EFFECTS OF LIQUID LOADING ON SURFACE ACOUSTIC-WAVES IN SOLIDS

We study the effect of liquid loading on the characteristics of surfac e acoustic waves propagating along the (100) surface of silicon. A non viscous liquid layer of infinite thickness in contact with a solid sub strate causes changes in the wave velocity and the attenuation of surf ace waves along the liquid-solid boundary. More importantly, we examin e an additional branch of the Rayleigh surface that is induced by the liquid loading. We also find that the pseudosurface wave, which is res tricted only to certain directions on the free surface, extends to all directions on the liquid-loaded (100) surface. Calculating the acoust ic Poynting vectors associated with these surface-related acoustic mod es, we find that the Rayleigh wave and the induced Rayleigh wave emit energy only into the liquid, whereas the pseudosurface wave emits ener gy both into the liquid and solid substrate.