CHARACTERIZATION OF HOMOEPITAXIAL DIAMOND FILMS BY NUCLEAR METHODS

Isotopically marked C-13 diamond films were deposited by microwave-plasma-assisted chemical vapour deposition homoepitaxially on {100} and {111} natural diamond substrates. The deposition was performed at 0.5 and 1.5 vol.% (CH4)-C-13 diluted in H-2. In order to study the influence of nitrogen on diamond growth, N-2 was admired with the process gas for some samples. The thickness of the homoepitaxial films was determined by Rutherford backscattering, the crystalline quality by ion channelling measurements and hydrogen concentrations by nuclear reaction analysis. The defect density and growth rate of {111} films were found to increase at the higher methane concentration. The growth rate of {100} films also increased, but the defect density decreased at the higher methane concentration. The admixture of nitrogen with the process gas yielded about 25% higher growth rates and better crystalline qualities.