Piezoelectric thin film devices

A new class of thin-film device structures has become available with the development of thin-film piezoelectric films by sol gel methods or by magnetron sputtering. In particular, sol gel techniques for ceramics such as lead zirconate titanate allow the fabrication of films of 1-4-μm thickness on surfaces of complex shape with crack propagation within the film being controlled by process methods and buffer layer structures. Rapid thermal annealing methods have recently simplified fabrication procedures for film fabrication on silicon. Devices are described using both planar and coaxial geometry for application in surface acoustic wave (SAW) and bulk wave transducers, coaxial sensors, optical modulators, and silicon-based resonators. Current limitations due to electrodes and mechanical effects are examined