| 摘要 |
PURPOSE:To avoid the leakage between cells and improve the reliability by a method wherein first and second capacitor electrodes are formed in a lower trench part with an insulating film in between and the first capacitor electrode is connected to the source or drain of a MOS-FET. CONSTITUTION:A plurality of semiconductor column-shape protrusions isolated by trenches formed on a substrate lengthwise and breadthwise are arranged into a matrix. The trench is composed of an upper trench part V1 and a lower trench part V2 and a MOS capacitor is composed of a thick insulating film 130 on the inside wall of the trench part V2, a first capacitor electrode 131 on the insulating film 130, an insulating film 105 and a second capacitor electrode 106. The electrode 131 is connected to the source or drain region of a MOS-FET formed on the side wall of the protrusion. Further, a P-type layer 132 is formed on the bottom of the trench part V2 as a channel stopper. With this constitution, a highly reliable direct RAM free from the leakage between cells can be formed easily. |
