Studies on defect reduction in AlGaN heterostructures by integrating an in-situ SiN interlayer

Ferdinand Scholz, Kamran Forghani, Martin Klein, Oliver Klein, Ute Kaiser, Benjamin Neuschl, Ingo Tischer, Martin Feneberg, Klaus Thonke, Sergey Lazarev, Sondes Bauer, Tilo Baumbach

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3 Citations (Scopus)

Abstract

We have decreased the dislocation density in AlxGa1̃xN epitaxial layers grown on sapphire wafers by introducing an in-situ deposited SiN nanomask layer. Taking together results obtained by transmission electron microscopy, photoluminescence, cathodoluminescence, and X-ray diffraction, we were able to derive a schematic model about the AlGaN growth on the SiN nanomask: On the open pores of the nano-mask, Garich AlGaN hillocks develop, whereas on the SiN layer Al-rich AlGaN nucleates owing to the reduced selectivity of Al-containing material. Once the hillocks are formed, Ga-rich material is more efficiently incorporated on the inclined side-facets leading to an Al-rich coverage of the central c-plane part of the hillocks. We observed a bending of the dislocations towards the side-facets of the hillocks, which eventually leads to dislocation bundles with increased probability of dislocation annihilation, separated by fairly defect-free regions. Thus, we could achieve a significant reduction of the edge-type dislocation density in these epitaxial layers.

Original languageEnglish
Article number08JJ07
JournalJapanese Journal of Applied Physics
Volume52
Issue number8 PART 2
DOIs
Publication statusPublished - Aug 2013
Externally publishedYes

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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