| 摘要 |
<p>PURPOSE:To enable a single operation by an internal power source and to increase a deletable and writable number by executing deleting operation and writing operation by utilizing a tunnel phenomenon. CONSTITUTION:At the time of a deleting mode, a prescribed voltage is impressed between respective word lines WL1 and WL2 and respective bit lines BL1 and BL2 so that the moving of an electric charge can be generated by the tunnel phenomenon between the drain area and floating gate of all memory transistors Q1-Q4. Then, at the time of a writing mode, the prescribed voltage is impressed between the respective word lines WL1 and WL2 and the respective bit lines BL1 and BL2 so that the moving of the electric charge can be generated by the tunnel phenomenon between the drain area and floating gate only for one of the memory transistors Q1-Q4 which is detected by a raw decoder and a column decoder. Then, a deleting/writing is respectively executed. Namely, not only at the deleting mode time but also at the writing mode time, the writing is executed by utilizing the tunnel phenomenon. Thus, the operation can be executed only by the internal power source and the deleting and writing number can be increased.</p> |
