KINETICS OF MICROCLUSTERS IN NONEQUILIBRIUM PLASMA MAGNETRON SPUTTERING

The kinetics of niobium microcluster formation in a magnetron sputteri ng system with an argon pressure of similar to 0.2 to 0.5 Torr have be en investigated. The electromagnetic boundary conditions strongly infl uence the condensation processes of the sputtered particles. The sputt ering yield is a function of the electric field in the negative-glow r egion. Momentums and energies of particles extracted from the sputteri ng chamber were analyzed by using a magnetic field deflector and a ret arding-potential energy analyzer. From these quantities, particle dens ity distributions in the space of mass and velocity were estimated. Th e results showed the following features of the nonequilibrium plasma s ystem: (1) densities of particles increase in the low-velocity region because of the thermalization process, (2) three distributions of clus ters exist and the cluster with the highest velocity shows a clear mas s dependence, (3) positively charged particles exist widely in the low -velocity region. The kinetics of the microclusters were clarified by analysing the mass dependence of the most-probable speed.