Effect of interfacial oxygen on the microstructure of MBE-grown homoepitaxial N-polar GaN

D. F. Storm, T. McConkie, D. S. Katzer, B. P. Downey, M. T. Hardy, D. J. Meyer, David Smith

Research output: Contribution to journalArticle

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Abstract

We have investigated the microstructure of homoepitaxial N-polar GaN layers grown by rf-plasma-assisted molecular beam epitaxy on freestanding GaN substrates. The structural quality of the epitaxial layers improves when the sheet density of oxygen present on the substrate surface diminishes. An initial sheet density of oxygen of ∼0.5 monolayer (ML) results in a highly defective epitaxial layer, while an epitaxial layer with no visible threading dislocations was grown on a substrate with an initial oxygen sheet density of ∼0.08 ML. The significant reduction in oxygen was achieved by using several cycles of Ga deposition and thermal desorption prior to the start of epitaxial growth combined with an initial ultrathin 15-A˚ AlN nucleation layer. These results indicate that reducing the density of oxygen on the surfaces of freestanding N-polar GaN substrates is vital for obtaining high quality homoepitaxial N-polar GaN layers.

Original languageEnglish (US)
Pages (from-to)14-17
Number of pages4
JournalJournal of Crystal Growth
Volume409
DOIs
StatePublished - Jan 1 2015

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Molecular beam epitaxy
Oxygen
Epitaxial layers
microstructure
Microstructure
oxygen
Substrates
Monolayers
Thermal desorption
Dislocations (crystals)
Epitaxial growth
Nucleation
molecular beam epitaxy
Plasmas
desorption
nucleation
cycles

Keywords

  • A1. Defects
  • A1. Impurities
  • A3. Molecular beam epitaxy
  • B1. Nitrides
  • N-polar nitrides

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Materials Chemistry
  • Inorganic Chemistry

Cite this

Effect of interfacial oxygen on the microstructure of MBE-grown homoepitaxial N-polar GaN. / Storm, D. F.; McConkie, T.; Katzer, D. S.; Downey, B. P.; Hardy, M. T.; Meyer, D. J.; Smith, David.

In: Journal of Crystal Growth, Vol. 409, 01.01.2015, p. 14-17.

Research output: Contribution to journalArticle

Storm, D. F. ; McConkie, T. ; Katzer, D. S. ; Downey, B. P. ; Hardy, M. T. ; Meyer, D. J. ; Smith, David. / Effect of interfacial oxygen on the microstructure of MBE-grown homoepitaxial N-polar GaN. In: Journal of Crystal Growth. 2015 ; Vol. 409. pp. 14-17.
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AU - Hardy, M. T.

AU - Meyer, D. J.

AU - Smith, David

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