The Modeling and Fabricating of Film Bulk Acoustic Resonators Using Sputtered PZT Films with Various Thickness

Abstract

In this study, the modeling and experimental results for the resonant characteristics of Pb(Zr, Ti)O₃ (PZT) films with various thicknesses have been investigated in film bulk acoustic wave resonators (FBARs). PZT films and Pt electrodes were fabricated by rf magnetron sputtering. The electrodes and PZT were patterned by simple lift-off processing and then the back side of the silicon was etched by 45wt% KOH. The crystal structure of PZT films with 0.5, 1 and 2 μ m thickness was investigated by x-ray deflection (XRD) and scanning electron microscopy (SEM). The dielectric constant and performance characteristics of PZT FBAR strongly depended on the film thickness. The resonant frequency of PZT films decreased with increasing film thickness. The resonant frequency with 0.5 μ m thickness PZT FBAR is 1.48 GHz.

Keywords:

• PZT
• FBAR
• resonant frequency