High-performance Thin-Film Transistors with ITZO/IGZO Hetero junction

Abstract

This study systematically investigates the electrical performance and stability of bilayer hetero junction ITZO/IGZO thin-film transistors (TFTs) with variable channel structure. The 7.5 nm ITZO / 7.5 nm IGZO channel structure TFT achieves optimal device performance, exhibiting a saturation mobility of 40.71 ± 0.75 cm2/Vs, a subthreshold swing of 0.19 ± 0.01 V/dec, a threshold voltage of 3.25 ± 0.18 V, and an on/off current ratio of approximately 108. Compared to single-channel ITZO TFTs, the optimized heterojunction ITZO/IGZO TFT demonstrates enhanced mobility and stability, which can be attributed to the formation of a two-dimensional electron gas (2DEG) at the hetero junction interface. Furthermore, this study provides experimental confirmation of a 2DEG’s at the interface, underscoring its crucial role in improving device performance. These findings highlight the potential of bilayer heterojunction TFTs for next-generation displays. © 2025, John Wiley and Sons Inc. All rights reserved.