| 摘要 |
PURPOSE:To perform writing and erasing readily even at a low voltage by relatively increasing the voltage between a floating gate and a semiconductor substrate. CONSTITUTION:Since a recess shaped groove is formed in the side surface of a floating gate 12, the surface area is largely increased. The capacitance between the floating gate 12 and a control gate 16 is largely increased. Therefore, the capacitance ratio between the capacitance between the control gate 16 and the floating gate 12 and the capacitance between the floating gate 12 and a semiconductor substrate 2 at a channel region becomes large. Even if the voltage of the control gate is constant or a low voltage, the voltage between the floating gate 12 and the semiconductor substrate 2 at the channel region becomes relatively high. Thus writing or erasing can be performed readily by using the low voltage. |
