Observations Of Single Electron Trapping/Detrapping Events In Tunnel Oxide Of Superflash((R)) Memory Cell

Erase instabilities and erase performance degradation due to single-electron trapping events in tunnel oxide of SST split-gate SuperFlash(R) 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 traping/detrapping associated with anode hole injection, SuperFlash(R) cell does not show any hole-related processes in tunnel oxide. A different behavior of SuperFlash(R) cell compared to conventional stacked-gate cell during erase operation due to different cell structures has been analyzed.