Journal article

Thermal stability of GaN investigated by Raman scattering

We have investigated the thermal stability of GaN using Raman scattering, Noninvasive optical monitoring of the degradation of GaN during high-temperature processing has been demonstrated. GaN samples grown by molecular-beam epitaxy (MBE) and metalorganic vapor phase epitaxy (MOCVD) were studied. Characteristic features in the Raman spectrum identify three thermal stability regimes: (I) annealing below 900 degrees C does not affect the GaN Raman spectrum; (2) annealing between 900 degrees C and 1000 degrees C results in the appearance of disorder-induced Raman scattering between the E-2 and A(1)(LO) phonon; (3) annealing at temperatures higher than 1000 degrees C gives rise to distinct Raman modes at 630 cm(-1), 656 cm(-1) and 770 cm(-1). The evolution of the Raman spectrum of GaN with increasing annealing temperature is discussed in terms of disorder-induced Raman scattering. We find clear indications for an interfacial reaction between GaN and sapphire for annealing temperatures higher than 1000 degrees C.

    Keywords: DIODES


    • EPFL-ARTICLE-152647

    Record created on 2010-10-05, modified on 2017-05-12


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