Journal of Nanomaterials / 2013 / Article / Tab 3 / Review Article
Technical Solutions to Mitigate Reliability Challenges due to Technology Scaling of Charge Storage NVM Table 3 (a) Key advantages of nanocrystal NVM as compared to standard FG flash memory. (b) Critical challenges of nanocrystal NVM.
(a) Key advantages of nanocrystal NVM References 1 Excellent inherent immunity to trap assisted tunneling of SILC through defects in tunnel oxide [38 –43 ] 2 Tunnel oxide thickness can be further scaled down below 8 nm (critical limitation for standard FG flash memory) [41 –53 ] 3 Low operating voltage, fast write and erase speed [38 , 39 , 41 –44 ] 4 Multiple bit storage [51 , 58 ] 5 Eliminate floating gate interference especially for ultradense NAND flash memory [52 ] 6 Leverage existing Si material technology and CMOS compatible process [41 –53 ] 7 Simpler device structure which yielded fewer process steps that further reduce fabrication costs [40 , 52 ] 8 Superior tolerance to radiation effects as compared to standard FG flash memory [55 , 58 ] 9 Nitrided silicon nanocrystal NVM has shown larger memory window and faster program speed [47 ]
(b) Critical challenges of nanocrystal NVM References 1 Nanocrystals are not fabricated through lithography process; thus variability in fabrication process is critical towards memory properties of nanocrystal NVM [40 –42 , 50 ] 2 Concern on charge leakage through surrounding oxide if thinning of surrounding oxide continues and density of nanocrystals increases [40 , 41 , 50 , 52 –54 ] 3 Optimal nanocrystal memory performance requires formation of nanocrystals of optimal size and density and preserving them during subsequent processing steps [40 , 41 , 43 –45 , 50 , 52 , 54 ] 4 Impact of charge localization of nanocrystals to operating window [54 ]