Bending stability of flexible amorphous IGZO thin film transistors with transparent IZO/Ag/IZO oxide–metal–oxide electrodes

We investigated the electrical and optical properties of indium zinc oxide (IZO)/Ag/IZO oxide–metal–oxide (OMO) multilayer for a flexible and transparent electrode of the electronic applications. The optimized OMO multilayer structures with excellent sheet resistance of 5.65 Ω/sq as well as average transmittance of 87.7% in the visible range were employed as the source and drain (S/D) electrodes of thin film transistors (TFTs). In addition, the a-IGZO TFT with OMO S/D electrodes exhibited the enhanced electrical performance in comparison to the TFT with single IZO S/D electrodes, resulted from lowering work function by inserting Ag mid-layer between the oxide layers. Furthermore, the same TFTs were fabricated on a polyimide (PI) substrate to verify the potential of OMO electrode for flexible devices. The TFTs on PI substrate were found to be significantly resistant to dynamic bending with only 5.37% reduction in field effect mobility and slight change in threshold voltage from 0.21 V to 0.72 V even after 10,000 cycles of repeated bending at a radius of curvature of 10 mm.