Emission mechanisms of titanium oxide ions during sputtering

By cesiating an oxygenated titanium surface, the work-function dependence of the sputtered atomic and oxide-ion yields during 500-eV ${\mathrm{Ne}}^{+}$ bombardment were measured. The experimental data indicate that the negative titanium oxide ions are formed mostly by the fragmentation of the surface lattice while the positive oxide ions, especially at low oxygen coverages, are probably formed primarily by the recombination of the sputtered atomic ions and neutrals.