Growth and characterization of unintentionally doped GaN grown on silicon(1 1 1) substrates

M. Leys, Kai Cheng, J. Derluyn, S. Degroote, M. Germain, G. Borghs, C. A. Taylor, P. Dawson

    Research output: Chapter in Book/Report/Conference proceedingConference contribution


    In this paper we present an optimization study of the quality of unintentionally doped GaN layers grown on Si(1 1 1) substrates. The GaN layers which were investigated here were grown as semi-insulating/high resistivity buffer layers in "standard" high electron mobility transistor (HEMT) GaN/AlGaN structures. High-resolution X-ray diffraction (HR-XRD) studies revealed that the full-width at half-maximum (FWHM) of the asymmetric (1̄ 1 0 2) peak decreases strongly with increasing growth temperature and saturates at a value of around 830 arcsec at a growth temperature of 1130 °C. This means that at these high growth temperatures the density of notably the edge-type dislocations is strongly reduced. Optical characterization was carried out by means of low-temperature (6 K) photoluminescence spectroscopy. The spectra showed that both blue- (BL) and yellow luminescence (YL) bands were present in samples grown at temperatures below 1100 °C. Secondary ion mass spectroscopy (SIMS), showed that the unintentionally incorporated carbon concentration in the layers decreased with increasing growth temperature. We attribute the BL to recombination involving donor-acceptor pairs CGa-CN. The origin of the YL band can be attributed as follows: because the YL intensity strongly decreases with decreasing (edge) dislocation density this transition is based on the VGa-ON complex captured at edge-type dislocations. Alternatively, the involvement of carbon cannot be completely excluded. © 2008 Elsevier B.V. All rights reserved.
    Original languageEnglish
    Title of host publicationJournal of Crystal Growth|J Cryst Growth
    PublisherElsevier BV
    Number of pages2
    Publication statusPublished - 15 Nov 2008
    Event14th International Conference on Metal Organic Vapor Phase Epitaxy - Metz, FRANCE
    Duration: 1 Jun 20086 Jun 2008


    Conference14th International Conference on Metal Organic Vapor Phase Epitaxy
    CityMetz, FRANCE


    • A1. Impurities
    • A1. Line defects
    • A1. Point defects
    • A3. Metalorganic vapor-phase epitaxy
    • B1. Nitrides
    • B3. High electron mobility transistor


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