Two-dimensional fluid simulation of spatial distribution of dust particles in a capacitively coupled silane plasma

In this work, we develop a two-dimensional fluid model to study the spatial density distributions of dust particles in a radio frequency capacitively coupled silane plasma. Unlike those scenarios based on the one-dimensional fluid model, in this work, the nonuniformity of the radial density distributions of dust particles is attributed mainly to the radial components of the electric field force and the ion drag force acting on the dust particles, leading to the two local density peaks near the electrode edges. It seems that dust particles tend to overcome the support of the electric field force and move much closer to the electrodes, as one of the density peaks indicates. Moreover, with the decrease of the radii of the discharge electrodes or the distance between them, the radial component of the ion drag force is enhanced, resulting in more dust particles gathering near the electrode edge region, and forming a ring-shaped particle density distribution. In the case of the discharge electrodes wrapped with dielectric materials, the uniformity of the radial density distributions of dust particles between the two electrodes is improved. Finally, the vortex motion of a single dust particle near the electrode edge region is also simulated in this work.