隨著可攜式電子產品市場需求逐年增加，雖然快閃記憶體朝著低成本高密度發展，但是元件製程和物理的限制使得要繼續遵循摩爾定律變的更為困難。以三維堆疊式的複晶矽薄膜電晶體做為記憶體可提供超高密度記憶體一個良好的解決方案。
傳統TANOS快閃記憶體擁有快速的寫入/抹除 操作; 使用氧化鋁做為阻擋層能增加閘極耦合比; 氮化鉭做為金屬閘極能夠有效抑制電子由閘極注入而減慢抹除速度。熱退火可以提高氧化鋁的介電常數，但是在高溫熱退火條件下會使氧化鋁結晶，儲存在電荷儲存層中的電子會經由這些結晶的晶界流失到金屬閘極，此現象造成傳統TANOS可靠度問題，有研究團隊使用二氧化矽附蓋於氧化鋁之上或是使用能隙工程方式來改善TANOS可靠度問題，但這些方法會犧牲閘極耦合比以及寫入/抹除 速度。

在本研究中提出以矽奈米晶體做為電荷儲存層的TANOS複晶矽快閃記憶體能夠有效的改善傳統TANOS的寫入/抹除 速度和可靠度問題，而此元件擁有在高溫下(1500C)極佳的資料保存能力(>108 sec 的5 % 電子流失)。
擁有極佳性能的NCs-TANOS對於傳統非揮發性記憶體的尺寸微縮提供良好的解決方案，並能實際應用於三微堆疊式記憶體以及下一世代快閃記憶體。

The market demand for portable electric equipment increase dramatically year by year. Although Flash develop toward low cost and high density, following Moore’s law to continue the scaling due to the device fabrication and physics limitations of the device. The three-dimensional (3D) multi-layer-stack memory basing on poly-Si TFT is another path to ultra-high density memory.
The conventional TANOS NVM behaves fast P/E operations because Al2O3 blocking layer increases the gate coupling ratio, and TaN immunizes the gate injection. The dielectric constant of the Al2O3 can be enlarged by rapid thermal annealing, but high temperature causes Al2O3 to crystallize, resulting in stored charge leaking to gate. Using sealing SiO2 or bandgap engineering (BE) can reduce this leakage, but those may sacrifice the coupling ratio and P/E speed.
In this thesis, we propose TANOS TFT Flash memory with silicon nanocrystals (Si-NCs) as charge-trapping layer, and named it NCs-TANOS. NCs-TANOS can improve the progam/erase speed and reliability issues of the conventional TANOS NVM , and exhibits excellent high-temperature (850C) retention ( >108 sec for 5% charge loss).
The excellent performance NCs-TANOS that provides a promising solution to overcome the limitation of the conventional NVM for future scaling, 3D stack NVM and next generation Flash memory application.
 

Chapter 1
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Chapter 4
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