Removal of a Thin SiO2 Layer by Low-Energy Hydrogen Ion Bombardment at Elevated Temperatures

Abstract

Low-energy (0.5, 1.0 keV) hydrogen ion bombardment at elevated temperatures (450–500°C) was shown to be useful as a surface cleaning method to remove a thin oxide layer (presumably SiO2) on Si substrates. In situ Auger electron spectroscopy (AES) analysis indicated that the SiO2 layer dissociated under the presence of ion implanted hydrogen at elevated temperatures. Neither hydrogen ion bombardment at room temperature (RT) nor postannealing after the RT ion bombardment had any removal effect regarding the oxide layer. By comparison, He+ ion bombardment, combined with postannealing at 500°C, produced a Si-rich SiOx surface, but the surface oxide could not be removed completely. Consideration of hydrogen and helium ion bombardments indicated that a chemical sputtering effect caused by the ion implanted hydrogen atoms in SiO2 played a significant role in the removal of SiO2.