The evolution of the Si-SiO2 interface morphology of low-dose low-energy separation by implanted oxygen materials was investigated by transmission electron microscopy and atomic force microscopy. The Si-SiO2, interface morphology and the RMS roughness are strongly affected by the implantation conditions and the annealing process. Three main types of the domains including round, square, and pyramid shapes with the step-terrace structure were observed on the buried SiO2 surface. Round domains are observed in the early stage of the annealing process, while the square and pyramid domains are observed after the high temperature annealing. The mean RMS roughness decreases with increasing time and annealing temperature, while in the 1350 degrees C 4-h annealed samples, the mean RMS roughness decreases with either increasing the implantation dose or decreasing implantation energy. The scaling analysis shows that the Si-SiO2 interfaces were found to be self-affine on the short length scales with a roughness exponent above 0.50. Qualitative mechanisms of Si-SiO2 surface flattening are presented in terms of the variations of morphological features with the processing conditions. (c) 2005 Elsevier B.V. All rights reserved.