$V_{t}$ Retention Distribution Tail in a Multitime-Program MLC SONOS Memory Due to a Random-Program-Charge-Induced Current-Path Percolation Effect
| Autor: | Tahui Wang, M.Y. Lee, C.W. Li, Chih-Yuan Lu, Kuang-Chao Chen, Yueh-Ting Chung, Tzu-I Huang, You-Liang Chou, J.P. Chiu |
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| Rok vydání: | 2012 |
| Předmět: |
Exponential distribution
Materials science Condensed matter physics Charge (physics) Poisson distribution Flash memory Standard deviation Electronic Optical and Magnetic Materials symbols.namesake Distribution (mathematics) Percolation Electronic engineering symbols Distribution model Electrical and Electronic Engineering |
| Zdroj: | IEEE Transactions on Electron Devices. 59:1371-1376 |
| ISSN: | 1557-9646 0018-9383 |
| Popis: | A Vt retention distribution tail in a multitime-program (MTP) silicon-oxide-nitride-oxide-silicon (SONOS) memory is investigated. We characterize a single-program-charge-loss-induced ΔVt in NOR-type SONOS multilevel cells (MLCs). Our measurement shows the following: 1) A single-charge-loss-induced ΔVt exhibits an exponential distribution in magnitudes, which is attributed to a random-program-charge-induced current-path percolation effect, and 2) the standard deviation of the exponential distribution depends on the program-charge density and increases with a program Vt level in an MLC SONOS. In addition, we measure a Vt retention distribution in a 512-Mb MTP SONOS memory and observe a significant Vt retention tail. A numerical Vt retention distribution model including the percolation effect and a Poisson-distribution-based multiple-charge-loss model is developed. Our model agrees with the measured Vt retention distribution in a 512-Mb SONOS well. The observed Vt tail is realized mainly due to the percolation effect. |
| Databáze: | OpenAIRE |
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