HIGH-TEMPERATURE, HIGH-RATE HOMOEPITAXIAL GROWTH OF DIAMOND IN AN ATMOSPHERIC-PRESSURE FLAME

Homoepitaxial growth of diamond at temperatures in the range of 1150-1500-degrees-C has been achieved on millimeter sized {100} and {110} natural diamond seed crystals using a laminar, premixed oxygen-acetylene flame in air. Growth rates of 100-200-mu-m/h have been observed. Microscope and naked eye observations show the original cylindrical shaped seed crystals growing into polyhedral shaped crystals with identifiable {100}, {110} and {111} faces. Examination under optical and scanning electron microscopes reveals terraces on the {100} faces. The deposited diamond is clear and exhibits Raman spectra almost identical to that of natural diamond. Laue X-ray diffraction analyses have confirmed the epitaxial nature of the growth. The deposition temperatures and growth rates reported are the highest ever observed for the homoepitaxial synthesis of diamond crystals at low pressures.