Initial growth of heteroepitaxial diamond on Ir (0 0 1)/MgO (0 0 1) substrates using antenna-edge-type microwave plasma assisted chemical vapor deposition

Initial growth of heteroepitaxial diamond on Ir (0 0 1)/MgO (0 0 1) was investigated by scanning electron microscopy, reflection high-energy electron diffraction (RHEED) and atomic force microscopy. Bias-enhanced nucleation (BEN) was performed by antenna-edge-type microwave plasma assisted chemical vapor deposition. In BEN, diamond crystallites nucleated and grew along the [-1 1 0] and [1 1 0] directions of iridium. Diamond was likely to nucleate on protruded iridium areas. After BEN, in addition to the diamond diffraction spots, iridium bulk diffraction spots, which were not observed before BEN, were observed by RHEED. The iridium surface appeared to be protruded and changed by the high ion current density in BEN. Under [0 0 1] selective growth conditions, diamond crystallites, which were less than 10 nm in diameter, were etched by H₂ plasma. Diamond nucleated areas corresponded to the surface ridges of iridium along the [-1 1 0] and [1 1 0] directions at 10-40 nm intervals before BEN.