Diamonds have been efficiently nucleated on the flash-annealed and reconstructed silicon (100) substrate by hot filament chemical vapor deposition. A relatively high diamond nucleation density of about 10(10) cm(-2) in the nucleation time of only 20 min was confirmed by a Raman peak at the wave number of 1332 cm(-1) and a scanning electron microscope image of the oriented nuclei with square-like shapes. The core-level spectra of C-1s and Si-2p using x-ray photoelectron spectroscopy indicated that the diamond had been nucleated on the C-modified substrate believed to be a SiC layer. If so, this study demonstrates that the diamond can be efficiently nucleated on a high quality SiC surface.