Cut-off characteristics of leaky Sezawa and pseudo-Sezawa wave modes for thin-film characterization

A new method of determining the elastic constants, density, and thickness of thin-film materials with the line-focus-beam acoustic microscope is developed using propagation characteristics of leaky Sezawa and pseudo-Sezawa waves in the neighborhood of the cut-off region. It is demonstrated for a sample of gold film on fused quartz that the values of the stiffness constant, C44, and density are, respectively, about 11% and 5.5% less than those for polycrystalline bulk gold, and the thickness is determined as 6370 Å.