Fabrication of piezoelectric thick films for high frequency transducers

Piezoelectric PZT thick film elements have been fabricated by using a screen printing laser liftoff process, with film thickness from 20 to 100μm. Various patterns were screen printed on a sapphire substrate and sintered at 1250°C for densification. After sintering, the PZT elements were bonded to a final target substrate, which could be a backing material for ultrasonic transducers. Next, the PZT elements were released from the sapphire substrate. This process has the potential to make large quantities of thick film elements and arrays at very low cost. The obtained films have a free dielectric constant of about 2000, remnant polarization of 39.8μC/cm², thickness-mode coupling factor of about 0.49, and are very promising for making high frequency transducers.