ROLE OF KINETIC-ENERGY OF SPUTTERED PARTICLES IN THIN-FILM FORMATION

Attempts have been made to clarify the effect of kinetic energy of depositing particles on the properties of sputtered films. Two sputter deposition methods for preparing alloy films were examined: co-sputter deposition with multiple elemental targets (co-sputtering) and sputter deposition with a single alloy target (alloy sputtering). First, energy distributions (EDs) of sputtered ions from elemental nickel, silicon and boron targets and also those from an amorphous Ni-Si-B alloy target were measured with an ultrahigh vacuum secondary ion mass spectrometry system. By comparing the obtained EDs of the same ion species from the different source materials, it was found that the most probable energy E(m) and the average energy E(a) of the ions emitted from the alloy target were lower than those emitted from the elemental targets. Second, changes in surface morphology of the film prepared by co-sputtering were more uniform in comparison with those of the film prepared by alloy sputtering which exhibited strong contrast in the transmission electron micrograph. The difference in the morphologies could be primarily explained in terms of the difference in the EDs of the sputtered particles.