METHOD FOR READING NONVOLATILE MEMORY CELL

摘要

PROBLEM TO BE SOLVED: To correctly read an NROM cell storing two bits.

SOLUTION: This method includes a step for changing a read reference level for reading a group of memory cells as a function of changes in a threshold voltage distribution of a different group of memory cells. The changing step includes: a step for determining a history read reference level of a group of history cells associated with a group of memory cells of a nonvolatile memory cell array; a step for allowing correct reading of the group of history cells; a step for selecting a memory read reference level according to the first read reference level, and a step for reading the nonvolatile memory array cells.

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