Simple active-layer patterning of solution-processed a-IGZO thin-film transistors using selective wetting method

In this paper, we report a selective-patterning method of active layers for the fabrication of solution-based amorphous indium-gallium-zinc-oxide thin-film transistors (a-IGZO TFTs). Using simple stamping of a reusable poly(dimethylsiloxane) (PDMS) substrate onto a SiOX/Si substrate, the surface of SiOx/Si was easily changed to the hydrophobic state because the PDMS substrate contains a large amount of methyl ligands. By combining oxygen plasma treatments through a shadow mask, the active layer was self-defined through selective coating of the a-IGZO solution owing to the difference of the wetting properties. The electrical performance of the resulting TFTs was comparable with that of TFTs fabricated with the conventional method. Because the proposed method is very simple and the PDMS substrate is reusable compared to other selective-wetting methods that use self-aligned monolayers, it is expected to be applicable to the fabrication of low-cost and large-area electronic applications.