The oxidation of SiGe film epitaxial grown on top of SOI wafers has been studied. These SiGe/SOI samples were oxidized at 700,900, 1100 degrees C. Germanium atoms were rejected from SiGe film to SOI layer. A new Si1-xGex (x is minimal) layer formed at SiGe/Si interface. As the germanium atoms diffused, the new Si1-xGe, (x is minimal) layer moved to Si/SiO2 interface. Propagation of threading dislocation in SiGe film to SOI substrate was hindered by the new SiGe/Si interface. Strain in SOI substrate transferred from SiGe film was released through dislocation nucleation and propagation inner. The relaxation of SiGe film could be described as: strain relaxed through strain equalization and transfer process between SiGe film and SOI substrates. Raman spectroscopy was used to characterize the strain of SiGe film. Microstructure of SiGe/SOI was observed by transmission electron microscope (TEM). (c) 2005 Published by Elsevier B.V.