Heteroepitaxial diamond films on silicon substrates and on iridium layers:Analogies and differences in nucleation and growth

Heteroepitaxy on single-crystal substrates has been one of the hot topics o f chemical vapor deposition (CVD) diamond research during the last decade. Its ultimate goal, the realization of large-area high-quality single-crysta l diamond films or free-standing wafers, is now within reach. In the presen t article, we summarize some of the typical features for the deposition on silicon substrates and compare them with the nucleation and growth on iridi um buffer layers, currently the most promising substrate for diamond hetero epitaxy. It is shown that under optimum conditions, the latter films are no longer polycrystalline. Based on this strategy, the future realization of large-area single-crystal diamond will provide a base material for many hig hly sophisticated applications in different fields such as electronics.