Deposition and Characterization of Ultra-Smooth Nanocrystalline Diamond Films Using a Graphite-Grid Assisted Hot Filament CVD Method
Nanocrystalline diamond films (NDFs) were deposited on mirror-polished silicon (100) substrates using a graphite-grid assisted hot filament chemical vapor deposition (HFCVD) technique. The evidence of nanocrystallinity, smoothness and purity was obtained by characterizing the sample with various advanced analyses. A graphite-grid was used as the DC electrode, which was pre-coated by diamond films and could emit electron when a negative bias was applied to the under electrode. The results show that the film consists of nanocrystalline diamond grains with sizes of about 7-15nm. The Raman spectroscopy, XRD pattern, HR-TEM image and SAED pattern of the films indicate the presence of nanocrystalline diamond. Surface roughness is measured as Ra<20nm by the profilometry scans. A large quantity of electrons emission from the graphite-grid and positive ions bombardment to the graphite-grid results in an enormous enhancement of the generation of diamond nuclei. Density of a diamond nuclei as high as 1010~1011/cm2 can be attained with this method. NDFs can be deposited on mirror-polished Si substrate surfaces without damaging surface pretreatment for nucleation enhancement. These ultra-smooth films will display excellent performances, which make them the best candidates for semiconductor and MEMS applications.
Chengyu Jiang, Geng Liu, Dinghua Zhang and Xipeng Xu
F. H. Sun et al., "Deposition and Characterization of Ultra-Smooth Nanocrystalline Diamond Films Using a Graphite-Grid Assisted Hot Filament CVD Method", Materials Science Forum, Vols. 532-533, pp. 249-252, 2006