Method of manufacturing high speed bipolar transistor

Abstract

In a method for manufacturing a bipolar transistor with the SST structure in which a P-type base region consists of a P.sup.+ -type extrinsic base region, a P-type link base region and a P-type intrinsic base region, a silicon oxide film, for example, is formed in advance in a formation region of the P-type link base region and the P-type intrinsic base region on the surface of an N-type epitaxial layer, and a P.sup.+ -type polycrystalline silicon film and a silicon nitride film that cover at least the formation region of the P-type base region are formed. An emitter opening surrounded by a gap part and a base lead-out electrode consisting of the P.sup.+ -type polycrystalline silicon film are formed. A P.sup.+ -type extrinsic base region and a P-type intrinsic base region are formed by applying heat treatment after forming a BSG film on the surface so as to fill in the gap part. A spacer consisting of the BSG film is formed on the side face of the emitter opening, and an emitter lead-out electrode consisting of the N.sup.+ -type polycrystalline silicon film is formed. By applying a heat treatment again, a P-type link base region and an N.sup.+ -type emitter region are formed.