本研究利用自組裝奈米球微影術(Nanosphere Lithography, NSL)結合蒸鍍技術與熱 退火製程在非晶矽基材與氮氣離子佈植非晶矽基材上製備出大面積有序排列之鎳金屬 矽化物奈米點陣列，並探討所製備之鎳金屬點陣列與非晶矽基材在不同溫度下熱退火處 理之界面反應。 從穿透式電子顯微鏡(Transmission Electron Microscopy, TEM) 及選區電子繞射 (Select Area Electron Diffraction, SAED) 分析中，發現鎳金屬奈米點陣列在非晶矽基材上 反應時，在低溫退火300 oC 時就已完全轉換成低電阻NiSi 相。與先前本實驗室研究結 果說明由於基材有固定晶面並且最低能量考量的關係在單晶矽基材上350 oC 即生成高 電阻NiSi2 相。此結果說明沒有固定結晶晶面的非晶矽基材能夠使高電阻NiSi2 相生成延 遲。 另一部分，我們以同樣條件在具有氮氣離子佈植之非晶矽基材上製備鎳金屬奈米點 陣列結構，並以同樣退火條件下觀察奈米尺度之鎳金屬奈米點陣與氮氣離子佈植非晶矽 基材之界面反應。結果顯示具有氮氣離子佈植非晶矽基材其NiSi 溫度窗為300-500 oC， 較第一部分能夠延長低電阻NiSi 相熱穩定性約150 oC 之溫度差距，造成如此差異的結 果，推測為鎳金屬點陣與非晶矽基材反應時，氮氣會因其與矽的溶解度低的原因而被排 出至矽化物晶界以及矽化物與非晶矽基材界面處，降低其界面能，從而延長NiSi 相的溫 度窗。上述結果顯示，相信在未來光電以及先進奈米元件之研究上將具有很大的研究潛 力。;In the present study, we have demonstrated that 2D periodic arrays of nickel silicide nanodots can be successfully fabricate on the amorphous silicon substrates and nitrogen ion implanted amorphous silicon substrates by using the polystyrene nanosphere lithography(NSL), evaporation technique and thermal annealing process. The interfacial reactions of the nickel nanodots on amorphous silicon substrate after different heat treatments have also been investigated. From the TEM and SAED analysis, low resistivity NiSi nanodots were found to form on amorphous silicon at annealing temperature as low as 300 oC. From our earlier researches and other previous studies, the growth of high resistivity NiSi2 nanodots was found to be more favorable for the miniature size Ni metal nanodots on crystal Si substrates at annealing temperature as low as 350oC. The results indicated that the amorphous silicon exhibited significant beneficial effects on the enhanced growth of low resistivity NiSi and improved the stability of NiSi nanodots. Other studies was Ni metal dots on nitrogen ion implanted amorphous silicon substrate at various heat treatments. The incorporation of N2 to a-Si substrates exhibited excellent effects on improving the thermal stability of NiSi nanodots. The process window of low resistivity NiSi in the Ni nanodots/a-Si(N2 +) sample was greatly extended by 150 oC as compared to that in the Ni nanodots/a-Si sample. The results indicated that the presence of N2 is thought to lower the NiSi nanodots/a-Si(N2 +) interface energy and to block the Ni diffusion paths. Both the Ni metal nanodots on the amorphous silicon substrate and nitrogen ion implanted amorphous silicon substrate annealed at 900oC, highly curled and tangled amorphous nanowires were observed to grow from silicide nanodots regions.
