|Thesis abstract: |
The MEMS (Micro Electro Mechanical System) technology is becoming more and more important for several applications. One of this, particularly interesting, is the assisted navigation, for which MEMS sensors find their place in smartphones and other consumer devices. For what concerns accelerometer and gyroscope, the MEMS technology is the one that offers the best quality-price ratio: many devices use a 6-DOF (Degree Of Freedom) MEMS sensor, three-axis accelerometer and three-axis gyroscope.
Unfortunately, the gyroscope is not precise enough, and it needs to be corrected by a magnetometer, that has to be able to measure magnetic fields with the same intensity of the Earth¿s field. The sensors that will be under consideration are two: AMR and Lorenz-Force (MEMS) based sensors. AMR technology is already well established in the world of magnetic sensors, and today is one of the most used. However, it has some intrinsic limits, for example it doesn¿t respect the specific of ultra-thin packages for the next years, because the sensor for the z-axis needs to be tilted, and its height is too large for next-years ultrathin packages. Lorentz-Force based magnetometers are instead a new technology, which today does not reach the performance guaranteed by other technologies such as AMR. This type of sensors has however many potential advantages, because they can be fabricated in the same technology as the 6-DOF units. Therefore they potentially allow the integration of a 9-DOF inertial sensor in a single ultrathin chip.
The research will concern the identification of the specifications, the device simulation and design and the design of experimental setups and associated electronics.