| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the erroneous writing in an unselected memory cell in a nonvolatile semiconductor memory of virtual grounding system in which MOS transistor having a charge storage layer consisting of a silicon nitride film in the gate insulating film is used as a memory cell. SOLUTION: In a nonvolatile semiconductor memory of virtual grounding system in which MOS transistor having a charge storage layer consisting of a silicon nitride film in the gate insulating film is used as a memory cell, after injecting electrons into all the memory cells M1-M16 by applying a high voltage to the gates and drains, and making a current flow from the drains into the sources, data are re-written column by column sequentially from the memory cell M1 where the source of the memory cell in the memory cell array is arranged at the endmost position of the memory cell array, in the direction of the memory cell M16 where the drain of the memory cell in the memory cell array is arranged at the endmost position of the memory cell array.</p> |
