控制電漿位置以成長類鑽奈米尖錐

Deposition of Nano Diamond-like Tip by Plasma Position Controlling

10.6409/JMSE.200303.0031

林啓瑞(C. R. Lin)；周上智(S. C. Chou)；洪新欽(H. C. Hung)；許庭瑋(T. W. Hsu)

微波電漿化學氣相沉積 ； 電漿鞘 ； 類鑽碳尖錐 ； 電位降 ； Microwave Plasma Chemical Vapor Deposition ； Plasma sheath ； Diamond-like carbon tip ； Potential drop

材料科學與工程

35卷1期（2003 / 03 / 01）

31 - 35

繁體中文

由於類鑽碳(DLC)膜具有優於鑽石膜的良好場效發射特性，且可製作成圓錐或方錐狀，因此具有特殊尖端放電特性，所以一直是場效發射元件的研究重點。本研究利用微波頻率為2.45GHz之微波電漿化學氣相沈積(MPCVD)系統來沈積奈米尖錐類鑽膜，使甲烷及氫氣的混和反應氣體激發形成電漿與P-type (100)矽晶片相接觸，在不外加任何負偏壓的條件下，利用電漿本身之電漿鞘電位降產生電場，加速帶正電較輕的氫離子對sp^2叢聚及非晶質碳的非等向性蝕刻。此外，其他高能離子、碳氫物種、氫原子基亦會對sp^2叢聚及非晶質碳產生等向性蝕刻，歷經3小時的蝕刻和沈積之交互作用後，成功沈積出奈米尖錐結構之類鑽碳膜。以能量散佈頻譜儀檢測晶片，並未發現過渡金屬元素，證明成長的奈米尖錐類鑽碳膜並非依循一般奈米碳管的成長機制。透過拉曼光譜分析及歐傑電子光譜分析儀，確認所成長膜爲高sp^3鍵結之類鑽碳膜。

Because of diamond-like carbon (DLC) film has better field emission properties than diamond film, and extraordinary electron discharge effect from tip, this DLC film has been widely studied in the arena of field-emission devices. In this study, microwave plasma chemical vapor deposition (MPCVD) system with frequency 2.45 GHz was used for exciting mixing reaction gases of methane and hydrogen to produce plasma bulk. The p-type (100) silicon substrate surface was put to contact with plasma. Without any extra negative bias being necessary, nano-tip diamond-like carbon film with few nano-size diamonds and many sp^3 bonding was successfully deposited in 3 hours by the plasma sheath potential drop method. This introduces an electric field to accelerate positive and lighter hydrogen ions to etch out sp^2 clusters and amorphous carbons anisotropically. Besides, high energy ions, hydrocarbon species and hydrogen are diffused to etch out sp^2 clusters and amorphous carbons isotropically. As-grown film was analyzed by the energy dispersion spectrometer. The result shows that there is no transient metal incorporated in the film. This suggests that the DLC nano-tip grow mechanism is not similar to general grow mechanism of carbon nanotubes. Finally, Raman spectrometer was used for confirming that higher amount of sp^3 bonding is incorporated in the film.