The Study On Particles Transport Characteristics In A RF Plasma Sheath

In order to understand the law of spatiotemporal profiles and transport characteristics of the physical quantity in plasma, study theoretically the physical and chemical mechanism in the gas discharge, offer the best technological parameter in obtaining the film of good quality, and support technically the improvement of the technique in etching or filling of material, the movement of the particles in the radio frequency (rf) plasma discharge are investigated. In plasma, the sheath plays a crucial role in controlling the movement of the charged particles towards the electrodes (or the target). The ion energy distribution (IED) and the ion angular distribution (IAD) at the electrode are affected by the collision and movement of the particles in the sheath, and this is important in film fabrication and ion etching. In this article, with a self-consistent fluid model, we study the transport characteristics of the rf sheath in low pressure, high density plasma, and a Monte Carlo (MC) method is applied to calculate the IAD at the electrode. We present the spatiotemporal variations of the voltage amplitude, the ion density and the electron density inside the sheath. Furthermore, we study the effects of various rf frequency on the voltage at the electrode, the sheath width, the IED and IAD impinging on the rf-biased electrode. It is found that the IED at the electrode merges into a single peak when the rf frequency increases. The incident angles of ions impinging on the electrode are small angles and the IAD turns narrower with increasing of the rf frequency. The IED and IAD are affected by changing plasma densities, rf-bias powers and electron temperature. Therefore, plasma etching anisotropy can be improved by increasing rf frequency or rf-bias power.