Evaluation of coatings produced by low-energy ion assisted deposition of co on silicon

Abstract

Ion assisted deposition (LAD) is a commonly used technique in modem surface modification treatments. Ever since the introduction of LAD (IBAD) methods it has been debated whether the low-energy ion beam, intended for the formation of dense coatings on surface, can also cause ion mixing, how it can influence incorporation of admixtures into thin films and on the growth of films under variable ion-to-atom ratios and deposition rates. The purpose of this study is to determine the influence of 200 and 500 eV Ar– ion beams on the evolution of Co coatings formed on Si by means of IAD, when the ion-to-atom ratio and deposition rate were varied in the intervals of 0.1–0.9 and 3.4–10.2x10^14 at/(cm^2s) respectively. The composition of the thin films produced by the IAD technique has been investigated using Rutherford back scattering of 2.0 MeV He ions. The thickness of the Co layers deposited on Si exhibited major dependencies on ion-to-atom ratio. This decreases with increase of this ratio. The relative amount of argon captured into coatings was two to three times more when the energy of assisting ions increases from 200 to 500 eV. A minor mixing effect is observed in an interface region at both energies applied for IAD. A quantitative evaluation of ion irradiation effects during low-energy IAD of Cobalt on Silicon is given.