GaN/Alumina/GaN structures were fabricated to reduce dislocation density in GaN. Alumina films were deposited on GaN templates by electron cyclotron resonance plasma sputtering. GaN was re-grown onto the alumina films by metalorganic vapor phase epitaxy. It was found that GaN on alumina selectively re-grown from pinholes in alumina by annealing prior to GaN re-growth. Hardly any of the dislocations in the GaN template propagated through the interlayer. Most of dislocations were terminated or bent at the interface between the alumina and re-grown GaN. On the other hand, new vertical dark lines and horizontal dislocations were generated in re-grown layer. The vertical lines were found to correspond to an inversion domain from convergent beam electron diffraction analysis.

Fabrication of GaN/Alumina/GaN Structure to Reduce Dislocations in GaN. M.Hiroki, K.Kumakura, T.Makimoto, N.Kobayashi, T.Kobayashi: Japanese Journal of Applied Physics, 2004, 43[4B], 1930-3