| 摘要 |
PURPOSE:To increase the range of a voltage between an emitter and a base by forming the fourth and fifth layers of semiconductor crystal between the first and second layers and between the second and third layers, and forming the barrier of the fourth layer smaller than that of the fifth layer in a structure that the fourth, second and fifth layers become quantum wells. CONSTITUTION:N-type GaAs layers 11, 12 having 10<1>cm<-3> of impurity density respectively have thicknesses of 300Angstrom and 200mum to form emitter and collector regions. N-type GaAs layers having 10<17>cm<-3> have 50Angstrom of thickness to form a base region. Undoped AlxGa1-xAs layers 14, 15, 16 have 0.2 and 0.3 of molar ratio of aluminum, 50Angstrom of thickness, and are interposed between the layers 11 and 12, and between the layers 12 and 13. 21, 22, 23 designate emitter, base and collector electrodes. The layers 11, 12, 13, 14, 15 are formed by an MBE method with N-type GaAs layer 13 as a substrate. Thus, a current at resonance time is increased to increase the range of a voltage between the emitter and the base in which a switching current is flowed.. |
