Effects of Carbon Contaminations on Electron-Induced Damage of SiO2 Film Surface at Different Electron Primary Energies

Dependence of the electron-induced damage of the clean and carbon-contaminated SiO2 film surfaces during the Auger electron spectroscopy measurement was investigated under irradiation of electrons at different primary energies. The variation in the intensity of the Si-LVV elemental peak with the increase in the electron dose was measured and analyzed within the scheme of the two-step decomposition model [J. Surf. Sci. Soc. Jpn. 25, 212 (2004) (in Japanese)]. The results clearly revealed that the speed of the decomposition of SiO2 induced by the electron irradiation is decreased by a small amount of carbon contaminations of ~0.03 nm thickness on the SiO2 surface. The effects of carbon contaminations on the reduction in the electron-induced degradation of SiO2 is significant for the low-primary energy of electrons of 3 keV, and no effects were confirmed at the primary energy of 15 keV. These findings suggest that the primary energy dependence is attributed to the fact that interactions between primary electrons and atoms in the near surface region is much significant when primary electrons with the lower primary energy are irradiated.