Early formation of thick diamond films on Si substrates

The early formation of the thick diamond films has been investigated to obtain a better understanding of the characteristic of diamond nucleation. At the early stage in hot cathode direct current discharge plasma chemical vapor deposition of diamond films, well-distributed black spots of 0.3 mm in diameter are found on the Si substrates, the spacing of two adjacent spots is about 1 mm. For the X-ray photoelectron spectroscopy experiment of the Si surface with spots, SiC is detected in the spot regions. The SEM analysis indicates that the nuclei and growth of diamond particles may preferentially occur on the spot regions. The result implies that the existing of these spots is beneficial to enhance the adhesion between diamond films and Si substrates.