Room-temperature fabrication of flexible gallium-doped zinc oxide thin-film transistors on plastic substrates

Bottom-gate-type oxide thin-film transistors (TFTs) on flexible plastic substrates have been fabricated, with Gallium-doped ZnO (GZO) by radio frequency (RF) sputtering as the channel material at room temperature. The devices use SiO₂ as gate insulator and indium tin oxide (ITO) as gate, source and drain electrodes. To optimize performance of AZO TFTs, we studied effects of different oxygen/argon gas flow ratio on electrical properties of TFTs. We found that O₂/Ar flow ratio influence the performance of GZO TFTs very significantly. Finally, we gained high performance GZO TFTs with excellent electrical properties, such as a drain current on/off ratio of 10⁷, a subthreshold swing of 394mV/decade, a threshold voltage of 3.2V, and a field effect mobility of 20.7cm²/ V·s in saturation region.