METHOD OF PROGRAM OPERATING FOR NONVOLATILE MEMORY DEVICE

PURPOSE: A method for programming a nonvolatile memory device is provided to reduce the width of threshold voltage distribution by reducing the threshold voltage of cells excessively programmed. CONSTITUTION: A memory cell array(310) includes a plurality of string structures. Each string structure(330) includes a source selection transistor(SST), a plurality of memory cells, and a drain selection transistor(DST) which are in serial connection with each other. Memory cells in the string structure are in connection with each other through word-lines. A drain selection transistor is selectively connected with the string structure and bit-lines(BL). A page buffer(320) stores data to be recorded in a specific memory cell.