No abstract

We studied the environmental stability of amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs) with single-layer (SiO 2 ) and bilayer (SiO 2 /SiN x ) passivation under high-humidity (80%) storage. During the 30 days of investigation, all single-layer passivated TFTs showed negative turn-ON voltage shifts ( V ON ), the size of which increased with storing time. The negative V ON is attributed to donor generation inside the active a-IGZO caused by the diffusion of ambient hydrogen/water molecules passing through the SiO 2 passivation layer. The X-ray photoelectron spectroscopy depth profile for the SiO 2 passivated structures confirms that the concentration of oxygen vacancies, which is initially larger at the a-IGZO/SiO 2 interface, compared with the bulk a-IGZO, decreases after 30 days of storage under high humidity. This can be explained as the passivation of oxygen vacancies by diffused hydrogen. On the other hand, all bilayer passivated TFTs showed good air stability at room temperature and high humidity (80%).Index Terms-Amorphous-indium-gallium zinc oxide (a-IGZO), oxide thin-film transistors (TFT) reliability, SiO 2 and SiN x passivation layer, TFT.

No abstract

No abstract