Nondestructive visualization of threading dislocations in GaN by micro raman mapping

Abstract

Threading dislocations (TDs) in a HVPE-grown c-plane (0001) GaN single crystal were analyzed by micro Raman spectroscopy mapping. The mapping image exhibited the pairs of higher and lower wavenumber regions of peak shift of GaN, which corresponded to the compressive and tensile strains due to TDs. By comparing X-ray topography and etch pit images, the contrasts are considered as the edge component of TDs. By analyzing the existing 290 TDs in 80 × 80 μm2, the directions of the contrast were mainly dominant toward A few brighter contrasts toward were also observed. These TDs are affiliated with Burgers vectors and respectively. Judging from experimental and simulated result, it is confirmed that the contrast in the Raman mapping image of the has a larger magnitude than the