The Mobility Enhancement of Indium Gallium Zinc Oxide Transistors via Low-temperature Crystallization using a Tantalum Catalytic Layer

Abstract

High-mobility indium gallium zinc oxide (IGZO) thin-film transistors (TFTs) are achieved through low-temperature crystallization enabled via a reaction with a transition metal catalytic layer. For conventional amorphous IGZO TFTs, the active layer crystallizes at thermal annealing temperatures of 600 degrees C or higher, which is not suitable for displays using a glass substrate. The crystallization temperature is reduced when in contact with a Ta layer, where partial crystallization at the IGZO back-channel occurs with annealing at 300 degrees C, while complete crystallization of the active layer occurs at 400 degrees C. The field-effect mobility is significantly boosted to 54.0 cm(2)/V.s for the IGZO device with a metal-induced polycrystalline channel formed at 300 degrees C compared to 18.1 cm(2)/V.s for an amorphous IGZO TFT without a catalytic layer. This work proposes a facile and effective route to enhance device performance by crystallizing the IGZO layer with standard annealing temperatures, without the introduction of expensive laser irradiation processes.