Title: Dislocation reduction in GaN film using Ga-lean GaN buffer layer and migration enhanced epitaxy
Authors: Wong, Yuen-Yee
Chang, Edward Yi
Wu, Yue-Han
Hudait, Mantu K.
Yang, Tsung-Hsi
Chang, Jet-Rung
Ku, Jui-Tai
Chou, Wu-Ching
Chen, Chiang-Yao
Maa, Jer-Shen
Lin, Yueh-Chin
Department of Materials Science and Engineering
College of Photonics
Department of Electronics Engineering and Institute of Electronics
Keywords: Molecular beam epitaxy;Gallium nitride;Dislocations;Ga-lean gallium nitride;Migration enhanced epitaxy;Atomic force microscopy;High-resolution X-ray diffraction;Transmission electron microscopy
Issue Date: 29-Jul-2011
Abstract: A GaN buffer layer grown under Ga-lean conditions by plasma-assisted molecular beam epitaxy (PAMBE) was used to reduce the dislocation density in a GaN film grown on a sapphire substrate. The Ga-lean buffer, with inclined trench walls on its surface, provided an effective way to bend the propagation direction of dislocations, and it reduced the dislocation density through recombination and annihilation processes. As a result, the edge dislocation density in the GaN film was reduced by approximately two orders of magnitude to 2 x 10(8) cm(-2). The rough surface of the Ga-lean buffer was recovered using migration enhanced epitaxy (MEE), a process of alternating deposition cycle of Ga atoms and N(2) radicals, during the PAMBE growth. By combining these two methods, a GaN film with high-crystalline-quality and atomically-flat surface can be achieved by PAMBE on a lattice mismatch substrate. (C) 2011 Elsevier B.V. All rights reserved.
URI: http://dx.doi.org/10.1016/j.tsf.2011.03.054
ISSN: 0040-6090
DOI: 10.1016/j.tsf.2011.03.054
Volume: 519
Issue: 19
Begin Page: 6208
End Page: 6213
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