A study of semi-insulating GaN grown on AlN buffer/sapphire substrate by metalorganic chemical vapor deposition

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Yu H., Ozturk M. K. , Ozcelik S. , Ozbay E.

Journal of Crystal Growth, cilt.293, sa.2, ss.273-277, 2006 (SCI Expanded İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 293 Konu: 2
  • Basım Tarihi: 2006
  • Doi Numarası: 10.1016/j.jcrysgro.2006.05.056
  • Dergi Adı: Journal of Crystal Growth
  • Sayfa Sayıları: ss.273-277


We report the remarkably improved crystal quality of semi-insulating GaN grown by metalorganic chemical vapor deposition on an AlN buffer layer, which is deposited on sapphire substrate. The electrical and structural properties are characterized by dark current-voltage transmission line model and X-ray diffraction measurements. It is found that the crystal quality of the GaN epilayer is strongly related with the growth temperature of the decreased-temperature GaN interlayer. In comparison with the normal GaN grown on sapphire, the crystal quality is remarkably improved along with a semi-insulating electrical character. The high-mobility field effect transistors device based on the semi-insulating GaN shows good pinch off properties. Our electrical measurement results of GaN grown directly on an AlN buffer indicated that the as-grown-undoped GaN is naturally semi-insulating material. The origination of the residual donors in normal GaN grown on sapphire substrate is also discussed. © 2006 Elsevier B.V. All rights reserved.