Study of threading dislocation density reduction in AlGaN epilayers by Monte Carlo simulation of high-resolution reciprocal-space maps of a two-layer system

S. Lazarev, M. Barchuk, S. Bauer, K. Forghani, V. Holý, F. Scholz, T. Baumbach

Research output: Contribution to journalArticle

8 Citations (Scopus)


High-resolution X-ray diffraction in coplanar and noncoplanar geometries has been used to investigate the influence of an SiN x nano-mask in the reduction of the threading dislocation (TD) density of high-quality AlGaN epitaxial layers grown on sapphire substrates. Our developed model, based on a Monte Carlo method, was applied to the simulation of the reciprocal-space maps of a two-layer system. Good agreement was found between the simulation and the experimental data, leading to an accurate determination of the dislocation densities as a function of the overgrowth layer thickness. The efficiency of the SiN x nano-mask was defined as the ratio of the TD densities in the AlGaN layers below and above the mask. A significant improvement in the AlGaN layer quality was achieved by increasing the overgrowth layer thickness, and a TD density reduction scaling law was established.

Original languageEnglish
Pages (from-to)120-127
Number of pages8
JournalJournal of Applied Crystallography
Issue number1
Publication statusPublished - Feb 2013
Externally publishedYes



  • epitaxial layers
  • high-resolution X-ray diffraction
  • nano-masking
  • threading dislocation density

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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