PIEZOELECTRIC/MAGNETOSTRICTIVE MEMS RESONANT SENSOR ARRAY FOR IN-PLANE MULTI-AXIS MAGNETIC FIELD DETECTION

This paper reports the demonstration of an array of piezoelectric/magnetostrictive micro electromechanical system (MEMS) magnetic resonant sensors (PM-MRS) for multi-axis magnetic field (H-field) detection. An array of 43 MHz aluminum nitride (AlN) piezoelectric resonators vibrating along different in-plane directions (.) but coated with a magnetostrictive layer (Fe65.6Co9.4B25) with the same easy axis (EZ) exhibit unique mechanical/electrical responses as a function of the applied H-field and its direction, enabling a high resolution multi-axis H-field detection. The sensor design yields resonators with a high quality factor (Q similar to 1500) and electromechanical coupling coefficient (k(t)(2) similar to 2%) -the highest value ever reported for an AlN PM-MRS. This sensor system paves the way for low power magnetometers that enables single-chip multi-axis H-field detection.