| 摘要 |
<p>PURPOSE: To suppress deterioration of a gate insulating film and degradation of characteristics by injecting electrons to a floating gate under a condition where drain breakdown strength is mild and performing write-in, by giving the prescribed write-in voltage to a control gate preceding giving write-in voltage to a drain. CONSTITUTION: Write-in voltage V2, V1 of a word line and a bit line are generated synchronizing with a clock CK, V1 is delayed for V2 by the prescribed timeΔT through a delay circuit 5, V2, V1 are outputted to a word line 4 and a bit line 6 respectively, and they are supplied to a control gate and a drain of a memory transistor. Therefore, since V1 is applied to a drain when V2 reaches write-in voltage, electrons are injected into a floating gate of the memory transistor under a condition where drain breakdown strength is mild, and write-in is performed. Thereby, drain breakdown when starting of write-in is evaded, and degradation of an insulation film of a gate and degradation of characteristics of a transistor can be suppressed.</p> |
