Electron microscopy of gallium nitride growth on polycrystalline diamond

R. F. Webster, D. Cherns, M. Kuball, Q. Jiang, D. Allsopp

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Abstract

Transmission and scanning electron microscopy were used to examine the growth of gallium nitride (GaN) on polycrystalline diamond substrates grown by metalorganic vapour phase epitaxy with a low-temperature aluminium nitride (AlN) nucleation layer. Growth on unmasked substrates was in the (0001) orientation with threading dislocation densities ≈7 ×109 cm-2. An epitaxial layer overgrowth technique was used to reduce the dislocation densities further, by depositing silicon nitride stripes on the surface and etching the unmasked regions down to the diamond substrate. A re-growth was then performed on the exposed side walls of the original GaN growth, reducing the threading dislocation density in the overgrown regions by two orders of magnitude. The resulting microstructures and the mechanisms of dislocation reduction are discussed.

Original languageEnglish
Article number114007
JournalSemiconductor Science and Technology
Volume30
Issue number11
DOIs
Publication statusPublished - 15 Oct 2015

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Keywords

  • electron microscopy
  • gallium nitride
  • growth
  • polycrystalline diamond

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