Title :
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
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;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
DOI :
10.1109/TUFFC.2014.2975
