Dependence of secondary ion emission on the mass of the bombarding ions (Z1-dependence)

Abstract

The results of measurements of the positive secondary‐ion yield S+ and the sputtering efficiency γ at a primary‐ion energy of 12 keV under dynamical conditions are reported. He+, Ne+, Ar+, Kr+, and Xe+ions served as bombarding ions (Z1‐dependence). 14 elements are investigated (Z2‐dependence), and the sputtering yields S were added wherever they were available from the literature. The positive secondary ion yield decreases with increasing mass of the bombarding ions. Using the values of S, S+, and γ as functions of Z1 and Z2, the Schroeer model of adiabatic surface ionization is examined and the exponents n are determined by a quotient method. The different dependences of S and S+ are discussed on the basis of this model.