Material Characterization by Line-Focus-Beam Acoustic Microscope

Measurements of Thin-Film Elastic Properties by Line-Focus Acoustic Microscopy

“…[2]. The acoustic probe consists of a buffer rod with a transducer at one end and a cylindrical lens at the other.…”

“…Due to the interference of the specular reflection of the normally incident wave and the radiation of the leaky SAWs excited by the wave incident at a critical angle, the V(z) curve shows oscillatory behavior with period Az. The SAW velocity, v, has a functional relation with this period, which is given as [1,2] [ 2 ]-112…”

“…A measurement model for the V(z) curve has been described in detail elsewhere [10]. The V(z) curve may be expressed by (2) where k f is the wave number in the coupling fluid, Ll (kx) and L2(kx) are characteristic functions of the acoustic lens, and S(kx) is the reflectance function for the fluid-loaded specimen. In Ref.…”

“…The spacing, ilz, of peaks or valleys in the calculated V(z) curve is determined by a processing procedure analogous to the one used for the experimental V(z) curve, which has been described in Ref. [2]. Upon substitution of the detennined ilz in Eq.…”

“…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.…”