| 摘要 |
PURPOSE:To obtain a structure, in which the length of a base is short and the capacity of a collector is small, 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 an emitter 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 the P-type GaAs base 1 layer 4 and a part of the semi-insulating semiconductor layer 11 are etched, and a part of the collector 2 layer 3 is exposed. Then, the resist is removed. The P-type GaAs base 2 layer, the N-type AlGaAs emitter 1 layer, and the N<+> type GaAs emitter 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 collector 1 layer are exposed. The resist part is removed. An emitter electrode 10 is formed at a part, where the base 1 layer is not present. A base electrode 9 and a collector electrode 8 are formed on the exposed base and collector layers. Thus the base length can be made very short and the collector capacity can be made small. In this way, excellent high frequency characteristics can be obtained.
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