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Impact of native defects and impurities in m−HfO 2 and β−Si 3 N 4 on charge trapping memory devices: A first principle hybrid functional study
Author(s) -
Lu Wenjuan,
Dai Yuehua,
Wang Feifei,
Jin Bo
Publication year - 2017
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201600360
Subject(s) - trapping , charge (physics) , materials science , fixed charge , impurity , electron , optoelectronics , molecular physics , chemistry , physics , nuclear physics , ecology , organic chemistry , quantum mechanics , biology
Using hybrid density functional calculations, this paper systematically investigated the common defects in m‐HfO 2 and β ‐Si 3 N 4 trapping layer, respectively, on the performance of charge trapping memory (CTM) devices. Defects may act as charge traps or fixed charges, however, only traps can be used to store charges. Thus, firstly, the paper distinguished traps or fixed charges of defects in trapping layer through the band alignment method. Then we can restrain the formation of defects that act as fixed charges in manufacturing CTM devices, which is very meaningful in improving the performance of CTM. Secondly, it studied the storage performance of traps in m‐HfO 2 and β ‐Si 3 N 4 by analyzing the formation energy, the atomistic structural change during program/erase (P/E) cycles, and localization energy. The simulation results found that only some defects can be charge traps in m‐HfO 2 and β ‐Si 3 N 4 , and the charge transition of these traps only appeared between certain charged states. In addition, these traps show reversible structural change during P/E cycles and different localizing abilities for holes and electrons. Therefore, this study would provide some theoretical guidance for improving the performance of CTM.