Patterned silicon-on-insulator (SOI) materials have been fabricated by masked separation by implantation of oxygen (SIMOX) technique. The formed SOI structure was analyzed by cross-sectional transmission electron microscopy (XTEM). The patterned SOI materials prepared with low-dose and low-energy SIMOX technique exhibit high quality featured by defect free transition of SOI and bulk silicon region and high degree of surface planarity. Furthermore, the buried oxide (BOX) layer is of high integrity at such a low-dose ion implantation. The fabricated excellent quality patterned SOI materials will be the desirable substrates for system-on-a-chip (SOC) applications. (C) 2003 Elsevier B.V. All rights reserved.