The damage distributions in Si(1 0 0) surface after 1.0 and 0.5 keV Ar+ ion bombardment were studied using MEIS and Molecular dynamic (MD) simulation. The primary Ar+ ion beam direction was varied from surface normal to glancing angle. The MEIS results show that the damage thickness in 1.0 keV Ar ion bombardment is reduced from about 7.7 nm at surface normal incidence to 1.3 nm at the incident angle of 80degrees. However, the damage thickness in 0.5 keV Ar ion bombardment is reduced from 5.1 nm at surface normal incidence to 0.5 nm at the incident angle of 80degrees. The maximum atomic concentration of implanted Ar atoms after I keV ion bombardment is about 10.5 at% at the depth of 2.5 nm at surface normal incidence and about 2.0 at% at the depth of 1.2 nm at the incident angle of 80degrees. However, after 0.5 keV ion bombardments, it is 8.0 at% at the depth of 2.0 nm for surface normal incidence and the in-depth Ar distribution cannot be observable at the incident angle of 80degrees. MD simulation reproduced the damage distribution quantitatively. (C) 2002 Elsevier Science B.V. All rights reserved.