- 學位論文
在氮氣電漿中添加氮氣對超奈米微晶鑽石薄膜微結構生長 在氮氣電漿中添加氮氣對超奈米微晶鑽石薄膜微結構生長的影響
Effect of N2 addition in Ar plasma on the development of microstructure of ultra-nanocrystalline diamond films
摘要
奈米微晶鑽石(UNCD)薄膜因兼具良好的物理化學性質及平坦的表面，適合於電子元件的應用，且具有負電子親和力的特性。 本實驗藉由微波電漿輔助化學氣相沈積法 ( MPECVD )成長氮氫共同摻雜成長鑽石薄膜，在不同氣氛在矽基板上成長UNCD後發現，在沉積UNCD的條件下，由於氣氛中的氮氣及氫氣的不同成長條件，使得成長鑽石膜時的微結構明顯產生變化，進而研究改變氫氣及氮氣流量對場發射性質的影響以及改變氫氣流量對鑽石晶粒大小的影響。藉由拉曼的量測、SEM、場發射的量測及可見光光譜量測等來分析，其微結構和場發射的影響。本實驗最佳數據為:當氫流量8sccm和氮流量20sccm時，有最佳的場發射特性，最低起始電場5.78 V/μm。 在不同氫氣流量時，因為氫氣會蝕刻二次再孕核點，以及選擇性蝕刻SP2鍵結，可發現晶粒大小的改變，在氫流量為零時，鑽石晶粒大小約為20-50nm，隨著氫流量增加，鑽石晶粒有變大，至於氮氣的流量的改變對鑽石晶粒沒有明顯的影響，且晶粒的大小與表面形貌對電子場發射特性有顯著的影響。
並列摘要
The ultra-nanocrystalline diamond films (UNCD) posses marvelous physical &Chemical properties and have been widely investigated. The incorporation of N2 into reaction gas has been reported to effectively increase the conductivity of the materials and enhanced the electron field properties (EFE) of these films. The characteristics of The UNCD films, however, were pronouncedly affected by their microstructure, which, in turn, was intimately correlated with the constituents in plasma. In this study, we systematically investigated the effect of the plasma, the H2/N2/Ar rate, on the characteristics, especially the EFE behavior, of the UNCD films. It is found that, while the UNCD films grown in Ar plasma contain ultra-small grain size (~5 nm), incorporation of H2 or N2 into the plasma monotonously increased the size of the grains. Moreover, it modified profoundly the morphology of the UNCD grains, from equi-axed geometry to plate-like one. The optical emission spectroscopic investigation indicated that the induction of the CH-band due to the addition of H2 and the CN-band due owing to the addition of N2 into Ar plasma is the main cause, which alters the Raman structure and microstructure of the UNCD films. How the change in the OES altered these characteristics of the UNCD films will be discussed.