| 摘要 |
PURPOSE:To improve the charge storage amount of a capacity element for storing information and to improve its integration by forming silicon oxide films of substantial ly equal thickness on different crystal surfaces by a partial pressure oxidizing method for determining an oxidizing velocity by the oxygen supply amount. CONSTITUTION:With a PSG film 33 as a mask an Si3N4 film 32 and an SiO2 film 30 are etched, a substrate 1 is further etched to form a fine hole 4. Thereafter, the films 33, 32 and 30 are removed by etching. Then, after they are temporarily thermally oxidized, the oxide film is removed by etching to align the surfaces of an active region and fine holes 4. Thereafter, the thermal oxidation of the surface is conducted by a high temperature partial pressure oxidizing method to form SiO2 films 5 as insulating films on the main surface of the substrate, the four sides of the holes 4 and the bottoms of the holes 4. Since the thermal silicon oxide films are formed on the surfaces by the high temperature partial pressure oxidizing method, the films 5 of substantially equal thickness are obtained. Since the films 5 of the sidewalls are formed of small thickness similarly on the bottom of the hole 4 in this manner, charge storage amount to become information can be increased. |
