Thin films of piezoelectric and ferroelectric materials are playing a growing role as critical elements in microwave acoustic devices, infrared imagers, integrated optic circuits, optical displays, and high-performance semiconductor memories. In this review, we discuss recent progress in the control of growth, structure, and properties of the main candidate materials, such as ZnO, AIN, PZT-based solid solutions, bismuth titanate (Bi4Ti3O12), LiNbO3, LiTaO3, and KNO3. Brief mention is also made of the role and status of ferroelectric polymers and liquid crystals. The emphasis of the review is primarily on vacuum-processed films, intended for integration into solid-state or semiconductor components. © 1990, American Vacuum Society. All rights reserved.