| 摘要 |
PURPOSE:To make small a difference in sizes between the original pattern size and finished size of active region by forming a nitrogen ion implantation layer at the surface of substrate of active region and thereafter forming a field oxide film to the substrate of nonactive region with the nitrogen ion implantation layer used as the oxidation resistant mask. CONSTITUTION:An implantation layer 22 is formed at the region in the depth of about 0.2-0.5mum from the surface of substrate by implanting the nitrogen ion N<+> or oxygen ion O<+> to the entire part of substrate 21. After coating a silicon substrate 21 with a resist 23, an aperture 24 is formed. Thereafter, the nitrogen ion N<+> is implanted to the surface of silicon substrate 21 exposed from the aperture 24 to form a nitrogen ion implantation layer 25 at the surface of active region. Thereafter, the resist 23 is removed and oxidation is carried out. Accordingly, the nitrogen ion implantation layer 25 works as the oxidation resistant mask and a thick field oxide film 26 is formed in the inactive region of substrate 21. The silicon layer of substrate under the nitrogen ion implantation layer 25 becomes the active region 28 perfectly isolated by the field oxide film 26 and the insulation layer 27. |
