Interface scattering dominated carrier transport in hysteresis-free amorphous InGaZnO thin film transistors with high- k HfAlO gate dielectrics by atom layer deposition

作者：Ting Huang, Yan Zhang, Haonan Liu, Ruiqiang Tao, Chunlai Luo, Yushan Li, Cheng Chang, Xubing Lu, Takeo Minari, Jun‐Ming Liu · 发表于：Semiconductor Science and Technology · 年份：2021 · DOI：10.1088/1361-6641/ac3e05 · 被引用次数：11 · 研究领域：Thin-Film Transistor Technologies、Semiconductor materials and devices、ZnO doping and properties

Abstract In this work, we systematically investigated the carrier transport of hysteresis-free amorphous InGaZnO (a-IGZO) thin film transistors (TFTs) incorporating high- k (HfO 2 ) x (Al 2 O 3 ) y gate dielectrics with different composition and permittivity by atomic layer deposition. A dielectric surface morphology dominated interface scattering carrier transport mechanism is demonstrated, and the effect of the dielectric polarization and the interface states on the carrier mobility is discovered in TFT devices gated by high quality dielectrics with negligible charge trap effect. Accordingly, an a-IGZO TFT gated by (HfO 2 ) 0.5 (Al 2 O 3 ) 0.5 dielectric with the smoothest surface exhibits the best performance in terms of a preferable field-effect mobility of 18.35 cm 2 V −1 s −1 , a small subthreshold swing of 0.105 V decade −1 , a high on/off current ratio of 4.6 × 10 6 , and excellent stability under positive bias stress.