Triple base bipolar phototransistor

摘要

A high gain phototransistor uses lateral and vertical transistor structures and a triple base. The base regions of two vertical structures are in the bulk of a semiconductor substrate while the base of a single lateral structure is adjacent a light receiving phototransistor surface. Minority carrier generation extends from the base region of the lateral transistor to the base regions of the vertical transistors and is present in the vertical regions within a diffusion length of the optically generated carriers of the lateral base. The bases of all three transistor structures are electrically connected. The collector electrodes of one of the vertical structures and the lateral structure are electrically connected, while the emitter electrodes of the other of the vertical structures and the lateral structures are electrically connected. Finally, the remaining vertical collector and emitter electrodes are electrically connected via a buried layer adjacent the phototransistor wafer substrate.