在不同超奈米鑽石薄膜核層上成長微米晶鑽石薄膜之特性研究
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2011
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鑽石具有優異之物理、化學、機械性質，所以鑽石膜之合成為目前熱門之研究課題，鑽石薄膜具有好的電子場發射特性，適於製造場發射器。而化學汽相沉積法(Chemical Vapor Deposition, CVD)已被應用於成長鑽石薄膜。在這項研究中，我們使用微波電漿輔助化學汽相沉積法(Microwave Plasma Enhanced Chemical Vapor Deposition, MPECVD)成長鑽石薄膜，探討在不同超奈米晶鑽石薄膜上成長微米晶鑽石薄膜的生長機制與微結構特性研究。在獲得好品質鑽石薄膜，我們使用拉曼光譜儀，場發射掃描電子顯微鏡（SEM）與電子場發射設備 (EFE)與可見光發射光譜儀(OES)，穿隧式電子顯微鏡(TEM)分析鑽石薄膜結構特性，並對其成長機制進行探討。在甲烷/氬氣電漿中可成長2-10 nm的超奈米鑽石結構。在甲烷/氬氣電漿中加入氫氣成長超奈米鑽石薄膜，隨時間與氫氣流量增加，大晶粒比例增加，起始電場值增加；然後，接著進一步在改變H2含量與時間所鍍成之不同超奈米鑽石薄膜核層上，再固定最佳化的相同鍍膜參數來成長微米晶鑽石薄膜，發現所成長MCD/UNCD1薄膜90 min，在電子場發射中起始電場值可自19.00 V/μm下降到10.50 V/μm，可能由於MCD/UNCD晶粒上和周圍形成奈米鑽石晶粒，導致晶界密度提高。
Diamond has excellent physical, chemical, and mechanical properties, etc.. So, the syntheses of diamond films are the hot research topics. The diamond films have good field emission properties and are suitable for the application to the field emission devices. The chemical vapor deposition (CVD) has been applied to grow diamond films. In this study, in order to understand the growth mechanism and the microstructure characteristics, we used microwave plasma enhanced chemical vapor deposition (MPECVD) technique to grow different ultrananocrystalline diamond (UNCD) thin films as nuclear layers for fabricating microcrystalline diamond (MCD) thin films. In order to investigate the as deposited good quality diamond thin films, we used Raman spectroscopy, field emission scanning electron microscopy (SEM), electron field emission (EFE) technique, optical emission spectroscopy (OES), and transmission electron microscopy (TEM) to analyze characteristics of MCD/UNCD thin films, and discuss their growth mechanism. The UNCD structure of ultra-nanoparticles with grain size 2–10 nm can be grown in the methane / argon plasma. The growth and properties of UNCD thin films have been changed profoundly by adding hydrogen. The increase of hydrogen flow rate and deposition time has enhanced the proportion of large diamond grains. This leads to the increment of turn-on electric field. However the decrease from 19.00 V/μm to 10.50 V/μm for turn-on electric field of microcrystalline diamond thin films grown on various as deposited nuclear layers of ultrananocrystalline diamond thin films has been observed. This is presumably ascribed to the increase in the grain boundary density of nanocrystalline diamonds formed on or around the grains of MCD/UNCD .
Diamond has excellent physical, chemical, and mechanical properties, etc.. So, the syntheses of diamond films are the hot research topics. The diamond films have good field emission properties and are suitable for the application to the field emission devices. The chemical vapor deposition (CVD) has been applied to grow diamond films. In this study, in order to understand the growth mechanism and the microstructure characteristics, we used microwave plasma enhanced chemical vapor deposition (MPECVD) technique to grow different ultrananocrystalline diamond (UNCD) thin films as nuclear layers for fabricating microcrystalline diamond (MCD) thin films. In order to investigate the as deposited good quality diamond thin films, we used Raman spectroscopy, field emission scanning electron microscopy (SEM), electron field emission (EFE) technique, optical emission spectroscopy (OES), and transmission electron microscopy (TEM) to analyze characteristics of MCD/UNCD thin films, and discuss their growth mechanism. The UNCD structure of ultra-nanoparticles with grain size 2–10 nm can be grown in the methane / argon plasma. The growth and properties of UNCD thin films have been changed profoundly by adding hydrogen. The increase of hydrogen flow rate and deposition time has enhanced the proportion of large diamond grains. This leads to the increment of turn-on electric field. However the decrease from 19.00 V/μm to 10.50 V/μm for turn-on electric field of microcrystalline diamond thin films grown on various as deposited nuclear layers of ultrananocrystalline diamond thin films has been observed. This is presumably ascribed to the increase in the grain boundary density of nanocrystalline diamonds formed on or around the grains of MCD/UNCD .
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微波電漿輔助化學汽相沉積法, 超奈米晶鑽石薄膜, 穿隧式電子顯微鏡, MPECVD, UNCD, TEM