Surface related degradation of sensitivity in lateral transistor magnetic sensors

It is shown that the sensitivity of silicon lateral P-N-P magneto-transistors can have a significant dependency on the operating conditions of their surface. The sensitivity of experimental devices built were observed to change by as much as an order of magnitude, depending on the design, as the surface conditions were swept from accumulation to inversion. The surface conditions between the emitter and the collector of such devices need to be stabilized with a constant biased gate for reproducible magnetic field measurements in addition to employing a fabrication process that yields consistent surface conditions and minimum surface state and charge density