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

摘要

Abstract: Creare is developing microfabrication techniques to manufacture low-cost, multi-dimensional ultrasonic transducer arrays with single- and multi-layer piezoelectric elements for low impedance and high sensitivity. The manufacturing approach is scaleable for fabrication of transducer arrays in the frequency range of 10 - 50 MHz in dense or sparse array configurations. Our approach employs the following processes: (1) Physical Vapor Deposition (PVD or sputtering) of high-quality, piezoelectric films using reactive sputtering of metallic targets and (2) Novel use of state-of-the-art photolithography and masking to provide the interlayer electrodes, element interconnections, and array element fabrication. To date, Creare has successfully demonstrated that piezoelectrically active thick films of PZT material can be deposited by using a reactive sputtering approach. In addition, these thick, multi-layer PZT films have been formed into high aspect ratio elements using dicing to fabricate a 12 MHz transducer. Array designs based on these films show that expected performance should meet the requirements for high resolution biomedical imaging.!3