Microstructures of threading dislocation bundles included in CVD homoepitaxial diamond plates

•Microstructures of dislocation bundles in CVD homoepitaxial diamond were investigated using etch-pits and TEM.•TEM indicated that the bundle traveled nearly parallel to the film growth [001] with a gradual divergence of < 15°.•It was shown that the threading dislocation bundles contained three types of undissociated and perfect dislocations.

The (001)-oriented chemical vapor deposition (CVD) homoepitaxial diamond films are known to include grown-in threading dislocation bundles parallel to the near-[001] growth direction; however their detailed microstructures have not yet been sufficiently elucidated. In this paper, we report microstructural configurations of such dislocation bundles, investigated by a combination of an etch pit method and cross-sectional transmission electron microscopy (TEM). The TEM images revealed that threading dislocations comprising the dislocation bundle were not extended, but perfect types and their lines propagated nearly along the [001] film growth direction with a gradual divergence. The Burgers vectors of the dislocations were classified into the following three types: b=1/2[±110], nearly perpendicular to the line direction of [001]; b=1/2[±101] or 1/2[0±11], including much lateral components; and a linear combination of several b=1/2[±110], 1/2[±101] and 1/2[0±11].

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