Flexible In-Ga-Zn-O Thin-Film Transistors on elastomeric substrate bent to 2.3 % strain

In this letter, a photolithographic fabrication process is used to manufacture Indium-Gallium-Zinc-Oxide (IGZO) Thin-Film Transistors (TFTs) with mobilities > 10cm2=Vs directly on a 80μm thick Polydimethylsiloxane (PDMS) substrate. Once the fabrication is completed, the PDMS is detached from a Silicon wafer used as carrier substrate. Due to the thermal mismatch between Silicon and PDMS, the release results in a reduction of the PDMS area by 7.2 %, which leads to the formation of out-of-plane wrinkles on the TFT surface. The reflattening of the wrinkles under tensile strain, enables device functionality while the TFTs are bent up to 2.3% strain. Mechanical stability of the TFTs with our wrinkled approach is shown by electrically characterizing them at bending radii down to 6 mm.