Thermal stability of strained SOI fabricated by Smart Cut technique was found to be high enough for the current Si process, particularly with SiO(2) protection films. The strain states, in-plane and out-of-plane lattice constants, were found not to change after annealing up to 1150 degrees C with SiO(2) films though those of thinner sSOI without the protection film gradually changed due to strain relaxation. it was also found that 3D correction of the orientation mismatch between the Si substrate and the strained Si was essential for precise evaluation of strain states. (c) 2008 Elsevier B.V. All rights reserved.