Research and Process Development of Molybdenum-based Nanocrystals for Nonvolatile Memory
| Autor: | Sheng-Chi Chen, 陳聖錡 |
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| Rok vydání: | 2008 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 96 In recently years, nanocrystals have been widely applied to overcome the issues of operation and reliability for conventional floating gate memories. The expected electrical characteristics of memory devices are good endurance, long retention time and small operation voltage. Among numerous memory devices with nanocrystals, nonvolatile memories with metal nanocrystals have been widely investigated. The advantages of metal nanocrystals are higher density of states around the Fermi level, stronger coupling with the conduction channel, wide range of available work functions and smaller energy perturbation due to carrier confinement. So metal nanocrystals can reduce the operate voltage of the flash memory, and increase the write/erase speed and the endurance. This work has studied on the effects of the high work function molybdenum (Mo) nanocrystals to the nonvolatile memory. Experimentally, the Mo nanocrystals were formed by high temperature rapid thermal annealing in N2. In addition, improvement in memory reliability by NH3 plasma treatment to the Mo nanocrystals has been observed. The effects of the Mo nanocrystals on the electron storage of the memory have been examined by the TEM, XPS, SIMS, C-V, and J-V measurements. The results show that Mo nanocrystals embedded in silicon oxide can achieve 67% retention of the stored charges and 54.5% endurance for memory reliability. With subsequent NH3 plasma treatment, the retention of the stored charges increases to 85% and the endurance for memory reliability increases to 85.2 %. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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