Effect of oxygen on stability performance of the IZO junctionless thin film transistors

Abstract

We report in this paper that low-voltage indium-zinc oxide (IZO) junctionless thin-film transistors (TFT) can be fabricated at room temperature, and the device stability performance influenced by oxygen pressure is studied. IZO junctionless TFT has a high mobility and novel structure, but the oxide channel layers are vulnerable due to the influence of oxygen and water molecules, which will lead to the degradation of the device stability. In this study, we fabricate transparent and conductive IZO thin-films at room temperature as channel layers, and source/drain electrodes by controlling the oxygen flow, and also analyze the effect of oxygen on the stability of oxide junctionless TFT. In order to operate at low-voltage (2 nanoparticle films as gate dielectric, which have electron double layers (EDL) effect and large gate capacitance, and the TFTs show excellent electrical performance with small operating voltage of 1 V, large on/off ratio(>106), small subthreshold swing(20 cm2/V·s). The study indicates that the resistivity of IZO thin-film fabricated in increasing oxygen content, leads the threshold voltage to drift in a positive direction, and makes operating mode of TFT change from depletion mode to enhanced mode.