| 摘要: | 本研究成功利用聚苯乙烯(Polystyrene, PS)奈米球微影術(Nanosphere Lithography，NSL)結合熱退火製程在(111)矽晶上製備出大面積、二維週期性排列的鎳金屬奈米點及矽化物奈米點陣列。並 探討所製備之鎳金屬點陣列與(111)矽晶基材間在不同溫度下熱退火處理時之界面反應。 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，可發現鎳金屬奈米點陣列在(111)Si基材上反應時，在低溫退火300 ℃時就已完全轉換為磊晶二矽化鎳(Epitaxial NiSi2，Epi-NiSi2) 。此結果指出鎳金屬奈米點在(111)Si基材進行界面矽化反應時，越小的鎳金屬奈米點越有利於Epi-NiSi2之磊晶反應成長。經鑑定後Epi-NiSi2之奈米點與(111)Si基材間之磊晶方位關係為[111]NiSi2//[111]Si，{220}NiSi2//{220}Si。此外，在較高溫退火試片中也觀察到Epi-NiSi2奈米點陣在(111)Si上有特定刻面形貌形成，經過鑑定比對之後，可知其刻面皆平行於<1 0>Si方向。另外在實驗中也可在矽基材上發現雙層奈米球模板的存在，而由雙層之奈米球模板製備出之Epi-NiSi2奈米點的結果來看，雙層奈米球模板可以在相同的球徑下可製備更小之奈米點陣列。 藉由結合奈米球微影術，熱處理製程，化學濕式選擇性蝕刻及電鍍技術，我們亦成功在矽晶與矽鍺基材上製備出大面積，形狀和尺寸可調變之金屬奈米結構(奈米碗及奈米柱)及奈米孔洞陣列。在本研究中也利用SEM，AFM，TEM及SAED分析針對所製備奈米結構之表面形貌的演變，尺寸均一性及其晶體結構等進行有系統的觀察鑑定。最後，從本實驗結果可清楚顯示若結合適當的控制技術及奈米球微影術不但能提供有效率又經濟的模板以在不同之基材上製備出尺度可調變之週期結構，進而能製備所需要之形狀，尺寸及週期性而不需要複雜之微影技術。 In the present study, we have demonstrated that 2D periodic arrays of nickel metal and silicide nanodots can be successfully fabricated on (111)Si substrates by using the polystyrene (PS) nanosphere lithography (NSL) technique and thermal annealing. The results of an investigation on the interfacial reactions between the Ni nanodots and (111)Si substrates after different heat treatments are reported. From the TEM and SAED analysis, only epitaxial NiSi2 nanodots were found to form on (111)Si at a temperature as low as 300 °C. The results indicated that the growth of epitaxial NiSi2 is more favorable for the samples with smaller Ni nanodot sizes. The epitaxial NiSi2 nanodots were found to grow with an epitaxial orientation with respect to the (111)Si substrates: [111]NiSi2//[111]Si and {220}NiSi2//{220}Si. In addition, these epitaxial NiSi2 nanodots formed on (111)Si were observed to be heavily faceted and the faceted edges of the NiSi2 nanodot were identified to be parallel to <1 0>Si directions. On the other hand, during the experiments, the double-layered arrays of PS spheres were occasionally found to form on silicon substrates. The epitaxial NiSi2 nanodot arrays formed from the bilayer masks exhibit larger interparticle spacings and smaller particle sizes. By combining the nanosphere lithography, heat treatments, wet chemical etching and electrodeposition techniques, we also successfully fabricate large-area shape- and size-tunable metal nanostructures (nanobowls and nanopillars) and nanohole arrays on Si and SiGe substrates. The morphology evolution, size uniformity and crystal structure of the produced nanostructures have been systematically investigated by SEM, AFM, TEM, and SAED analyses. The observed results present the exciting prospect that with appropriate controls, the colloidal NSL technique promises to offer an effective and economical patterning method for fabrication of a variety of well-ordered nanostructures with selected shape, size, and periodicity on different substrates without complex lithography. |
