Published online by Cambridge University Press: 25 February 2011
A low pressure chemical vapor deposition technique using water-alcohol vapors has been developed for the deposition of polycrystalline diamond films and homoepitaxial diamond films. The technique uses a low pressure (0.50 – 1.00 Torr) rf-induction plasma to effectively dissociate the water vapor into atomic hydrogen and OH. Alcohol vapors admitted into the chamber with the water vapor provide the carbon balance to produce diamond growth. At 1.00 Torr, high quality diamond growth occurs with a gas phase concentration of water approximately equal to 47% for methanol, 66% for ethanol, and 83% for isopropanol. A reduction in the critical power necessary to magnetically couple to the plasma gas is achieved through the addition of acetic acid to the water.alcohol solution. The lower input power allows lower temperature diamond growth. Currently, diamond depositions using water:methanol:acetic-acid are occurring as low as 300 ° C with only about 500 W power input to the 50 mm diameter plasma tube.