The photoacoustic (PA) technique is one of many techniques for measuring thermal conductivity of thin films. Compared with other techniques for thermal conductivity measurement, the photoacoustic method is relatively simple, yet is able to provide accurate thermal conductivity data for many types of thin films and bulk materials. In this work, the PA measurement in a high frequency range is made possible by a newly developed PA apparatus, which extends the limit of the PA technique. Thermal conductivities of with thicknesses from 0.05 to 0.5 μm on Si wafer, e-beam evaporated thin nickel film on Si wafer, and thermal barrier coatings are obtained. In addition to the commonly used phase shift fitting, which is only appropriate for thermally-thin films, an amplitude fitting method is developed and employed for measuring both thin films and bulk materials with smooth or rough surfaces. Comparing results by amplitude fitting to those obtained by other methods and reference values shows good agreements. Applications and limitations of the photoacoustic technique are discussed.
Photo-Acoustic Measurement of Thermal Conductivity of Thin Films and Bulk Materials
Contributed by the Heat Transfer Division for publication in the JOURNAL OF HEAT TRANSFER. Manuscript received by the Heat Transfer Division October 25, 1999; revision received, June 25, 2000. Associate Editor: A. Majumdar.
Wang , X., Hu, H., and Xu, X. (June 25, 2000). "Photo-Acoustic Measurement of Thermal Conductivity of Thin Films and Bulk Materials ." ASME. J. Heat Transfer. February 2001; 123(1): 138–144. https://doi.org/10.1115/1.1337652
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