INTERNAL-STRESS OF CHEMICAL-VAPOR-DEPOSITION DIAMOND FILM ON SILICON

The internal stress and strain of chemical vapour deposition (CVD) dia mond film deposited on silicon were observed and quantitatively determ ined by the bending beam technique and the X-ray diffraction peak broa dening. The internal stress of the diamond film varies with the growth parameters during the deposition. The crystallinity and quality of th e diamond film decline with increasing concentration of CH4/H-2, the r esult of which is the build-up of compressive stress. The compressive stress can be partly released by improving the diamond crystallinity o f the film. For instance, the addition of argon to higher concentratio ns of CH4/H-2 can effectively enhance the concentration of hydrogen at oms and therefore increase the ratio of sp(3)/sp(2) which is required for a high quality of diamond film. It is interesting to note the vari ation in the morphology of the CVD diamond film synthesized at higher ratios of CH4/H-2 from a ball-like shape to a mixture of {111} and {10 0} facets and finally to {100} facets as the concentration of argon in creases from O% to 33.3%.