OPERATING TECHNIQUE FOR REDUCING EFFECT OF COUPLING BETWEEN STORAGE ELEMENTS OF NONVOLATILE MEMORY OPERATED IN MULTIPLE DATA STATES

摘要

PROBLEM TO BE SOLVED: To minimize the effect of charge coupling between adjacent floating gates and to compress the distribution. SOLUTION: A flash electrically erasable and programmable ROM (EEPROM) in which storage elements are electrically floating gates is operated so that the effect of charge coupled between adjacent floating gates is minimized by programming again one part of cells after programming of adjacent cells. Also, second programming operation compacts the distribution for a charge level within at least some of the programming states. This increases the separation between states and allows more states to be included within a given storage window.