Large Area Deposition of Heteroepitaxial Diamond Thin Films on Ion-Irradiated Iridium3

Heteroepitaxy of diamond is one of the main topics in diamond research society for scientific and industrial point of view. There have been attempted to fabricate heteroepitaxial diamond thin films on foreign substrate such as cubic boron nitride, nickel, silicon, beta-silicon carbide and platinum. Our research group has started to study on heteroepitaxial growth of diamond on iridium/magnesium oxide (MgO) (001) stacking by using two-step dc plasma chemical vapor deposition method from 1995. Growth area of epitaxial diamond, however, is 3mm in diameter, which is limited by the form and the size of the grid used for pretreatment of ion irradiation. We have developed another pretreatment technique (planar diode type dc plasma) to enlarge the size of ion irradiation area. After this pretreatment, epitaxial diamond can be grown on whole iridium substrate surface with the size of 10x10x0.5 mm. The obtained epitaxial diamond thin film was transparent to visible light with a relative smooth surface. The growth process and the results of characterization will be presented in detail.