Title :
Study of data retention for nanocrystal Flash memories
Author :
Compagnoni, C. Monzio ; Ielmini, D. ; Spinelli, A.S. ; Lacaita, A.L. ; Previtali, C. ; Gerardi, C.
Author_Institution :
Dipt. di Elettronica ed Informazione, Politecnico di Milano, Italy
fDate :
30 March-4 April 2003
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 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 10 years of data storage. No measurable retention degradation is found up to at least 106 program/erase cycles, indicating that stress-induced leakage current (SILC) does not play a leading role in affecting the memory reliability. The SILC immunity of nanocrystal memories is explained by a physical model for charge leakage, accounting for lateral tunneling among the storage nodes.
Keywords :
failure analysis; flash memories; integrated circuit reliability; leakage currents; nanostructured materials; tunnelling; 10 year; 2.8 to 4 nm; 4.2 nm; SILC immunity; Si; Si nanocrystals; Si-SiO2; charge loss mechanism; data retention; direct tunneling; lateral tunneling; memory cells; memory reliability; minimum thickness; nanocrystal Flash memories; physical model; retention degradation; stress-induced leakage current; tunnel oxide thickness; uncycled memories; Current measurement; Dielectric substrates; Flash memory; Leakage current; Nanocrystals; Nonvolatile memory; Research and development; Stress measurement; Tunneling; Voltage;
Conference_Titel :
Reliability Physics Symposium Proceedings, 2003. 41st Annual. 2003 IEEE International
Print_ISBN :
0-7803-7649-8
DOI :
10.1109/RELPHY.2003.1197800
