Bending performance and bias-stress stability of the In-Ga-Zn-O TFTs prepared on flexible PEN substrates with optimum barrier structures

The effects of barrier layers and channel compositions on the device performances including the bending characteristics and bias-stress stabilities were investigated for the flexible In-Ga-Zn-O (IGZO) thin-film transistors (TFTs). The IGZO TFTs fabricated on the PEN treated with inorganic/organic double-layered barrier layer showed superior properties under the bending situation even at a curvature radius of 3.5 mm, which corresponded to the bending strain of 1.8 %. The IGZO channel composition was controlled by modulating the oxygen partial pressure during the sputtering process and the TFTs demonstrated highly stable performance at a O₂/(Ar+O₂) ratio of 2 %. The threshold shifts for the IGZO TFT were -0.1 and +0.1 V for negative- and positive-bias stress, respectively.