Effect of film chemistry on refractive index of plasma-enhanced chemical vapor deposited silicon oxynitride films: A correlative study

Journal Article (Journal Article)

Thick SiOxNy films were deposited by radiofrequency (rf) plasma chemical vapor deposition using silane (SiH4) and nitrous oxide (N2O) source gases. The influence of deposition conditions of gas flow ratio, rf plasma mixed-frequency ratio (100 kHz, 13.56 MHz), and rf power on the refractive index were examined. It was observed that the refractive index of the SiOxNy films increased with N and Si concentration as measured via x-ray photoelectron spectroscopy. Interestingly, a variation of refractive index with N2O:SiH4 flow ratio for the two drive frequencies was observed, suggesting that oxynitride bonding plays an important role in determining the optical properties. The two drive frequencies also led to differences in hydrogen concentration that were found to be correlated with refractive index. Hydrogen concentration has been linked to significant optical Absorption losses above index values of ∼1.6, which we identified as a saturation level in our films. © 2008 Materials Research Society.

Full Text

Duke Authors

Cited Authors

  • Naskar, S; Wolter, SD; Bower, CA; Stoner, BR; Glass, JT

Published Date

  • May 1, 2008

Published In

Volume / Issue

  • 23 / 5

Start / End Page

  • 1433 - 1442

International Standard Serial Number (ISSN)

  • 0884-2914

Digital Object Identifier (DOI)

  • 10.1557/jmr.2008.0176

Citation Source

  • Scopus