Electron-stimulated desorption of negative O− ions from the oxidized O/Ru surface

This paper reports on a study of the electron-stimulated desorption of negative oxygen ions from the O/Ru surface, which represents an additional factor responsible for the destruction of the protective oxide layer of the mirrors used in ultraviolet lithography. The cross section of degradation of the O/Ru layer due to the electron-stimulated desorption of the O+ and O− ions and the O atoms has been found to be 1.6 × 10−19 cm2. A comparison of the dependences of the electron-stimulated desorption yield of O+ and O− ions on the incident electron energy E with the ionization cross section of the adsorbate core level σ O2s (E) has revealed that the ionization of the O 2s level is the main channel of the electron-stimulated desorption of O− ions.