蒙特卡罗模拟金刚石薄膜化学气相沉积过程中甲烷浓度的影响

本工作采用蒙特卡罗模拟,研究了以CH4/H2气体混合物作为源料气体的电子辅助热丝化学气相沉积中甲烷浓度对气相沉积过程的影响.计算了典型实验条件下电子能量分布,研究了电子平均能量、碎片H及CH3数目的空间分布、H与CH3的比值及CH3携带的能量随甲烷浓度的变化.结果表明:当电子能量为2-3eV时,电子的数密度达到一峰值;平均电子能量随着甲烷浓度的增加而增加;电子与气体分子碰撞产生的碎片H、CH3和CH2的数密度随距热丝的距离而变化;随着甲烷浓度的增加,原子氢H的数目缓慢下降,然而,官能团CH3和CH2的数目缓慢上升;H与CH3的数量比随甲烷浓度的增加而减少;碎片CH3携带的能量处于1～5eV范围之内,且当甲烷浓度为1.3;时,该能量达到一最值.

Effect of Methane Concentration on Process of Chemical Vapor Deposition of Diamond Film by Monte Carlo Simulation

The effect of methane concentration on electron assisted chemical vapor deposition from mixture of methane and hydrogen was investigated by Monte Carlo simulation. Energy distribution of electrons under the typical experimental condition was simulated. Variations of average energy of electrons, space distribution of fragments H and CH_3, the ratio of H to CH_3 and the mobility energy of CH_3 with the methane concentration were studied. The results show that there is a peak value of electron number density when the electron energy is within the range of 2-3eV. The average energy of electron increases with increase of methane concentration. The number density of H,CH_3 and CH_2 depends upon the distance from hot filament.With increase of methane concentration, the number of -H decreases slowly, while the number of CH_3 and CH_2 increases slowly. The ratio of H to CH_3 decreases with increasse of methane concentration. The energy of CH_3 is in the range of 1-5eV. The energy of CH_3 reaches a maximum when the methane concentration is 1.3%.