Measurements of Thin-Film Elastic Properties by Line-Focus Acoustic Microscopy
Quantitative acoustic microscopy has been used to measure the velocity of leaky surface acoustic waves (SAWs) [1,2]. This technique measures a V(z) curve, which is a record of the voltage output V of the transducer as a function of the distance z between the acoustic lens and the specimen. Line-focus acoustic microscopy (LFAM) allows the measurement of the SAW velocity in specified directions. In earlier papers, LFAM has been used to determine the elastic constants of isotropic thin films [3,4] and anisotropic thin films [5–7]. The directional variation of the SAW velocity of a thin-layer/anisotropic substrate configuration may be quite different from that of the bare substrate. It follows that this variation can be used to determine the elastic properties of thin films.
KeywordsElastic Constant Mass Density Dispersion Curve Simplex Method Directional Variation
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