射频负偏压等离子体鞘层流体动力学模拟

Simulation of rf-Biased Plasma Sheath Using Hydrodynamic Method

采用流体动力学方法建立了一种自洽的无碰撞射频直流偏压等离子体鞘层动力学模型.模型中考虑了极板直流负偏压对离子运动的影响,模拟了在不同偏压条件下射频等离子体鞘层内各参量的时空演化特性.在该模型中,认为鞘层厚度是与时间有关的函数,并采用等效电路模型建立了鞘层瞬时厚度与鞘层电位降的关系.模拟结果表明,极板上电势呈非正弦周期性变化;鞘层厚度变化与极板电势变化周期相同,趋势相反,且略滞后于射频周期.

A self-consistent fluid model was developed describing the spatiotemporal characteristics of parameters in the radio-frequency plasma sheath under DC bias without molecule collision, considering the effect of DC negative bias of electrode on ion motion. In the model, the thickness of the sheath was regarded as a function of time, and the relationship between the instantaneous sheath thickness and potential drop of sheath was established by an equivalent circuit model. Simulation results showed that the electrode presents a cyclically non-sinusoidal potential. The variation cycles of both sheath thickness and potential of electrode are the same in opposite trends, and they lag slightly behind radio-frequency cycle.