NON VOLATILE SEMICONDUCTOR STORAGE DEVICE AND ITS CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor device which expands a setting range of a threshold voltage for a memory cell by practically increasing the threshold voltage of the memory cell for reading after programming; and to provide its control method.

SOLUTION: A NAND column has: n (n is an integer of≥3) memory cells MC which have charge storage layers FG and control gates CG, both mutually connected in series; a first selection gate transistor connected to a point between the one end of the n memory cells and a source line and a second selection gate transistor connected to a point between the other end of the n memory cells and a bit line. A control circuit applies a first voltage Vread_1 lower than a reading voltage Vread to be applied to the control gate of other non selected memory cells to the control gate CG (k-1) and CG (k+1) of the non selected memory cell adjacent to the selected memory cell in the NAND column when reading data.

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