Abstract: A unique SIMOX method was introduced to fabricate SGOI and resolve the problem of Ge loss.During the process,a SiO₂ layer was formed firstly pre-annealing to block the Ge out-diffusion.It results in full relaxed SGOI with Ge fraction amounts to 17at% as the X-ray rocking curve and Raman Spectra studies shown.The influences on heterostructure and compositional depth profiles by the surface oxide layer were explored by cross-sectional transmission electron microscopy and secondary ion mass Spectrometry studies.The final sample exhibits planar and continuous buried oxide layer,sharp interfaces and defects free SGOI.The results indicate that the additional step of thermal oxidation pre-annealing is vital for improving the crystalline quality of the SGOI.