Plasma and ion sources in large area coating: A review

Efficient deposition of high-quality coatings often requires controlled application of excited or ionized particles. These particles are either condensing (film-forming) or assisting by providing energy and momentum to the film growth process, resulting in densification, sputtering/etching, modification of stress, roughness, microstructure, texture, etc. In this review, the technical means are surveyed enabling large-area application of ions and plasmas, with ion energies ranging from a few electron volts to a few kiloelectron volts. Both semiconductor-type large area (single wafer or batch processing with ∼ 1000 cm2) and in-line web and glass-coating-type large area (> 107 m2 annually) are considered. Characteristics and differences between plasma and ion sources are explained. The latter include gridded and gridless sources. Many examples are given, including sources based on DC, RF, and microwave discharges, some with special geometries like hollow cathodes and E × B configurations.