Patent ID: 8901669

Claim:
A method of manufacturing an integrated circuit comprising a plurality of bipolar transistors including a first type bipolar transistor and a second type bipolar transistor, the method comprising: providing a substrate comprising a plurality of first isolation regions each separated from a second isolation region by an active region comprising a collector impurity of one of said bipolar transistors; forming a base layer stack over said substrate; forming a first emitter cap layer of a first effective thickness over the base layer stack in the areas of the first type bipolar transistor; forming a second emitter cap layer of a second effective thickness different to the first effective thickness over the base layer stack in the areas of the second type bipolar transistor; and forming an emitter over the emitter cap layer of each of said bipolar transistors, wherein the first type bipolar transistor comprises a collector profile that is different to the collector profile of the second type of bipolar transistor.