Resonant magnetic microsensor with μT resolution

This paper reports a resonant magnetic microsensor sensitive enough to measure, e.g., the earth magnetic field for compass applications. The sensor combines an electrostatically driven micromechanical resonator and a planar magnetic concentrator with two narrow gaps. For the device fabrication, silicon on insulator technology and epoxy-resin- based attachment of amorphous soft magnetic ribbons are combined. The narrow concentrator gaps are realized using a KrF excimer laser. The device characterization revealed a high sensitivity of up to 2.56 MHz/T and a resolution of 1.1 muT. To demonstrate the capability of the new device for compass applications, the horizontal earth magnetic field component was measured as a function of the horizontal sensor orientation.