NONVOLATILE SEMICONDUCTOR STORAGE DEVICE AND SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE

摘要

PROBLEM TO BE SOLVED: To improve the rewriting durability of a memory cell and to remarkably improve the reliability for reading data.

SOLUTION: A verify sense amplifier circuit 7 is arranged in a flash memory. The verify sense amplifier circuit 7 produces a discrimination current at verifying in accordance with the gate voltage Vgi produced by a voltage generating circuit. The level of this discrimination current is the current level at the same degree as those of respective memory currents of the memory cell S, capable of discriminating that the current at reading is flowing or not. Thus, by securing the memory current required for reading at verifying, the reliability of data reading is improved even for the memory cell S deteriorated by rewriting of data.

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