| 摘要 |
In a non-volatile semiconductor memory, a large current can be flowed through the memory cell during reading. The number of the column lines can be reduced. The electron injection to the floating gates of the respective memory cells is averaged to reduce the electron emission from the floating gates of the respective memory cells is also averaged to reduce the dispersion of the threshold voltages thereof. An increase in chip size due to latch circuits can be prevented. By noting that either of a plurality of "0" or "1" of the binary data are stored such in the memory cells of the memory cell bundle or block, a negative threshold voltage in allocated to the memory cells for storing the more bit side data of the binary data. A single column line is used in common for the two adjacent memory blocks. To inject electrons to the floating gates of the memory cells, voltage is increased gradually and stopped when electrons have been injected up to a predetermined injection rate. Electrons are once emitted from the floating gates, and thereafter the electrons are injected again to store one of a binary data. Further, the data latch circuits can be formed at any positions remote from the memory cell array.
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