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2000
Conference Paper
Titel
Plasma activation for directed vapor deposition - a new application for hollow cathode arc plasma
Abstract
In Directed Vapor Deposition (DVD) process metals or compounds will be evaporated with high rates by EB in reactive or non-reactive way. The vapor is entrained and conveyed towards the substrate by a supersonic jet exceeding deposition rates of 100 nm/s. The jet concentrates the vapor in a localized stream with very small opening angle. To overcome the restriction of low material density and columnar structure, which is demanded for certain applications or certain layers in layer stacks, an effective plasma activation for DVD coating was requested. Resulting demands on the plasma source are accordingly: - High plasma density to provide a high degree of ionization in the very dense vapor and jet gas atmosphere. - Plasma source has to be viable in the pressure range between 1 and 100 Pa. - Plasma has to be localized to match the spread of the vapor gas jet. - The charge carrier loss by jet stream must not disable the plasma function. It has been found all these demands can be fulfilled successfully by hollow cathode arc plasma discharge containing a low voltage electron beam (LVED). For coating of nonconductive layers on conductive layers additional pulsed bias applied to substrate is suited for periodical negative upcharging the surface to be coated.