Effect of SiOx/SiNx stacked gate dielectric structure on the instability of a-IGZO thin film transistors

Among amorphous oxide thin film transistors, amorphous indium gallium zinc oxide (a-IGZO) thin film transistors (TFT) is currently highlightened because of its advantages such as high mobility, transparent characteristic, flexibility and so on. It is required to ensure the stability of the device under various environments has to be verified before high-volume manufacturing. In this paper, the instability of amorphous InGaZnO TFT depending on the SiO _x/SiN_x stacked gate dielectric material is investigated through bias and light illumination stress test. Here, the TFT's instability characteristics are examined by the density of total trap states at the channel/gate dielectric interface (N_it).