GROWTH OF DIAMOND FILMS FROM MICROWAVE PLASMA IN CH4-CO2 MIXTURES

We have studied the growth of diamond films from microwave plasma usin g gas mixtures of CH4-CO2 (not previously reported in the literature) onto Si substrates. The diamond phase is obtained in the molar ratio.r ange 0.7 less-than-or-equal-to CO2/CH4 less-than-or-equal-to 1.38 +/- 0.05, in close agreement with the empirical model of Bachmann et al., with relevant implications for the diamond precursor species. The film morphology varies appreciably in the above range, the best films bein g obtained just at the border with the no-growth region.