Enhancement of TFT performance by purification of indium-zinc-tin oxide

In the present work, we studied the effect of purification of IZTO precursor on the performance of oxide TFT using high-k ZrO_x gate insulator. The unpurified IZTO TFT showed the saturation mobility (μ_sat) of 2.86 cm²/V, threshold voltage (V_th) of 0.43 V, subthreshold swing (SS) of 112 mV/dec., and a current ratio I_ON/I_OFF of ~10⁸. On the other hand, the purified IZTO TFT exhibited the μ_sat of 5.22 cm²/V, V_th of 0.36 V, SS of 90 mV/dec., and an I_ON/I_OFF of ~10⁸. The results suggest that the purification of oxide semiconductor precursor is important for high performance TFT.