Reduction of the threading dislocation density in GaN films grown on vicinal sapphire (0001) substrates

Shen, X. Q.; Matsuhata, H.; Okumura, H.
January 2005
Applied Physics Letters;1/10/2005, Vol. 86 Issue 2, p021912
Academic Journal
Structural properties of GaN films grown on vicinal sapphire (0001) substrates with various vicinal angles by plasma-assisted molecular beam epitaxy are investigated. High-resolution x-ray diffraction (HRXRD) results reveal the dramatic improvement of both tilting and twisting grain features of the GaN films when the vicinal angle is larger than 0.5° with the formation of multilayer macro-steps on the surface. The threading dislocation density reduces by over an order of magnitude estimated from the HRXRD results. Cross-sectional transmission electron microscopy observations clearly show that the formation and lateral propagation of macro-steps on the GaN surface play an important role in this dislocation reduction. A method for the reduction of threading dislocation density in GaN epilayers is proposed.


Related Articles

  • Hot hole relaxation dynamics in p-GaN. Ye, Hong; Hong Ye; Wicks, G. W.; Wicks, G.W.; Fauchet, P. M.; Fauchet, P.M. // Applied Physics Letters;8/21/2000, Vol. 77 Issue 8 

    The hot hole relaxation dynamics is studied in a Mg-doped p-type GaN film grown by molecular-beam epitaxy on sapphire. A nondegenerate femtosecond pump-probe technique is used, in which the holes are excited by an infrared pump and the hole dynamics is monitored by a tunable near ultraviolet...

  • P-type zinc-blende GaN on GaAs substrates. Lin, M.E.; Xue, G. // Applied Physics Letters;8/16/1993, Vol. 63 Issue 7, p932 

    Presents the properties of p-type cubic gallium nitride films. Fabrication of the magnesium-doped layers on vicinal (100) gallium arsenide substrates by plasma-enhanced molecular beam epitaxy; Hole mobilities of the material at room temperature; Use of x-ray diffractometry to confirm the cubic...

  • Deposition of highly resistive, undoped, and p-type, magnesium-doped gallium nitride films by.... Cheng Wang; Davis, Robert F. // Applied Physics Letters;8/16/1993, Vol. 63 Issue 7, p990 

    Presents a method for depositing highly resistive, undoped and p-type magnesium doped gallium nitride films by modified gas source molecular beam epitaxy. Carrier concentration and mobility measurement of the films; Indication on the role of magnesium-hydrogen complexes in achieving highly...

  • Influences of mask width, fill factor, HCl addition and C doping on wing tilts in the epitaxial laterally overgrown GaN films by hydride vapor phase epitaxy. Wang, F.; Zhang, R.; Tan, W. S.; Xiu, X. Q.; Lu, D. Q.; Gu, S. L.; Shen, B.; Shi, Y.; Wu, X. S.; Zheng, Y. D.; Jiang, S. S.; Kuech, T. F. // Applied Physics Letters;6/24/2002, Vol. 80 Issue 25, p4765 

    Crystal tilts in the epitaxial lateral overgrown (ELO) GaN region over SiO[sub 2] mask by hydride vapor phase epitaxial away from the opening region were investigated by scanning electron microscope and the four-circle x-ray diffraction method. The increased mask width and ratio of stripe...

  • Growth of gallium nitride thin films by electron cyclotron resonance microwave plasma-assisted molecular beam epitaxy. Eddy, C. R.; Moustakas, T. D.; Scanlon, J. // Journal of Applied Physics;1/1/1993, Vol. 73 Issue 1, p448 

    Provides information on a study that reported the growth of gallium nitride films using the electron cyclotron resonance microwave plasma-assisted molecular beam epitaxy method. Methodologies used; Results and discussion; Conclusions.

  • Influence of threading dislocations on the near-bandedge photoluminescence of wurtzite GaN thin films on SiC substrate. Qiu, X. G.; Segawa, Y.; Xue, Q. K.; Xue, Q. Z.; Sakurai, T. // Applied Physics Letters;8/28/2000, Vol. 77 Issue 9 

    Wurtzite GaN thin films have been grown on the 6H-SiC substrates by plasma-assisted molecular-beam epitaxy. The correlation between crystalline structure and photoluminescence (PL) properties is examined by high-resolution x-ray diffraction and PL measured at different temperatures from 5 to 300...

  • Stability of N- and Ga-polarity GaN surfaces during the growth interruption studied by reflection high-energy electron diffraction. Shen, X. Q.; Shen, X.Q.; Ide, T.; Cho, S. H.; Cho, S.H.; Shimizu, M.; Hara, S.; Okumura, H. // Applied Physics Letters;12/11/2000, Vol. 77 Issue 24 

    GaN films with N- and Ga-polarity were grown on sapphire (0001) substrates using different buffer layers by plasma-assisted molecular-beam epitaxy. The surface stability of each lattice-polarity film during the growth interruption was studied by reflection high-energy electron diffraction...

  • Study of GaN thin layers subjected to high-temperature rapid thermal annealing. Katsavets, N.I.; Laws, G. M.; Harrison, I.; Larkins, E. C.; Benson, T. M.; Cheng, T. S.; Foxon, C. T. // Semiconductors;Oct98, Vol. 32 Issue 10, p1048 

    A detailed study of the effect of rapid thermal annealing in a N[sub 2] or Ar atmosphere on the properties of thin GaN layers grown by molecular-beam epitaxy on sapphire substrates was performed. After rapid thermal annealing, an enhancement of the crystal quality of such films was observed....

  • Time of flight mass spectroscopy of recoiled ions studies of surface kinetics and growth... Kim, Esther; Berishev, I. // Journal of Applied Physics;1/15/1999, Vol. 85 Issue 2, p1178 

    Presents information on a study which demonstrated the high growth rate of gallium nitride thin films using gas source molecular beam epitaxy and time of flight mass spectroscopy of recoiled ions and reflection high energy electron diffraction. Experimental details; Results and discussion;...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics