Comparison of different piezoelectric materials for GHz acoustic microscopy transducers

Today acoustic microscopy transducers are based on zinc oxide, ZnO, films as piezoelectric material. Especially in the GHz range the insertion loss of existing ZnO transducers has to be improved for better imaging. The motivation for this work was to substitute the ZnO by the piezoelectric material lead zirconate titanate, PZT, with better electro mechanical properties. Novel technologies of sol-gel and metal organic chemical vapor deposition method (MOCVD) were used to realize high frequency PZT thin film transducers with 200 m aperture diameter. The transducers were characterized by electrical and acoustical measurement. Their performance for acoustic microscopy was evaluated.