Ar射频放电特性随时间演化的PIC／MCC模拟

PIC/MCC simulation of RF-discharge plasma

采用等离子体粒子模拟方法(PIC/MCC)方法对一维模型模拟了容性耦合等离子体(CCP)源放电过程中等离子体的动力学行为。在模拟氩气放电的过程中,综合考虑了电子与Ar之间的弹性碰撞、激发、电离以及Ar与Ar+之间的弹性碰撞和电荷交换过程。由模拟结果可知,射频极板附近鞘层区域在极短时间内形成,其厚度随着时间的增加而增厚;而射频极板处的粒子通量随着时间的增加逐渐减小。经过一段时间后,射频极板处平均粒子通量、平均电流以及鞘层平均厚度逐渐趋于平衡。在鞘层区域电流主要由位移电流构成,在等离子体区域电流主要由传导电流贡献。最后讨论了达到平衡态后等离子体密度、电势、电场强度和能量的空间分布情况。

In this paper, the one-dimensional particle-in-cell/Monte Carlo collision model is used to simulate time evolution of the Ar discharges produced by a single-frequency capacitively coupled reactor, by considering the elastic and inelastic collisions between Ar, Ar＋, Ar＊ and electrons. The results show that the sheath near the powered electrode is formed in a short time and thickness of the sheath increases with the simulation time, while fluxes of the electrons and Ar＋ ions at the powered electrode decrease with increasing time. The flux, potential, current and sheath thickness reach their equilibrium in a few hundred microseconds. The plasma density, potential, electric field and averaged energy are discussed.