Real-time monitoring of semiconductor growth by spectroscopic ellipsometry

B. Johs, J. Hale, C. Herzinger, D. Doctor, K. Elliott, G. Olson, D. Chow, J. Roth, I. Ferguson, M. Pelczynski, C. H. Kuo, S. Johnson

Research output: Contribution to journalConference articlepeer-review

14 Scopus citations


in situ Spectroscopic Ellipsometry (SE) is an optical technique which is well suited for the monitoring of epitaxial semiconductor growth, due to its high surface sensitivity and non-invasive nature. In this work, SE systems were installed on both MBE and MOCVD deposition systems to monitor the epitaxial growth of InxGa1-xAs and InxAl1-xAs compounds on InP substrates. The structures grown include thick lattice matched In0.53Ga0.47As buffer layers (for HBT collectors), and strained RTD structures. SE was used to monitor in real-time layer composition and thickness during growth. To enhance the precision and accuracy of the SE determined growth parameters, it was necessary to optimize the SE data analysis strategies. A methodology to determine the best spectral region for the SE data analysis in the presence of noise and systematic effects (such as angle of incidence uncertainty, detector wavelength shifts, surface roughness, uncertainty in surface temperature, non-ideal growth mods, etc.) is presented. Using the optimized data analysis strategies, long term SE-determined InxGa1-xAs composition accuracy (as verified by ex situ x-ray measurements) of ±0.002 in 'x' was achieved. SE thickness measurements of ultra-thin (<30 angstrom) strained AlAs barrier layers were also in excellent agreement (±0.5 angstrom) with real-time photo-emission oscillation measurements.

Original languageEnglish (US)
Pages (from-to)3-14
Number of pages12
JournalMaterials Research Society Symposium - Proceedings
StatePublished - Jan 1 1998
Externally publishedYes
EventProceedings of the 1997 MRS Fall Symposium - Boston, MA, USA
Duration: Dec 2 1997Dec 4 1997

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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