| 摘要 |
PURPOSE:To enable plural oxide films having different thicknesses to be formed simultaneously, by oxidizing a silicon wafer after previously implanting nitrogen into the surface of a section of the silicon wafer where a thinner oxide film is to be formed. CONSTITUTION:The surface of a silicon substrate is covered with a resist film 13 in a section (a). When nitrogen ions are implanted into the silicon substrate, no nitrogen penetrates into the section (a) while the section (b) is implanted with nitrogen atoms (n). The resist film is removed after completion of the ion implantation. The substrate is then thermal oxidized under certain conditions. A thin oxide film 14 is thereby formed on the surface of the section (b) where the rate of oxidation is controlled by the presence of nitrogen. On the surface of the section (a) where no nitrogen atoms are implanted, however, a thick oxide film 15 is formed according to the conditions in accordance with the temperature and the duration of the thermal oxidation. |
