| 摘要 |
PURPOSE:To prevent generation of notch without formation of a gap between an electrode and a protection layer by burying an aperture formed on the protection layer including a non-doped compound semiconductor layer to expose an active layer and forming an electrode extending up to the upper surface of the protection layer. CONSTITUTION:A GaAs layer 2 is formed on the surface of a GaAs substrate 1, next non-doped Al, Ga, As layers 3 is formed thereon and a Si-doped n-type GaAs channel layer 4 is then grown thereon. On these layers, a Si-doped Al, Ga1-xAs layer 5 (x=0.2 to 0.3) is formed and moreover non-doped GaAs layer 6 is grown. On these layers, a SiN layer 7 is then deposited, an aperture provided through the SiN layer 7 and non-doped GaAs layer 6 just under the such SiN layer is formed in three positions. At the central aperture, a lower layer gate electrode 13 and an upper layer gate 14 of Wsi/Ti/Au are formed. An ohmic electrode 12 is formed at the apertures in both sides in such a manner that the end portion thereof is extended up to the SiN layer 7 and the gate, source and drain electrodes are respectively connected with the bias voltage source.
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