This work presents a detailed study of data retention for nanocrystal Flash memories. Data retention has been investigated in memory cells, with tunnel oxide thickness ranging from 2.8 to 4 nm. Assuming the direct tunneling through the tunnel oxide as the main charge loss mechanism for uncycled memories, we show that a minimum thickness around 4.2 nm is required for the tunnel oxide to guarantee a 10 years data storage. No measurable retention degradation is found up to at least 10(6) program/erase cycles, indicating that the stress-induced leakage current (SILC) does not play a leading role in affecting the memory reliability. The SILC immunity of nanocrystal memories is finally explained by a physical model for charge leakage, accounting for lateral tunneling among the storage nodes.
Study of data retention for nanocrystal Flash memories
MONZIO COMPAGNONI, CHRISTIAN;IELMINI, DANIELE;SOTTOCORNOLA SPINELLI, ALESSANDRO;LACAITA, ANDREA LEONARDO;PREVITALI, CRISTIAN;
2003-01-01
Abstract
This work presents a detailed study of data retention for nanocrystal Flash memories. Data retention has been investigated in memory cells, with tunnel oxide thickness ranging from 2.8 to 4 nm. Assuming the direct tunneling through the tunnel oxide as the main charge loss mechanism for uncycled memories, we show that a minimum thickness around 4.2 nm is required for the tunnel oxide to guarantee a 10 years data storage. No measurable retention degradation is found up to at least 10(6) program/erase cycles, indicating that the stress-induced leakage current (SILC) does not play a leading role in affecting the memory reliability. The SILC immunity of nanocrystal memories is finally explained by a physical model for charge leakage, accounting for lateral tunneling among the storage nodes.File | Dimensione | Formato | |
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