X-ray topography characterization of gallium nitride substrates for power device development

Balaji Raghothamachar, Yafei Liu, Hongyu Peng, Tuerxun Ailihumaer, Michael Dudley, F. Shadi Shahedipour-Sandvik, Kenneth A. Jones, Andrew Armstrong, Andrew A. Allerman, Jung Han, Houqiang Fu, Kai Fu, Yuji Zhao

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Gallium nitride substrates grown by the hydride vapor phase epitaxy (HVPE) method using a patterned growth process have been characterized by synchrotron monochromatic beam X-ray topography in the grazing incidence geometry. Images reveal a starkly heterogeneous distribution of dislocations with areas as large as 0.3 mm2 containing threading dislocation densities below 103 cm−2 in between a grid of strain centers with higher threading dislocation densities (>104 cm−2). Basal plane dislocation densities in these areas are as low as 104 cm−2. By comparing the recorded images of dislocations with ray tracing simulations of expected dislocations in GaN, the Burgers vectors of the dislocations have been determined. The distribution of threading screw/mixed dislocations (TSDs/TMDs), threading edge dislocations (TEDs) and basal plane dislocations (BPDs) is discussed with implications for fabrication of power devices.

Original languageEnglish (US)
Article number125709
JournalJournal of Crystal Growth
StatePublished - Aug 15 2020


  • A1. Characterization
  • A1. Defects
  • A1. Substrates
  • A1. X-ray topography
  • A3. Hydride vapor phase epitaxy
  • B1. Nitrides

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry


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