Impact of the electrode material and shape on performance of intrinsically tunable ferroelectric FBARs

Author

Vorobiev, Alexey ; Gevorgian, S.

Author_Institution

Dept. of Microtechnol. & Nanosci., Chalmers Univ. of Technol., Gothenburg, Sweden

Volume

61

Issue

5

fYear

2014

fDate

41760

Firstpage

840

Lastpage

848

Abstract

Experiment-based analysis of losses in tunable ferroelectric xBiFeO₃-(1-x)BaTiO₃ (BF-BT) film bulk acoustic wave resonators (FBARs) is reported. The Q-factors, effective coupling coefficients, and tunabilities are considered as functions of surface roughness of the ferroelectric film, the acoustic impedance and shape of the electrodes/interconnecting strips, leakage of acoustic waves into the substrate via Bragg reflector, and the relative thicknesses of the electrodes and ferroelectric film. Compared with Al, the high acoustic impedance of Pt electrodes provides higher Q-factor, coupling coefficient, and tunability. However, using Pt in the interconnecting strips results in reduction of the Q-factor.

Keywords

acoustic resonators; barium compounds; bismuth compounds; bulk acoustic wave devices; electrodes; ferroelectric devices; ferroelectric materials; ferroelectric thin films; g-factor; losses; platinum; surface roughness; thin film devices; BF-BT FBAR; BiFeO₃-BaTiO₃; Bragg reflector; Pt; Q-factors; acoustic impedance; acoustic wave leakage; effective coupling coefficients; electrode material; electrode-interconnecting strip shape; experiment-based losses analysis; intrinsically tunable ferroelectric FBARs; relative electrode thicknesses; surface roughness; tunable ferroelectric film bulk acoustic wave resonators; Couplings; Electrodes; Film bulk acoustic resonators; Impedance; Q-factor; Resonant frequency;

fLanguage

English

Journal_Title

Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on

Publisher

ieee

ISSN

0885-3010

Type

jour

DOI

10.1109/TUFFC.2014.2975

Filename

6805697