Significant increase in conduction band discontinuity due to solid phase epitaxy of Al2O3 gate insulator films on GaN semiconductor

We have investigated band discontinuities and chemical structures of Al2O3 gate insulator films on n-type GaN semiconductor by photoemission and x-ray absorption spectroscopy. It is found that the solid phase epitaxy at the GaN crystal during annealing procedures at 800 °C leads to phase transformat...

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Bibliographic Details
Published in:Applied physics letters 2012-12, Vol.101 (23)
Main Authors: Toyoda, S., Shinohara, T., Kumigashira, H., Oshima, M., Kato, Y.
Format: Article
Language:English
Subjects:
Aluminum oxide
Conduction band
Discontinuity
Epitaxy
Gallium nitrides
Insulators
N-type semiconductors
Semiconductors
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Summary:We have investigated band discontinuities and chemical structures of Al2O3 gate insulator films on n-type GaN semiconductor by photoemission and x-ray absorption spectroscopy. It is found that the solid phase epitaxy at the GaN crystal during annealing procedures at 800 °C leads to phase transformation of Al2O3 films from amorphous to crystalline. Changes in crystallographic structures closely correlate with the significant increase in conduction band discontinuity at the Al2O3/GaN interface, which suggests that epitaxial Al2O3 films on GaN semiconductor, free from grain boundaries of Al2O3 polycrystalline, hold the potential for high insulation performance.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4769818