| 摘要 |
PURPOSE:To obtain high-performance memories by increasing the amount of charge accumulated in memory cells by a method wherein the junction capacitance is increased by providing columnar diffused regions immediately under the MOS capacitor on one electrode, and this junction capacitance is utilized as the memory cell capacitance. CONSTITUTION:A field oxide film 2 and the first diffused region 3 of higher concentration than that of a semiconductor substrate 1 and the same conductivity type are formed in the substrate 1, and a plurality of the second columnar diffused regions 12 of reverse conductivity type to that of the substrate 1 are formed in the first diffused region 3 of high concentration. Therefore, the third diffused region 4 of reverse conductivity type to that of the substrate 1 is formed. The second columnar diffused regions 12 are electrically connected to each other with this third diffused region 4. Then, a gate oxide film 5, a capacitor electrode 6, an insulator layer 7, a gate electrode 8, diffused layers 9, an insulation layer 10, and a wiring layer 11 are formed. Because of the addition of the juntion capacitance between the second columnar diffused regions 12 and the first diffused region 3, the marked increase in memory cell capacitance can be obtained. |
