| 摘要 |
PURPOSE:To form base electrodes separated from an emitter electrode with a minute interval in a small number of processes, by forming base electrodes in self-alignment by the use of overhanging structure generated by wet etching. CONSTITUTION:Pattern formation of an emitter electrode 11 made of AuGe/Ni/ Au making ohmic contact is performed on an emitter layer 1. By wet etching with the electrode 11 serving as mask, a base layer 2 is exposed to form an overhanging part 12. Then, pattern formation of base electrodes 13 is performed in self-alignment on the base layer 2 by lift-off process, in which resist is formed on a given part, and evaporated with CrAu from the surface, and then removed. Thereafter, removing a given region of the base layer 2 makes a collector layer 3 become exposed to form collector electrodes 14 on it.
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