A reliable process to fabricate self-supporting thin Si single crystals has been developed, which fundamentally uses MeV boron implantation followed by a selective etching technique. Several additional steps in the process including post-implantation annealing, fast rough etching, removal of the oxide layer and removal of the implanted layer, are presented in detail. The area of the self-supporting film is about 6 mm diameter supported by a thick Si sheet, and the thickness of the film is 1-5.5 /spl mu/m which is well controlled by an implantation energy of 0.6-MeV. After removal of the implanted layer, the flatness and the crystalline quality of the film is excellent. This can be shown by channeling experiments in transmission geometry using a wide He beam. Several experiments carried out using this material will be presented, as well as other possible application.