A hybrid of chemical dispersion and mechanical grinding process was developed to fabricate the mixture of nano-scale In_2O_3, Ga_2O_3 and ZnO oxide powders at the atomic ratio 1:1:2. As revealed by array diffraction (XRD) analysis, sputtering target containing sole IGZO4 phase could be obtained by sintering the oxide mixture pressed in disc form at temperatures > 1300°C for 6 hrs. The IGZO target was then transferred to a sputtering system and the thin-film transistors (TFTs) containing amorphous IGZO channels were fabricated. Post-annealing at 300°C for 1 hr in air ambient was performed in order to improve the device performance. Electrical measurements indicated that the TFT samples with saturation mobility (μ_(sat)) = 14.7 cm~2/Vs, threshold voltage (V_(rH)) = 0.57 V, subthreshold swing (S.S.) = 0.45 V/decade and on/off ratio = 10~8 could be achieved.
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