Role of threading dislocation structure on the x‐ray diffraction peak widths in epitaxial GaN films
作者:
B. Heying,
X. H. Wu,
S. Keller,
Y. Li,
D. Kapolnek,
B. P. Keller,
S. P. DenBaars,
J. S. Speck,
期刊:
Applied Physics Letters
(AIP Available online 1996)
卷期:
Volume 68,
issue 5
页码: 643-645
ISSN:0003-6951
年代: 1996
DOI:10.1063/1.116495
出版商: AIP
数据来源: AIP
摘要:
In this letter we demonstrate that the anomalously low (002) x‐ray rocking curve widths for epitaxial hexagonal GaN films on (001) sapphire are a result of a specific threading dislocation (TD) geometry. Epitaxial GaN films were grown onc‐plane sapphire by atmospheric pressure metalorganic chemical vapor deposition (MOCVD) in a horizontal flow reactor. Films were grown with (002) rocking curves (&ohgr;‐scans) widths as low as 40 arcsec and threading dislocation densities of ∼2×1010cm−2. The threading dislocations in this film lie parallel to the [001] direction and within the limit of imaging statistics, all are pure edge with Burgers vectors parallel to the film/substrate interface. These TDs will not distort the (002) planes. However, distortion of asymmetric planes, such as (102), is predicted and confirmed in (102) rocking curve widths of 740 arcsec. These results are compared with films with (002) rocking curves of ∼270 arcsec and threading dislocation densities of ∼7×108cm−2. ©1996 American Institute of Physics.
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