Rapid low-temperature processing of metal-oxide thin film transistors with combined far ultraviolet and thermal annealing

J. Leppäniemi (Corresponding Author), K. Ojanperä, T. Kololuoma, O.-H. Huttunen, J. Dahl, M. Tuominen, P. Laukkanen, H. Majumdar, A. Alastalo

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We propose a combined far ultraviolet (FUV) and thermal annealing method of metal-nitrate-based precursor solutions that allows efficient conversion of the precursor to metal-oxide semiconductor (indium zinc oxide, IZO, and indium oxide, In2O3) both at low-temperature and in short processing time. The combined annealing method enables a reduction of more than 100 °C in annealing temperature when compared to thermally annealed reference thin-film transistor (TFT) devices of similar performance. Amorphous IZO films annealed at 250 °C with FUV for 5 min yield enhancement-mode TFTs with saturation mobility of ∼1 cm2/(V·s). Amorphous In2O3 films annealed for 15 min with FUV at temperatures of 180 °C and 200 °C yield TFTs with low-hysteresis and saturation mobility of 3.2 cm2/(V·s) and 7.5 cm2/(V·s), respectively. The precursor condensation process is clarified with x-ray photoelectron spectroscopy measurements. Introducing the FUV irradiation at 160 nm expedites the condensation process via in situ hydroxyl radical generation that results in the rapid formation of a continuous metal-oxygen-metal structure in the film. The results of this paper are relevant in order to upscale printed electronics fabrication to production-scale roll-to-roll environments.
Original languageEnglish
Article number113514
JournalApplied Physics Letters
Issue number11
Publication statusPublished - 2014
MoE publication typeA1 Journal article-refereed



  • solution processes
  • condensation
  • thin film transistors
  • carrier mobility
  • ozone

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