High-density heteroepitaxial diamond nucleation on biased mirror-polished Si(100) in hot filament chemical vapor deposition

摘要

Abstract: Diamond is regarded as a negative electron affinity material because of the field emission from CVD diamond films at low applied fields (approximately 20 kV/cm), which makes diamond a potential candidate for flat panel display. In order to find the way of fabricating high quantity diamond films via CVD, the diamond nucleation process should be studied of the first importance. High density heteroepitaxial diamond nuclei on mirror-polished Si(100) substrate have been accomplished by DC glow discharge in a conventional hot filament chemical vapor deposition system. The glow discharge current density as high as 80 mA/cm$+2$/ was attained, which was mostly contributed by the silicon surface instead of the metal holder exposed in the plasma, as the negative bias was applied between the mesh and the substrate. The grown nuclei were characterized by scanning electron microscopy, atomic force microscopy, and surface enhanced Raman spectroscopy. After the first 10 min deposition, uniform, well-developed diamond nuclei of D(110)//Si(110) and D(100)//Si(100) with a film thickness of about 180 nm were achieved.!21