PURPOSE: To obtain the highly efficient bipolar element of simple construction by a method wherein a base electrode is provided in such a manner that at least a part of which will be present on the surface pinched between the collector electrode and the emitter electrode of the semiconductor layer selectively formed on a dielectric.

CONSTITUTION: A collector and an emitter contact aperture are provided on an oxide film 10, and a collector region 6 and an emitter region 8 are formed by diffusing phosphorus from said aperture part. Subsequently, a base contact aperture is provided, and a base electrode pick up region 22 is provided by ion-implanting boron. At this time, the apertures of the collector contact and the emitter contact are covered by a photoresist and the like, for example. After each region has been formed, an Al wiring 12 is provided. As above-mentioned, the collector region 6 is formed simultaneously with the emitter, and the transistor can be formed in a simple manner. Also, the capacitance between the collector and the substrate is turned to almost nil, and the capacitance between the base and the emitter and the base and the collector also becomes very small, thereby enabling to obtain a high speed transistor.