Energy Distribution Functions of Ions Generated by a Circular-type Anode Layer Ion Source

Abstract

An anode layer ion source, or an ALIS, is classified as a gridless ion source that produces a high-energy ion beam for either surface etching or thin film deposition. In the present work, the energy distribution functions of the ions generated in a circular ALIS were measured using a retarding field energy analyzer (RFA). Consequently, the average density and energy of the ions arriving at the ground surface were determined for the given range of process parameters. The IEDFs show two different groups of ions, namely, a narrow low energy group and a broad high energy group. The low-energy ions are probably generated in the background plasma and accelerated via the cathode sheath adjacent to the RFA. High-energy ions, on the other hand, are possibly generated in the discharge channel and gain an energy of up to 0.7eVanode through the anode sheath. The variations in average ion energies and densities as a function of process conditions could be due to the potential profile between the source and the ground surface.