因奈米碳管（carbon nanotube）具有獨特的準一維結構，且單壁奈米碳管（single-walled carbon nanotube）具有非凡的電子傳輸特性、高熱穩定性、良好的化性及機械穩定性，目前廣泛的被研究應用在各種奈米元件，而這些應用與半導性奈米碳管的特殊電性息息相關，因此本研究中進一步同時控制其碳管之準直性、管徑、以及區域密度並以其臨場製作上閘極奈米碳管電晶體（Top gate CNT field-effect transistors），是克服以往元件無法大面積製作應用上瓶頸之關鍵。
本研究利用Ni/SiO2雙層催化劑結構上層SiO2的鍍率控制奈米碳管的管徑，透過管徑的縮小以取得較高半導性碳管比例，並以高溫化學氣相沉積（thermal chemical vapor depositon）的方式於石英基板上側向成長水平且平行併列的半導性奈米碳管作為電晶體導電層，以此方式高密度且大面積的成長碳管可以改善過往使用單一碳管作為電晶體導電層造成開電流值過小的缺點，並經由氫氣前處理後的碳管製程，藉此通入高氧化還原能力的氣體使催化劑表面的氧化物還原成金屬，並且活化其表面幫助碳管成長，此一改善後的碳管製程能進一步提升了於石英基板上成長奈米碳管的產量和品質，且水平併列的準直性也不會在高密度下出現偏移，所成長的奈米碳管長度可達到50 μm以上。而利用微拉曼光譜分析儀所分析碳管的IG/ID 比值可大於20以上，表示碳管石墨化程度極佳。而改變催化劑上層結構SiO2的鍍率可以得到不同的碳管直徑分佈，藉此控制所製作的水平併列式碳管電晶體的電性表現，量測碳管的直徑範圍及碳管之管徑分佈是利用原子力顯微鏡(AFM)，當SiO2鍍率為1.0 Å/s，碳管平均直徑為1.39 nm；鍍率為0.5 Å/s，碳管平均直徑為1.17 nm；鍍率為0.2 Å/s，碳管平均直徑為1.11 nm。從實驗結果可以得到在雙層催化劑結構的上層SiO2結構的鍍率為0.2 Å/s時，以CVD方式側向成長高品質單壁奈米碳管所製作的上閘極電晶體，在此鍍率下具有良好場效特性的元件佔了整體的88.8％；當上層SiO2結構的鍍率上升到0.5 Å/s時，元件出現良好場效特性佔了整體的47.8％；當上層SiO2結構的鍍率達到1.0 Å/s時，元件出現良好場效特性僅佔了整體的36.8。整體來看，當上層SiO2結構的鍍率逐漸下降時，元件中碳管所表現的半導特性逐漸變得明顯，並且在鍍率下降後，使得高密度且高比例的半導性奈米碳管在電晶體通道間形成並連，而達到高開電流值以及高開關電流比值的元件特性，並且相較於使用奈米碳管溶液旋塗法所製作的成奈米碳管電晶體，更能有效的定位定向高密度奈米碳管。在實驗中選擇使用正光阻進行製作黃光微影能避免碳管在多次lift-off過程損失其品質和準直性，提升整體元件良率，以上閘極結構並配合調整ALD參數所製作的High K介電層相較於背閘極結構的元件設計方式更能避免高漏電流的情況發生。另外從二極量測可以發現退火處理對電晶體電性的影響，因奈米碳管製程後在碳管上可能吸附著許多碳氫有機物，加上電極金屬製作完後在大氣環境中吸附了氧分子，使得所使用的鈦金屬與氧氣分子形成Ti-O鍵結提高了接觸阻抗，元件經過真空高溫退火製程後去除了碳管上的有機物，並使鈦金屬與奈米碳管接觸面形成Ti-C針狀鍵結降低接觸阻抗，使得元件直流電流值提高，增強元件的電流特性。整體而言實驗成功的提升了元件的良率以及調變特性，與國外不同團隊之間的比較更能了解並且實踐奈米碳管在場效電晶體元件上之應用。

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