Property improvement of pulsed laser deposited boron carbide films by pulse shortening

T. Csákó, J. Budai, T. Szörényi

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Growth characteristics and surface morphology of boron carbide films fabricated by ablating a B 4 C target in high vacuum with a traditional KrF excimer laser and a high brightness hybrid dye/excimer laser system emitting at the same wavelength while delivering 700 fs pulses are compared. The ultrashort pulse processing is highly effective. Energy densities between 0.25 and 2 J cm -2 result in apparent growth rates ranging from 0.017 to 0.085 nm/pulse. Ablation with nanosecond pulses of one order of magnitude higher energy densities yields smaller growth rates, the figures increase from 0.002 to 0.016 nm/pulse within the 2-14.3 J cm -2 fluence window. 2D thickness maps derived from variable angle spectroscopic ellipsometry reveal that, when ablating with sub-ps pulses, the spot size rather than the energy density determines both the deposition rate and the angular distribution of film material. Pulse shortening leads to significant improvement in surface morphology, as well. While droplets with number densities ranging from 1 × 10 4 to 7 × 10 4 mm -2 deteriorate the surface of the films deposited by the KrF excimer laser, sub-ps pulses produce practically droplet-free films. The absence of droplets has also a beneficial effect on the stoichiometry and homogeneity of the films fabricated by ultrashort pulses.

Original languageEnglish
Pages (from-to)4707-4711
Number of pages5
JournalApplied Surface Science
Volume252
Issue number13 SPEC. ISS.
DOIs
Publication statusPublished - Apr 30 2006

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Keywords

  • Nanostructure
  • PLD
  • Surface morphology
  • Thickness distribution
  • Thin films
  • Ultrashort pulse processing

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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