SEMICONDUCTOR STORAGE DEVICE, WRITING METHOD THEREOF, AND STORAGE MEDIUM WITH WRITING METHOD STORED THEREIN

摘要

PROBLEM TO BE SOLVED: To suppress a deterioration in a memory cell due to overcurrent in a multivalued semiconductor storage device capable of storing ternary or more storage states.

SOLUTION: A current control circuit 8 generates three types of different stationary currents I1 to I3 and applies at least one current value selected among the three types of different current values to one of selected memory cells 10 to 13 in accordance with a data signal from the outside. Consequently, overcurrent is inhibited from flowing into the memory cells, and a multivalued memory cell is achieved which can store ternary or more information in one memory cell by making the different current values correspond to three types of different thresholds.

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