| 摘要 |
PURPOSE:To enable the high speed operation in a super fine structure, by providing a source having conduction band energy larger than an electron channel, and injecting electrons from the source into the electron channel via a barrier lower than the electron affimity difference. CONSTITUTION:A step is formed on a semi-insulative GaAs substrate 11. From an oblique direction with respect to the step, a Ga beam is projected in an As atmosphere, and an undoped GaAs layer 12 is grown. While the Ga beam is projected in the same way, the beam of Si being a dopant is projected from the same direction as Ga, and an Al beam is projected from an obliquely upper direction. Therefor, the amount of Al is large on the upper surface of the step, and decreases on the side surface of the step, as that an N<+> AlGaAs layer 21 is grown, wherein Al composition is less in the side surface of the step than the upper surface, and the doping quantity is large. The Al beam is cut off, and an N<+> GaAs layer 22 of a contact layer is grown. The N<+> GaAs layer 22 on the upper surface of the step is eliminated, and a gate electrode 14 is formed. Further, a source electrode 15 and an drain electrode 16 are formed.
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