Comparison With Nitride Interface Defects and Nanocrystals for Charge Trapping Layer Nanowire Gate-All-Around Nonvolatile Memory Performance

Abstract

This paper demonstrates novel silicon–oxide–nitride–nitride–oxide–silicon (SONNOS) and silicon-oxide-nanocrystals-oxide-silicon (SOncOS) nonvolatile memory (NVM) that is based on nanowires gate-all-around (GAA) structure. SONNOS and SOncOS NVM exploit doubly stacked Si3N4 (NN) interface defects and silicon nanocrystals as charge trapping layers, respectively. Experimental results reveal that SONNOS NVM has superior memory characteristics than SOncOS NVM. With respect to memory reliability, the SONNOS NVM retains 86% memory window after 104 program/erase cycles, and the memory window retains 42% of the originally stored charge after ten years. Such doubly stacked Si3N4 layers provide additionally charge trapping sites in CTL, improving the memory performance of NVM. In the future, SONNOS GAA NVMs will be easily integrated in 3-D nand flash memory applications.