Title :
Impact of Neutral Threshold-Voltage Spread and Electron-Emission Statistics on Data Retention of Nanoscale nand Flash
Author :
Miccoli, Carmine ; Compagnoni, Christian Monzio ; Amoroso, Salvatore Maria ; Spessot, Alessio ; Fantini, Paolo ; Visconti, Angelo ; Spinelli, Alessandro S.
Author_Institution :
Dipt. di Elettron. e Inf., Politec. di Milano, Milan, Italy
Abstract :
This letter presents a comparison of two different variability sources for data retention of nanoscale NAND Flash memories: the neutral threshold-voltage spread and the electron-emission statistics from the floating gate. Referring to fresh cells programmed to the same threshold-voltage level, the effect of the previous dispersion contributions on the data retention transients of a memory array is evaluated. Both effects are shown to result into a broadening of the array threshold-voltage distribution with time, but a quantitative assessment clearly shows that the neutral threshold-voltage spread dominates over the electron-emission spread, revealing that cell-to-cell parameter variations represent the major source of variability for data retention in nanoscale NAND Flash memories.
Keywords :
NAND circuits; electron emission; flash memories; logic gates; cell-to-cell parameter variations; data retention; electron-emission statistics; floating gate; memory array; nanoscale NAND flash memory; neutral threshold-voltage spread; threshold-voltage distribution; threshold-voltage level; Arrays; Dispersion; Doping; Flash memory; Nanoscale devices; Tunneling; Data retention; Flash memories; electron-emission statistics (EES); semiconductor-device modeling; threshold-voltage dispersion;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2010.2069082