Low temperature plasma process based on CO-rich CO/H-2 mixtures for high rate diamond film deposition

A low temperature process (350 degrees C<T<500 degrees C) for nanocrystalline diamond film growth by microwave plasma-enhanced chemical vapor deposition has been developed that yields high rates (up to 2.5 mu m/h) at relatively low plasma powers (0.5 kW). In contrast to the widely used H-2-rich mixtures of CH4 or CO and H-2 that exhibit monotonic decreases in the diamond growth rate as T is reduced from 800 to 400 degrees C, CO-rich mixtures of CO and H-2 exhibit an increase and sharp maximum as T is reduced. The results suggest a different diamond growth mechanism from the CO-rich mixtures. (C) 1997 American Institute of Physics.