Search

This work researched the effects of irradiation on the current-voltage characteristics and voltage magnetic sensitivity of the silicon magnetic sensitive transistor (SMST). The 1-MeV electron irradiation source was used to irradiate the SMST. The irradiation fluences were 1 × 1012 e/cm2, 1 × 1013 e/cm2 and 1 × 1014 e/cm2, respectively (the irradiation flux was 1 × 1010 cm−2·s−1). The experimental results demonstrate that the collector current (IC) of the SMST occurs attenuation after irradiation under the same collector voltage (VCE) and the base current (IB). The attenuated rate of the IC increases obviously with the enhance of electron irradiation fluence when the IB is the same. Moreover, the attenuated rate of the IC increases slight with the rise of the IB when the electron irradiation fluence is the same. When the supply voltage is 5.0 V (RL = 1.5 kΩ) and the IB is 4.0 mA, the voltage magnetic sensitivity (SV) of the SMST occurs attenuate after irradiation. The attenuated rate of the SV increases with the enhance of electron irradiation fluence.

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.

This paper presents a three dimensional (3D) magnetic field sensor composed of three Hall elements with similar characteristics. Through adopting complementary metal oxide semiconductor (CMOS) technology, the chips of Hall element were designed and fabricated on the p-type silicon substrate with high resistivity. Based on the wire bonding technology, the Hall sensors were packaged on printed circuit boards (PCBs), allocating on three faces of a synthetic resin cube (10 ´ 10 ´ 10 mm3) to form an orthogonally directional array. When the supply voltage is 5.0 V, the magnetic sensitivities in x axis, y axis and z axis are 137.7 mV/T, 137.2 mV/T and 136.7 mV/T at room temperature, respectively. The experimental results show that the packaging device can achieve the measurement to 3D magnetic field.

This paper presents a magnetically sensitive transistor using a nc-Si:H/c-Si heterojunction as an emitter junction. By adopting micro electro-mechanical systems (MEMS) technology and chemical vapor deposition (CVD) method, the nc-Si:H/c-Si heterojunction silicon magnetically sensitive transistor (HSMST) chips were designed and fabricated on a p-type orientation double-side polished silicon wafer with high resistivity. In addition, a collector load resistor ( R L ) was integrated on the chip, and the resistor converted the collector current ( I C ) to a collector output voltage ( V out ). When I B = 8.0 mA, V DD = 10.0 V, and R L = 4.1 kΩ, the magnetic sensitivity ( S V ) at room temperature and temperature coefficient ( α C ) of the collector current for HSMST were 181 mV/T and −0.11%/°C, respectively. The experimental results show that the magnetic sensitivity and temperature characteristics of the proposed transistor can be obviously improved by the use of a nc-Si:H/c-Si heterojunction as an emitter junction.

Based on the asymmetric base region transistor, a pressure sensor with temperature compensation circuit is proposed in this paper. The pressure sensitive structure of the proposed sensor is constructed by a C-type silicon cup and a Wheatstone bridge with four piezoresistors ( R 1 , R 2 , R 3 and R 4 ) locating on the edge of a square silicon membrane. The chip was designed and fabricated on a silicon on insulator (SOI) wafer by micro electromechanical system (MEMS) technology and bipolar transistor process. When the supply voltage is 5.0 V, the corresponding temperature coefficient of the sensitivity (TCS) for the sensor before and after temperature compensation are -1862 and -1067 ppm/℃, respectively. Through varying the ratio of the base region resistances r 1 and r 2 , the TCS for the sensor with the compensation circuit is -127 ppm/℃. It is possible to use this compensation circuit to improve the temperature characteristics of the pressure sensor.

In this paper the pressure-magneto-electric effect of Junction Field Effect Transistor (JFET) is discussed by using standard relaxation techniques. A theoretical evaluation of the pressure sensitivity and Hall sensitivity of then-channel silicon JFET with various geometries (W/L), gate voltages (V GS ) and drain voltages (V DS ) is made. The results show that whenP≠o,B=0, the current-pressure sensitivity is about 2.5%. cm2/N, supposingW/L≤1/2–1. Based on that, a junction field effect pressure sensor with high stability and low noise is designed.