| 摘要 |
PROBLEM TO BE SOLVED: To lower the working voltage of an HBT without degrading the characteristics of the cut-off frequency, the maximum oscillation frequency, the current gain, and the like, by a base layer composed of InGaAsSb doped with C at a high concentration in a state capable of obtaining a desired In composition.SOLUTION: A heterojunction bipolar transistor includes an n-type collector layer 104 composed of a group III-V compound semiconductor formed on a substrate 101, a p-type base structure 105 composed of InGaAsSb, constituted of a laminate structure of a plurality of first semiconductor layers 151 and second semiconductor layers 152 laminated in contact with each other, and formed on the collector layer 104, and an n-type emitter layer 106 composed of a group III-V compound semiconductor formed on the base structure 105. The first semiconductor layer 151 is doped with carbon, has In composition and Sb composition lower than those of the second semiconductor layer 152, and the second semiconductor layer 152 is in a state of less doping amount of carbon than the first semiconductor layer 151. |
