High gain p-n-p gated lateral bipolar action in a fully depleted counter-type: Channel p-MOSFET structure

Abstract

A three-terminal p-n-p gated lateral bipolar transistor in a counter-type channel p-MOSFET structure has exhibited experimentally ideal I-V characteristics in low-level injection, with a peak current gain exceeding 1000. Two-dimensional device simulation and additional experiments have revealed that high current gains with ideal bipolar I-V characteristics can be obtained only if the counter-type channel is fully depleted. Under this condition, not only the surface emitter-base junction barrier beneath the gate is lowered, but also the holes injected from the emitter almost go through the potential valley in the channel. An analytical model and its validity range have both been established to provide understanding of such behavior, and have been supported experimentally by two-dimensional device simulation. The measured I-V characteristics, including high-level injection, have also been appropriately reproduced.