| 摘要 |
PURPOSE:To increase a storage capacity by a method wherein a groove penetrating surface layer to a substrate and an electrode in the groove are provided while one of the electrodes opposing to said electrode is made into a substrate. CONSTITUTION:A charge storage part 5 formed of e.g. polycrystalline Si in a groove is connected to an N<+> diffusion layer 12 of cell selective transistor 9. One storage capacity CS1 as a depletion layer capacity between the storage parts 5 and a P type epitaxial layer 2 is smaller than other capacities. Next CS2 as another capacity between the storage part 5 and a high concentration P<+> or N<+> substrate to be a capacity equivalent to a capacity between a metallic layer and another metallic layer through the intermediary of a thin insulating film. Moreover CS3 is a capacity between the storage part 5 and e.g. a polycrystalline electrode 7 through the intermediary of the other insulating film to be equivalent to a capacity between a metallic layer and another metallic layer. In such a constitution, a capacity per unit space may be increased almost two times larger than a capacity of conventional structure. |
