The growth of carbonaceous contamination on surfaces undergoing ion bombardment

The development of carbonaceous polymer films, formed by the ion bombardment of surface adsorbed hydrocarbon molecules, is examined, and simple expressions describing the film growth are derived. The mean residence time of typical hydrocarbon molecules is shown to be several orders longer than inferred from earlier work, and the polymerization cross-section is found to be comparable to the projected molecular area. Methods are discussed for minimizing contamination build-up on surfaces undergoing ion bombardment. (author)