NONVOLATILE MEMORY DEVICE AND PROGRAMMING METHOD THEREOF

PURPOSE: A nonvolatile memory device and a programming method thereof are provided to program a selected memory cell to have a dense threshold voltage distribution by controlling an F-N tunneling. CONSTITUTION: A threshold voltage of a selected memory cell is verified(S120). A bit line voltage of the selected memory cell is set according to a threshold voltage of the selected memory cell determined by a preprogram verification process(S130). A program voltage is applied to the selected memory cell in which the bit line voltage is set(S150). A program state of the selected memory cell to which the program voltage is applied is verified(S160). [Reference numerals] (AA) Start; (BB,DD) No; (CC,EE) Yes; (FF) End; (S110) Bit line precharge; (S120) Preprogram verification; (S131) Memory cell to be programmed?; (S132) Bit line voltage maintenance according to a preprogram verification result; (S133) Program prohibition voltage application to a bit line; (S150) Memory cell program; (S160) Post program verification passed?;