| 摘要 |
PURPOSE:To implement a small structure for a collector capacity and an emitter capacity, by removing a part of a base-electrode taking out layer and a part of a semi-insulating semiconductor layer by etching, regrowing a very thin base layer, and growing a collector layer thereon. CONSTITUTION:On a semi-insulating GaAs substrate 1, layers 2, 3, 11 and 4 are formed. Then, a resist mask is formed. A part of a P-type GaAs base 1 layer 4 and a part of the semi-insulating semiconductor layer are etched, and a part of the emitter 2 layer 3 is exposed. The resist is removed. The P-type GaAs base 2 layer, the N-type GaAs collector 1 layer and the N<+> type GaAs collector 2 layer are grown again. A part of the base 1 layer is etched. A part of the base 2 or 1 layer and a part of the emitter 1 layer are exposed. The resist part is removed. A collector electrode 10 is formed on a part, where the base 1 layer is not present. A base electrode 9 and an emitter electrode 8 are formed on the exposed base and emitter layers. Thus, the base length is made very short. The collector capacity and the emitter capacity can be made small. In this way, excellent high frequency characteristics are obtained.
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