標題: Numerical simulation of bottom oxide thickness effect on charge retention in SONOS flash memory cells
作者: Gu, Shaw-Hung
Hsu, Chih-Wei
Wang, Tahui
Lu, Wen-Pin
Ku, Yen-Hui Joseph
Lu, Chih-Yuan
電子工程學系及電子研究所
Department of Electronics Engineering and Institute of Electronics
關鍵字: oxide thickness;positive oxide charge-assisted tunneling;Shockley-Read-Hall (SRH) rate equation;SONOS retention mechanisms
公開日期: 1-一月-2007
摘要: In this paper, bottom-oxide thickness (T-bo) and program/erase stress effects on charge retention in SONOS Flash memory cells with FN programming are investigated. Utilizing a numerical analysis based on a multiple electron-trapping model to solve the Shockley-Read-Hall rate equations in nitride, we simulate the electron-retention behaviour in a SONOS cell with T-bo from 1,8 to 5.0 nm. In our model, the nitride traps have a continuous energy distribution. A series of Frenkel-Poole (FP) excitation of trapped electrons to the conduction band and electron recapture into nitride traps feature the transitions between the conduction band and trap states. Conduction band electron tunneling via oxide traps created by high-voltage stress and trapped electron direct tunneling through the bottom oxide are included to describe various charge leakage paths. We measure the nitride-charge leakage current directly in a large-area device for comparison. This paper reveals that the charge-retention loss in a high-voltage stressed cell, with a thicker bottom oxide (5 nm), exhibits two stages. The charge-leakage current is limited by oxide trap-assisted tunneling in the first stage and, then follows a 1/t time dependence due to the FP emission in the second stage. The transition time from the first stage to the second stage is related to oxide trap-assisted tunneling time but it prolonged by a factor.
URI: http://dx.doi.org/10.1109/TED.2006.887219
http://hdl.handle.net/11536/11269
ISSN: 0018-9383
DOI: 10.1109/TED.2006.887219
期刊: IEEE TRANSACTIONS ON ELECTRON DEVICES
Volume: 54
Issue: 1
起始頁: 90
結束頁: 97
顯示於類別:期刊論文


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  1. 000243280500013.pdf