| 摘要 |
PURPOSE:To reduce an area of an insulating isolation region, and to increase a degree of integration of the IC by specifying the thickness of a field oxide film. CONSTITUTION:An oxide film 102 and an oxidation-resisting film 103 are formed to the surface of a semiconductor substrate 101. Photo-resist films 104 are formed selectively onto the surface of the film 103, and the films 103 of sections exposed are removed. The films 104 are removed, the surface of the substrate 101 is oxidized selectively while using the films 103 as masks, and the field oxide films 105 are formed. The thickness of the films 105 is controlled so as to be kept within a range of 2,500-3,000Angstrom on completion at that time. When the thickness of the films 105 exceeds 6,000Angstrom , the SiO2 films intrude too much when Si is oxidized selectively, and both a degree of integration and storage capacitance lower. When the thickness of the films 105 reaches less than 2,500Angstrom , an impurity implanted into the films 105 oozes or penetrates to the substrate side on implantation through a succeeding ion implantation process, and electrical characteristics degrade remarkably. |
