An ultra-sensitive piezoelectric-on-silicon flapping mode MEMS lateral field magnetometer

We experimentally demonstrate the sensing of lateral magnetic fields using the piezoelectric effect in a resonant MEMS thin-film piezoelectric-on-silicon (TPoS) CMOS-compatible magnetometer. The proposed out-of-plane flapping resonant mode offers strong electromechanical coupling through the piezoelectric Aluminum Nitride (AlN) transducer to enhance the responsivity of the device while operating at atmospheric pressure. The responsivity is here defined as the ratio of output motional current to the external magnetic field strength, normalized over the input excitation current of the device. We have experimentally measured a responsivity of 12156 ppm/T while operating the device at a resonant frequency of 159 kHz, despite even an air-damped quality factor of 526 under ambient conditions.