Diamond synthesis by using very high frequency plasmas in parallel plate electrodes configuration

By using very high frequency (100 MHz) plasma, diamond was synthesized with only rf power in parallel plate electrodes configuration from a mixture gas of methane and hydrogen. Deposition conditions are similar to those used so far in medium pressure methods, i.e., the pressure, methane concentration, substrate temperature, and rf power used are 90-20 Torr, 5-0.5%, 900 degrees C, and 400-1000 kW, respectively. This plasma is very stable and the power density used is small. Furthermore, diamond formed at a pressure lower than that used in dc plasma chemical vapor deposition. These results suggest the possibility of the application of this method to large area deposition of diamond. However, the quality of the diamonds obtained are not yet very high. Methods of improvement are also discussed. (C) 1997 American Institute of Physics. [S0003-6951(97)00344-6].