Microwave plasma reactor design for high quality and high rate diamond synthesis

Since the first demonstration of microwave plasma assisted chemical vapor deposition (MPACVD) of diamond by Matsumoto [1] microwave plasma reactor technologies have evolved into a variety of commercially available technologies which have been applied to numerous applications. Some of the most notable applications are the synthesis: (1) of optical quality large area (~10cm diameter), thick, free standing polycrystalline diamond (PCD) plates and (2) of multi-carat, single crystal diamond (SCD) plates with properties that suggest potential and significant, gem, optical, and electronic applications. Recently the evolution of MPACVD diamond reactor technologies has resulted in diamond synthesis occurring at pressures of 150-300 torr and associated high discharge power density ranges of 150-1000 W/cm³ [2,3]. These new reactor designs have resulted in the production of high quality diamond at rates of 10-100 microns/hour and have involved the development of new and potentially important commercial MPACVD reactor configurations that operate over the 50-400 torr regime.