A microelectromechanical systems-based vertical magnetometer-accelerometer with the modulated frequency difference in one microstructure

Abstract

This paper presents a vertical magnetometer-accelerometer capable of detecting simultaneously both the acceleration and the geomagnetic field. The conceived sensor detects the magnetic field by the Lorentz force and differentiates the magnetic field and the acceleration by the modulated frequency difference. The process uses a silicon-on-glass (SOG) wafer and the goldsilicon eutectic bonding for the wafer-level hermetic packaging. When the 10 mA current flows through the conductor, the measured resistances are an average of 10Ω, so in total, 1 mW is consumed in the current driving element. When 35 μT and lg is applied to the sensor at the same time, the fusion sensor has a sensitivity of 73 mV/g in acceleration sensing mode, and a sensitivity of approximately 1.63mV/μT in magnetic field sensing mode. This newly developed sensor can be used in portable navigators that need a small size, low cost and low power electronic compass. © 2008 The Japan Society of Applied Physics.