Epitaxy of Al films on GaN studied by reflection high-energy electron diffraction and atomic force microscopy
作者:
Q. Z. Liu,
L. Shen,
K. V. Smith,
C. W. Tu,
E. T. Yu,
S. S. Lau,
N. R. Perkins,
T. F. Kuech,
期刊:
Applied Physics Letters
(AIP Available online 1997)
卷期:
Volume 70,
issue 8
页码: 990-992
ISSN:0003-6951
年代: 1997
DOI:10.1063/1.118458
出版商: AIP
数据来源: AIP
摘要:
Epitaxy of Al films deposited on GaN has been studied using reflection high-energy electron diffraction (RHEED), atomic force microscopy (AFM), x-ray diffraction, and ion channeling techniques. Al (111) films have been found to grow epitaxially on GaN (0001) surfaces with Al 〈21¯1¯〉‖GaN〈21¯1¯0〉. For growth at 15 and 150 °C with a deposition rate of 0.26 Å/s, the epitaxial quality of the film was poor initially, as evidenced by the observation of diffuse RHEED patterns. After a few monolayers, a sharp and streaky RHEED pattern develops and is maintained during subsequent deposition, indicating an improvement in epitaxial quality with a two-dimensional growth mode. AFM studies indicate that the initial GaN surface quality is a significant factor in achieving epitaxial growth, and that the size of Al epitaxial islands increases substantially for higher growth temperatures. X-ray diffraction and ion channeling results confirm the epitaxial nature of the Al films in spite of a significant lattice mismatch of 10.2&percent;. ©1997 American Institute of Physics.
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