This study investigates the effect of hydrogen incorporation on amorphous indium-gallium-zinc oxide thin-film transistors (a-IGZO TFTs) The threshold voltage (V-th) and subthreshold swing (SS) of hydro gen-incorporated a-IGZO TFTs were improved and the threshold voltage shift (Delta V-th) in hysteresis loop was also suppressed from 4 V to 2 V The physical property and chemical composition of a-IGZO films were analyzed by X ray diffraction and X ray photoelectron spectroscopy respectively Experimental results show that the hydrogen induced passivation of the interface trap states between active layer and dielectric is responsible for the improvement of SS and V-th (C) 2010 Elsevier Ltd All rights reserved