氩气浓度对热丝法化学气相沉积纳米金刚石膜的影响

Influence of Ar Concentration on Nano-crystalline Diamond Films Prepared by Hot-filament Chemical Vapor Deposition

采用热丝化学气相沉积方法,以Ar+CH4+H2混合气体作为气源,通过改变氩气浓度,在单晶硅(100)基片上沉积纳米金刚石膜;采用扫描电子显微镜、原子力显微镜、X射线衍射仪和拉曼光谱仪等分析了纳米金刚石膜的形貌、微结构以及残余应力。结果表明:随着氩气浓度的增大,膜的晶粒尺寸逐渐减小到纳米级;由于晶粒细化导致膜内残余应力由拉应力变为压应力,并且压应力随氩气浓度的增大呈现先增大后减小的趋势;当氩气体积分数为98%时,即在贫氢的气氛中成功获得了平均晶粒尺寸为54 nm、均方根粗糙度约为14.7 nm的纳米金刚石膜。

Nano-crystalline diamond （NCD） films were deposited on single crystal Si （100） with Ar＋CH4＋H2 gas mixtures as gas source using hot filament chemical vapor deposition method with different Ar volume fractions. The surface morphology, rnicrostructure and residual stress of the nano-crystalline diamond films were analyzed by using SEM, AFM, XRD and Raman spectrometry. The results show that the grain sizes decreasd to nanometer dimensions with the increase of Ar volume fraction. The film residual stress transformed from the tensile stress to compressive stress due to the grain refining. The residual compressive stress increased first and then decreased as increasing the Ar volume fraction. It was found that NCD films with an average grain size of 54 nm and a roughness of about 14. 7 nm had been successfully synthesized in the poor-hydrogen atmosphere with 98%Ar.