TEM INVESTIGATIONS ON THE HETEROEPITAXIAL NUCLEATION OF CVD DIAMOND ON (001)-SILICON SUBSTRATES

A bias-enhanced nucleation process for the heteroepitaxial diamond gro wth by microwave plasma CVD on silicon is studied with TEM. Samples nu cleated for different times are investigated and a time schedule of cr ystal phase formation is found: nanocrystalline beta-SiC with small st atistical deviations from the heteroepitaxial orientation forms rapidl y at the silicon substrate surface. The layer containing the nanocryst als grows and forms ridges parallel to the [110](Si) directions. Diamo nd nucleation occurs only on top of this layer, whereby the deviations from the heteroepitaxial orientation are taken over and extended. Fin ally, the beta-SiC side of the diamond crystals is etched by the plasm a. (C) 1997 Elsevier Science S.A.