Piezoelectric materials for BAW resonators and filters

Author

Löbl, H.P. ; Klee, M. ; Metzmacher, C. ; Brand, W. ; Milsom, R. ; Lok, P. ; van Straten, F.

Author_Institution

Philips Res. Lab., Aachen, Germany

Volume

1

fYear

2001

fDate

2001

Firstpage

807

Abstract

Thin film bulk acoustic wave (BAW) resonators and filters are appropriate for mobile communication systems operating at high frequencies between 0.5 and 10 GHz. c-axis orientated AlN films are used for medium bandwidth applications. Electromechanical coupling factors k _t of 0.25±0.03, which are close to the bulk data, have been found in AlN thin films using optimum sputter conditions. The correlation between k_t and AlN film orientation is discussed. Resonator Q values of approx. 450 are reported at 2.6 GHz and a Q of 250 was realized at 9.2 GHz. A physical model is shown to accurately predict the frequency responses of BAW resonators and band-pass filters. For wide bandwidth applications PbZr_xTi_1-xO₃ (PZT) films are investigated. They exhibit large coupling coefficients

Keywords

Q-factor; acoustic filters; acoustic resonators; aluminium compounds; band-pass filters; bulk acoustic wave devices; lead compounds; piezoelectric thin films; sputtered coatings; 0.5 to 10 GHz; AlN; AlN thin film; PZT; PZT thin film; PbZrO3TiO3; Q-factor; band-pass filter; bulk acoustic wave filter; bulk acoustic wave resonator; c-axis orientation; electromechanical coupling coefficient; frequency response; mobile communication system; piezoelectric material; sputter deposition; Acoustic waves; Bandwidth; Film bulk acoustic resonators; Frequency; Mobile communication; Piezoelectric films; Piezoelectric materials; Predictive models; Resonator filters; Sputtering;

fLanguage

English

Publisher

ieee

Conference_Titel

Ultrasonics Symposium, 2001 IEEE

Conference_Location

Atlanta, GA

Print_ISBN

0-7803-7177-1

Type

conf

DOI

10.1109/ULTSYM.2001.991845

Filename

991845