Highly transparent IGZO-TFTs uses IGZO source and drain electrodes with a composite insulation layer structure

In this paper, the characteristic that the proper oxygen partial pressure during sputtering can change IGZO from semiconductor to conductor was used to fabricate IGZO-TFTs. Firstly, in order to determine the optimum parameters for the preparation of IGZO thin films as active layer and source/drain electrode, the influence of oxygen partial pressure on the conductivity and transmittance of IGZO thin films prepared by magnetron sputtering was studied, then a highly transparent IGZO-TFT device based on IGZO source/drain electrode was fabricated, in which an ultra-thin layer of atomic layer deposited (ALD) alumina under the original PMMA insulation layer was added to make a composite insulation layer structure. The mobility of the device is 6.07 cm2/Vs, the switching ratio is 0.87 × 104, threshold voltage and sub-threshold swing are 2.6 V and 3.5 V/decade, respectively. And the transmittance of the device in the visible light range is more than 80%, showing a good optical transmittance.