OPERATING PRINCIPLE OF DUAL COLLECTOR MAGNETOTRANSISTORS STUDIED BY 2-DIMENSIONAL SIMULATION

Dual collector magnetotransistors are magnetic-field-sensitive devices currently developed in several laboratories. Optimized sensor design is often attempted by trial and error rather than by established desig n rules. This motivated the present comprehensive study of the operati on of magnetotransistors by accurate two-dimensional numerical simulat ions. We model vertical and lateral transistors as obtained by industr ial IC technology on the basis of data provided by the chip manufactur er. We consider the entire device structure with the full, complex dev ice geometry, and the physically proper boundary conditions. Our simul ations reveal the details, controversial hitherto, of the operating pr inciple of these devices. In particular we find that, in the case of t he vertical transistor, it is essentially the emitter injection modula tion effect which dominates the sensor response. In the case of the la teral transistor, the magnetic sensitivity is predominantly determined by minority-carrier deflection, though side effects are involved as w ell. By variation of the doping profile and the device geometry we der ive rules for optimized magnetotransistor design.