驱动电流密度对低压容性射频鞘电势及离子动能的影响

研究了离子轰击被加工材料表面的能量与射频驱动电流密度之间的关系，在Lieberman的低压容性射频等离子鞘模型基础上，考虑Bohm速度对应的鞘前电势差，将鞘前电势差与Lieberman的鞘内电势合并，发展了Lieberman的模型，并推出了总电势差与驱动电流密度的关系式，利用总鞘电势差计算了经时间平均的鞘电场加速后离子获得的动能，由于鞘电势差和平均离子动能及其增幅随电流密度的增加而增加，因此射频驱动电流密度对鞘电势差及平均离子动能起激励作用，通过实验，测量了时间平均鞘电势差及驱动电流密度值，实验结果与理论结果吻合较好，因此验证了理论分析的正确性。

Effect of Driving Current Density on Low-Pressure Capacitive Radio Frequency Plasma Sheath Potential Difference and Ion Kinetic Energy

The relation between the ion impinging kinetic energy on the material surface and the driving radio frequency(RF)current density is investigated.Based on Lieberman's low-pressure capacitive RF plasma sheath model,the presheath potential drop corresponding to Bohm velocity is considered and combined with the inner sheath potential to develop the mentioned model.The relation between total potential difference and driving RF current density is derived and is utilized to calculate the average ion kinetic energy after the acceleration of time-average total sheath potential difference.With the increasing driving current density,both the sheath potential difference and the average ion kinetic energy are enhanced.Therefore,the RF driving current density plays an impelling role on sheath potential difference and average ion kinetic energy.The experimental results of time-average sheath potential difference versus RF driving current density demonstrate a fine agreement with the analytical model and verify the validity of the theoretical(analysis.)