Portal de Periódicos da CAPES

A 3D micromechanical compass

2007; Elsevier BV; Volume: 142; Issue: 2 Linguagem: Inglês

10.1016/j.sna.2007.08.025

1873-3069

Jukka Kyynäräinen, Jaakko Saarilahti, H. Kattelus, Anu Kärkkäinen, Tor Meinander, A. Oja, Panu Pekko, Heikki Seppä, Mika Suhonen, Heikki Kuisma, Sami Ruotsalainen, Markku Tilli,

Acoustic Wave Resonator Technologies

We have designed and fabricated micromechanical magnetometers intended for a 3D electronic compass which could be embedded in portable devices. The sensors are based on the Lorentz force acting on a current-carrying coil, processed on a single crystal silicon resonator, and they are operated in vacuum to reach high enough Q values. Sensors for all cartesian components of the magnetic field vector can be processed on the same chip. The vibration amplitude is detected capacitively and the resonance is tracked by a phase-locked-loop circuit. The fabrication process is based on aligned direct bonding of a double side polished silicon wafer and a SOI wafer. Magnetometers measuring the field component along the chip surface have a flux density resolution of about 10 nT/√Hz at a coil current of 100 μA. Magnetometers measuring the field component perpendicular to the chip surface are currently less sensitive with a flux density resolution of about 70 nT/√Hz. The standard deviation of the signal was less than 1% over a period of a few days.