Investigation of AlGaN buffer layers on sapphire grown by MOVPE

Date
2004
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Source Title
Proceedings of SPIE Vol. 5366, Light-Emitting Diodes: Research, Manufacturing, and Applications VIII
Print ISSN
0277-786X
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Publisher
SPIE
Volume
5366
Issue
Pages
183 - 190
Language
English
Type
Conference Paper
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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.

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Keywords
Al/MO ratio, AlGaN, MOVPE, Sapphire, V/III ratio, Electric breakdown, Electric reactors, Light transmission, Metallorganic vapor phase epitaxy, Optical fibers, Optoelectronic devices, Photoconducting materials
Citation
Published Version (Please cite this version)