Reactive high power impulse magnetron sputtering of CFx thin films in mixed Ar/CF4 and Ar/C4F8 discharges

S. Schmidt, C. Goyenola, G. K. Gueorguiev, J. Jensen, G. Greczynski, I. G. Ivanov, Z. Czigány, L. Hultman

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The reactive high power impulse magnetron sputtering processes of carbon in argon/tetrafluoromethane (CF4) and argon/octafluorocyclobutane (c-C4F8) have been characterized. Amorphous carbon fluoride (CFx) films were synthesized at deposition pressure and substrate temperature of 400 mPa and 110 C, respectively. The CFx film composition was controlled in the range of 0.15 <x <0.35 by varying the partial pressure of the F-containing gases from 0 mPa to 110 mPa. The reactive plasma was studied employing time averaged positive ion mass spectrometry and the resulting thin films were characterized regarding their composition, chemical bonding and microstructure as well as mechanical properties by elastic recoil detection analysis, X-ray photoelectron spectroscopy, transmission electron microscopy, nanoindentation, and water droplet contact angle measurements, respectively. The experimental results were compared to results obtained by first-principles calculations based on density functional theory. The modeling of the most abundant precursor fragment from the dissociation of CF4 and C4F8 provided their relative stability, abundance, and reactivity, thus permitting to evaluate the role of each precursor during film growth. Positive ion mass spectrometry of both fluorine plasmas shows an abundance of CF+, C+, CF2 +, and CF3 + (in this order) as corroborated by first-principles calculations. Only CF3 + exceeded the Ar+ signal in a CF4 plasma. Two deposition regimes are found depending on the partial pressure of the fluorine-containing reactive gas, where films with fluorine contents below 24 at.% exhibit a graphitic nature, whereas a polymeric structure applies to films with fluorine contents exceeding 27 at.%. Moreover, abundant precursors in the plasma are correlated to the mechanical response of the different CFx thin films. The decreasing hardness with increasing fluorine content can be attributed to the abundance of CF3 + precursor species, weakening the carbon matrix.

Original languageEnglish
Pages (from-to)21-30
Number of pages10
JournalThin Solid Films
Volume542
DOIs
Publication statusPublished - Sep 2 2013

Fingerprint

Fluorine
Magnetron sputtering
fluorine
impulses
magnetron sputtering
Thin films
Plasmas
thin films
Argon
positive ions
Partial pressure
Mass spectrometry
partial pressure
carbon
mass spectroscopy
Carbon
Gases
Positive ions
argon
Amorphous carbon

Keywords

  • c-C4F8
  • Carbon fluoride
  • Carbon tetrafluoride
  • First principle calculations
  • High power impulse magnetron sputtering
  • Positive ion mass spectrometry
  • Tetrafluoromethane
  • X-ray photoelectron spectroscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry
  • Metals and Alloys
  • Surfaces, Coatings and Films
  • Surfaces and Interfaces

Cite this

Schmidt, S., Goyenola, C., Gueorguiev, G. K., Jensen, J., Greczynski, G., Ivanov, I. G., ... Hultman, L. (2013). Reactive high power impulse magnetron sputtering of CFx thin films in mixed Ar/CF4 and Ar/C4F8 discharges. Thin Solid Films, 542, 21-30. https://doi.org/10.1016/j.tsf.2013.05.165

Reactive high power impulse magnetron sputtering of CFx thin films in mixed Ar/CF4 and Ar/C4F8 discharges. / Schmidt, S.; Goyenola, C.; Gueorguiev, G. K.; Jensen, J.; Greczynski, G.; Ivanov, I. G.; Czigány, Z.; Hultman, L.

In: Thin Solid Films, Vol. 542, 02.09.2013, p. 21-30.

Research output: Contribution to journalArticle

Schmidt, S, Goyenola, C, Gueorguiev, GK, Jensen, J, Greczynski, G, Ivanov, IG, Czigány, Z & Hultman, L 2013, 'Reactive high power impulse magnetron sputtering of CFx thin films in mixed Ar/CF4 and Ar/C4F8 discharges', Thin Solid Films, vol. 542, pp. 21-30. https://doi.org/10.1016/j.tsf.2013.05.165
Schmidt, S. ; Goyenola, C. ; Gueorguiev, G. K. ; Jensen, J. ; Greczynski, G. ; Ivanov, I. G. ; Czigány, Z. ; Hultman, L. / Reactive high power impulse magnetron sputtering of CFx thin films in mixed Ar/CF4 and Ar/C4F8 discharges. In: Thin Solid Films. 2013 ; Vol. 542. pp. 21-30.
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