Investigation of AlGaN buffer layers on sapphire grown by MOVPE
Author(s)
Date
2004Source Title
Proceedings of SPIE Vol. 5366, Light-Emitting Diodes: Research, Manufacturing, and Applications VIII
Print ISSN
0277-786X
Publisher
SPIE
Volume
5366
Pages
183 - 190
Language
English
Type
Conference PaperItem Usage Stats
168
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127
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Abstract
In this work, AlGaN layers were grown on sapphire by metal-organic vapor phase epitaxy (MOVPE) on (0001)-oriented sapphire substrates, with the intention to investigate the effect of varying Al/MO and V/III ratios on the Al incorporation into the AlGaN layers. The parameters Al/MO and V/III describe the proportions of source material inside the reactor. With the help of optical transmission measurements, characteristic cut-off wavelengths of the Al xGa(1-x)N layers were determined. These wavelengths were used to calculate the Al content x of the layers, leading to values between 26.6% and 52.1%. Using the two process parameters Al/MO and V/III as input and the Al content of the AlGaN layers as a response variable, the experimental results were further investigated with the help of the software STATGRAPHICS. An estimated response surface for the variable x was generated. It was found that the Al incorporation is only tunable within a wide range for high V/III ratios of about 900. For constant Al/MO ratios and varying V/III ratios, two different growth characteristics were observed at high and low Al/MO values. This behavior is ascribed to the superposition of two oppositional effects.
Keywords
Al/MO ratioAlGaN
MOVPE
Sapphire
V/III ratio
Electric breakdown
Electric reactors
Light transmission
Metallorganic vapor phase epitaxy
Optical fibers
Optoelectronic devices
Photoconducting materials