以新穎之微波電漿束化學氣相沈積法進行奈米碳管及鑽石膜之圖案成長

Patterned Growth of Carbon Nanotubes and Diamond Films by a Novel Microwave Plasma Jet CVD System

廖國材(Guo-Tsai Liau)

指導教授 ： 林啟瑞 ； 蘇春熺

國立臺北科技大學/機電學院/製造科技研究所/碩士(2006年)

https://doi.org/10.6841/NTUT.2006.00321

摘要

利用天線引導微波之微波電漿束化學氣相沉積系統是一種開發中的成長鑽石膜及圖案式奈米碳管的技術。本研究突破系統設計上的困難，利用自組裝的微波電漿束化學氣相沉積 (Microwave Plasma Jet Chemical Vapor Deposition, MPJCVD)成功地成長鑽石薄膜及奈米碳管，且利用獨特的選擇性區域成長技術成功的於圖案區域成長奈米碳管及鑽石薄膜。微波電漿束化學氣相沈積法的原理係以高溫電漿噴流解離通入之甲烷、氫氣、與氮氣等氣體，進行氣相沉積。此微波電漿束具有高密度電漿之優點，因而可改善傳統微波電漿密度分佈不均之問題。本研究所用之電漿束大小約為1 cm3。

本研究分別使用射頻磁控濺鍍金屬鐵觸媒及溶膠凝膠法製備鐵觸媒於基板上，此兩種製備觸媒的方式皆可成長出高準直性的奈米碳管，而濺鍍法製備者，其奈米碳管的成長速率較慢，可能是因為其觸媒活性較差的緣故。此外，本研究對矽晶片基材以鑽石粉末配合超音波震盪進行前處理，成長鑽石膜藉由不同製程參數之調整，可成功地合成出晶粒大小達微米級及奈米級的鑽石薄膜。

使奈米碳管成長於特定圖案區域內的關鍵在於使觸媒佈置於該特定區域內。本研究使用的第一種方式為噴墨列印技術，係將溶膠凝膠法製得之奈米鐵觸媒溶液裝填於市售之噴墨印表機的墨水匣內，使觸媒依照電腦設計之圖案噴塗於矽或銅等基材上，用以成長奈米碳管，其中噴塗之最小圖案尺寸為50μm。本研究藉此使奈米碳管成長於各個直徑為100μm之圓點內，因而形成陣列。使用場發射電子分析儀量測該碳管陣列的場發射性質發現其起始電場為2.25 V/μm。本研究方法是使用阻障層輔助射頻磁控濺鍍系統濺鍍鐵觸媒，使奈米碳管成長於30×40 μm2之矩形圖案內，因而形成陣列。此法所得之碳管陣列式的起始電場可低至1.1 V/μm。至於選區成長鑽石薄膜的關鍵在於提供其成核位置，其中以阻障層搭配各種前處理方式可在特定區域內產生刮痕而提供成核位置，幫助成長鑽石薄膜。實驗結果證明此種方式確實可行且前處理方式以鑽石膏擦拭較容易控制其區域性刮痕的均勻度。

關鍵字

微波電漿束 ； 圖案成長 ； 奈米碳管 ； 鑽石薄膜

並列摘要

This study is made on a microwave plasma jet chemical vapor deposition (MPJCVD) system, which utilizes an antenna to guide generated microwave and is a developing technique to grow diamond films. Such MPJCVD system is a self-designed and self-assembled apparatus and becomes a proven useful tool to grow submicron diamond films in this study. The advantageous concentrated jet of the generated microwave plasma can largely improve the uniformity of plasma density, which is usually an inherent problem in traditional microwave plasma systems. The MPJCVD of this study can provide a plasma jet with a cross-section of about 1 cm3.
Both radio frequency magnetron sputtering and sol-gel methods were used to prepare necessary iron catalysts for successfully growing high-aligned carbon nanotubes (CNTs). The sputtered catalysts were shown to cause a slower growth rate of CNT, compared with those sol-gelled ones. On the other hand, silicon substrates were pretreated with ultrasonic-energized diamond powders in this study in order to grow diamond films. Microscaled and nanoscaled diamond films were successfully grown, depending on controlled various process parameters of MPJCVD system.
The issue of growing CNTs as patterns is drawn from spreading catalysts into certain designed area. The first method of spreading catalysts in this study is the ink-jet printing process. A catalytic solution made from sol-gel method was firstly poured into the ink cartridge of a commercial jet printer. Such iron catalysts were then print on silicon an copper substrates according to computerized patterns. The minimum pattern size of jet print is nearly 50μm. A array, consisting of 100 μm circular dots, of carbon nanotubes were thus produced by MPJCVD. The second method of spreading catalysts is the mesh shielding process. Iron catalysts were spread on silicon substrates with the aid of a mesh in an RF sputtering system. A array, consisting of 30 × 40 μm2 rectangular dots, of carbon nanotubes were thus produced by MPJCVD. The turn-on voltages of field emission for as-grown CNTs were measured as 2.25 V/μm and 1.1 V/μm for circular dot array and rectangular dot array, respectively.
The provision of nucleation sites is the key to grow diamond films within selected area. Results show that local scratching of diamond pastes with the aid of a shielding mesh is the most efficient way to provide nucleation spots as designed patterns.

並列關鍵字

microwave plasma jet ； patterned growth ； carbon nanotubes ； diamond films

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