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 VDD=10.0 V,all the base currents Ib1 of SMST1 and Ib2 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 coefficientαV of the collector output voltage of the sensor is 0.044%/℃.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.