Improvement in performance of solution-processed indium–zinc–tin oxide thin-film transistors by UV/O 3 treatment on zirconium oxide gate insulator

We studied solution-processed amorphous indium–zinc–tin oxide (a-IZTO) thin-film transistors (TFTs) with spin-coated zirconium oxide (ZrO x ) as the gate insulator. The ZrO x gate insulator was used without and with UV/O 3 treatment. The TFTs with an untreated ZrO x gate dielectric showed a saturation mobility (μ sat ) of 0.91 ± 0.29 cm 2 V −1 s −1 , a threshold voltage ( V th ) of 0.28 ± 0.36 V, a subthreshold swing (SS) of 199 ± 37.17 mV/dec, and a current ratio ( I ON / I OFF) of ∼10 7 . The TFTs with a UV/O 3 -treated ZrO x gate insulator exhibited μ sat of 2.65 ± 0.43 cm 2 V −1 s −1 , V th of 0.44 ± 0.35 V, SS of 133 ± 24.81 mV/dec, and I ON / I OFF of ∼10 8 . Hysteresis was 0.32 V in the untreated TFTs and was eliminated by UV/O 3 treatment. Also, the leakage current decreased significantly when the IZTO TFT was coated onto a UV/O 3 -treated ZrO x gate insulator.