Charge loss behavior of manos-type flash memory cell with different levels of charge injection

In this study, we found that the charge loss behavior of MANOS device for NAND Flash memory application is highly dependent on the amount of injected charges (defined as Q
_inj
(=C
_ox
timesDeltaV
_FB
)). Beyond the critical amount of Q
_inj
(defined as Q
_c
), the direction of dominant charge loss path changes from SiO
₂
towards Al
₂
O
₃
. This result was verified by experimental and simulation results through the comparison between ONO and ONA stacks. For detailed analyses, we investigated the impact of blocking oxide thickness and retention temperature. For further understanding, we performed long-term retention measurements up to ~10
⁶
s at different level of Q
_inj
to investigate the correlation between the energy trap level (E
_TA
) and Q
_inj
.