Patent ID: 6906363

Claim:
A semiconductor device with a bipolar transistor, comprising: (a) a semiconductor substrate; (b) an isolation dielectric formed on the substrate to define a transistor section for a bipolar transistor; the transistor section being divided into an emitter/base subsection and a collector extraction subsection by the isolation dielectric; (c) an intrinsic base region formed in the emitter/base subsection; (d) a graft base region formed in the emitter/base subsection; the graft base region being contacted with the isolation dielectric; (e) an emitter region formed in the emitter/base subsection to overlap with the intrinsic base region; (f) a collector extraction region formed in the collector extraction subsection; (g) a stopper dielectric layer formed on the substrate to cover the transistor section and the isolation dielectric; and (h) an interlayer dielectric layer formed on the stopper dielectric layer to cover the transistor section and the isolation dielectric; the interlayer dielectric layer having an emitter contact plug for electrical connection to the emitter region, a base contact plug for electrical connection to the graft base region, and a collector contact plug for electrical connection to the collector extraction region; the base contact plug being located over the isolation dielectric in such a way as to contact the graft base region near its bottom end corner.