Improvements in the reliability of a-InGaZnO thin-film transistors with triple stacked gate insulator in flexible electronics applications

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 (Vth) 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.