| 摘要 |
Provided are a epitaxial wafer for a heterojunction bipolar transistor with which it is possible to further reduce turn-on voltage. Also provided is a heterojunction bipolar transistor. An epitaxial wafer for a heterojunction bipolar transistor (100) provided with a collector layer (103) comprising GaAs, a base layer (104) formed on the collector layer (103) and comprising InGaAs, and an emitter layer (105) formed on the base layer (104) and comprising InGaP; wherein, for the base layer (104), the In composition is reduced from the emitter layer (105) side towards the collector layer (103) side. |
