Characterisation of Excimer iamp photo-deposited ultrathin oxynitride films

S. Lynch, G. M. O'Connor, G. M. Crean, J. Y. Zhang, Z. Geretovszky, P. Bergonzo, I. W. Boyd

Research output: Contribution to journalConference article

1 Citation (Scopus)

Abstract

Excimer lamp deposited ultra-thin (< 250A) silicon dioxide and silicon oxynitride films were characterised using spectroscopic ellipsometry (SE) and Fourier transform infrared (FT-IR) spectroscopy. SE analysis of the photo-deposited SiO2 films revealed no variation in the refractive index (n) of the films for deposition temperatures of 200°C and 300°C. Using a Bruggeman effective medium approximation (EMA), SE analysis was employed to determine both the silicon oxynitride layer thicknesses and compositions as a function of deposition temperatures and gas ratio, defined as (N2O/(N2O+NH3)). From this analysis the optical properties of the silicon oxynitride thin films were extracted. It was observed that the refractive index for the 200°C and 300°C series of samples decreased from n=1.81 to 1.46 and n=1.72 to 1.46 respectively as a function of increasing gas flow ratio. FT-IR analysis revealed spectral features characteristic of Si-O, Si-N, Si-H and N-H bonding. The most significant feature in all recorded spectra was a mixed spectral absorption band ranging from 800cm-1 to 1300cm-1. Both the integrated band area and peak wavenumber of this absorption band was found to be sensitive to the degree of nitridation and layer thickness of the thin films. The N-H stretching bond density was calculated from the N-H peak at 3360cm-1 using appropriate calibration factors. A slight decrease in the N-H bond density with increasing gas flow rate was observed. This variation in bond density was significantly less than that observed for PECVD silicon oxynitride films.

Original languageEnglish
Pages (from-to)302-310
Number of pages9
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume2403
DOIs
Publication statusPublished - Apr 10 1995
EventLaser-Induced Thin Film Processing 1995 - San Jose, United States
Duration: Feb 1 1995Feb 28 1995

Keywords

  • Excimer lamp
  • Fourier transform infrared spectroscopy
  • Optical properties
  • Photo-chemical deposition
  • Refractive index
  • Silicon oxynitride
  • Spectroscopic ellipsometry

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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