Cross-sectional TEM study of unepitaxial crystallites in a homoepitaxial diamond film

摘要

We investigated the structure of unepitaxial crystallites (UC; non-epitaxial crystallites) in homepitaxial diamond films on Ib (001) diamond substrate grown by the chemical vapor deposition (CVD), employing field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HRTEM) The UC was classified into two types depending on the orientation relationship to the homoepitaxial film; one rotates by 70.5deg around the common <110>axis, corresponding to #SIGMA#3 coincidence site lattice (CSL) relation. The other type does not have any particular angular relationship. It was found that the growth of the former type is closely related to a lattice dislocation on the substrate surface as well as the homoepitaxial film. On the other hand, there was hardly any lattice dislocation observed at the bottom of the latter type. A nanometer-sized crystalline diamond particle was observed at the nucleation site of the latter one.