Effect of Surface Pretreatments on Nanocrystalline Diamond Deposited On Silicon Nitride Substrates

The deposition of diamond films on a Si3N4 substrate is an attractive technique for industrial applications because of the excellent properties of diamond. Pretreatment of substrate is very important prior to diamond deposition to promote nucleation and adhesion between coating and substrate. Deposition of nanocrystalline diamonds films on silicon nitride substrate have been carried out by HF-CVD technique using mixture of methane and hydrogen gases. Different pretreatment of substrate including chemical etching consists of hot acid etching and basic etching and mechanical etching were used to study the quality of diamond formed on the substrate. The structure and morphology of diamond coating have been studied using X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) while diamond film quality has been characterized using Raman spectroscopy. AFM was used to investigate the effect of chemical etching and mechanical pretreatment on the surface roughness of the substrates and the resultant morphology of nanocrystalline diamond. It was found that diamond film deposited on as-received, basic etched and grinded substrate shows the morphology of cauliflower while blasted and acidic etched substrates produce smooth, continuous diamond film. However, the Raman investigation did not show any deviation in quality of diamond film for any pretreatment.




References:
[1] Haubner, R., A. Köpf, and B. Lux, Diamond deposition on hardmetal
substrates after pre-treatment with boron or sulfur compounds. Diamond
and Related Materials, 2002. 11(3-6): p. 555-561.
[2] Schade, A., S.M. Rosiwal, and R.F. Singer, Influence of surface
topography of HF-CVD diamond films on self-mated planar sliding
contacts in dry environments. Surface and Coatings Technology, 2007.
201(14): p. 6197-6205.
[3] Cappelli, E., et al., Diamond nucleation and adhesion on sintered nitride
ceramics. Diamond and Related Materials, 2002. 11(10): p. 1731-1746.
[4] Meng, X.M., et al., Application of CVD nanocrystalline diamond films
to cemented carbide drills. International Journal of Refractory Metals
and Hard Materials, 2008. 26(5): p. 485-490.
[5] Yang, S., et al., Diamond films with preferred <110> texture by hot
filament CVD at low pressure. Diamond and Related Materials, 2008.
17(12): p. 2075-2079.
[6] Fabisiak, K., et al., Structural characterization of CVD diamond films
using Raman and ESR spectroscopy methods. Optical Materials, 2006.
28(1-2): p. 106-110.
[7] Belmonte, M., et al., Surface pretreatment of silicon nitride for CVD
diamond deposition. Journal of American Ceramic Society, 2003. 86(5):
p. 749-754.
[8] Yoon, J.-B., et al. Fabrication of a single crystal silicon substrate for
AM-LCD using vertical etching of (110) silicon. in Materials Research
Society Symposium Proceeding. 1995: Materials Research Society.
[9] Liu, H. and D.S. Dandy, in Diamond Chemical Vapor Deposition:
Nucleation and early growth stage. 1995, Noyes Publications: Park
Ridge, N.J.
[10] Chowdhury, S., E.d. Barra, and M.T. Laugier, Study of mechanical
properties of CVD diamond on SiC substrates. Diamond and Related
Materials, 2004. 13: p. 1625- 1631.
[11] Liang, X., et al., Effect of pressure on nanocrystalline diamond films
deposition by hot filament CVD technique from CH4/H2 gas mixture.
Surface and Coatings Technology, 2007. 202(2): p. 261-267.
[12] Lu, F.X., et al., Novel pretreatment of hard metal substrate for better
performance of diamond coated cutting tools. Diamond and Related
Materials, 2006. 15(11-12): p. 2039-2045.
[13] Zuiker, C., et al., Physical and tribological properties of diamond films
grown in argoncarbon plasmas. Thin Solid Films, 1995. 270(1-2): p.
154-159.
[14] Sakamoto, Y. and M. Takaya, Preparation of diamond-coated tools and
their cutting performance. Journal of Materials Processing Technology,
2002. 127(2): p. 151-154.