Effects of X-ray Irradiation on the Noise Behavior of Amorphous Indium-Gallium-Zinc-Oxide TFTs

Abstract

In this paper, the response of low-frequency noise under and after the X-ray irradiation for amorphous indium-gallium-zinc-oxide (a-IGZO) thin film transistors (TFTs) is analyzed. With fixed irradiation dose, the noise stays the same regardless of the TFT under and after X-ray irradiation. The noise mechanism is analyzed to be mainly the carrier mobility fluctuation. The coincidence of the noise of TFTs under and after X-ray irradiation further confirms that there is no direct relation between X-ray irradiation and the noise behavior. The mechanism of the positive charge trapping in the oxide layer under X-ray for the threshold voltage (V-th) shift of the TFT does not affect its noise behavior. With more stable and larger SNR by 20 dB than low-temperature polycrystalline-silicon (LTPS) TFT, a-IGZO TFT is believed to be a more suitable device for applying to X-ray active pixel sensing circuits. (c) 2020 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.