In this article, the authors propose an improved approach-separation by implanted oxygen (SIMOX) layer transfer process-to fabricate thin-film silicon on insulator (SOI). The top Si layer, a low-dose SIMOX wafer, was transferred upside down onto a thermally oxidized Si handle wafer by a bonding technique and etch-stop thinning process. Spectroscopic ellipsometry indicated a thin-film SOI with the device layer of 147.5 +/- 3.1 nm. An atomic-scale sharp interface between the device layer and buried oxide layer was observed by high-resolution transmission electron microscopy.