Ionized Cluster Beam Technique for Thin Film Deposition

Abstract

The ionized cluster beam (ICB) technique can be classified as an ion-assisted technique for film formation, and it has the feature of transferring low energy and equivalently high current beams. The clusters can be created by condensation of supersaturated vapour atoms produced by an adiabatic expansion process. These clusters are large size macro-aggregates of 100–2,000 atoms formed by pure expansion of vapourized solid state materials. The clusters are first partially ionized by an electron impact, then the kinetic energy can be added to the ionized clusters. The ICB has unique capabilities of film deposition due to cluster properties and its low energy ion beam transport in a range from thermal energy to a few hundred eV, with the ability to use the effective influence from the ions without space charge problems. This allows high quality deposition and epitaxy of materials at low temperature onto a wide variety of substrates and even permits the formation of thin film materials not previously possible.