| 摘要 |
A non-volatile memory device that can prevent a functional failure in the programming process of a cell from occurring in an overwriting process, by stopping a current path from being formed through the sources of a previously programmed cell and that of a currently selected cell which is to be programmed. The present device includes a modified structure for a memory cell of an EEPROM device. The present device includes an additional overwrite transistor to separate a sense transistor from a source in the region of an active area which is expanded toward the source of the sense transistor. The overwriting transistor includes a gate formed in a single layered structure of a second conductivity layer, integrally connected with the second conductivity layer of the sense transistor. Further, a second gate insulating layer is formed between the source and the sense transistor on the substrate. Accordingly, an electric path is prevented from forming through sources of the previously programmed cell and that of the selected cell to be programmed and, in turn, to prevent the overwriting process from having any programming failure.
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