| 摘要 |
<P>PROBLEM TO BE SOLVED: To extend lifetime of flash memory by reducing an erasure frequency of each memory cell. <P>SOLUTION: A nonvolatile semiconductor memory device 3 comprises; a memory block which is provided in each of a plurality of semiconductor regions 202 and in which a plurality of nonvolatile memory cells having a memory transistor and a selection transistor connected in series are arranged in a matrix shape; a plurality of word lines WL which are connected to control gates of a plurality of memory transistors so as to connect the memory transistors in a same row in common; and a plurality of selection gate lines SG which are connected to gates of a plurality of selection transistors so as to connect the selection transistors in a same row in common. A row decoder 20 applies a first negative voltage to a selection word line whose data is to be erased, and applies a second positive voltage to a non-selection word line whose data is not to be erased, in a state of applying an erasure voltage to a semiconductor region when performing erasure. <P>COPYRIGHT: (C)2012,JPO&INPIT |
