INTEGRATED CIRCUIT HAVING LIGHTLY DOPED EXPITAXIAL COLLECTOR LAYER SURROUNDING BASE AND EMITTER ELEMENTS AND HEAVILY DOPED BURIED COLLECTOR LARGER IN CONTACT WITH THE BASE ELEMENT

摘要

An integrated circuit is provided in which a heavily doped buried layer within the collector of a transistor extends into contact with the base thereof to form the major portion of the collector-base junction. The buried layer enhances the current gain bandwidth by minimizing the width of the collector-base depletion region and the shift thereof into the collector for high-current densities. The effects of capacitances at the collector-base junction and at the junctions of resistors and isolating walls adjacent the transistor are minimized by a lightly doped epitaxial layer within the collector of the transistor.