Sputter-processed oxide films are typically annealed at high temperature (activation process) to achieve stable electrical characteristics through the formation of strong metal-oxide chemical bonds. For instance, indium-gallium-zinc oxide (IGZO) films typically need a thermal treatment at 300 °C for ≥1 h as an activation process. We propose an open-air plasma treatment (OPT) to rapidly and effectively activate sputter-processed IGZO films. The OPT effectively induces metal-oxide chemical bonds in IGZO films at temperatures as low as 240 °C, with a dwell time on the order of a second. Furthermore, by controlling the plasma-processing conditions (scan speed, distance a between plasma nozzle and samples, and gas flow rate), the electrical characteristics and the microstructure of the IGZO films can be easily tuned. Finally, OPT can be utilized to implement a selective activation process. Plasma-treated IGZO thin-film transistors (TFTs) exhibit comparable electrical characteristics to those of conventionally thermal treated IGZO TFTs. Through in-depth optical, chemical, and physical characterizations, we confirm that OPT simultaneously dissociates weak chemical bonds by UV radiation and ion bombardment and re-establishes the metal-oxide network by radical reaction and OPT-induced heat.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2017R1A2B3008719) and Department of Energy through the Bay Area Photovoltaics Consortium under Award Number DE-EE0004946. Part of this work was performed at the Stanford Nano Shared Facilities (SNSF), supported by the National Science Foundation under award ECCS-1542152.
© 2018 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Materials Science(all)