Amorphous Indium Gallium Zinc Oxide Semiconductor Thin Film Transistors Using O₂ Plasma Treatment on the SiN_x Gate Insulator

Abstract

In this study, we investigated the role of processing parameters on the electrical characteristics of amorphous In–Ga–Zn–O (a-IGZO) thin film transistors (TFTs) fabricated using DC magnetron sputtering at room temperature. Processing parameters including the oxygen partial pressure, annealing temperature, and channel thickness have a great influence on TFT performance and better devices are obtained at a low oxygen partial pressure, annealing at 200 °C, and a low channel thickness. We attempted to improve the a-IGZO TFT performance and stability under a gate bias stress using O 2 plasma treatment. With an O 2 plasma treated gate insulator, remarkable properties including excellent bias stability as well as a field effect mobility (µ FE ) of 11.5 cm 2 V -1 s -1 , a subthreshold swing ( S ) of 0.59 V/decade, a turn-on voltage ( V ON ) of -1.3 V, and an on/off current ratio ( I ON / I OFF ) of 10 5 were achieved.