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Title: Flat GaN epitaxial layers grown on Si(111) by MOVPE using step-graded AlGaN intermediate layers
Authors: Cheng, Kai ×
Leys, Maarten
Degroote, Stefan
Van Daele, Benny
Boeykens, Steven
Derluyn, Joff
Germain, Marianne
Van Tendeloo, Gustaaf
Engelen, Jan
Borghs, Gustaaf #
Issue Date: Apr-2006
Publisher: Minerals metals materials soc
Series Title: Journal of Electronic Materials vol:35 issue:4 pages:592-598
Abstract: In this work, we report on the growth by metalorganic vapor phase epitaxy (MOVPE) of GaN layers on AlN/Si(111) templates with step-graded AlGaN intermediate layers. First, we will discuss the optimization of the AlN/Si(111) templates and then we will discuss the incorporation of step-graded AlGaN intermediate layers. It is found that the growth stress in GaN on high-temperature (HT) AlN/Si(111) templates is compressive, although, due to relaxation, the stress we have measured is much lower than the theoretical value. In order to prevent the stress relaxation, step-graded AlGaN layers are introduced and a crack-free GaN epitaxial layer of thickness >1 mu m is demonstrated. Under optimized growth conditions, the total layer stack, exceeding 2 mu m in total, is kept under compressive stress, and the radius of the convex wafer bowing is as large as 119 m. The crystalline quality of the GaN layers is examined by high-resolution x-ray diffraction (HR-XRD), and the full-width-at-half maximums (FWHMs) of the x-ray rocking curve (0002) omega-scan and (-1015) omega-scan are 790 arc sec and 730 arc sec, respectively. It is found by cross-sectional transmission electron microscopy (TEM) that the step-graded AlGaN layers terminate or bend the dislocations at the interfaces.
ISSN: 0361-5235
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Electrical Engineering - miscellaneous
Physics and Astronomy - miscellaneous
ESAT - ELECTA, Electrical Energy Computer Architectures
ESAT - STADIUS, Stadius Centre for Dynamical Systems, Signal Processing and Data Analytics
× corresponding author
# (joint) last author

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