Secondary Ion Emission from Si Subjected to Oxygen Ion Bombardment

Abstract

The secondary ion yields and energy distribution of positive ion species sputtered from an Si surface under O+2 ion bombardment were measured using UHV-SIMS. The SIMS spectra obtained contained peaks due to the following cluster ion species; Si+, SiO+, Si+2, Si2O+, SiO+2, Si2O+2 and Si2O+3. The secondary ion yield was found to exhibit a depend on the primary ion energy. The secondary Si ion yield increased gradually with increasing energy, but the secondary cluster ion yield first increased and then decreased gradually through a maximum at an energy of 10∼15 keV. The most probable energies of cluster ions such as Si2O+ and Si2O+3 were also found to vary with the primary ion energy. The FWHM values in the energy distributions decreased linearly with increase in the mass of the sputter ion species, while the tail factor decreased with the mass of the cluster ions.