Patent ID: 6495904
Filing Date: 2002-12-17
Classification: H01L

Abstract:
A bipolar transistor structure comprising:a semiconductor material substrate structure defined by a dielectric isolation structure formed at the periphery of the semiconductor material substrate structure, the semiconductor material substrate structure having: a bottom substrate of a first conductivity type; a buried layer of a second conductivity type overlying the bottom substrate; a collector region of the second conductivity type overlying the buried layer; a sink region of the second conductivity type extending from the upper surface of the semiconductor material substrate structure: to the buried layer, the sink region being adjacent to the collector region; a base region of the first conductivity type overlying the collector region and spaced apart from the sink region; an extrinsic base region of the first conductivity type extending from the upper surface of the semiconductor material substrate structure into the base region; and an emitter region of the second conductivity type extending from the upper surface of the semiconductor material substrate structure into the base region, the emitter region being spaced apart from the extrinsic base region; a patterned silicon oxide layer at least partially overlying the dielectric isolation structure, the patterned silicon oxide layer having: a first oxide portion that extends partially over the upper surface of the semiconductor material substrate structure in the extrinsic base region; and a second oxide portion that extends partially over the upper surface of the semiconductor material substrate structure in the emitter region; and a single patterned polysilicon layer at least partially overlying the semiconductor material substrate structure, the single patterned polysilicon layer having: a first polysilicon portion of the first conductivity type formed at least partially on the first oxide portion and in contact with the extrinsic base region; and a second polysilicon portion of the second conductivity type formed at least partially on the second oxide portion and in contact with the emitter region.