The static characteristics and low frequency noise of amorphous InHfZnO (a-IHZO) thin film transistor (TFT) were comprehensively investigated. The effective mobility extracted from the transfer curve and gate-to-channel capacitance-voltage characteristic is compared with that obtained by Y-function adopted on amorphous-oxide-semiconductor TFT. The static characteristics at low temperature show nearly independent electrical property of a-IHZO TFT, illustrating the degenerate behavior of a-IHZO TFT inversion layer. Noise measurement was performed on a-IHZO TFT and indicates that fluctuations stem from carrier trapping-detrapping at the interface between the oxide and channel layer and/or in bulk traps. Based on the analysis with static characteristics and low frequency noise of a-IHZO TFT, a numerical model was proposed and the model including band-tail states conduction and interface traps provides a good agreement with the experimental results. (C) 2013 Elsevier B. V. All rights reserved.