The effect of substrate on high-temperature annealing of GaN epilayers: Si versus sapphire



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González Díaz, Germán and Artús, L. and Calleja, E. and Cuscó, R. and Iborra, E. and Jiménez, J. and Pastor, D. and Peiró, F. (2006) The effect of substrate on high-temperature annealing of GaN epilayers: Si versus sapphire. Journal of Applied Physics, 100 (4). ISSN 0021-8979

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We have studied the effects of rapid thermal annealing at 1300 degrees C on GaN epilayers grown on AlN buffered Si(111) and on sapphire substrates. After annealing, the epilayers grown on Si display visible alterations with craterlike morphology scattered over the surface. The annealed GaN/Si layers were characterized by a range of experimental techniques: scanning electron microscopy, optical confocal imaging, energy dispersive x-ray microanalysis, Raman scattering, and cathodoluminescence. A substantial Si migration to the GaN epilayer was observed in the crater regions, where decomposition of GaN and formation of Si3N4 crystallites as well as metallic Ga droplets and Si nanocrystals have occurred. The average diameter of the Si nanocrystals was estimated from Raman scattering to be around 3 nm. Such annealing effects, which are not observed in GaN grown on sapphire, are a significant issue for applications of GaN grown on Si(111) substrates when subsequent high-temperature processing is required.

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© American Institute of Physics. This work has been supported by the Spanish Ministry of Science and Technology under Contract Nos. MAT2004-0664 and MAT2004-02875. The authors wish to thank Dr. M. Marsal for her expert assistance with the EDX measurements.

Uncontrolled Keywords:Molecular-Beam Epitaxy, Light-Emitting-Diodes, Raman-Scattering,Silicon-Nitride, Gallium Nitride, Implanted GaN, Si (111), Nanocrystals, Modes.
Subjects:Sciences > Physics > Electricity
Sciences > Physics > Electronics
ID Code:27430
Deposited On:25 Nov 2014 11:44
Last Modified:10 Dec 2018 14:58

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