AlN-based film bulk acoustic resonator devices with W/SiO2 multilayers reflector for rf bandpass filter application

In this article, a reactively sputtered aluminum nitride (AIN) piezoelectri c film and its application for a film bulk acoustic resonator (FBAR) device are presented. The FBAR is composed of an AIN film sandwiched between top aluminum (Al) and bottom gold (,Au) electrodes and an acoustic reflector bl ock of SiO2/W stacked multilayers. Both the top and bottom electrodes are c onnected by a transmission line. The insertion loss (S-21) and return loss (S-11) were 6.1 and 37.19 dB, respectively. Using the empirical definition technique, the series resonance frequency (f(s)) and parallel resonance fre quency (f(p)) were found to be 1.976 and 2.005 GHz, respectively. Based on these findings, the effective electromechanical coupling coefficient (K-eff (2)) and the quality factor (Q) were also obtained as 3.53% and 4261. respe ctively. (C) 2001 American Vacuum Society.