| 摘要 |
The present invention provides a semiconductor nonvolatile memory device for storing multi-bit data comprising a memory cell having a source region S and a drain region D formed at the surface of a semiconductor substrate, a gate insulator film and a control gate CG formed on a channel region CH between the source region S and the drain region D and a nonconductive trap gate in the gate insulator film. Furthermore, an indentation 4 is provided at the surface of the semiconductor substrate covering a region from a position in the vicinity of the drain region in the channel region to the drain region. By providing the indentation 4 on the drain region side of the channel region, the trap gate is positioned in the direction of a channel current flowing from the source region S to the drain region D. Then, the a charge having run through the channel region CH is injected efficiently into the trap gate on the indentation. Therefore, a hot charge can be injected into the trap gate without applying a high voltage to the control gate etc. <IMAGE>
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