Integrated magnetic-sensitive differential circuit based on heterojunction silicon magnetic-sensitive transistor

This paper presents an integrated magnetic-sensitive differential circuit, consisting of two heterojunction silicon magnetic-sensitive transistors (HSMSTs) with opposite magnetic-sensitive directions and two collector load resistors. The two HSMSTs have a common emitter (E), two bases (B1, B2), two collectors (C1, C2) and two output terminals of the collector voltage. Through using the micro-electro-mechanical system (MEMS) technology and the chemical vapour deposition (CVD) method, chips were designed and fabricated on a p-type 〈100〉 double-side polished silicon wafer with a high resistivity. When VDD = 10.0 V and IB = 6.0 mA, the magnetic sensitivity (Sv) of the proposed differential circuit was 275 mV/T at room temperature and its temperature coefficient (αST) was −1.668%/°C. The experimental results show that the magnetic sensitivity and temperature characteristics of proposed magnetic field sensors can be improved by using integrated differential circuits based on HSMSTs.