DESIGN, FABRICATION AND CHARACTERIZATION OF A CMOS-MEMS STATIC TO LOW FREQUENCY MAGNETIC FIELD SENSOR

This PhD thesis reports the design, modeling, simulation, fabrication and
characterization of a novel CMOS-MEMS magnetic field sensor (main device). This
sensor consists of two major components, 1) resonating shuttle and 2) set of torsional
coils. Each component works as magnetic sensor itself. The linear response of these
devices to a wide range of magnetic fields make them suitable for applications where
weak fields require to be measured with high resolution. The working of the main
CMOS-MEMS resonant magnetic sensor is based on a shift in resonant frequency of
the shuttle in the presence of magnetic field. The flexural beams of the shuttle are
designed so that axial forces from the side torsional coils are exerted on them when
exposed to the magnetic field. The axial forces causes a positive shift in the resonance
frequency of the shuttle. The operation of the resonating shuttle based sensor is based
on the differential change in the amplitude of the shuttle and this differential change is
sensed by optical sensing method.