Effect of steps on dislocations in CVD diamond grown on {001} substrates

Abstract Single crystal CVD synthetic diamond samples grown on (001) substrates have been studied using X‐ray topography, photoluminescence imaging, cathodoluminescence imaging and transmission electron microscopy. X‐ray section topographs sampling a plane very close to the surface of a (010) cross‐sectional slice show contrast that is closely correlated with photoluminescence image contrast relating to differences in incorporation of point defects on step risers and terraces during growth. The point defect content is too low to influence X‐ray topography contrast and therefore the correlation suggests a difference between the dislocation content for terrace and riser growth. Dislocations imaged in cathodoluminescence have been observed to follow paths that are strongly influenced by step flow during growth. Transmission electron micrographs show [001] dislocations with sections of <110> 60° or edge dislocations in configurations consistent with formation as a result of step flow growth. It is proposed that a passing riser can cause dislocations to switch from [001] to [101] line direction when this minimises the increase in the energy associated with the dislocation as riser growth proceeds. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)