Vacuum ultra-violet spectroscopic ellipsometry study of single-and multi-phase nitride protective films

S. M. Aouadi, A. Bohnhoff, T. Amriou, M. Williams, J. N. Hilfiker, N. Singh, J. A. Woollam

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

This paper reports on a systematic investigation of the optical properties of Ta1-xZrxN single-phase and ZrN-Ag multi-phase films fabricated by unbalanced magnetron sputtering using vacuum ultraviolet spectroscopic ellipsometry (VUV-SE). VUV-SE is a newly developed technique that was used to evaluate the strength and energy of the interband electronic excitations/transitions in these films. The energy of the interband transition was found to be altered by any changes in the elemental composition for single-phase materials. For example, it was found to increase with the increase in the covalent character of the bond as more Zr atoms are substituted for by Ta atoms in the ZrN rock-salt structure. In contrast, the peak positions did not vary in the multi-phase structures because the constituent phases were immiscible and retained their electronic structure. However, the strength and width of the interband transition were found to change to reflect changes in phase composition and microstructure. The optical and electronic properties of these materials were simulated using density functional theory (DFT) within the generalized gradient approximation. The calculated refractive indices and density of states were in good agreement with the VUV-SE data.

Original languageEnglish (US)
Article numberS01
Pages (from-to)S1691-S1701
JournalJournal of Physics Condensed Matter
Volume18
Issue number32
DOIs
StatePublished - Aug 16 2006

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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