Fall 2010 IAB
September 15 to 17

Prof. David Horsley

MEMS Technology for Advanced Magnetic Sensors

Magnetic field sensors have a variety of low-field applications including magnetic imaging, orientation sensing, navigation, and the detection of vehicles and weapons. This talk will describe two approaches to realize new low-field sensors based on exploiting existing commercial technology. The first approach is to use a standard MEMS inertial sensor process to fabricate a silicon Lorentz-force magnetometer. This type of device is capable of a resolving a magnetic flux density of approximately 10 nT in a 1 Hz bandwidth, one thousand times smaller than earth’s magnetic field. The second approach combines silicon MEMS with magnetoresistive (MR) sensors. The most sensitive MR sensors, magnetic tunnel junction (MTJ) sensors, show excellent high-frequency noise performance in magnetic recording applications but have a low-frequency resolution that is limited by 1/f noise to approximately 1 nT/rt-Hz. Using MEMS to mechanically modulate a low-frequency magnetic field signature to a much higher frequency promises a thousand-fold improvement in the low-frequency resolution of these sensors - approaching the performance of a SQUID magnetometer in a room-temperature, chip-scale device.