AHighly Reliable Multi-level and2-bit/cell Operation ofWrapped-Select-Gate (WSG)SONOS

electric field atp-njunction, whileforthethickONO stacks High-performance wrapped-select-gate (WSG) SONGS (60/80/100), theelectric field atthegapincreased gradually asshown (silicon-oxide-nitride-silicon) memorycells withmulti-level and inFig. 5. 2-bit/cell operation havebeensuccessfully demonstrated. The Figures 6 and7 demonstrated thedrain andgatedisturbance source-side injection mechanism withdifferent ONO thickness in performance oftheWSG-SONOSmemorywithdifferent ONO WSG-SONOS memorywas wellinvestigated. The differentthickness forthe multi-level operation, respectively. Fromthese figures, programming efficiency oftheWSG-SONOSmemorywithdifferentwecaneasily observe that thethick topoxide will contribute tobetter ONO thickness canbeexplained bythelateral electrical field extractedgate disturbance while thedrain disturbance isnotaffected bytheONO fromthesimulation. Furthermore, multi-level storage iseasily obtainedthickness. Moreover, thethin bottom oxide exhibits better P/E cycling andwellVthdistribution isalso presented. Highprogram/erase speed performance resulted intheVFl shift owingtotheless interface states (1Ous/5ms) andlowprogramming current (3.5uA) areperformed to generation asindicated inFig.8.To sumup,theONO thickness achieve themulti-level operation withexcellent gateanddrain (50/80/100) usedintheWSG-SONOSmemoryshould beoptimized to disturbance, second-bit effect, data retention andendurance. gethighperformance andbetter reliability.