Expeditious and eco-friendly solution-free self-patterning of sol–gel oxide semiconductor thin films

Due to its simplicity and low-cost manufacturing, self-patterning has been considered a promising candidate to replace conventional photolithography. However, most solution-based self-patterning methods require toxic materials, lengthy processes and generate extensive material waste, thus hindering eco-friendly and also economic mass production. Therefore, this work presents an expeditious and eco-friendly solution-free self-patterning method to fabricate patterned indium gallium zinc oxide (IGZO) thin-film transistors (TFTs). This faster and simpler two-step process requires within only 10 min to generate the selective wetting and dewetting regions on the dielectrics via a simultaneous stamping and thermal treatment (SST) and then an ultraviolet ozone exposure. As a result, well-defined IGZO patterns were formed without residues. Extremely suppressed lateral and vertical leakage currents were obtained in self-patterned IGZO TFTs by eliminating leakage paths found in non-patterned devices (appx. 10⁻¹¹ A versus 10⁻⁵ A, respectively). Furthermore, the recyclability of the surface energy modification stamp (SEMS) used in the proposed SST process was confirmed, as the IGZO patterns and uniform electrical performances remained clear through nine patterning processes using a single SEMS. Overall, the proposed solution-free self-patterning method will contribute to the realization of next-generation printed electronics by enabling their mass production.