Cmos-compatible bipolar transistor with reduced collector/substrate

Abstract

A bipolar transistor with a collector, a base and an emitter disposed in vertical succession includes a semiconductor substrate, insulating oxide zones disposed in the substrate for separating adjacent transistors, and a buried collector terminal layer at least partly disposed on the insulating oxide zones. An insulator structure laterally surrounding a collector. A subcollector is surrounded by the insulating oxide zones, has the same conductivity type with a lower impedance than the collector, is disposed under the collector and under the insulator structure, and is electrically connected to the collector. The insulator structure covers the buried collector terminal layer, laterally insulates the collector from the buried collector terminal layer, and has lateral surfaces extending inside the insulating oxide regions up to the subcollector. The buried collector terminal layer is in direct contact with the subcollector. The collector is electrically connected to the buried collector terminal layer only through the subcollector. The insulator structure has a contact hole extending to the buried collector terminal layer laterally of the active transistor zone, and a metallization filling the contact hole. A process for producing the bipolar transistor includes producing an insulator structure on a substrate for determining a location for a collector; and producing the collector by selective epitaxy only inside the insulator structure, for laterally insulating the collector with the insulator structure. An integrated circuit and method include such bipolar transistors and CMOS transistors.