超奈米微晶鑽石薄膜在場發射元件上的應用與發展

The development and application of the ultra-nano crystalline diamond film in field emission device

劉竣誠(Chun-Cheng Liu)

指導教授 ： 戴念華 ； 李紫原 ； 林諭男

國立清華大學/工學院/材料科學工程學系/碩士(2007年)

摘要

本研究論文的內容，先是探討超奈米微晶鑽石成長在鉬、鎢金屬薄膜
以及鉬、鎢金屬塊材的情形，由於碳原子在各種金屬上的碳溶解度以及擴散係數的不同，可以發現鑽石成長在鎢金屬上比在鉬金屬來得快，沉積在薄膜上比在塊材上來得迅速，最主要的發現在於沉積在鉬、鎢金屬薄膜上會有一層明顯的金屬碳化物的存在，而在塊材上似乎看不到這一層的存在。再來是利用氧電漿蝕刻的方式很乾淨的將鑽石薄膜圖紋化，藉由不同光罩圖形製作出平面以及立體的場發射元件，之後再對圖紋化後的鑽石結構做氫電漿、氬電漿、氮+氧電漿處理，可以清楚看出在氫電漿處理下表面形成碳氫鍵結後，對鑽石的場發射性質有很大的改善，最大電流密度可以高達3400 mA/cm2，也發現鑽石表面碳氧鍵結的形成會大幅度降低鑽石的場發射性質，主要的原因在於碳氫鍵結會提升鑽石的負電子親和力(NEA)，而碳氧鍵結會降低負電子親和力的程度甚至會讓它變成正的電子親和力。平面場發射元件雖然不如預期量測得到場發射性質，但是也確定了常被用來當作絕緣體的氧化矽的絕緣效果。本實驗也用溼蝕刻的方式，搭配鋁膜以及氮化鈦當做犧牲層，選區成長出鑽石薄膜，可以乾淨低去除非鑽石區域而不破壞鑽石圖紋化區域的形狀。

關鍵字

奈米鑽石 ； 場發射 ； 成核

並列摘要

In this work, the ultra-nano crystalline diamond film(UNCD) was grown on the molybdenum(Mo-Si)、tungsten(W-Si) films and molybdenum(Mo-B)、tungsten(W-B) bulks by microwave plasma enhanced chemical vapor deposition(MPECVD). The XRD and XPS analysis showed there is metallic carbide forming in the interface between diamond and metal films. In contrast, there is no metallic carbide forming between diamond and metal bulks.
From SEM measurement, diamond deposited on the W-Si film was faster than on the Mo-Si film. The SEM also showed the grow rate in films are faster than bulks.
Diamond film can be well patterned by dry etching of oxygen plasma. Using Al film be a mask, The diamond film can be pattern to produce 2-D lateral field emitter and 3-D field emitter. After hydrogen plasma treatment, the maximum current density can up to 3400 mA/cm2.XPS analysis also showed the surface of diamond was hydrogenated by hydrogen plasma.
The other way to produce diamond film devices is selective area deposition(SAD). Taking Al and TiN as sacrificial layer, successfully pattern diamond by wet-etching process.

參考文獻

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