The feasibility of grazing angle sputtering for removal of a surface layer to improve depth resolution of high resolution Rutherford backscattering spectroscopy (HRBS) is examined. A Si(001) wafer with a SiO2 layer of thickness 4.5 nm is irradiated by 0.5 keV Xe+ ions at a grazing angle of 15degrees. The wafer is investigated in situ by HRBS. After removal of a part of SiO2 layer by the grazing angle sputtering, the observed Si step at the SiO2/Si interface in the HRBS spectrum becomes slightly sharper than the virgin sample, indicating that the grazing angle sputtering is useful for improvement of depth resolution in a deeper region. (C) 2004 Elsevier B.V. All rights reserved.