| 摘要 |
PURPOSE:To increase the capacitance of a capacitor per unit area in a semiconductor memory to contrive its high integration and decrease occurrences of malfunctions and soft errors by making the most of a dielectric films as a capacitor after forming the dielectric film even at the lower face of an accumulation electrode. CONSTITUTION:A resist film is patterned on the upper face of an accumulation electrode 18 and insulating films 16 are treated by an isotropic etching using the resist film and the accumulator electrode 18 as masks. Although each film thickness of the insulating films 16 decreases gradually, even then insulating films 16 at the lower side of the above electrode 18 are etched sidewise with the decrease of each film 16. After removing the resist film on the electrode 18, if the whole surface of a substrate 11 is allowed to deposit a silicon nitride film, all of the exposed face of the electrode 18 is covered with the above silicon nitride film. After that, a dielectric film 19 consisting of a silicon nitride film and a thin oxide film is formed by patterning polysilicon, a thin oxide film, and a silicon nitride film; besides, a plate electrode 20 consisting of polysilicon is formed. The dielectric film 19 is formed not only at upper and side faces of the accumulation electrode 18 but also at the lower face of the above electrode, and then, its film 19 is utilized as a capacitor for charge storage. |
