Low energy light ion sputtering of metals and carbides

Abstract

For a great number of ion-target combinations similarities in low energy sputtering have been found. ¹¹Near the threshold energy for sputtering E _th, the energy dependence of the sputtering yield can be written as S = Y (E/E _th)^1/4 (1 – E _h/E)7/2, E _th and Y depend only on the surface binding energy E _B and the ion-target atom mass ratio. Using this relation the energy dependence of the sputtering yield of B₄C, SiC, TiC, TaC, WC is compared with the yields from S, Si, Ti, Ta, W, for H, D and He in the energy range of 50 eV to 8 keV. A strong similarity of the energy dependence, i.e. E_th , and Y, can be found between the carbide and the heavier component of the compound. This leads to the assumption, that the target surface is depleted of the light component due to preferential sputtering and the sputtering process is dominated by the heavy component.