| 摘要 |
PURPOSE:To equalize the thickness of an Si3N4 film, and to avoid the lowering of withstand voltage of a capacitance element by removing an SiO2 film in a field region while forming an inversion preventing layer into the region through ion implantation and forming the Si3N4 film including the inversion preventing layer when the Si3N4 film is used as the insulating film of the capacitance element. CONSTITUTION:A thick field SiO2 film 4 is formed around a P type Si substrate 1, sections except the transistor forming region of the substrate 1 surrounded by the film 4 are coated with a mask of a resist film 22, and an N<+> type layer is formed to the surface layer section of the substrate 1 exposed through the implantation of As ions. The thick film 4 is removed through etching while using the film 22 as a mask, and B ions less than the quantity of As ions implanted are implanted while using the film 22 as a mask again. Consequently, the shallow P<+> type inversion preventing layer is formed onto the substrate 1 in the field region while the active region of the N<+> type layer is kept as it is, the film 22 is removed, and the Si3N4 film 23 through nitriding is formed directly onto the whole surface. Accordingly, the film 23 with uniform film thickness is prepared, and the capacitance element is formed through a normal method. |
