射频辉光放电CH_4等离子体一维流体动力学模拟

One-dimensional Simulation of RF CH_4 Plasma in a Fluid Model

完整建立一个关于射频辉光放电CH4等离子体的流体动力学模型.模型包括基于迁移-扩散近似的粒子平衡方程、电子能量平衡方程,共包含了20种粒子(环境气体粒子,激发态粒子,离子和电子)和49类化学反应(电子-中性环境粒子、离子-中性环境粒子、激发态粒子-激发态粒子(中性环境粒子)).结果表明,在强电场区域有较高的电子反应率系数;等离子体中除源气体CH4外,H2,C2H6,C3H8,C2H4和C2H2也有较高的密度含量;激发态粒子中,CH3含量最高,密度约为1019m-3;在较低放电压力时(如18 Pa),CH5+在离子成分中密度含量最高,当放电压力较高时(如67Pa),C2H5+在离子成分中占主导地位;除C2H5+外,其它各离子和激发态粒子在极板上的粒子流量随功率的增大逐渐升高.

A one-dimensional fluid model for RF methane plasma is presented.Equations of particle balance with drift-diffusion approximation for fluxes,and electron energy balance are solved.Totally 20 species（neutrals,radicals,ions,and electrons） are included in the model,as well as 49 reactions（27 electron reactions,7 ion-neutral reactions,and 15 neutral-neutral reactions）.It is found that high electron reaction-rate occurs at high electric-field region.Besides inlet gas CH4,neutral gases H2,C2H6,C3H8,C2H4,and C2H2 also show high densities in the plasma.The main radical in plasma is CH3,with a density of about 1019m-3.At low pressures（e.g.,18Pa） the most important ion is CH＋5.At high pressures（e.g.,67Pa） C2H＋5 becomes the dominant ion.Radical and ion fluxes towards electrode（except C2H＋5） increase slightly with power.