A6.1 - Magnetic Microsensors: Quo Vadis?
- SENSOR+TEST Conferences 2009
2009-05-26 - 2009-05-28
Congress Center Nürnberg
- Proceedings SENSOR 2009, Volume II
- A6 - Magnetic Sensors I
- J. Marien, A. Schuetze - Saarland University, Saarbrücken, Germany
- 17 - 22
Magnetic sensors are used for contactless and wearless detection of a wide range of magnetic fields. This includes extremely low fields of a few fT (10-15 T) generated by the activity of human brain cells up to hundreds of mT (0.1 T) of modern rare earth magnets. During the last 20 years magnetic sensors have become very popular for detecting different physical properties like electric current, mechanical position, speed, angle, rotational speed or the earth magnetic field for electronic compass applications, because they are extremely reliable, small, cheap and easily integrated within electronics. There are different physical effects which are used to build magnetic sensors. Hall sensors and magneto resistive (MR)-sensors are today’s mainstream sensors manufactured in quantities of hundreds of millions devices per year. Current Hall sensors are seamlessly integrated in CMOS logic devices and thus often include the complete signal path, computational logic and digital interfaces. MR sensors, on the other hand, are normally made in a proprietary thin film process and are heterogeneously integrated into sensing systems. The two technologies differentiate mainly in the detectable field range and in the product of resolution and speed. In addition to these mainstream technologies for large volume applications, specific sensing principles are used especially for low field/low noise applications. Currently, fluxgate and SQUID sensors are used especially in medical applications or for magnetic imaging. A fairly new approach is the use of chip scale atomic magnetometers to measure the total field, a technology that is similar to chip scale atomic clocks, which have already proven their high potential.