Dislocations in chemical vapor deposition (111) single crystal diamond observed by synchrotron X-ray topography and their relation with etch pits

Dislocations in chemical vapor deposited (111) single crystal diamond were studied by synchrotron X-ray topography. By analyzing X-ray topography images with various g vectors using the contrast extinction criterion, mixed dislocations with b = a/2 [011] and edge dislocations with b = a/2 [011] are determined. Then, etch pits were formed using O-2/H-2 plasma; observations by X-ray topography and atomic force microscopy revealed that etch pits formed on the dislocations. Hence, we investigated the relationship between the types of dislocations structure and the formation of etch pits. The results showed that the etch pits were larger in diamond samples with mixed dislocations than in those of edge dislocations.