| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a semiconductor memory in which rewriting with a block unit can be performed and the number of times of substantial rewriting can be increased. SOLUTION: Non-volatile storage elements in which accumulated electric charges of a floating gate are erased by a tunnel current through a tunnel insulation film are arranged in a matrix state, the above erasing can be performed for each block to which plural non-volatile storage elements of which control gates are coupled to the same word line are divided, a ground potential of a circuit is given to a block selected at the time of write-in for a source line of non-volatile storage elements being common to each block, potential difference between a floating gate and a source/drain is made less for a non- selection block. Or in one memory block, occurrence of a tunnel current is prevented or reduced by making such constitution of word lines and source lines that high voltage is not supplied to word lines in a memory block being non-selection at the time of write-in.</p> |
