| 摘要 |
PROBLEM TO BE SOLVED: To improve writing gate disturb characteristics in an FN writing/FN deletion flash memory. SOLUTION: A tunnel insulating film 4, a floating gate electrode 5, an inter- layer insulating film 6, and a control electrode 7 are successively formed on a channel area interposed between a drain area and a source area on the surface of a semiconductor substrate in a non-volatile semiconductor memory. A drain diffusion area 10 is formed with high concentration impurity so as to be faced through the tunnel insulating film 4 to the floating gate electrode 5. On the other hand, a source diffusion area 12 is formed with low concentration impurity so as to be faced through the tunnel insulating film 4 to the floating gate electrode 5. At the time of the writing operation of the memory cell, a depletion layer is spread in the source diffusion layer 12 so that any high electric field can be prevented from being generated in the tunnel insulating film 4. Thus, it is possible to reduce the leakage of electrons to the source diffusion layer 12 in a non-selective memory cell, and to improve writing gate disturb characteristics.
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