| 摘要 |
There is disclosed a method of monitoring a source contact in a flash memory by which whether a source contact having a narrow contact area contacts or not can be easily monitored using over-erase cell characteristic in a flash cell, in a flash memory device in which a source line is formed by a local interconnection method. In the present invention, in order to monitor a contact state at source contacts, the same voltage to the erase condition of a cell is applied to respective terminals (VG terminal, VD terminal, VS terminal and VSS terminal) wherein all the electrons existing at a floating gate in all the cells connected to the VS terminal and VSS terminal become turned on so that they can be over-erased. On the other hands, as electrons existing at the floating gate in two cells shared by any source contacts having a defect contact are not erased, the cells remain turn-off. In this state, if test voltages (VG=0V, VD<5V, VS=float, VSS= ground) are applied, the current flow from the VD terminal to the VSS terminal is broken in the portion having a contact defect, thus allowing the contact state of the source contacts to be monitored.
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