METHOD FOR FABRICATING HETEROJUNCTION BIPOLAR TRANSISTOR

摘要

PURPOSE: A method for fabricating heterojunction bipolar transistor(HBT) is provided to reduce external capacitance by eliminating the damage to a base electrode and a base layer and by etching a collector layer widthwise. CONSTITUTION: The first photoresist layer is formed on the base layer to surround the base electrodes(35,35') and emitter electrodes(39). By using the first photoresist layer as a mask, both side surfaces of the base layer and a part of both side surfaces of the collector are dry-etched so that the etch side surface of the base layer and the collector is positioned inside the side surface of the first photoresist layer by a horizontal width. The first photoresist layer is removed. The second photoresist layer(51) is formed on the base layer to coincide with the etched surface of the collector layer so that the base electrodes, the emitter electrode, both side surfaces of the dry-etched base layer and both side surfaces of the collector layer are surrounded. The collector layer is wet-etched and removed until the vicinity of the base layer appears by using the second photoresist layer as a mask. The second photoresist layer is eliminated.