Preparation of IGZO sputtering target and its applications to thin-film transistor devices

Abstract

Nano-scale In2O3, Ga2O3 and ZnO powder mixture prepared by a hybrid process of chemical dispersion and mechanical grinding was adopted for the In-Ga-Zn-O (IGZO) sputtering target fabrication. A pressure-less sintering at 1300 C for 6 h yielded the target containing sole InGaZnO4 phase with relative density as high as 93%. Consequently, the thin-film transistor (TFT) devices containing amorphous IGZO channels were prepared by using the self-prepared target and the electrical measurements indicated the TFT subjected to a post annealing at 300 degrees C exhibits the best device performance with the saturation mobility = 14.7 cm(2)/V s, threshold voltage = 0.57 V, subthreshold gate swing = 0.45 V/decade and on/off ratio = 10(8). Capacitance-voltage measurement indicated that post annealing effectively suppresses the interfacial traps density at the IGZO/SiO2 interface and thus enhances the electrical performance of TFT. (C) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.