| 摘要 |
PURPOSE:To decrease the contact resistance of an emitter electrode remarkably in comparison with a conventional value, by coating the entire upper surface of an emitter with the emitter electrode. CONSTITUTION:A protective layer is formed on a multilayer structure material, which is formed by epitaxy and is a base material for a heterojunction bipolar transistor. A mask material layer is formed at a part corresponding to an emitter thereon. With the mask material layer as a mask, the protective layer at the peripheral part is etched away. The multilayer structure material at the peripheral part of the mask is further etched. Thus a base material layer is exposed, or the emitter material layer at the peripheral part under the state the emitter material layer is attached is converted into a semiconductor region having the same type as a base. Then, the entire surface is coated with photoresist. The photoresist undergoes dry etching, and the mask layer or the protective layer formed on the emitter is exposed. Thereafter, the mask layer and the protecting layer are etched away. By using the photoresist remaining at the peripheral part of the emitter, an emitter electrode metal is evaporated and formed by liftoff.
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