| 摘要 |
PURPOSE:To reduce the cepacitance of bit lines, to increase the speed and the sensitivity of signal reading and to implement high density, by providing an insulating film direcly beneath an impurity diffused layer, which serves the role of the bit line. CONSTITUTION:An n<+> type impurity region 6, a capacitor insulating film 7 and a capacitor electrode 8 form a capacitor part. Signals are stored in the n-type impurity region. A transfer transistor is formed by the n-type impurity region 6, an n-type impurity region 12, a gate oxide film 10 and a gate electrode 11. An aluminum interconnection 17 is a word line. The n-type impurity region 12 and a titanium silicide film 15 serve the role of bit lines. At this time, an embedded oxide film 5 is present directly beneath the n-type impurity region 12 so as to contact with said n-type impurity region. Therefore the capacitance of a depletion layer between the n-type impurity region 12 and a p-type silicon substrate 1 becomes almost Zero. Thus the capacitance of the bit lines becomes small. |
