Deposition of Oxide Thin Films by Ultrasonic Spray Pyrolysis Deposition for InGaZnO Thin-Film Transistor Applications

This letter used ultrasonic spray pyrolysis deposition (USPD) to deposit SnO
₂
:F, Al
₂
O
₃
, and InGaZnO thin films to, respectively, serve as the bottom gate, gate dielectric layer, and channel layer of a thin-film transistor. For comparison, the sputter-deposited InGaZnO thin film was prepared as the reference sample. X-ray diffraction and X-ray photoelectron spectroscopy were used to observe the crystal structure and oxygen vacancy of the InGaZnO thin films. The optical characteristics were observed using the photoluminescence spectrum and an optical spectrometer. The InGaZnO-based TFT deposited by USPD shows competitive electrical characteristics compared with the sputter-deposited one. However, the USPD-deposited InGaZnO-based TFT has unstable negative bias illumination stress characteristic. Nevertheless, this letter provides an alternative and relatively cost-effective method for fabricating InGaZnO TFTs.