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

Abstract

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- $\mu \text{m}$ polyimide substrate are sensitive to bending radius and the changes in threshold voltage ( $\Delta \mathrm {V}_{\mathrm {TH}}$ ) fits well by analytical modeling. DG driving TFTs are found very stable under tensile strain ( $\varepsilon$ ) 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 $\Delta \mathrm {V}_{\mathrm {TH}}$ (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.