PIEZOELECTRIC THIN-FILMS

The history of the developments in materials, fabrication methods and applications of piezoelectric thin films are reviewed. The materials for the piezoelectric thin films are non-ferroelectric and ferroelectric sulfides, oxides and nitrides. Epitaxial films and polar axis oriented films are useful for the practical applications of piezoelectric thin films. The most widely used piezoelectric thin film material is the polar axis oriented ZnO thin film. The surface acoustic wave filters for TV-IF filters made of the polar axis oriented ZnO thin films on glass substrates are produced at the production rates of several million pieces per month in 1991.