Title :
Composite ferroelectric fbars that are switchable between the first and second harmonics: experimental demonstration
Author :
Vorobiev, Andrei ; Gevorgian, Spartak
Author_Institution :
Dept. of Microtechnol. & Nanosci., Chalmers Univ. of Technol., Gothenburg, Sweden
Abstract :
Digital switching between the first and second harmonics, in a composite thin-film bulk acoustic wave resonator (FBAR), is demonstrated experimentally. The FBAR consists of two 180-nm-thick paraelectric-phase Ba0.25Sr0.75TiO3 films separated by a 50-nm-thick SrRuO3 conducting layer. The resonant frequency of this composite resonator (with Pt bottom and Al top electrodes) is switched from 3.6 GHz to 7.6 GHz, where the polarity of the 5 V dc bias is reversed on one of the ferroelectric films. The frequency switching ratio (f2/f1 ≥ 2) depends on the thickness of the electrodes. Some adjustment of f2/f1 is possible by changing the applied dc bias.
Keywords :
acoustic resonators; barium compounds; bulk acoustic wave devices; conducting materials; ferroelectric devices; ferroelectric thin films; strontium compounds; thin film devices; Ba0.25Sr0.75TiO3; SrRuO3; composite ferroelectric FBARs; composite thin-film bulk acoustic wave resonator; conducting layer; dc bias polarity; digital switching; electrodes; ferroelectric films; first harmonics; frequency 3.6 GHz to 7.6 GHz; frequency switching ratio; paraelectric-phase films; resonant frequency; second harmonics; size 180 nm; size 50 nm; voltage 5 V; Electrodes; Film bulk acoustic resonators; Frequency measurement; Harmonic analysis; Q-factor; Resonant frequency; Switches;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
DOI :
10.1109/TUFFC.2014.006501
