Propagation of dislocations in diamond (111) homoepitaxial layer

Dislocations in a diamond (111) homoepitaxial layer were investigated in terms of the line directions and types. After a thick homoepitaxial layer was grown on a {111} high-pressure high-temperature (HPHT) substrate using chemical vapor deposition (CVD), the Raman spectra of diamond were taken using a confocal setup to obtain the spatial distribution of the peak positions of the diamond Raman line. Dislocations in the CVD layer and HPHT substrate were detected as local stress variation in the peak position images. The line directions of dislocations were, respectively, [112] for the HPHT substrate and [011] for the CVD layer. Local stress variation was in the [$1¯1¯2$] direction in both the CVD layer and the HPHT substrate. The Burgers vector deduced from the local stress-variation direction indicated the dislocation structures, respectively, as an edge type for [112] dislocations in the HPHT substrate and as a 60° mixed type for [011] dislocations in the CVD layer. Because both dislocations had the same slip plane, the line direction and dislocation type changed on the same slip plane at the CVD layer/HPHT substrate interface, when dislocation in the HPHT substrate reached the CVD layer.