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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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

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ASJC Scopus subject areas

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

Cite this

Scholz, F., Forghani, K., Klein, M., Klein, O., Kaiser, U., Neuschl, B., ... Baumbach, T. (2013). Studies on defect reduction in AlGaN heterostructures by integrating an in-situ SiN interlayer. Japanese Journal of Applied Physics, 52(8 PART 2), [08JJ07]. https://doi.org/10.7567/JJAP.52.08JJ07