| 摘要 |
PURPOSE:To obtain a trench-dug capacitor structure of a substrate electrode type capable of decreasing electric field applied on a capacitor insulating film, by completely isolating a common capacitor electrode from an MOS transistor substrate. CONSTITUTION:A capacitor electrode constituted of a first polycrystalline silicon film 8 and a second polycrystalline silicon film 10 is limited, buried, and formed in a trench 6. An N-type layer 11 which is linked with the diffusion layer of an MOS transistor in the later process can be formed in a self-alignment manner. Thus an N<+> type Si substrate 1 is applied to the common electrode of all capacitors; capacitor electrodes 8, 10 buried in each trench are turned into independent storage nodes for each capacitor; an MOS transistor part turns to the common electrode. Thereby a substrate electrode type trench-dug memory cell structure constituted of a substrate 3 dielectrically isolated from the N<+> type Si substrate is obtained. |
