Patent ID: 6853017

Claim:
A bipolar transistor structure comprising: a dielectric trench isolation structure formed in a semiconductor substrate to define a substrate active device region; a collector region having a first conductivity type formed in the substrate active device region beneath a surface thereof; a base region having a second conductivity type that is opposite the first conductivity type formed in the substrate active device region above the collector region and extending to the surface of the substrate active device region such that the surface of the substrate active device region forms a surface of the base region; a layer of dielectric material formed directly on the dielectric trench isolation structure and directly on a part of the surface of the base region to define an edge of the layer of dielectric material that is formed directly on the surface of the base region; a discrete layer of polysilicon that is doped to the first conductivity type and that is formed directly on the layer of dielectric material and directly on the layer of dielectric material such that a first region of the discrete layer of polysilicon overlies the dielectric trench isolation structure and a second region of the discrete layer of polysilicon extends beyond the edge of the layer of dielectric material and into direct contact with the surface of the base region to provide a polysilicon emitter contact region on the surface of the base region; and an emitter junction region having the first conductivity type formed in the base region beneath and in electrical contact with the polysilicon emitter contact region.