PURPOSE: To form a collector electrode easily by a method wherein a semi-conductor film of a different kind is shaped between a collector layer and a connecting layer for the collector layer, only the collector layer and the connecting layer for the collector layer are etched selectively, only the collector layer is etched, the film of a different kind is etched and a collector connecting layer is formed.

CONSTITUTION: An N+ GaAs collector connecting layer 2, N-Ga0.7Al0.3As 3, an N-GaAs collector layer 4, a P+ GaAs base layer 5, an N-Ga0.7Al0.3As emitter layer 6, an N- Ga1-xAlxAs layer 7 while (x) is decreased gradually to 0 from 0.3, an N-GaAs base connecting layer 8 and an N+ GaAs emitter connecting layer 9 are superposed on semi-insulating GaAs. A mask is formed and the layer 9 is shaped through etching, and Mg id implanted and activated to form a P-external base 10. The layers 5∼10 are removed through etching up to its midway of the layer 5 by a mixed liquid of a tartaric acid aqueous solution and H2O0 water, an SiO2 film 11 is etched by CF4+H2 by using a resist mask 12, and the layer 5 is etched selectively by CCl2F2 and etching is stopped on the layer 3. An element is isolated through etching, and a predetermined electrode is attached. According to the method, a collector electrode can be formed easily to a hetero-junction transistor, and characteristic distribution in a wafer is improved.