| 摘要 |
PURPOSE:To obtain a flash memory capable of increasing data rewriting frequency by a method wherein a delay means delaying the impression time of the third level voltage on a source line from that of the first and second level voltages is to be provided. CONSTITUTION:The title non-volatile semiconductor memory is provided with a word line driving means 20 to impress a selected word line 13 with the first level voltage in the first operation mode time, a substrate driving means 22 to impress the specific region of a semiconductor substrate corresponding to the selected memory cells with the second level voltage furthermore, a source line driving means 21 to impress a selected source line with the third level voltage as well as a delaying means 24 to delay the impression time of the third level voltage on the source line from that of the first and second level voltages. Through these procedures, a depletion layer is spread in the semiconductor substrate while enabling the depletion layer to be injected with electrons from a source region 3. Finally, the electrons are to be injected in a floating gate 9. |
