Differential Structure and Characteristics of a New-Type Silicon Magnetic Sensitivity Transistor

A differential structure magnetic sensor is proposed. It is comprised of two new-type silicon magnetic sensitivity transistors (SMSTs) with similar characteristics and has a common emitter, two bases and two collectors. The sensor is fabricated by micro electromechanical system technology on a ?100? high resistivity silicon wafer. At room temperature, when supply voltage V_DD=10.0 V, all the base currents I_b1 of SMST1 and I_b2 of SMST2 equal 6.0 mA, the absolute magnetic sensitivity for the two SMSTs are 46.8 mV/kG and 56.1 mV/kG, respectively, and the absolute magnetic sensitivity for the sensor is 102.9 mV/kG. Meanwhile, the temperature coefficient α_V of the collector output voltage of the sensor is 0.044%/°C. The experimental results show that the magnetic sensitivity and the temperature characteristics of the sensor can be improved and ameliorated compared with a single SMST.