| 摘要 |
PURPOSE:To simplify manufacturing process, and realize high density integration, by simplifying the constitution of memory capacitors formed in a trench without decreasing soft error resistance, and by narrowing the width of the trench. CONSTITUTION:On a substrate constituted of a P-type substrate 1, an SiO2 layer 2, and a P-type layer 3, trenches 15 are arranged in the form of a lattice, in which memory capacitors are arranged, and a MOS transistor is arranged on the upper surface of the P-type layer 3 made up in the form of an island. An SiO2 film 4 for the capacitors is formed so as to surround the substrate composed of the P-type substrate 1 made up in the form of an island, the SiO2 layer 2 and the P-type layer 3. Further, an electric charge storing layer 5 of polysilicon is arranged so as to surround the SiO2 film 4. This layer 5 is brought into contact with an N<+> type layer 7 via a window 14. An SiO2 film 12 for isolating cells is formed around the electric charge storing layer 5 of polysilicon. Therefore it is unnecessitated to form a cell plate in the trenches 15, and the width of trenches can be made small. Thereby, simplifying manufacturing process, and enabling high density integration. |
