Cathodoluminescence imaging for the determination of dislocation density in differently doped HVPE GaN

In this study we report the potential and limitations of the cathodoluminescence dark spot (DS) counting as a method for the determination of dislocation density and distribution in GaN, produced by the hydride vapour phase epitaxy (HVPE). Different GaN sample series (s.i. GaN:Fe and n-type GaN:Si) were used, in order to study the dependence of the results of the DS-counting on the dopant type and concentration. By the direct comparison of these results to classical defect selective etching, the DS-measurements were validated. It could be shown that each of the both methods have their particular restrictions, which must be considered in their application.

► Direct comparison of dark spot counting and defect selective etching for s.i. GaN. ► Evaluation of the potential and limitations for both of the methods for s.i. GaN. ► Study of dislocation density and relative error as a function of dopant content. ► Maximum dopant concentration for DS counting in s.i. GaN is 1×1018/cm3.