Determination of dislocation density in GaN/sapphire layers using XRD measurements carried out from the edge of the sample

Abstract

In this paper, we show a novel measurement approach for determination of the threading dislocations density in GaN/sapphire structures using X-ray diffractometry at edge scans geometry. The presented method is based on measurements carried out both: classically from the surface and from the edge of the sample. Edge scans allow measurements of planes parallel to the growth direction, which permit the unambiguous determination of the number of edge dislocations. This is a new measurement approach that facilitates the characterization of structures. In addition, obtained results have been confirmed by using the wet etching method. In comparation with the obtained results, it can be concluded that both methods give the same results within the experimental uncertainty.