Interface scattering dominated carrier transport in hysteresis-free amorphous InGaZnO thin film transistors with high-k HfAlO gate dielectrics by atom layer deposition. (16th December 2021)

• Record Type: Journal Article
• Authors: Huang, Ting; Zhang, Yan; Liu, Haonan; Tao, Ruiqiang; Luo, Chunlai; Li, Yushan; Chang, Cheng; Lu, Xubing; Minari, Takeo; Liu, Junming
• Is Part Of: Semiconductor science and technology. Volume 37:Number 2(2022)
• Publication Date: 2021-12-16
• Subjects: amorphous InGaZnO -- thin film transistors -- high-k dielectric -- interface scattering -- field-effect mobility; Semiconductors -- Periodicals; 621.38152
• DOI: 10.1088/1361-6641/ac3e05
• Languages: English
• ISSNs: 0268-1242

Abstract

Abstract: In this work, we systematically investigated the carrier transport of hysteresis-free amorphous InGaZnO (a-IGZO) thin film transistors (TFTs) incorporating high- k (HfO2 ) x (Al2 O3 ) 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 (HfO2 )0.5 (Al2 O3 )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.