IONIZATION IN PLASMA-ASSISTED PHYSICAL VAPOR-DEPOSITION SYSTEMS

In this paper we discuss recent developments in plasma-assisted physic al vapour deposition processes, extending on earlier work, and emphasi zing the characteristics of the various enhanced ionization systems. T he non-uniform natures of the ion and vapour distributions in these sy stems are discussed in the context of theoretical models and empirical studies covering these effects. The ionization efficiencies of the su ccessful commercial systems are shown to be over 3.5%, although cautio n is necessary in determining the location of samples relative to sour ces which themselves enhance ionization, such as the unbalanced magnet ron or arc source, as inhomogenous or ''beamy'' plasmas can be generat ed with consequential ionization variations. Nevertheless, with approp riate equipment design full-scale mass production of coated components can be achieved.