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 A.