Defect reduction of laterally regrown GaN on GaN/patterned sapphire substrates

Dong Sing Wuu*, Hsueh Wei Wu, Shih Ting Chen, Tsung Yen Tsai, Xinhe Zheng, Ray-Hua Horng

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


Structural properties of GaN epilayers on wet-etched protruding and recess-patterned sapphire substrates (PSSs) have been investigated in detail using high-resolution double-crystal X-ray diffraction (DCXRD) and etch-pit density methods. The DCXRD results reveal various dislocation configurations on both types of PSSs. The etch pits of GaN on the recess PSS exhibit a regular distribution, i.e. less etch pits or threading dislocation density (TDD) onto the recess area than those onto the sapphire mesas. On the contrary, an irregular distribution is observed for the etch pits of GaN on the protruding PSS. A higher crystal quality of the GaN epilayer grown onto the recess PSS can be achieved as compared with that onto the protruding PSS. These data reflect that the GaN epilayer on the recess PSS could be a better template for the second epitaxial lateral overgrowth (ELOG) of GaN. As a result, the GaN epilayers after the ELOG process display the TDDs of around ∼106 cm-2.

Original languageEnglish
Pages (from-to)3063-3066
Number of pages4
JournalJournal of Crystal Growth
Issue number10
StatePublished - 1 May 2009


  • A1. Defects
  • A1. Etching
  • A3. Metalorganic chemical vapor deposition
  • B1. Nitrides
  • B1. Patterned sapphire substrate
  • B3. Light-emitting diodes

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