The effects of the processing conditions on the formation of buried oxide (BOX) layers in low-dose low-energy separation by implanted oxygen materials were investigated by using infrared spectroscopy and transmission electron microscopy. In as-implanted samples, the Si-O-Si stretching frequency increases either with increasing the oxygen dose or with decreasing implantation energy because the oxide composition becomes stoichiometric. However, the plateau frequencies were observed above a certain dose due to the compressive stress in the BOX layers. Upon ramping up to 1100 degrees C, the compressive stress decreases. Annealing beyond 1100 degrees C, the out diffusion of oxygen atoms was detected. (c) 2004 Elsevier B.V. All rights reserved.