title: Enhanced ZnO Thin-Film Transistor Performance Using Bilayer Gate Dielectrics.
abstract: We report ZnO TFTs using Al2O3/Ta2O5 bilayer gate dielectrics grown by atomic layer deposition. The saturation mobility of single layer Ta2O5 dielectric TFT was 0.1 cm(2) V(-1) s(-1), but increased to 13.3 cm(2) V(-1) s(-1) using Al2O3/Ta2O5 bilayer dielectric with significantly lower leakage current and hysteresis. We show that point defects present in ZnO film, particularly VZn, are the main reason for the poor TFT performance with single layer dielectric, although interfacial roughness scattering effects cannot be ruled out. Our approach combines the high dielectric constant of Ta2O5 and the excellent Al2O3/ZnO interface quality, resulting in improved device performance.
authors.affiliation: Materials Science and Engineering, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia.
authors.forename: Fwzah H
authors.initials: FH
authors.lastname: Alshammari
authors.affiliation: Materials Science and Engineering, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia.
authors.forename: Pradipta K
authors.initials: PK
authors.lastname: Nayak
authors.affiliation: Materials Science and Engineering, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia.
authors.forename: Zhenwei
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Materials Science and Engineering, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia.
authors.forename: Husam N
authors.initials: HN
authors.lastname: Alshareef
keywords: aluminum oxide; bilayer; tantalum oxide; thin film transistor; zinc oxide