HETEROEPITAXIAL DIAMOND FILMS ON SILICON(001) - INTERFACE STRUCTURE AND CRYSTALLOGRAPHIC RELATIONS BETWEEN FILM AND SUBSTRATE

The interfaces between highly (001)-oriented diamond films and the sil icon (001) substrates were investigated by high-resolution electron mi croscopy. It was found that heteroepitaxially oriented grains which ex hibit a defined orientation relationship to the substrate lattice grow directly on the clean silicon surface. The majority of the grains obs erved have their basic axes parallel or almost (within a few degrees) parallel to the basic axes of silicon. In addition, grains with about 14 degrees and 70 degrees rotation around a [110] axis are also observ ed. In the latter case the lattice is in twin relation to that of the ideally oriented nonrotated grains. In all cases the interface structu re is well defined and the angular deviation of the two lattices is co mpensated by appropriate interface dislocations. These dislocations ar e either of the 60 degrees type or are Lomer dislocations formed by th e reaction of two types of 60 degrees dislocations. The observed orien tation relationships can be explained on the basis of the near-coincid ence-site lattice of the two materials.