Method for fabricating a bipolar transistor of the self-aligned double-polysilicon type with a heterojunction base and corresponding transistor

Abstract

A self-aligned double-polysilicon type bi-polar transistor with a heterojunction base comprises a semiconducting heterojunction region lying over an active region of a semiconductor substrate and over an isolating region delimiting the active region, and incorporating the intrinsic base region of the transistor. An emitter region situated above the active region and coming into contact with the upper surface of the semiconducting heterojunction region. A polysilicon layer forming the extrinsic base region of the transistor, situated on each side of the emitter region and separated from the semiconducting heterojunction region by a separation layer comprising an electrically conducting connection part situated just outside the emitter region. This connection part ensures an electrical contact between the extrinsic base and the intrinsic base.