| 摘要 |
PROBLEM TO BE SOLVED: To enable high speed operation by more reducing capacitance of a junction between a base layer (3) and a collector layer (2) of a photo transistor (1). SOLUTION: The base layer (3) wherein an emitter layer (4) is formed on an upper part and a collector electrode (7) are formed on an intrinsic or semi- insulating semiconductor substrate (2). The substrate (2) between the base layer (3) and the collector electrode (7) is made a depletion region under an operating condition that a prescribed voltage is applied across the emitter and the collector. The base layer (3) and the emitter layer (4) are overlapped with each other, and a lamination structure is formed on the collector, so that the area of the base layer is reduced so as to be equal to the area of the emitter layer. COPYRIGHT: (C)2003,JPO
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