Interaction of GaN epitaxial layers with atomic hydrogen

GaN surface passivation processes are still under development and among others hydrogen treatments are investigated. In this study, we use non-destructive optical and electrical probes such as spectroscopic ellipsometry (SE) and surface potential Kelvin probe microscopy (SP-KPM) in conjunction with...

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Bibliographic Details
Published in:Applied surface science 2004-08, Vol.235 (3), p.267-273
Main Authors: Losurdo, M., Giangregorio, M.M., Capezzuto, P., Bruno, G., Namkoong, G., Doolittle, W.A., Brown, A.S.
Format: Article
Language:English
Subjects:
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Condensed matter: structure, mechanical and thermal properties
Cross-disciplinary physics: materials science
rheology
Ellipsometry
Exact sciences and technology
GaN
Interaction with atomic hydrogen
Physics
Surface reactivity
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Summary:GaN surface passivation processes are still under development and among others hydrogen treatments are investigated. In this study, we use non-destructive optical and electrical probes such as spectroscopic ellipsometry (SE) and surface potential Kelvin probe microscopy (SP-KPM) in conjunction with non-contact atomic force microscopy (AFM) for the study of the different reactivity of Ga-polar and N-polar GaN epitaxial layers with atomic hydrogen. The GaN epitaxial layers are grown by molecular beam epitaxy on sapphire (0 0 0 1) substrates, and GaN and AlN buffer layers are used to grow N-polar and Ga-polar films, respectively. The atomic hydrogen is produced by a remote rf (13.56 MHz) H 2 plasma in order to rule out any ion bombardment of the GaN surface and make the interaction chemical. It is found that the interaction of GaN surfaces with atomic hydrogen depends on polarity, with N-polar GaN exhibiting greater reactivity. Furthermore, it is found that atomic hydrogen is effective in the passivation of grain boundaries and surface defects states.
ISSN:0169-4332
1873-5584
DOI:10.1016/j.apsusc.2004.05.152