On the Finite-Element Analysis of Resonance MEMS Structures based on Acoustic Lamb Waves

Pavel S Marinushkin ,Fyodor Zograf ,Alexey Levitsky ,Valentina A Bakhtina

doi:10.33180/infmidem2020.303

Abstract

This paper considers issues of modeling ultra-high frequency MEMS resonators based on acoustic Lamb waves. In addition, the analysis of factors that determine whether it is possible to increase resonators working frequency and quality factor is carried out. Influence of resonator excitation scheme and acoustic waveguide thickness for a range of piezoelectric materials (i.e. AlN, ZnO, GaN) on phase velocity for acoustic Lamb wave zero modes is investigated. As a result, we've got estimations determining dependence of resonators electromechanical coupling coefficient on their geometry.

Highlights

The growing demand for developing modern space telecommunication devices and constructing new prospective ones, radar and radio navigation systems condition the necessity of substantial working frequency increase of frequency-selective devices
Due to the mentioned above reasons, in recent years most researches have been focused on developing microelectromechanical (MEMS) resonators that have a rather small size, high quality factor values, active device integration function, good resistance to impact and vibration loads and possess many other advantages over the rest of the devices with similar functions [1, 2]
In aluminum nitride film (Fig. 8) electromechanical coupling coefficient for mode S0 in resonators with double IDT reaches its maximum at film relative thickness of t/λ ≈ 0.4 and has a value ~ 5%

Summary

Introduction

The growing demand for developing modern space telecommunication devices and constructing new prospective ones, radar and radio navigation systems condition the necessity of substantial working frequency increase of frequency-selective devices. Due to the mentioned above reasons, in recent years most researches have been focused on developing microelectromechanical (MEMS) resonators that have a rather small size, high quality factor values, active device integration function, good resistance to impact and vibration loads and possess many other advantages over the rest of the devices with similar functions [1, 2]. Increase of MEMS resonators working frequencies based on the widely used constructive options involves significant challenges. Resonators based on elements with flexural oscillations reach their scaling limits at frequencies of hundreds of megahertz. It happens because the size needed for higher frequencies is difficult to implement. With size decrease the dynamic impedance of such resonators increases, which impedes interfacing with highfrequency devices

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Conclusion