DRIVING FORCE FOR DIAMOND GROWTH IN LOW PRESSURE VAPOR PHASE
金刚石低压气相生长的驱动力

Driving forces for diamond and graphite growth in CH4/H2 mixtures are calculated in consideration of activated effect of super-equilibrium atom hydrogen on graphite under 4.8 kPa pressure. The driving force for diamond growth is positive with simultaneous negative driving force for graphite in the suitable ranges of temperature and mole fraction of CH4. The result indicates that the chemical potential of carbon in the vapor phase is higher than that in diamond and lower than that in graphite simultaneously. So diamond is deposited without graphite co-deposition, and the preexisting graphite will be etched during diamond deposition process.