Enhancement of the electrical characteristics of thin-film transistors with multi-stack zinc tin oxide channel layers produced with 2 different solution concentrations*

Thin-film transistors (TFTs) fabricated with amorphous oxide semiconductors (AOS) have garnered much interest as it can be used in display applications mainly in AMOLEDs or AMLCDs, because of their high charge carrier mobility. Several investigations have shown that AOS have relatively high mobility in spite of being amorphous. Compounds such as indium gallium zinc oxide (IGZO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO) and zinc tin oxide (ZTO) are good examples of AOS materials. In this work, we report the optimization of solution-processed ZTO TFTs to enhance the electrical characteristics, including field effect mobility. We prepared 0.05M and 0.2M concentrations of zinc tin oxide precursor solution and TFTs were fabricated. Optimization of the channel layer was performed by multi-stacking the layers produced with 2 different concentrations as 0.05M/0.2M/0.05M/0.2M and the electrical characteristics were obtained for TFTs fabricated with it. The mobility and ON/OFF ratio of the multi-stacked devices were found to be higher than the ones in the other two samples produced with single concentration. Details of experimental methods and recent results will be presented.