Surface investigations on different nucleation pathways for diamond heteroepitaxial growth on iridium

The heteroepitaxial growth of diamond was investigated on iridium (001) using Bias Enhanced Nucleation (BEN). Two different nucleation pathways were observed corresponding to proper BEN conditions: the first leads to isolated diamond crystals partially in epitaxy. The second pathway involves the formation of domains where a very high epitaxial ratio of diamond crystals close to 100% is revealed after growth. This nucleation pathway, unique to iridium, was studied by electron spectroscopies and field emission gun scanning electron microscopy. Starting from an iridium surface with a poor carbon amount, several mechanisms were taking place during BEN. Our results support subplantation of carbon ions and preferential nucleation within furrows created at the iridium surface. Diamond films 80 mu m thick, grown from domains exhibit polar and azimuthal misorientations close to the state of the art. (C) 2011 Elsevier B.V. All rights reserved.