| 摘要 |
PURPOSE:To reduce a leak current and to raise a gate voltage, by superposing n type AlxGa1-xAs on GaAs to form a heterojunction and by adjusting a composition ratio x to raise a potential barrier in the vicinity of a gate electrode. CONSTITUTION:A non-added GaAs channel 12, AlxGa1-xAs and Si-added Alx Ga1-xAs 14 and 15 are superposed on a half-insulating GaAs substrate 11. A composition ratio x is set at a fixed value of about 0.3 for the layers 13 and 14. The ratio of the layer 15 to the layer 14 is at the same value on the interface with the latter, and it increases gradually to x=0.4 on the surface. Electrodes 16 and 17 of AuGe/Au are attached for alloying, resistance connction layers 18 are provided on the channel 12, and an A gate electrode 19 is attached. A layer 20 is an electron storage layer. According to this constitution, the potential barrier on a contact interface between the gate electrode 19 and an electron supplying layer 15 is made larger than usual, and a leak current from the electrode 19 to the layer 15 is reduced. Thus, some margin can be left by setting a high gate voltage. |
