| 摘要 |
PURPOSE:To provide an enhansment-type FET (E-FET) and a depression-type FET (D-FET) on the same substrate, by inserting separation layers having a different thickness from each other between gate electrodes and a channel layer. CONSTITUTION:A P<->-type undoped GaAs layer 1 and an N-type GaAs layer 15 for forming an N-type channel are provided on a semi-insulating GaAs substrate 10. Undoped (or N<->-type or P<->-type slightly doped) GaAs or AlXGa1-XAs layers 16 and 17, E-FET and D-FET gate metallic electrodes 31 and 30 and source and drain electrodes 32-34 are further provided. The threshold voltage can be controlled by appropriately selecting thicknesses C1 and C2 of separation layers 16 and 17 when a doping layer (channel layer) 15 has a constant doping level and a constant thickness (d). |
