| 摘要 |
PURPOSE:To obtain an FET having a high gate withstand voltage by a method wherein an ion implanted layer is formed on a semiconductor substrate and is covered with an insulating film, a column type insulating film having an overhang type insulating film is provided thereon, and drain.source regions are formed by self-alignment according to ion implantation through the ion implanted layer using the overhang type insulating film as the mask. CONSTITUTION:The Si ion implanted layer 3 is formed in the surface layer of the semiinsulating GaAs substrate 1, the whole surface is covered with the AlN film 4, and an SiO2 film 5 and an Si3N4 film 6 are laminated to be adhered thereon. Then dry etching is performed to form the film 5 into the columnar film 7 at the central part, and to form the film 8 consisting of the film 6 in the overhang type, Si ions are implanted through the film 4 using the overhang type film as the mask, and the drain region 9 and the source region 10 of high impurity concentration are provided by selfalignment. After then, an Si3N4 film 11 is adhered on the whole surface, the films 8, 7 being made unnecessary are removed together with the film 11 adhered thereon, the film 4 in a generated opening 13 is also removed, a gate electrode 14 is provided on the exposed layer 3, and a drain electrode 15 an a source electrode 16 and fixed respectively to the regions 9, 10 interposing the films 4 between them. |
