Полупроводниковые Инжекционные Сенсоры Магнитного Поля Комбинированного Типа Для Беспроводных Информационных Сетей

Detectors Based on Field Effect Transistors

“…When the semiconductor is limited in the direction transverse to the electric field, then the Lorentz force can be compensated by the force of the Hall electric field, and the flow of charge carriers will cease to be deflected by the magnetic field. What was said above fully applies to the FET channel, placed in a transverse magnetic field [30], while, for the magnetoresistive effect to appear, the transverse dimensions of the channel must be greater than its length. This condition is satisfied, for example, by an FEJT of the KP303 type (analogue of 2N5556) with an n-type channel and a p-n junction as a gate, therefore it can be used as a magnetically sensitive fieldeffect transistor (MFET).…”

“…A decrease in the mean free path of charge carriers along the direction of the electric field is equivalent to a decrease in their mobility, and hence, according to (2), the saturation current FET. The relative change in the mobility of charge carriers in weak magnetic fields, with sufficient dimensions of the sample transverse to the electric field, is described by the formula [30]:…”

“…However, standard industrial transistors of the KP303 type can be used to detect weak magnetic fields as sensor elements in a combined bridge sensor based on four FEJTs, because in this case, an internal mechanism of increasing the sensitivity arises in both legs of the bridge in each pair of series-connected FE-JTs [30]. Fig.…”

“…With this inclusion of FEJT, an internal mechanism for increasing the sensitivity operates in each arm of the bridge for a pair of transistors [30]: a decrease in the mobility of charge carriers in a magnetic field in any of the MFEJT transistors leads to an increase in the voltage drop across it and a decrease in the voltage drop across the paired FEJT, which causes an additional an increase in the resistance of the MFEJT channel and an additional decrease in the resistance of the FEJT channel, and, hence, an additional increase in the voltage U. Resistor trimmer serves for precise zero setting (bridge balancing) in the absence of a magnetic field. As with all magnetic field sensors, a prerequisite for using such a scheme is strict adherence to the orientation of all elements.…”