First three-dimensional numerical analysis of magnetic vector probe

We studied the operation of multi-collector bipolar transistors with directional magnetic field sensitivity. The complex three-dimensional (3D) device consists of four crosswise-arranged lateral transistors with one common central emitter. To analyze the electrical characteristics and sensor performance, we modeled the complete device structure using technological and physical parameters, extracted from experimental measurements on real devices. Because of the complex geometry, a full 3D numerical analysis of carrier flow and electrostatic potential is required in order to study the effects of an arbitrarily oriented magnetic field. Full 3D analysis is essential also in devices whose contact areas differ widely. In this case, a simplified analysis confined on the 2D central mirror plane is inadequate even for the mere electric device behavior at zero magnetic field. This reflects the problem of current calibration inherent in 2D approximations of devices with truly 3D structures. To overcome this discrepancy, we implemented, for the first time, the 3D galvanomagnetic transport vector equations in a state-of-the-art general purpose device simulator.<
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