DocumentCode
1464349
Title
Variations of 
Retention Loss in a SONOS Flash Memory Due to a Current-Path Percolation Effect
Author
Chou, Y.L. ; Chung, Y.T. ; Wang, Tahui ; Ku, S.H. ; Zou, N.K. ; Chen, Vincent ; Lu, W.P. ; Chen, K.C. ; Lu, Chih-Yuan
Author_Institution
Dept. of Electron. Eng., Nat. Chiao Tung Univ., Hsinchu, Taiwan
Volume
32
Issue
4
fYear
2011
fDate
4/1/2011 12:00:00 AM
Firstpage
458
Lastpage
460
Abstract
Discrete nitride program charge loss in a small-area SONOS Flash memory cell during retention is observed. Our measurement shows that a retention Vt of a programmed SONOS cell exhibits a stepwise evolution with retention time. Individual single-program charge-loss-induced threshold voltage shifts (ΔVt) are characterized. We find the following: 1) The magnitude of ΔVt exhibits an exponential distribution, which is believed due to a current-path percolation effect caused by random program charges and substrate dopants, and 2) program-state Vt retention loss has large variations in different cells and P/E cycles due to the percolation effect. We develop a Monte Carlo analysis to take into account the distribution of ΔVt and a tunneling front model to study the spread of a retention Vt distribution in a SONOS Flash memory.
Keywords
Monte Carlo methods; exponential distribution; flash memories; Monte Carlo analysis; SONOS flash memory cell; current-path percolation effect; discrete nitride program charge loss; exponential distribution; program-state retention loss; random program charges; single-program charge-loss-induced threshold voltage shifts; substrate dopants; tunneling front model; Exponential distribution; Flash memory; Logic gates; Monte Carlo methods; Noise; SONOS devices; Tunneling; Percolation; SONOS; retention loss; single-program charge;
fLanguage
English
Journal_Title
Electron Device Letters, IEEE
Publisher
ieee
ISSN
0741-3106
Type
jour
DOI
10.1109/LED.2011.2109031
Filename
5723684
Link To Document