The effect of AlN buffer growth parameters on the defect structure of GaN grown on sapphire by plasma-assisted molecular beam epitaxy

Yuen Yee Wong, Edward Yi Chang, Tsung Hsi Yang, Jet Rung Chang, Yi Cheng Chen, Jui Tai Ku, Ching Ting Lee, Chun Wei Chang

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

The defect structure of GaN film grown on sapphire by plasma-assisted molecular beam epitaxy (PAMBE) depends on the growth temperature and thickness of the aluminum nitride (AlN) buffer layer. High-resolution X-ray diffraction was used to measure symmetric (0 0 0 2) and asymmetric (1 0 1̄ 2) rocking curve (ω-scans) broadening, which allowed the estimation of screw threading dislocation (TD) and edge TD densities, respectively. For GaN grown on lower-temperature buffer, the density of screw TD was increased while the density of edge TD was decreased. Further examinations revealed that the edge TD was closely related to stress in GaN film and the screw TD was controlled by AlN surface roughness. Since the GaN defect was dominated by edge TD, the total TD was also effectively suppressed with the use of lower-temperature buffer with appropriate thickness.

Original languageEnglish
Pages (from-to)1487-1492
Number of pages6
JournalJournal of Crystal Growth
Volume311
Issue number6
DOIs
Publication statusPublished - 2009 Mar 1

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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