| 摘要 |
PURPOSE:To increase the amplification factor of a unipolar transistor as well as to reduce the noise thereof by a method wherein an n-AlyGA1-yAs is superposed on an n-AlxGa1-xAs, and an n-Aly'Ga1-y'As and an n-Alx'Ga1-x'As are superposed through the intermediary of an n type Ga layer, and composition ratio of x-y' are properly selected. CONSTITUTION:The barrier 1 of an n-AlyGa1-yAs is contacted with the emitter layer E of an n-AlxGa1-xAs and an n-Ge base layer B is superposed thereon. Subsequently, the barrier 2 of an n-Aly'Ga1-y'As is contacted with the above, an n-Alx'Ga1-x'As collector layer C is superposed, and they are selected into o>=x, x'>=y and y'. The As can be doped in extreme high density and the base width can also be reduced markedly by using Ge for the base B. Also, as a forbidden band width increases when the composition of Al is increased and the effective barrier when viewed from the base B is increased in height, the possibility of dropping of an electron to the conduction band level of the base region is little, and the possibility of running to a collector C as a hot electron increases. According to this constitution, the characteristics of a supersonic transistor can be improved remarkably. |
