CHARACTERIZATION OF HOMOEPITAXIAL DIAMOND FILMS BY NUCLEAR METHODS

Isotopically marked C-13 diamond films were deposited by microwave-pla sma-assisted chemical vapour deposition homoepitaxially on {100} and { 111} natural diamond substrates. The deposition was performed at 0.5 a nd 1.5 vol.% (CH4)-C-13 diluted in H-2. In order to study the influenc e of nitrogen on diamond growth, N-2 was admired with the process gas for some samples. The thickness of the homoepitaxial films was determi ned by Rutherford backscattering, the crystalline quality by ion chann elling measurements and hydrogen concentrations by nuclear reaction an alysis. The defect density and growth rate of {111} films were found t o increase at the higher methane concentration. The growth rate of {10 0} films also increased, but the defect density decreased at the highe r methane concentration. The admixture of nitrogen with the process ga s yielded about 25% higher growth rates and better crystalline qualiti es.