Abstract
Lamb wave microresonators with wavelengths k of 5–8 lm, vibrating in the S0 mode, and having 75 electrode pairs were fabricated and
characterized. The results were compared to theoretical predictions obtained by finite element simulation. The active material was a 1 lmthick Al0.85Sc0.15N thin film. Two types of acoustic isolation solutions were implemented: the first one with freestanding plates fixed by two
bridges to a device frame [freestanding Lamb wave resonator (FS-LWR)] and the second one containing an acoustic W/SiO2 5-layer reflector
[solidly mounted Lamb wave resonator (SM-LWR)]. All devices showed excellent agreement with FEM predictions, regarding resonance frequency and piezoelectric coupling. The quality factors of the SM-LWR devices were 5–6 times larger than the ones of the freestanding structures fabricated by the same Al0.85Sc0.15N deposition process: we achieved a figure of merit of 12–18 (Qp ¼ 771, Qs ¼ 507, k2 ¼ 2.29%) at an
operation frequency of 1430 MHz, which is so far the best performance realized with a MEMS Lamb wave resonator having a large number
of electrode fingers. This performance opens up perspectives for filter applications.
characterized. The results were compared to theoretical predictions obtained by finite element simulation. The active material was a 1 lmthick Al0.85Sc0.15N thin film. Two types of acoustic isolation solutions were implemented: the first one with freestanding plates fixed by two
bridges to a device frame [freestanding Lamb wave resonator (FS-LWR)] and the second one containing an acoustic W/SiO2 5-layer reflector
[solidly mounted Lamb wave resonator (SM-LWR)]. All devices showed excellent agreement with FEM predictions, regarding resonance frequency and piezoelectric coupling. The quality factors of the SM-LWR devices were 5–6 times larger than the ones of the freestanding structures fabricated by the same Al0.85Sc0.15N deposition process: we achieved a figure of merit of 12–18 (Qp ¼ 771, Qs ¼ 507, k2 ¼ 2.29%) at an
operation frequency of 1430 MHz, which is so far the best performance realized with a MEMS Lamb wave resonator having a large number
of electrode fingers. This performance opens up perspectives for filter applications.
| Originalsprache | Englisch |
|---|---|
| Aufsatznummer | 114 |
| Seiten (von - bis) | 1-4 |
| Fachzeitschrift | Applied Physics Letters |
| Jahrgang | 114 |
| Ausgabenummer | 223103 |
| DOIs | |
| Publikationsstatus | Veröffentlicht - 3 Juni 2019 |