FULL 3-DIMENSIONAL NUMERICAL-ANALYSIS OF MULTI-COLLECTOR MAGNETOTRANSISTORS WITH DIRECTIONAL SENSITIVITY

We have studied the operation of multi-collector bipolar transistors w ith directional magnetic-field sensitivity. The complex three-dimensio nal (3D) device consists of four crosswise-arranged lateral transistor s with one common central emitter. To analyse the electrical character istics and sensor performance, we have modelled the complete device st ructure using technological and physical parameters extracted from exp erimental measurements on real devices. Because of the complex geometr y, a full 3D numerical analysis of carrier flow and electrostatic pote ntial is required in order to study the effects of an arbitrarily orie nted magnetic field. A simplified analysis confined to the 2D central mirror plane is inadequate even for the mere electric device behaviour at zero magnetic field. This reflects the problem of current calibrat ion inherent in 2D approximations of devices with widely differing con tact areas. To overcome this discrepancy, we have implemented for the first time the 3D galvanomagnetic transport vector equations in a stat e-of-the-art general-purpose device simulator.