THE GROWTH OF (100) ORIENTATED DIAMOND FILMS

Quasi-equilibrium calculations were performed on the C-H and C-H-O sys tems to calculate the thermodynamic stability of diamond and graphite phases under CVD conditions. Exclusive diamond growth is dependent, in part, on the increased thermodynamic stability of H-terminated crysta llographic surfaces. This feature was included in the methodology by e stimating the surface enthalpies by group additivity methods. The lowe r boundary in the Bachmann ternary diagram which defines the demarcati on line between the growth and non-growth regions was calculated. The gradient of the line is a strong function of the degree of stabilizati on of the H-terminated diamond surfaces. Using mixtures of CH4-CO-H-2 of compositions close to the CO line of the phase diagram, (100) facet ed films were grown by microwave assisted CVD at rates of 1.5-2.0 mum h-1.