The fabrication and characterization of a microfabricated acoustic Lamb-wave device driven by a piezoelectric PZT (modified lead zirconate titanate Pb(Zr-x,Ti1-x)O-3) sol-gel thin film for use in mass-transport, mass-filtering and fluid-delivery systems are presented. Ultrasonic flexural plate waves (FPWs) at frequencies of the order of megahertz are generated and detected in a thin acoustic composite membrane by using two interdigitated transducers (IDTs) patterned on a 0.75 mu m thick piezoelectric ceramic PZT film, which provides high acoustic power for physical translation of fluid and microparticles. (C) 1998 Elsevier Science S.A.