Microfabrication of acoustic-wave devices

摘要

This paper deals with the technology of acoustic-wave sensor devices. The use of planar technologies for their fabrication gives them advantageous properties such as high reproducibility, small size and low production costs. Most acoustic-wave sensors are made of piezoelectric-crystal wafers. They are highly stable and reproducible and low-cost device fabrication is possible because the wafers are suited to be used in standard integrated circuit (IC) equipment such as metal-evaporation depositors and photo-lithographic machinery. The silicon-implementation of acoustic devices gives the possibility of making use of the best-developed technology ever: the silicon IC-technology. Additional features are the possibility of integration of electronic circuitry on the acoustic device and the development of new types of devices. However, the silicon implementation is hampered by difficulties in the development of reproducible piezoelectric thin films. Nonetheless, a few successes in this field have been reported. New technologies in which piezoelectric quartz and silicon wafers are combined could increase the performance of silicon integrated acoustic-wave devices.