Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Structural and optical investigation of plasma deposited silicon carbon alloys: Insights on Si-C bond configuration using spectroscopic ellipsometry

Journal Article · · Journal of Applied Physics
DOI:https://doi.org/10.1063/1.1899758· OSTI ID:20709642
; ; ; ;  [1]
  1. Instituto di Metodologie Inorganiche e dei Plasmi-Consiglio Nazionale delle Ricerche, IMIP-CNR, e Consorzio Interuniversitario INSTM, Dipartimento di Chimica, Universita di Bari, via Orabona 4, 70126 Bari (Italy)
Amorphous (a-Si{sub 1-x}C{sub x}:H) and microcrystalline ({mu}c-Si{sub 1-x}C{sub x}:H) thin films have been deposited by plasma-enhanced chemical-vapor deposition using SiF{sub 4}-CH{sub 4}-H{sub 2} rf plasmas. Gas flow rates have been varied to deposit films with different carbon content and microstructure. The microstructure and optical properties have been investigated by IR/Raman spectroscopy and by spectroscopic ellipsometry in the energy range of 1.5-5.0 eV. Ellipsometric spectra have been analyzed in terms of the tetrahedron model combined with the Bruggeman effective-medium approximation to determine the film microstructure and silicon-carbon-bond configurations. Correlation between Si-C bond configurations and optical properties of films has been studied as a function of carbon content and microstructure. It is found that the optical properties and the band gap value depend not only on the carbon content, but also on the Si-C bond configuration and microcrystallinity. The films consist of Si-centered Si-Si{sub 4-v}C{sub v} (v=0-3) Si-centered tetrahedra with segregation of {mu}c-Si. The amorphous matrix changes from Si-Si{sub 3}C to Si-SiC{sub 3} with the increase of the {mu}c-Si phase. The optical gap is found to increase with both carbon content and microcrystallinity.
OSTI ID:
20709642
Journal Information:
Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 10 Vol. 97; ISSN JAPIAU; ISSN 0021-8979
Country of Publication:
United States
Language:
English