Bulk acoustic wave (BAW) resonator-based MEMS magnetic field sensor

This paper experimentally demonstrates a MEMS magnetic field sensor which is working at ∼ 0.873 GHz resonant frequency. The Bulk Acoustic Wave (BAW) resonators are most suitable for high-frequency (GHz) operation and, therefore, appropriate for high-sensitivity magnetic field sensors. The sensor has a multilayer stack of (Si/SiO₂/Pt/ZnO/Fe₆₅Co₃₅) thin films with Fe₆₅Co₃₅ as a magnetic field-sensing layer and Zinc Oxide (ZnO) as piezoelectric actuation layer. The influence of an external applied magnetic field up to 1847 Oe has been investigated in terms resonance frequency shift due to ΔE effect. The magnetic sensor shows sensitivity (S) of 48.23 ppm/mT with outstanding performance at high frequency and large magnetic field range (0–1847 Oe). The developed MEMS magnetic field sensors are compact, exceptionally sensitive, and possess potential utility in diverse sectors, including automotive, defense, robotics, medical apparatus, space technology, geophysics, and industrial gauging.