title: Lanthanum aluminum oxide thin-film dielectrics from aqueous solution.
abstract: Amorphous LaAlO3 dielectric thin films were fabricated via solution processing from inorganic nitrate precursors. Precursor solutions contained soluble oligomeric metal-hydroxyl and/or -oxo species as evidenced by dynamic light scattering (DLS) and Raman spectroscopy. Thin-film formation was characterized as a function of annealing temperature using Fourier transform infrared (FTIR), X-ray diffraction (XRD), X-ray reflectivity (XRR), scanning electron microscopy (SEM), and an array of electrical measurements. Annealing temperatures ≥500 °C result in thin films with low leakage-current densities (∼1 × 10(-8) A·cm(-2)) and dielectric constants ranging from 11.0 to 11.5. When incorporated as the gate dielectric layer in a-IGZO thin-film transistors (TFTs), LaAlO3 thin films annealed at 600 °C in air yielded TFTs with relatively low average mobilities (∼4.5 cm(2)·V(-1)·s(-1)) and high turn-on voltages (∼26 V). Interestingly, reannealing the LaAlO3 in 5%H2/95%N2 at 300 °C before deposition of a-IGZO channel layers resulted in TFTs with increased average mobilities (11.1 cm(2)·V(-1)·s(-1)) and lower turn-on voltages (∼6 V).
authors.affiliation: Department of Chemistry, University of Oregon , Eugene, Oregon 97403-1253, United States.
authors.forename: Paul N
authors.initials: PN
authors.lastname: Plassmeyer
authors.forename: Kevin
authors.initials: K
authors.lastname: Archila
authors.forename: John F
authors.initials: JF
authors.lastname: Wager
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Page
keywords: aqueous solution process; dielectric; lanthanum aluminum oxide; metal-oxide; thin-film transistor