Bipolar transistor and method of producing the same

Abstract

A dummy emitter (a dummy collector, in an inverted type) is formed in the portion corresponding to an emitter (a collector, in the inverted type) region, on a multiplayer structural material including layers for forming emitter, base and collector, and using it as mask, an external base region is exposed by etching, and a projection of the emitter (the collector, in the inverted type) region is formed, while the dummy emitter (the dummy collector, in the inverted type) is inverted into an emitter (a collector, in the inverted type) electrode, thereby forming an emitter (a collector, in the inverted type) electrode metal layer covering the whole upper surface of the emitter (the collector, in the inverted type). Using the thus formed emitter (the collector, in the inverted type) electrode metal layer, a base electrode metal layer is formed, by self-alignment, adjacent to the emitter (the collector, in the inverted type). In another method, on a multilayer structural material, impurities are introduced outside the portion corresponding to the base region of a bipolar transistor in order to insulate, at least, a portion of the layer forming the base, and if necessary a portion of the layer forming the emitter and a portion of the layer forming the collector. Further, an extension layers and the layer forming the collector, and an extension type dummy emitter (a dummy collector, in the inverted type) is formed which extends from the emitter (the collector, in the inverted type) on the base portion to the insulating region formed by transforming from the semiconductor material forming the base, and using it as mask, the external base region is exposed to form an emitter-including layer and the dummy emitter (the dummy collector, in the inverted type) is replaced by an emitter (a collector, in the inverted type) electrode metal layer covering the whole upper surface of the emitter-including layer.