Investigation of target erosion profiles sputter-eroded by a low-energy broad ion beam

Abstract

The demand for ion beam sputtering (IBS) coated substrates is growing. In order to find new fields of application for IBS coating technology, it is necessary to understand in detail the distributions of the involved particles in an industrial-scale reactive coating process. In pursuit of this goal, in the present investigation, profiles sputter-eroded from tantalum, silicon, and silicon dioxide targets by a low-energy broad ion beam (ion energy ≤ 1.9 keV, ion source RIM-20) are measured with a mechanical profilometer and compared. To approximate the discrete and two-dimensional erosion data accurately, an empirical function is developed. For an applied target tilt angle of 55°, the results indicate that the actual angle-dependent ion-solid interaction mechanisms at the atomic level have a rather subordinate role in the macroscopic surface modification of the target in terms of the qualitative distribution of the erosion profile. The applied process geometry seems to have a much larger impact. Furthermore, in the case of silicon, a linear erosion rate as a function of erosion time is observed. Thus, the form of the broad erosion profile does not seem to have a measurable effect on the erosion rate.