| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device, having an HBT structure (and having the HBT structure as the main constituent), whereby it has an advantage in its low-voltage operation, and the sheet resistance of its base layer is so reduced as to increase its fmax and Gain, and further enables its high-efficiency operation, in particular, its emitter layer can be so formed as to have proper controllability and high quality, and furthermore, its emitter injection efficiency can be obtained stably. SOLUTION: In the semiconductor device having an HBT (heterojunction bipolar transistor) which has, on a semiconductor substrate, a first conductivity-type emitter layer, a second conductivity-type base layer, and a first conductivity-type collector layer, the main components of the emitter and collector layers are GaAs and the main component of the base layer is Ge. COPYRIGHT: (C)2008,JPO&INPIT
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