Study of fluorine contamination on MgO(100) surfaces

The fluorine contamination on MgO(100) surfaces is studied using Electron Stimulated Desorption (ESD) and Auger Electron Spectroscopy (AES). While Ar+ ion sputtering is very effective to clean the carbon contamination on the surface, the fluorine content does not significantly decrease. Thermal treatments of the sample considerably increase the F surface concentration due to its diffusion from the bulk to the surface. Heating the sample at 700 K simultaneously with H2O exposure produces a decrease in the fluorine signal. The ion kinetic energy distribution of the F+ ion shows two peaks at 2.4 and 5 eV. The threshold energy of the F+ ion desorption is at 60 eV.