Exploiting Hygroscopic Nature of IGZO Precursor Thin Films for Adhesive Tape Patterning

Abstract We have developed a facile technique for the patterning of solution-processed metal-oxide precursor thin films using adhesive tape. In the proposed method, a water-based, nitrate-type, indium–gallium–zinc oxide (IGZO) precursor solution was spin-coated and annealed at a moderate temperature ranging from 40 to 70 °C to partly eliminate the evaporative compositions. Subsequently, the unnecessary parts of the semidried thin layer were removed by adhesive tape. The criteria for successful patterning were characterized in terms of the adhesion force and volume fraction using AFM and QCM. Further, an investigation of the drying kinetics of the thin films using a precision microbalance revealed that the temporal margin for successful patterning was significantly regulated by the hygroscopic nature of the constituent nitrates in the aqueous thin film. The patterned IGZO semiconductor was successfully operated with a good mobility of 2.9 cm2/(V·s) after a subsequent thermal oxidation process.