Two-dimensional numerical analysis of novel magnetotransistor with partially removed substrate

We present exact two-dimensional numerical simulations of novel magnetotransistor structures currently fabricated by combining standard bipolar technology with anisotropic etching. The disadvantage of high, noise producing, and power consuming substrate current encountered in conventional dual collector magnetotransistors is avoided by etching a cavity from the wafer back up to the epitaxial layer. By this means the parasitic emitter-base-substrate transistor is eliminated. The resulting magnetic field sensitivity is comparable to that of the original device structures, while the undesirable substrate current is efficiently suppressed. Our simulations also show that side-effects of the etching process do not cause a serious degradation of the sensor performance.<>