| 摘要 |
PURPOSE:To ensure excellent withstand-voltage characteristics in a capacitor cell while increasing the capacitance of a capacitor by making the film thickness of an insulating film in a flat section thinner than that of the insulating film in a groove section. CONSTITUTION:An oxide film 2 for isolating elements is formed onto a substrate 1, and a groove 7 in approximately 1mum depth is shaped through etching. An oxide film 8 in approximately 150Angstrom thickness is formed on the inner surface of the groove and a flat section through an oxidation method. A resist layer 9 is shaped so as to coat only the groove section and the periphery of an opening section for the groove, and the oxide film 8 is removed through etching while using the resist layer 9 as a mask. When the resist layer 9 is peeled and the whole is oxidized through the normal oxidation method again, an oxide film 3 in approximately 100Angstrom thickness is formed on the flat section while the oxide film 8 is also oxidized to shape an oxide film 3' in approximately 170Angstrom thickness. Accordingly, the two oxide films 3, 3' having different thickness are formed, and polysilicon is deposited on these oxide films, thus shaping a capacitor electrode 4. |
