AHighPerformance andScalable FinFETBE-SONOSDevice forNAND FlashMemoryApplication
Tzu‐Hsuan Hsu, Hang-Ting Lue, Wu-Chin Peng, Chia-Wei Wu, Szu-Yu Wang, Ming-Tsung Wu, Shih-Ping Hong, Jung-Yu Hsieh, Tahone Yang, Kuang‐Chao Chen, Kuang-Yeu Hsieh · 2008
A high-performance bodytiedFinFETBE-SONOSdevice isdemonstrated, suitable forNAND Flash memory scaling beyond30nm technology node.BE-SONOSoffers efficient holetunneling eraseandexcellent dataretention. Whenintegrated into a FinFETstructure, a much higher program/erase speed isobtained, owingtotheinherent field enhancement (FE)effect around thefintip. Inthis work, a veryscaled (36nm) FinFETBE-SONOSwithsuccessful NAND array functions, including fastblockerase speed( 0.6), successful self-boosting program-inhibit window, goodreaddisturb property (>lOOK read), andexcellent cycling endurance (>1OK) aredemonstrated. I.Introduction Recently SONOS-type devices areproposed tosolve thescaling limitation offloating-gate devices. SONOS devices arenaturally immunetothefloating-gate interference issues. Moreover, thediscrete charge storage property isfreefromSILCandprovides better few-electron storage capability. Therefore, itisapromising approach for Flash memoryscaling. However, theconventional SONOShasfundamental problems in thetrade-off between erasespeedanddataretention. Therefore, BE-SONOS[1]wasproposed. BE-SONOSusesabandgap engineered ONO barrier toprovide efficient holetunneling erase athighfield, while eliminate thecharge loss atlowfield during retention. Compared with SONOSusing asingle ultra-thin tunnel oxide ( 4nm),BE-SONOS showssuperior eraseperformance. Thisisbecause BE-SONOSuses hole-tunneling injection forerase, while SONOSorMANOS withthick tunnel oxidecannot beerased byholetunneling, andmustrely on electron de-trapping, whichisinefficient andrequires veryhighelectric field (>14MV/cm). Intermsofdevice scaling, FinFETdevice issuperior tothe