Nonvolatile memory device having flag cells for storing MSB program state

摘要

A nonvolatile memory device comprises a memory cell array comprising memory cells arranged in rows and first columns and flag cells arranged in the rows and second columns. The device further comprises a page buffer configured to read flag data bits from flag cells in a selected row via the second columns, and a judgment unit configured to judge whether memory cells in the selected row are programmed with MSB data based on the flag data bits read by the page buffer.