Multiple parallel channels for improved resistance to repeated bending and unbending of amorphous indium–gallium–zinc oxide thin film transistors

A simple approach has been taken to improve the resistance to the repeated bending and unbending of amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors (TFTs). Splitting a conventional thin film active layer of a-IGZO into numerous parallel quasi-one-dimensional sub-channels at micrometer scale, separated by relatively compliant gap regions, allowed improved flexibility of the overall device structure as well as lower strain in the active region. Such scheme resulted in somewhat degraded initial device performance due to the exposure of side walls of the quasi-one-dimensional sub-channels and possible damages there introduced during the photolithography process. However, inherent flexibility of the device structure as proposed herein worked favorably for at least 50 times longer device lifetime under repeated bending and unbending with the bending radius of 3 mm as compared to the reference device having a typical thin film active layer. It is therefore proposed that the device structure as adopted in this study can be a potential candidate for flexible thin film transistors.