高气压MPCVD沉积金刚石的光谱研究  

Optical Spectroscopy for High-Pressure Microwave Plasma Chemical Vapor Deposition of Diamond Films

作　　者：曹为[1] 马志斌[1] 

机构地区：[1]武汉工程大学材料科学与工程学院湖北省等离子体化学与新材料重点实验室,湖北武汉430073

出　　处：《光谱学与光谱分析》2015年第11期3007-3011,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(10875093)资助

摘　　要：采用微波等离子体化学气相沉积方法(microwave plasma chemical vapor deposition,MPCVD)在高沉积气压(34.5kPa)下制备多晶金刚石,利用发射光谱(optical emission spectroscopy,OES)在线诊断了CH4/H2/O2等离子体内基团的谱线强度及其空间分布,并利用拉曼(Raman)光谱评价了不同O2体积分数下沉积出的金刚石膜质量,研究了金刚石膜质量的均匀性分布问题。结果表明:随着O2体积分数的增加,C2,CH及Hα基团的谱线强度均呈下降的趋势,而C2,CH与Hα谱线强度比值也随之下降,表明增加O2体积分数不仅导致等离子体中碳源基团的绝对浓度下降,而且碳源基团相对于氢原子的相对浓度也降低,使得金刚石的沉积速率下降而沉积质量提高。此外,具有刻蚀作用的OH基团的谱线强度却随着O2体积分数的增加而上升,这也有利于降低金刚石膜中非晶碳的含量。光谱空间诊断发现高沉积气压下等离子体内基团分布不均匀,特别是中心区域C2基团聚集造成该区域内非晶碳含量增加,最终导致金刚石膜质量分布的不均匀。Polycrystalline diamond growth by microwave plasma chemical vapor deposition（MPCVD）at high-pressure（34.5kPa）was investigated.The CH4/H2/O2 plasma was detected online by optical emission spectroscopy（OES）,and the spatial distribution of radicals in the CH4/H2/O2 plasma was studied.Raman spectroscopy was employed to analyze the properties of the diamond films deposited in different oxygen volume fraction.The uniformity of diamond films quality was researched.The results indicate that the spectrum intensities of C2,CH and Hαdecrease with the oxygen volume fraction increasing.While the intensity ratios of C2,CH to Hαalso reduced as a function of increasing oxygen volume fraction.It is shown that the decrease of the absolute concentration of carbon radicals is attributed to the rise volume fraction of oxygen,while the relative concentration of carbon radicals to hydrogen atom is also reducing,which depressing the growth rate but improving the quality of diamond film.Furthermore,the OH radicals,role of etching,its intensities increase with the increase of oxygen volume fraction.Indicated that the improvement of OH concentration is also beneficial to reduce the content of amorphous carbon in diamond films.The spectrum space diagnosis results show that under high deposition pressure the distribution of the radicals in the CH4/H2/O2 plasma is inhomogeneous,especially,that of radical C2 gathered in the central region.And causing a rapid increase of non-diamond components in the central area,eventually enable the uneven distribution of diamond films quality.

关 键 词：高气压微波等离子体 CVD金刚石膜 发射光谱 拉曼光谱 均匀性 

分 类 号：TQ164.8[化学工程—高温制品工业]