Probability Level Dependence of Failure Mechanisms in Sub-20 nm NAND Flash Memory
Duckseoung Kang, Kyung-Hwan Lee, Myounggon Kang, Seongjun Seo, Dong Hua Li, Yuchul Hwang, Hyungcheol Shin · IEEE Electron Device Letters · 2014
We extracted final ΔVth, time constant, and activation energy (Ea) of each mechanism in retention characteristics of sub-20-nm NAND flash main-chip according to the probability level (P level) of Vthcumulative probability distribution. As a result, we confirmed that at lower P level, the final ΔVthof each mechanism increases sensitively according to P/E cycling stress. Temperature dependence of the final ΔVthof each mechanism also increases with lowering P level, whereas trap-assisted tunneling (TAT) mechanism of corner area has complex characteristics on temperature. Interface trap recovery, TAT (plane), and TAT (corner) mechanism have larger Eaat high P level, whereas the Eaof detrapping mechanism decreases because of barrier lowering effect.