PURPOSE: To make an emitter contact area fine, to make also an emitter layer fine and to reduce a parasitic capacity by a method wherein a part near an end of an emitter electrode formed on a semiconductor substrate via an insulating film is connected to the emitter layer and the emitter electrode which does not exist toward the side of a base electrode from this connection part and which is not overlapped with the base electrode is formed.

CONSTITUTION: An n+ emitter layer 6 is formed by diffusing an impurity from a part where poly-Si side walls 2 are connected to an Si substrate 11; a p+ base layer 8 is formed by diffusing an impurity from a part where base- extraction poly-Si 3 is connected to the Si substrate 11; accordingly, a distance between an N+ emitter and a P+ base is decided by a film thickness of an SiO2 film 12; they can be brought very close to each other; a base resistance can be reduced. Since a distance between the N+ emitter layer 6 and an N+ collector layer 9 is secured by poly-Si emitter electrodes 1, 2, a required breakdown strength can be obtained. In addition, when a width of the poly-Si emitter electrode 1 is changed, the breakdown strength can be set freely.