Nanostructure of fluorocarbon films deposited on polystyrene from hyperthermal C3F5+ ions

F. Ahu Akin, Inkook Jang, Mark L. Schlossman, Susan B. Sinnott, Gerry Zajac, Erick R. Fuoco, Muthu B.J. Wijesundara, Ming Li, Aleksey Tikhonov, Sai Venkatesh Pingali, Amanda T. Wroble, Luke Hanley

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Abstract

Fluorocarbon films were grown on polystyrene in vacuum from 25- to 100-eV mass-selected C3F5+ ion beams. The films were analyzed by X-ray photoelectron spectroscopy, atomic force microscopy, and X-ray reflectivity after exposure to the atmosphere for 4-8 weeks. The X-ray reflectivity indicates films that range from ∼30 to 60-Å thick. The thinner films form at lower ion energies, where the ion penetration depth and efficiency of film formation are lowest. X-ray reflectivity estimates air-fluorocarbon film roughness values of ∼6 Å for 25- and 50-eV films but ∼20 Å for the 100-eV films. The fluorocarbon-polystyrene-buried interface displays similar roughness and trends with ion energy. The AFM roughness trends are similar, but the absolute AFM roughnesses are only ∼1/4 of the X-ray reflectivity values. This discrepancy is attributed to tip effects and the method of determining roughness by AFM. The AFM images and power spectral densities of the 100-eV films displayed quasi-periodic cones spaced 300-700 Å apart. Such features are either absent or of much lower amplitude in the 25- and 50-eV films. Classical molecular dynamics simulations of C3P 5+ deposition on polystyrene at energies of 50 and 100 eV/ion reveal that etching at the higher energy is largely responsible for the dissimilar film structures obtained experimentally. These results demonstrate that deposition of the fluorocarbon polyatomic ion C3F 5+ allows control of film nanostructure at the surface and buried interface.

Original languageEnglish (US)
Pages (from-to)9656-9664
Number of pages9
JournalJournal of Physical Chemistry B
Volume108
Issue number28
StatePublished - Jul 15 2004

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All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

Akin, F. A., Jang, I., Schlossman, M. L., Sinnott, S. B., Zajac, G., Fuoco, E. R., Wijesundara, M. B. J., Li, M., Tikhonov, A., Pingali, S. V., Wroble, A. T., & Hanley, L. (2004). Nanostructure of fluorocarbon films deposited on polystyrene from hyperthermal C3F5+ ions. Journal of Physical Chemistry B, 108(28), 9656-9664.