High-Performance Amorphous Indium Gallium Zinc Oxide Thin-Film Transistors Fabricated by Atomic Layer Deposition

Abstract

This letter reports the fabrication of high-performance amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) via atomic layer deposition at a substrate temperature of 250 °C. The film thickness of In2O3, Ga2O3, and ZnO varied linearly with the number of deposition cycles. The cation composition of the IGZO film was controlled by an alternate stacking of In2O3, Ga2O3, and ZnO atomic layers. The fabricated a-IGZO TFTs exhibited a high electron mobility of 22.1 cm2/Vs, threshold voltage of 2.41 V, subthreshold gate swing of 0.30 V/decade, and an ${I}_{{ \mathrm{\scriptscriptstyle ON}}/{ \mathrm{\scriptscriptstyle OFF}}}$ ratio of $> \textsf {1} \times \textsf {10}^{\textsf {8}}$ .