SiOxNy thin films with variable refraction index: Microstructural, chemical and mechanical properties

✍ Scribed by V. Godinho; M.C. Jiménez de Haro; J. García-López; V. Goossens; H. Terryn; M.P. Delplancke-Ogletree; A. Fernandez

• Book ID: 104001915
• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 696 KB
• Volume: 256
• Category: Article
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2010.02.045

✦ Synopsis

In this work amorphous silicon oxynitride films with similar composition (ca. Si 0.40 N 0.45 O 0.10 ) were deposited by reactive magnetron sputtering from a pure Si target under different N 2 -Ar mixtures. Rutherford backscattering (RBS) studies revealed that the coatings presented similar composition but different density. The mechanical properties evaluated by nanoindentation show also a dependence on the deposition conditions that does not correlate with a change in composition. An increase in nitrogen content in the gas phase results in a decrease of hardness and Young's modulus.

The microstructural study by high resolution scanning electron microscopy (SEM-FEG) on nonmetalized samples allowed the detection of a close porosity in the form of nano-voids (3-15 nm in size), particularly in the coatings prepared under pure N 2 gas. It has been shown how the presence of the close porosity allows tuning the refraction index of the films in a wide range of values without modifying significantly the chemical, thermal and mechanical stability of the film.