Photoacoustic characterization of the mechanical properties of thin film materials

Feifei Zhang*, Sridhar Krishnaswamy, Dong Fei, Douglas A. Rebinsky

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review


Two high frequency photoacoustic techniques were applied to investigate the mechanical properties of two sets of thin film materials in this work. Broadband photoacoustic guided-wave method was used to measure the guided-wave phase velocity dispersion curves of nano-structured diamond-like carbon hard coatings. The experimental velocity spectra were analyzed by a nonlinear optimization approach in conjunction with a multi-layer wave-propagation model. The derived Young's moduli using the broadband photoacoustic technique were compared with line-focus acoustic microscopy and nano-indentation tests and good quantitative agreement is found. In a second set of experiments, ultra-thin two-layer aluminum and silicon nitride thin film materials were tested using the femtosecond transient pump-probe method using high frequency bulk waves generated by the ultra-fast laser pulses. The measured moduli of silicon nitride thin layers are in the range of 270 - 340 GPa. Photoacoustic methods are shown to be suitable for in-situ and non-destructive evaluation of the mechanical properties of thin films.

Original languageEnglish (US)
Article number13
Pages (from-to)89-98
Number of pages10
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - Oct 7 2005
EventTesting, Reliability, and Application of Micro- and Nano-Material Systems III - San Diego, CA, United States
Duration: Mar 8 2005Mar 10 2005


  • Femtosecond pump-probe technique
  • Mechanical properties
  • Photoacoustic guided-wave method
  • Thin films

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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