Investigations on LGS and LGT crystals to realize BAW resonators
The LGS family are promising materials for the design of high quality bulk acoustic wave resonators. We have manufactured many plano-convex 10 MHz 5th overtone Y-cut resonators using langasite (LGS, La(3)Ga(5)SiO(14)) and langatate (LGT, La(3)Ga(5.5)Ta(0.5)O(14)) crystals. We observed that the quali...
| Veröffentlicht in: | IEEE transactions on ultrasonics, ferroelectrics, and frequency control. - 1986. - 55(2008), 11 vom: 13. Nov., Seite 2384-91 |
|---|---|
| 1. Verfasser: | |
| Weitere Verfasser: | , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2008
|
| Zugriff auf das übergeordnete Werk: | IEEE transactions on ultrasonics, ferroelectrics, and frequency control |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't La3Ga5.5Tao.5O14 La3Ga5SiO14 Oxides Silicates |
| Zusammenfassung: | The LGS family are promising materials for the design of high quality bulk acoustic wave resonators. We have manufactured many plano-convex 10 MHz 5th overtone Y-cut resonators using langasite (LGS, La(3)Ga(5)SiO(14)) and langatate (LGT, La(3)Ga(5.5)Ta(0.5)O(14)) crystals. We observed that the quality factor strongly depends on the polishing method, the supplier of the material, and on the energy trapping. For quartz crystals, we have found that resulting IR spectra exhibit absorption peaks more or less deep, linked to defects. These predominant criteria are not surprising, but they have to be defined in manner similar to that used for quartz crystal. A satisfying machining and polishing method has been first applied to elaborate high Q resonators, and a comparison between samples of LGS and LGT materials from different suppliers is established. In addition, LGT resonators are characterized by their motional parameters and frequency-temperature curves. Nevertheless, one of the main results is that the measured Q x f product is not the expected one. We present results of Q-factor versus radius of curvature: it appears that an optimization should be performed and that this last one cannot be directly transposed from that of quartz crystal resonator. Currently, the best resonator that we have made has a Q x f product of 1.4 x 10(13) on its 5th overtone (1.7 x 10(13) on its 9th overtone). This result is slightly higher than the similar parameter obtained on a state-of-the-art SC-cut quartz crystal resonator working at the same frequency |
|---|---|
| Beschreibung: | Date Completed 30.01.2009 Date Revised 03.12.2008 published: Print Citation Status MEDLINE |
| ISSN: | 1525-8955 |
| DOI: | 10.1109/TUFFC.946 |