Reduced Mechanical Strain in Bendable a-IGZO TFTs Under Dual-Gate Driving

We report the reduced strain in bendable amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistor (TFT) with dual-gate (DG) driving. The performance of the fabricated TFTs on a 15-μm polyimide substrate are sensitive to bending radius and the changes in threshold voltage (AVTH) fits well by analytical modeling. DG driving TFTs are found very stable under tensile strain (ε) compared with single-gate (SG) TFTs. Technology computer-aided design strain distribution confirms a 25% less strain on a-IGZO layer for DG TFT structure compared with SG TFT and the maximum tensile strain is observed at the center of the TFT channel. The SG and DG TFTs under 1 mm radius exhibit ΔV
_TH
(V) shift of -1.5 and -0.3 V, respectively, from the flat state, which is due to the reduced strain in the DG TFT.