title: Non-uniform Composition Profiles in Inorganic Thin Films from Aqueous Solutions.
abstract: A variety of metal oxide films (InGaOx, AlOx, "HafSOx") prepared from aqueous solutions were found to have non-uniform electron density profiles using X-ray reflectivity. The inhomogeneity in HafSOx films (Hf(OH)4-2x-2y(O2)x(SO4)y·zH2O), which are currently under investigation as inorganic resists, were studied in more detail by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and medium-energy ion scattering (MEIS). The HAADF-STEM images show a greater concentration of heavy atoms near the surface of a single-layer film. MEIS data confirm the aggregation of Hf at the film surface. The denser "crust" layer in HafSOx films may directly impact patterning resolution. More generally, the phenomenon of surface-layer inhomogeneity in solution-deposited films likely influences film properties and may have consequences in other thin-film systems under investigation as resists, dielectrics, and thin-film transistor components.
authors.affiliation: Department of Chemistry & Biochemistry and Materials Science Institute, University of Oregon , Eugene, Oregon 97403, United States.
authors.forename: Kurtis C
authors.initials: KC
authors.lastname: Fairley
authors.affiliation: Department of Chemistry & Biochemistry and Materials Science Institute, University of Oregon , Eugene, Oregon 97403, United States.
authors.forename: Devin R
authors.initials: DR
authors.lastname: Merrill
authors.affiliation: Department of Chemistry & Biochemistry and Materials Science Institute, University of Oregon , Eugene, Oregon 97403, United States.
authors.forename: Keenan N
authors.initials: KN
authors.lastname: Woods
authors.affiliation: Department of Chemistry & Biochemistry and Materials Science Institute, University of Oregon , Eugene, Oregon 97403, United States.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Ditto
authors.affiliation: Department of Physics and Astronomy, Rutgers University , Piscataway, New Jersey 08854, United States.
authors.forename: Can
authors.initials: C
authors.lastname: Xu
authors.affiliation: School of Chemical, Biological, and Environmental Engineering, Oregon State University , Corvallis, Oregon 97331, United States.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Oleksak
authors.affiliation: Department of Physics and Astronomy, Rutgers University , Piscataway, New Jersey 08854, United States.
authors.forename: Torgny
authors.initials: T
authors.lastname: Gustafsson
authors.affiliation: Department of Chemistry & Biochemistry and Materials Science Institute, University of Oregon , Eugene, Oregon 97403, United States.
authors.forename: Darren W
authors.initials: DW
authors.lastname: Johnson
authors.affiliation: Department of Chemistry and Chemical Biology, Rutgers University , Piscataway, New Jersey 08854, United States.
authors.forename: Eric L
authors.initials: EL
authors.lastname: Garfunkel
authors.affiliation: School of Chemical, Biological, and Environmental Engineering, Oregon State University , Corvallis, Oregon 97331, United States.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Herman
authors.affiliation: Department of Chemistry & Biochemistry and Materials Science Institute, University of Oregon , Eugene, Oregon 97403, United States.
authors.forename: David C
authors.initials: DC
authors.lastname: Johnson
authors.affiliation: Department of Chemistry & Biochemistry and Materials Science Institute, University of Oregon , Eugene, Oregon 97403, United States.
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Page
keywords: HAADF-STEM; HafSOx; MEIS; XRR; aqueous solution; crust; inhomogeneity; metal oxide thin film