Semiconductor memory device

摘要

A memory cell is formed of a sense access transistor for data sensing, a restore access transistor for data restoration and a memory capacitor for data storage. Sense access transistor couples the memory capacitor to a sense bit line according to a signal on a sense word line. The restore access transistor couples the memory capacitor to a restore bit line provided separate from the sense bit line according to a signal on a restore word line. Electric charges in the memory capacitor are transferred to a sense amplifier through the sense bit line and sense data in a sense amplifier is transferred to original memory capacitor through a restore amplifier and the restore access transistor. Output signal lines of the sense amplifier are electrically isolated from the sense and restore bit lines. Thereby, it is possible to reduce the access time of a semiconductor memory device.