In this work the performance of bottom gate thin film transistors (TFTs) with transparent amorphous gallium tin zinc oxide (GSZO) active layers fabricated by radio frequency sputter deposition using a single GSZO target on SiO2/Si wafers will be presented. Trap density and its energetic distribution, and oxygen chemisorption were found to play a critical role in determining the operational characteristics of the device, all of which can be controlled by the oxygen incorporation and substrate temperature during deposition, along with the post-deposition annealing. In addition device instability, with respect to the electrical stress and optical illumination, can be suppressed by suitably tailoring these parameters. TFTs exhibiting a drain current (ID) of 10-6 A and on/off current ratio (Ion/off ) of 106 was achieved. A stable TFT has been achieved under electrical stress for 2% oxygen flow exhibiting ΔVT as low as ~0.5 V for 3hr stress under a gate bias of 1.2 and 12 V, with good optical stability.
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