A power transistor has a plurality of small emitter-base complexes arranged in an array. These complexes are electrically insulated from the surrounding semiconductor material by separating regions such that for the current supply to the collectors, a joint subcollector layer and thereupon a collector metallization exist outside of the emitter-base complexes and reaching up to the separating regions. The individual emitter-base complexes are electrically connected with each other via strip-shaped base supply lines and strip-shaped emitter supply lines, and also with a base contact surface and an emitter contact surface.