Design and fabrication of aluminum nitride Lamb wave resonators towards high figure of merit for intermediate frequency filter applications

Abstract

A design guideline for one-port aluminum nitride (AlN) Lamb wave resonators (LWRs) working at S0 mode with high performance is reported. A fabricated 252 MHz LWR, with an aperture of 200 μm, 12 fingers, and 1.5 μm thick AlN, is found to have a remarkably high figure of merit (FOM), which exhibits a high ratio of the resistance at parallel resonance (Rp) to the resistance at series resonance (Rs) of 1317 and a corresponding product of the effective coupling coefficient (k2eff) and quality factor (Q) exceeding 52. Consisting of such resonators, a 6-stage ladder filter with a low pass-band insertion loss (IL) of 4.5 dB and steep filter skirts is achieved, offering significant advantage of size savings.

A Universal Biomolecular Concentrator To Enhance Biomolecular Surface Binding Based on Acoustic NEMS Resonator

“…After a power is applied to the electrodes, acoustic waves are generated in the piezoelectric nanoplate via the converse piezoelectric effect. 39 When the resonator works in liquid, the acoustic streaming effect is generated because of the dissipation of acoustic energy into liquid, which is experimentally verified by the decrease of quality factor ( Q ) from 1175 to 56 (Supporting Information, Figure S2 ). Consequently, four symmetric counter-flowing Rankine microvortices (SCRMVs) are formed close to the resonator’s central region, and a virtual micropocket is further generated, where biomolecules are massively trapped and concentrated; hence, the concentration of the target biomolecules at the surface is larger than the bulk concentration ([A] s > [A] 0 ), and the molecule diffusion is enhanced by the hydrodynamic flow ( Figure 1 E).…”

Q-Factor Enhancement of Thin-Film Piezoelectric-on-Silicon MEMS Resonator by Phononic Crystal-Reflector Composite Structure

“…Step 6. Polyimide is applied as a protective layer on the top of the device to protect the top From Newton-Laplace equation, the acoustic velocity, v in the resonator could be approximated by E p ρ [30][31][32][33][34]:…”

50O-terminated ALN MEMS filters based on lamb wave resonators

“…In an LWR, the value R p /R s is closely related to resonator geometries. To obtain a 140 MHz LWR filter, the IDT pitch is chosen to be 35 μm, the aperture of the resonator is set to 350 μm and the IDT finger number is set to 6 [13].…”

“…The blue curve represents the resonator with a layer of mass load and the red curve represents the resonator without mass loading layer.978-1-4799-8955-3/15/$31.00 ©2015 IEEE Resonators both with and without mass load are fabricated. The fabrication process is the same as what is reported in literature[13]. The electrical performance of the resonators is measured in an RF probe station at atmosphere pressure.…”