A piezoelectric-on-silicon width-extensional mode Lorentz force resonant MEMS magnetometer

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Original languageEnglish
Pages (from-to)169-177
Journal / PublicationSensors and Actuators, A: Physical
Online published25 Apr 2017
Publication statusPublished - 15 Jun 2017


In this paper, we present a unique micromachined magnetometer based on a width-extensional (WE) mode thin-film piezoelectric-on-silicon (TPoS) resonator for detection of magnetic fields applied normal to the plane of fabrication. The reported device targets operation in ambient pressure rather than vacuum, which should simplify packaging requirements. To compensate for a lower quality (Q) factor when operating in ambient pressure, the strong electromechanical coupling provided by the piezoelectric Aluminium Nitride (AlN) transducer has the advantage of greatly enhancing the sensitivity performance of the device. The reported device is based on a rectangular plate that is driven into the WE resonance mode by an in-plane Lorentz force pair that results from an external out-of-plane magnetic field. Two design generations of the proposed device topology are presented herein, with the latter design generation showing a substantial improvement over the former. The resonant frequency of the most recent design generation is 18 MHz, and its associated Q-factor was 1500 under ambient conditions. We have experimentally calibrated the sensitivity of the device, which was found to be 63.27 mV/T under ambient conditions. The measured result agrees well with both our analytical and finite element model.

Research Area(s)

  • Magnetic field sensors, Micromechanical devices, Piezoelectric devices, Resonant sensors