High resolution visualization of acoustic wave fields within surface acoustic wave devices

We present the submicron visualization of surface acoustic wave (SAW) fields within interdigital transducers (IDTs) obtained by a scanning acoustic force microscope. Utilizing the nonlinear force curve of the tip-to-surface interaction, a periodic deflection of the cantilever appears when the SAWs are excited intermittently. This deflection depends on the amplitude of the surface oscillation and was measured by lock-in technique. SAWs with operating frequencies above 600 MHz were detected. The influence of the mass loading on the local oscillation amplitude was studied for various layer thicknesses of the IDT electrodes. (C) 1997 American Institute of Physics.