V-pits formation in InGaN/GaN: influence of threading dislocations and indium content

Abstract

Two sets of InGaN/GaN MOVPE-grown samples were studied by high-resolution x-ray diffraction techniques together with statistical analysis of atomic force microscope images in order to determine the impact of In concentration and threading dislocations (TDs) density on the V-pit formation. It was shown that in our samples, the density of V-pits in the epilayer matched the TD density with a screw component in the substrate.

Pure edge TDs do not affect the V-pit density. The In concentration influences the size of the V-pits, but not their density.

Keywords

• V-pits
• InGaN
• GaN
• dislocations
• x-ray diffraction
• diffuse scattering
• XRD
• RSM