| 摘要 |
PURPOSE:To permit the thickness of the active layer of a compound semiconductor device to be precise for uniforming its characteristics by constituting the device region by three selective epitaxial layers of N type GaAs, N<+> type GaAlAs and N<+> type GaAs and prescribing the geometry of the active layer by the selective etching of the semiconductor layers of different kinds. CONSTITUTION:A semiinsulative GaAs substrate 11 is coated with an insulative film 12 of SiO2 or the like, in which an openig is made. On the exposed substrate 11, a composite structure comprising an N type GaAs layer 14 to be an active layer, N<+> type GaAlAs layer 15 for a source electrode, and N<+> type GaAs layer 16 for a drain electrode is formed by epitaxial growth. After the film 12 is removed, the whole surface is newly coated with an insulative layer 17, and a resist mask 18 to prescribe the electrode regions of source, drain and gate is provided to etch the film 17 into a reference film showing the relative position-relations between these electrode systems. After that, the mask 18 is replaced with a mask 19 to provide source and drain electrodes 20 and 21 on the exposed surfaces of the layer 16. Then the mask 19 is replaced with a mask 22 to form a gate electrode 23 on the layer 16 between the electrodes 20 and 21. |
