Reliable peripheral anchor-assisted transfer printing of ultrathin SiO₂ for a transparent and flexible IGZO-based inverter

This study demonstrates the utility of a printable ultrathin silicon dioxide (SiO₂) substrate for developing highly transparent and flexible electronic devices. SiO₂ provides a wider thermal process window than that of plastics, which is necessary for producing various electronics. To manipulate this fragile material, we employed a supportive handling substrate and transfer printing process using a sacrificial layer and protruding SU-8 anchors. In particular, we characterized the interfacial stress level and mechanics between the SiO₂ substrate and the anchors during the retrieval process. We also manipulated the configuration of the corner of the SiO₂ substrate to develop a reliable transfer printing process, which resulted in a high transfer yield with no distortion or fracture of the SiO₂ patterns. As an example to demonstrate the utility of this method, we successfully developed a transparent and flexible thin-film inverter based on amorphous indium gallium zinc oxide (IGZO) with an 84.7% average optical transmittance on a polyethylene terephthalate (PET) film with an adhesive layer.