| 摘要 |
PURPOSE:To facilitate the control of a threshold voltage and to improve the gate withstand voltage by providing an N<-> type layer on the surface of a semi- insulating substrate. CONSTITUTION:An N<-> type AlGaAs layer 12 necessarily has a forbidden band width larger than a semi-insulating GaAs substrate 1 of the lower layer of the layer 12, and both accordingly from a hetero-junction. Then, a gate electrode 13 made of a high melting point metal such as silicide of TiW is formed at the prescribed position on the layer 12. With the electrode 13 as a mask a silicon (Si) is introduced through the layer 12 into a semi-insulating GaAs substrate 11, then heat treated to activate the implanted Si ions, thereby forming two N<+> type regions 14, 15. Then, source and drain electrodes 16, 17 which are ohmically contacted with the regions 14, 15, i.e., source and drain regions 14, 15 are formed through the layer 12. |
