等离子体发射光谱学是探究等离子体参数、等离子体基团分布的有效工具。利用发射光谱技术对CH4/H2微波等离子体进行原位在线测量，研究了微波等离子体气相沉积过程中等离子体内部的基团种类以及甲烷体积分数对等离子体中各基团谱线强度的影响,测量分析了等离子体中各基团的空间分布以及甲烷体积分数对空间分布的影响。结果表明，C2基团的发射光谱强度随甲烷体积分数的升高而迅速增强，CH、Hβ、Hγ与C2相对强度的比值随甲烷体积分数的增加而降低，并逐步趋于饱和；各基团空间分布的均匀性随甲烷体积分数的增加而变差。

Optical emission spectroscopy is an effective tool to measure plasma parameters and species distribution in plasma. Optical emission spectroscopy is used to measure the microwave plasma of CH4/H2 in situ. The internal radicals, the influence of methane volume fraction on radical emission intensity, and spatial distribution of the radicals and the influence of methane volume fraction on the spatial distribution in MPCVD plasma are investigated. The results show that the optical emission intensity of C2 in plasma increases with the methane volume fraction increasing obviously. Intensity ratios of CH, Hβ, Hγ to C2 reduce with increasing methane volume fraction. The spatial distributions of the radicals especially of C2 become inhomogeneous with the methane volume fraction increasing.