STRUCTURAL CHARACTERISTICS OF DIAMOND FILMS PREPARED BY THERMAL CHEMICAL VAPOR-DEPOSITION PROCESSES

Diamonds were synthesized by thermal chemical vapor deposition on molybdenum and silicon substrates. Using CH2-H-2 as the precursor gas mixture, distinct growth steps on (111) faces were observed for diamonds prepared at 950-degrees-C on molybdenum substrates. No growth spirals were found on the (111) planes, indicating an apparent layerwise growth induced by a two-dimensional nucleation process rather than a screw dislocation mechanism. As the temperature of the molybdenum substrate was increased to 1060-degrees-C, the (100) planes of diamond were dominant in the film's surface morphology with no distinct growth steps observed. The termination of the outermost surface of the diamond films by CH2 groups was suggested by Fourier transform IR analysis.