High precision characterization of SAW materials and devices

Abstract

Three original methods, developed and used for the characterization of SAW materials and devices, are presented: an electric scanning force microscope, a laser induced SAW pulse propagation method, and an optical glass fibre interferometer. The electric scanning force microscope enables to map dielectric and piezoelectric properties in nanoscale. Two examples of its use in developing SAW thin film solutions are shown: PZT layers on Si and laser deposited LiNbO/sub 3/ layers on sapphire. The laser induced SAW pulse technique is shown to be a useful method to evaluate the mechanical properties of thin coatings in SAW preparation techniques and to determine unknown material constants of new substrate materials. The optical interferometer has been developed in such a way that the SAW velocity can be determined with an accuracy of 10/sup -5/ within transducer and reflector grating structures. This property has been used to determine the key parameters of potential materials for SAW waveguide resonator filters.