Compositional Engineering of Hf‐Doped InZnSnO Films for High‐Performance and Stability Amorphous Oxide Semiconductor Thin Film Transistors
Jinhyeok Park, Hae‐Jun Seok, Chan‐Hwi Kim, Sung Hyeon Jung, Hyung Koun Cho, Han‐Ki Kim
Abstract
Abstract The Hf‐doped indium zinc tin oxide (Hf:InZnSnO) channel for high performance and stable transparent thin film transistors (TFTs) is developed by using a simultaneous cosputtering of InZnSnO and HfO 2 targets. The effects of In and Hf composition in Hf:InZnSnO channel on the performance and stability under bias stress for the Hf:InZnSnO channel‐based TFTs are investigated. Herein, the In cations enhance the electrical properties, while the Hf cations reduce the oxygen vacancies in the Hf:InZnSnO channel layer. Adjusting the atomic ratio of In of the InZnSnO target improves the performance of the Hf:InZnSnO‐based TFTs, while introducing an adequate amount of HfO 2 improves the bias stabilities and hysteresis characteristics of the Hf:InZnSnO‐based TFTs. The transparent TFT with optimized Hf:InZnSnO channel, with a stoichiometry of Hf 0.27 In 25.96 Zn 6.99 Sn 6.16 O 60.62 , that is cosputtered at RF power of 100 W applied to InZnSnO target (In:Zn:Sn = 4:1:1 at%), and RF power of 50 W applied to HfO 2 target exhibits a field effect mobility of 11.84 cm 2 V −1 s −1 and low shift of threshold voltage of less than 2.5 V under bias stress for 3000 s. The high performance and stability of the Hf:InZnSnO channel‐based TFTs demonstrate the feasibility of transparent TFTs‐related next‐generation display applications.