Determination of the bonding qualities of layered gold/silicon systems using higher SAW modes

Dispersion curves of SAWs propagating on the surface of a layered system wee obtained by measurement of the surface wave velocities for various ultrasonic frequencies. Results are presented for two and three layered specimens: gold/silicon and gold/chromium/silicon. A comparison with numerically simulated dispersion curves shows that Sezawa modes were measured. The elastic constants, namely c11 and c44, of gold films with thicknesses up to 2 micrometers were determined by minimization the difference between the theoretical and the experimental values in a least-square sense. The resulting Young modulus E yields information about a stiffer layer structure caused by the influence of an chromium interlayer. The modification of the interface between film and substrate is characterized. The results confirm the use of chromium for better adhesion.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.