Patent ID: 7521328

Claim:
A method of fabricating a bipolar transistor comprising the steps of: forming first and second device isolation trenches in a substrate; forming a photoresist pattern exposing a first sidewall and a first bottom portion of the first trench and a second sidewall and a second bottom portion of the second trench and masking the remaining portions of the first and second trenches, wherein the photoresist pattern exposes substantially all of the first and second sidewalls, and exposes about half of the first bottom portion of the first trench and about half of the second bottom portion of the second trench; forming an emitter on both the first sidewall and the first bottom portion of the first trench, and a separate collector on both the second sidewall and the second bottom portion of the second trench by implanting ions using the photoresist pattern as a mask, wherein a surface of the substrate at the first sidewall and the first bottom portion of the first trench, and the second sidewall and the second bottom portion of the second trench are exposed while the ions are implanted; removing the photoresist pattern; and filling the first and second trenches with an insulation layer to form a device isolation structure that covers the previously formed emitter and collector.