射频等离子体鞘层动力学模型

在流体力学方程的基础上建立了一种自洽的无碰撞射频等离子体鞘层动力学模型.这种自洽性包含两个方面:一方面,由于考虑了瞬时鞘层电场对离子运动的影响,因此该模型适用于描述任意频率段的射频鞘层演化过程;另一方面,在模型中采用等效电路方法来自洽地确定极板上的瞬时电位与瞬时鞘层厚度之间的关系.采用数值方法模拟出鞘层的瞬时厚度及极板的瞬时电位变化、鞘层内离子密度和电场强度等物理量的时空变化.结果表明,当射频场的频率小于或等于离子等离子体频率时,离子流密度明显地随时间变化 关键词： 射频 离子 鞘层 流体力学

DYNAMICAL MODEL OF THE RADIO-FREQUENCY PLASMA SHEATH

A self-consistent model for the dynamics of the capacitive radio-frequency (RF) plasma sheath driven by a sinusoidal current source is obtained under the assumptions of time-dependent,collisionless ion motion and inertialess electrons. The model consists of fluid equations describing the charge transport in the sheath coupled to an equivalent circuit model of the sheath to predict the characteristics of it at any RF frequency. Some numerical results have been obtained for the instantaneous sheath thickness, the instantaneous voltage and the ion flux density on the substrate, etc. It has been shown that when the RF frequency is less than the ion plasma frequency, the ion flux density will strongly depend on the time.