184.108.40.206 Temperature dependence of the sputtering yield
This chapter explains the energy dependence of sputtering yield. The sputtering yield, i.e. the number of removed atoms per incoming particle, reaches a maximum at energies in the keV range and decreases at higher energies, while the production of atomic defects in the bulk is steadily increasing with energy above the displacement energy. The decreasing yield at higher energies is ascribed to the increasing penetration of the incoming particle and the simultaneously reduced energy deposition in the surface region. The chapter talks about dependence of sputtering yield on crystal orientation. The sequence of threshold energies for sputtering of Ag and Cu by Ar+ is the same as that of calculated surface binding energies. The same sequence of sputtering yields of low indexed lattice directions as for copper are observed for Ag and Au. Dependences of sputtering yield on angle of incidence as well as angular and energy distribution of the sputtered atoms are complex. The effect of target temperature on sputtering yields is generally small for temperatures not too close to the melting point. This indicates the weak temperature dependence of the basic collision processes. Temperature sensitive recombination and clustering processes, which cause the strong temperature dependence of defect production in the bulk, have no effect on the sputtering yield as the sputtered atoms leave the specimen.