals; Substrates; Thin film transistors
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2014.2303796

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 cm 2 /Vs with on and off ratio of 10 7 . 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.