| 摘要 |
PURPOSE:To facilitate smooth switching operation of a divided emitter type transistor in a high frequency range by forming isolating grooves so as to surround emitter regions formed separately from each other. CONSTITUTION:In an NPN transistor, a collector region is composed of N<+> type and N<-> type semiconductor layers 1 and 2 and a base region is composed of a P-type semiconductor layer 3. Isolating grooves 5a, 5b... are formed so as to surround emitter regions 4a, 4b... which are formed in the semiconductor layer 3 separately from each other to make island shapes. Base electrodes 7a, 7b... are provided on a field insulating film 6 and the field insulating films between the emitter regions 4a, 4b... and the isolating grooves 5a, 5b... through contact holes. Then, polycrystalline silicon emitter ballast resistance layers 8a, 8b... and emitter electrodes 9a, 9b... are formed. A structure with which the divided emitters can operate as independent small signal transistors is provided in the common base region.
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