以金-硫化鎘殼核奈米粒子為懸浮閘極之非揮發性記憶體研究

Abstract

近幾年來以金屬奈米粒子作為記憶體的懸浮閘極已經廣泛地被許多研究團隊作為研究。比較半導體奈米粒子和金屬奈米粒子兩者，金屬奈米粒子作為懸浮閘極材料選擇的主要優點是其具有較高的功函數、較多的電荷捕捉狀態等等，故以金屬奈米粒子作為快閃記憶體的電荷捕捉中心是最佳的選擇之一。 在本篇論文中，製造金氧半電容記憶體元件並利用靜電力方式將化學合成出來的金奈米粒子和金-硫化鎘核殼奈米粒子自組裝在已修飾上胺基的穿隧氧化層上分別作為記憶體元件的懸浮閘極。而也比較金奈米粒子與金-硫化鎘核殼奈米粒子懸浮閘極記憶體的記憶時間和電荷捕捉能力。在記憶時間方面，到了104秒後，金-硫化鎘核殼奈米粒子元件還剩餘83 %的儲存電荷，而金奈米粒子元件卻只剩餘36 %的儲存電荷，推測為金-硫化鎘核殼奈米粒子的位能井結構和較大的穿隧位能障所引起。另外，金-硫化鎘核殼奈米粒子元件的電荷捕捉能力也大於金奈米粒子元件。

In recent years, metal nanoparticles (NPs) floating gate memory has already attracted a lot of attention by research teams worldwide. The metal nanoparticle owns numerous properties such as high work function and high charge trapping state compared to semiconductor materials; which make it becomes the best candidate materials for charge trapping center in flash memory. In this thesis, we fabricated metal oxide semiconductor (MOS) memory devices featuring either Au core-only NPs or Au@CdS core/shell NPs within the SiO2 layer. Self-assembly of the chemically synthesized Au and Au@CdS NPs led to their immobilization onto the amine-terminal modified tunnel oxide. Also, we compared the retention time and charge storage capability of nonvolatile memory devices incorporating floating gates containing Au nanoparticles (NPs) and Au@CdS core/shell NPs. The charge remaining of the Au@CdS NP-based memory device was 83 % at 104 s, compared with 36 % for the Au NP-based memory device, presumably because of the Au@CdS NPs’ quantum well structure and larger tunneling barrier. Moreover, the charge storage capability of the Au@CdS NP-based memory device is higher than that of the Au NP-based memory device.