This paper discusses the requirements for piezoelectric thin film applications to radio frequency (RF) surface and bulk acoustic wave (SAW/BAW) devices. First, we survey the basic properties of RF SAW/BAW devices. We then discuss how device performances depend on the acoustic and piezoelectric properties of the piezoelectric thin films. Next, we discuss the effects of crystal grains and their boundaries within the thin films, and show how the binding strength of crystal grains affects the excitation and propagation of acoustic waves. Finally, we present basic design and characterization procedures for an SAW transversal filter employing an AlN/diamond structure.
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