Comparative study of InGaZnO thin-film transistors with single and dual NbLaO gate dielectric layers

Amorphous InGaZnO thin-film transistor using NbLaO gate dielectric with low La content is prepared and shows acceptable performance with a carrier mobility of 15.7 cm²V^-1s^-1. Moreover, the gate-dielectric/InGaZnO interface can be improved by inserting a buffer layer of NbLaO with higher La content between the gate dielectric and InGaZnO layer, thus resulting in better device performance in terms of higher carrier mobility (28.5 cm²V^-1s^-1), lower threshold voltage (2.5 V), higher on current (252 μA) and smaller hysteresis (0.4 V). Therefore, the HNbLaO is a potential candidate as buffer layer for improving the electrical performance of InGaZnO thin-film transistor.