Research of the Monolithic Integrated 3-D Magnetic Field Sensor Based on MEMS Technology

A monolithic-integrated 3-D magnetic field sensor is proposed in this paper, which is composed of four silicon magnetic sensitive transistors and a Hall magnetic field sensor. Using microelectromechanical system (MEMS) technology, the chip of the sensor was designed and fabricated on a p-type silicon wafer with a higher resistivity. At the room temperature, the magnetic sensitivities S
_xx
and S
_yy
on the x- and y-directions are 77.5 and 78.6 mV/T at power supply V
_DD
= 5.0 V and base injection current I
_b
= 1.0 mA, respectively. In addition, the magnetic sensitivity S
_zz
on the z-axis is 77.4 mV/T at V
_DD
= 5.0 V. The experimental results show that the proposed sensor has a good uniformity of magnetic sensitivity, besides achieving the measurement to 3-D magnetic fields and the cross sensitivities are less than 3% at B ≤ 0.8 T.