Observations of single electron trapping/detrapping events in tunnel oxide of SuperFlash/spl trade/ memory cell

Erase instabilities and erase performance degradation due to single-electron trapping events in tunnel oxide of SST split-gate SuperFlash/spl trade/ memory cells have been detected and analyzed for the first time. Whereas the instabilities of erase characteristics in stacked-gate flash memories ("erratic erase") are attributed to hole trapping/detrapping associated with anode hole injection, SuperFlash/spl trade/ cell does not show any hole-related processes in tunnel oxide. A different behavior of SuperFlash/spl trade/ cell compared to conventional stacked-gate cell during erase operation due to different cell structures has been analyzed.