Synchrotron radiation x-ray topography and defect selective etching analysis of threading dislocations in GaN.

Research output: Contribution to journalArticleScientificpeer-review


Research units

  • Institute of Electronic Materials Technology
  • Fraunhofer Institute for Integrated Systems and Device Technology
  • Albert-Ludwigs-Universität


The crystal quality of bulk GaN crystals is continuously improving due to advances in GaN growth techniques. Defect characterization of the GaN substrates by conventional methods is impeded by the very low dislocation density and a large scale defect analysis method is needed. White beam synchrotron radiation x-ray topography (SR-XRT) is a rapid and non-destructive technique for dislocation analysis on a large scale. In this study, the defect structure of an ammonothermal c-plane GaN substrate was recorded using SR-XRT and the image contrast caused by the dislocation induced microstrain was simulated. The simulations and experimental observations agree excellently and the SR-XRT image contrasts of mixed and screw dislocations were determined. Apart from a few exceptions, defect selective etching measurements were shown to correspond one to one with the SR-XRT results.


Original languageEnglish
Article number083504
Pages (from-to)1-9
Number of pages9
JournalJournal of Applied Physics
Issue number8
Publication statusPublished - 2014
MoE publication typeA1 Journal article-refereed

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