| 摘要 |
PURPOSE: A method for driving a flash memory cell is provided to improve an over-erase phenomenon and a read disturb phenomenon by performing a program operation under four voltage conditions and performing an erase operation under three voltage conditions. CONSTITUTION: The program operation is performed under the four conditions. A voltage higher than a voltage applied to a source electrode(7) is applied to a control gate(5) while a drain electrode(8) and a substrate are open. A voltage higher than a voltage applied to the drain electrode is applied to the control gate while the source electrode and the substrate are open. A voltage higher than a voltage equally applied to the source/drain electrode is applied to the control gate while the substrate is open. A voltage higher than a voltage equally applied to the source/drain electrode and the substrate is applied to the control gate. The erase operation is performed under following three conditions. A voltage higher than a voltage applied to the substrate is applied to the control gate while the source/drain electrode is open. A voltage higher than a voltage equally applied to the source/drain electrode and the substrate is applied to the control gate. A voltage lower than a voltage equally applied to the source/drain electrode is applied to the substrate and a voltage higher than a voltage equally applied to the source/drain electrode is applied to the control gate.
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