title: Stable and High-Performance Flexible ZnO Thin-Film Transistors by Atomic Layer Deposition.
abstract: Passivation is a challenging issue for the oxide thin-film transistor (TFT) technologies because it requires prolonged high-temperature annealing treatments to remedy defects produced in the process, which greatly limits its manufacturability as well as its compatibility with temperature-sensitive materials such as flexible plastic substrates. This study investigates the defect-formation mechanisms incurred by atomic layer deposition (ALD) passivation processes on ZnO TFTs, based on which we demonstrate for the first time degradation-free passivation of ZnO TFTs by a TiO2/Al2O3 nanolaminated (TAO) film deposited by a low-temperature (110 °C) ALD process. By combining the TAO passivation film with ALD dielectric and channel layers into an integrated low-temperature ALD process, we successfully fabricate flexible ZnO TFTs on plastics. Thanks to the exceptional gas-barrier property of the TAO film (water vapor transmission rate (WVTR)<10(-6) g m(-2) day(-1)) as well as the defect-free nature of the ALD dielectric and ZnO channel layers, the TFTs exhibit excellent device performance with high stability and flexibility: field-effect mobility>20 cm2 V(-1) s(-1), subthreshold swing<0.4 V decade(-1) after extended bias-stressing (>10,000 s), air-storage (>1200 h), and bending (1.3 cm radius for 1000 times).
authors.affiliation: Department of Materials Science and Engineering, National Taiwan University , 1, Section 4, Roosevelt Road, Taipei 106, Taiwan, R.O.C.
authors.forename: Yuan-Yu
authors.initials: YY
authors.lastname: Lin
authors.affiliation: Department of Materials Science and Engineering, National Taiwan University , 1, Section 4, Roosevelt Road, Taipei 106, Taiwan, R.O.C.
authors.forename: Che-Chen
authors.initials: CC
authors.lastname: Hsu
authors.affiliation: Department of Materials Science and Engineering, National Taiwan University , 1, Section 4, Roosevelt Road, Taipei 106, Taiwan, R.O.C.
authors.forename: Ming-Hung
authors.initials: MH
authors.lastname: Tseng
authors.affiliation: Department of Materials Science and Engineering, National Taiwan University , 1, Section 4, Roosevelt Road, Taipei 106, Taiwan, R.O.C.|Research Center for Applied Science, Academia Sinica , Taipei 115, Taiwan, R. O. C.
authors.forename: Jing-Jong
authors.initials: JJ
authors.lastname: Shyue
authors.affiliation: Department of Materials Science and Engineering, National Taiwan University , 1, Section 4, Roosevelt Road, Taipei 106, Taiwan, R.O.C.
authors.forename: Feng-Yu
authors.initials: FY
authors.lastname: Tsai
keywords: atomic layer deposition; flexible electronics; gas barrier; passivation; thin film transistors