This study examined the impact of the low-temperature stacking gate insulator on the gate bias instability of a-InGaZnO thin film transistors in flexible electronics applications. Although the quality of SiNx at low process/deposition temperature is better than that of SiOx at similarly low process/deposition temperature, there is still a very large positive threshold voltage (V-th) shift of 9.4 V for devices with a single low-temperature SiNx gate insulator under positive gate bias stress. However, a suitable oxide-nitride-oxide-stacked gate insulator exhibits a Vth shift of only 0.23 V. This improvement results from the larger band offset and suitable gate insulator thickness that can effectively suppress carrier trapping behavior. (C) 2015 Elsevier B.V. All rights reserved.