The oxygen ion -beam -induced surface roughening observed during SIMS depth profiling of both Si(100) and 10degrees disoriented Si(100) surface without flooding has been studied by atomic force microscopy (AFM). Facets have been created at the crater bottom and parameters such as RMS (root mean square) roughness, wavelength of the waves and orientation of the facets have been measured. The ripple amplitude increases with the depth of erosion from a critical depth of approximately 2.5 mum for O-2(+) (10-4.5 keV) bombardment. In this paper, we investigate the surface orientation dependence of the roughening in Si(100) and 10degrees disoriented-Si(100). The same transition phase of secondary ion intensities during monitoring of matrix secondary ions and a similar evolution of surface topography and RMS roughness have been observed on both kinds of samples. (C) 2004 Elsevier B.V. All rights reserved.