Fabrication of IGZO Sputtering Target and Its Applications to the Preparation of Thin-film Transistor (TFT) Devices

Abstract

A hybrid of chemical dispersion and mechanical grinding process was developed to fabricate the mixture of nano-scale In2O3, Ga2O3 and ZnO oxide powders at the atomic ratio 1:1:2. As revealed by x-ray diffraction (XRD) analysis, sputtering target containing sole IGZO(4) phase could be obtained by sintering the oxide mixture pressed in disc form at temperatures >= 1300 degrees 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 degrees 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 (mu(sat)) = 14.7 cm(2)/V.s, threshold voltage (V-TH) = 0.57 V, subthreshold swing (S.S.) = 0.45 V/decade and on/off ratio = 10(8) could be achieved.