| 摘要 |
PURPOSE:To prevent exposure of an interface between a silicon substrate and a gate insulating film and an interface between the gate insulating film and a gate electrode in a manufacturing process, to prevent contamination of the interfaces with foreign material and to make it possible to manufacture field effect transistors having high performance, by forming the gate insulating film by oxygen ion implantation and heat treatment. CONSTITUTION:An etching mask 4 for forming a gate electrode is removed. Thereafter oxygen ions are implanted at implanting energy of about 400 keV and at a dose amount of about 2.0X10<18>/cm<2>. Heat treatment is performed for about two hours in inactive gas such as nitrogen. Thus silicon dioxide layers 6 and 61 are formed. At this time, the silicon dioxide layer 6 is formed at a depth region (a boundary plane between the gate electrode 5 and a channel) of about 0.5mum from the surface. The silicon dioxide layer 61 is formed at a depth region of about 0.5mum from the surface in a region other than the gate electrode 5. The silicon dioxide layer 61 is made to function as an element isolating insulating film. |
