Enhancing carrier mobility of IGZO TFT fabricated by non-vacuum mist CVD with O3 assistance

Authors

  • Toshiyuki Kawaharamura,

    Corresponding author
    1. Institute for Nanotechnology, Kochi Univ. of Technology, 185 Miyanokuchi Tosayamada, Kami-city, Kochi 782-8502, Japan
    • Phone: +81 887 57 2747, Fax: +81 887 57 2714

    Search for more papers by this author
  • Takayuki Uchida,

    1. School of Syst. Eng., Kochi Univ. of Technology, 185 Miyanokuchi Tosayamada, Kami-city, Kochi 782-8502, Japan
    Search for more papers by this author
  • Dapeng Wang,

    1. Institute for Nanotechnology, Kochi Univ. of Technology, 185 Miyanokuchi Tosayamada, Kami-city, Kochi 782-8502, Japan
    Search for more papers by this author
  • Masaru Sanada,

    1. Institute for Nanotechnology, Kochi Univ. of Technology, 185 Miyanokuchi Tosayamada, Kami-city, Kochi 782-8502, Japan
    2. School of Syst. Eng., Kochi Univ. of Technology, 185 Miyanokuchi Tosayamada, Kami-city, Kochi 782-8502, Japan
    Search for more papers by this author
  • Mamoru Furuta

    1. Institute for Nanotechnology, Kochi Univ. of Technology, 185 Miyanokuchi Tosayamada, Kami-city, Kochi 782-8502, Japan
    2. School of Env. Sci. & Eng., Kochi Univ. of Technolongy, 185 Miyanokuchi Tosayamada, Kami-city, Kochi 782-8502, Japan
    Search for more papers by this author

Abstract

Recently, we succeeded in demonstrating an oxide TFT consisting of a channel layer (IGZO) and gate insulator (AlOx) continuously fabricated by non-vacuum mist CVD. In this report, each thin film and the interfaces of the films have been improved with ozone (O3) assistance, as the initial oxide TFT had poor characteristics compared with those of the IGZO TFT fabricated by the conventional vacuum process. A superhydrophilic interface between AlOx and IGZO was obtained by removing the adhered organic matter from the film surface. The breakdown fields (EBD) and dielectric constant (κ) of the AlOx thin films were improved from 6 to 8 MV/cm and from 6 to 7, respectively, and the carrier concentration of the IGZO thin film decreased from 1019 to 1016 cm–3. The oxide TFT exhibited field effect mobility (μlin) of 8.7 cm2/(Vs), sub-threshold slope (S) of around 0.3 V/dec. and hysteresis (ΔVH) of around 0.5 V. These values were obtained by improving each thin film and the interfaces of the films with O3 assistance. This result is an important first step toward non-vacuum oxide TFT fabrication processes. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Ancillary