| 摘要 |
PURPOSE:To increase the dielectric withstanding voltage of a thin SiO2 film such as gate dielectric withstanding voltage, and to improve the reliability of a cell by forming a gate insulating film consisting of a thin SiO2 film through a high-temperature oxidation method, through which comparatively high dielectric withstanding voltage is acquired, and shaping an insulator film in the periphery of a capacitor composed of a thick SiO2 film through a low-temperature wet oxidation method, through which dielectric withstanding voltage is easy to be deteriorated. CONSTITUTION:A capacitor electrode is shaped to an silicon substrate 1, and an SiO2 film 12' in 300-500Angstrom film thickness is formed onto the silicon substrate 1 through oxidation in a wet oxidizing atmosphere at a low temperature (750-900 deg.C) while an SiO2 film 15' in 1,500-2,500Angstrom film thickness is shaped onto a polycrystalline silicon film 14. The thickness of the SiO2 film 15' on the polycrystalline silicon film 14 is thinned to approximately 1,000-2,000Angstrom by etching the whole surface, and the SiO2 film 12' in 300-500Angstrom film thickness on the upper surface of the silicon substrate 1 is all removed through etching. A novel SiO2 film 12 in 300-500Angstrom film thickness is formed onto the silicon substrate 11 through oxidation in an oxidizing atmosphere at a high temperature (1,000-1,100 deg.C). Oxidation also progresses similarly onto the polycrystalline silicon film 14 at that time, and an SiO2 film 15 in 1,200-2,200Angstrom film thickness is formed. |
