| 摘要 |
PURPOSE:To prevent the accumulation of ion on gate electrodes at the time of ion implantation as well as to avoid contamination of the surface of a substrate and the knock-on of oxygen element by a method wherein parts of the substrate surface other than a region, in which ion implantation is to be performed, are coated with an insulating film and the upper part of this insulating film is coated with a poly Si film. CONSTITUTION:A P-type well 2, N-type channel cut regions 1', P-type channel cut regions 2' and a field oxide film 3 are formed in an N-type Si substrate 1 and thereafter, gate oxide films 4 and 4' are formed and after a phosphorus- doped poly Si layer is deposited by an LPCVD method, gate electrodes 5 and 5' are formed by patterning. Then, a photo etching is performed in a state that a P-type channel region is coated with a photo resist 6 to remove the oxide film other than the gate oxide film 4 and opening parts 7a and 7b are formed. Subsequently, the photo resist 6 is removed, a non-doped poly Si layer 8 is deposited on the whole surface by an LPCVD method and arsenic ions are implanted. Then, a heat treatment is performed in an atmosphere of oxygen, the poly Si layer is all converted into an Si oxide layer 9 and the arsenic ions are diffused to form source and drain regins 10a and 10b. |
