Patent ID: 7816763

Claim:
A bipolar transistor comprising: a first conductive buried layer in a surface of a silicon substrate; an epitaxial layer on the silicon substrate including the first conductive buried layer; base and emitter regions in a surface of the epitaxial layer, in which the base and emitter regions are spaced apart from each other by a predetermined interval; an opening formed by selectively removing the epitaxial layer such that a surface of the first conductive buried layer is partially exposed; a first conductive diffusion region in a surface of the first conductive buried layer corresponding to the opening; an interlayer dielectric layer formed on an entire surface of the silicon substrate; contact holes formed simultaneously by selectively removing the interlayer dielectric layer such that the surfaces of the base region, the emitter region, and the first conductive diffusion region are exposed; and base, emitter, and collector electrodes electrically connected to the base region, the emitter region, and the first conductive diffusion region through the contact holes, respectively; wherein: the contact hole for the collector electrode has a width wider than a width of the opening and the remaining contact hole, and forms a step structure.