Physical vapor deposition of multilayer lead-zirconate-titanate films for ultrasonic transducer fabrication

Creare is developing microfabrication techniques to manufacture low-cost, two-dimensional ultrasonic transducer arrays with multilayer piezoelectric elements. The approach is scaleable for fabrication of arrays in the frequency range of 1-100 MHz in dense or sparse array designs. Our approach employs the following processes: (1) high-rate physical vapor deposition (sputtering) of high-quality, dense, perovskite lead-zirconate-titanate (PZT) films as the piezoelectric material using reactive sputtering of a metallic target and (2) photolithography and masking to provide the interlayer electrodes. A 50 μm thick PZT film was used to measure a thickness mode coupling coefficient of approximately 0.4